diff --git a/packages/mosaic/framework/tools/git/issue-assign.sh b/packages/mosaic/framework/tools/git/issue-assign.sh
index 48d5c04b..1dad6987 100755
--- a/packages/mosaic/framework/tools/git/issue-assign.sh
+++ b/packages/mosaic/framework/tools/git/issue-assign.sh
@@ -3,6 +3,7 @@
 # Usage: issue-assign.sh -i ISSUE_NUMBER [-a assignee] [-l labels] [-m milestone]
 
 set -e
+set -o pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/detect-platform.sh"
@@ -33,25 +34,36 @@ Examples:
     $(basename "$0") -i 42 -l "in-progress" -m "0.2.0"
     $(basename "$0") -i 42 -a @me
 EOF
-    exit "${1:-1}"
+    exit "${1:-2}"
+}
+
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    usage >&2
 }
 
 # Parse arguments
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE="$2"
             shift 2
             ;;
         -a|--assignee)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ASSIGNEE="$2"
             shift 2
             ;;
         -l|--labels)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABELS="$2"
             shift 2
             ;;
         -m|--milestone)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
@@ -79,20 +91,35 @@ PLATFORM=$(detect_platform)
 case "$PLATFORM" in
     github)
         if [[ -n "$ASSIGNEE" ]]; then
-            gh issue edit "$ISSUE" --add-assignee "$ASSIGNEE"
+            prov_rc=0
+            gh issue edit "$ISSUE" --add-assignee "$ASSIGNEE" || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         fi
         if [[ "$REMOVE_ASSIGNEE" == true ]]; then
             # Get current assignees and remove them
-            CURRENT=$(gh issue view "$ISSUE" --json assignees -q '.assignees[].login' 2>/dev/null | tr '\n' ',')
+            # pipefail preserves the provider status through the pipeline;
+            # a FAILED lookup exits here instead of reading as a silent
+            # no-assignees skip (codex PR #1464). A successful lookup with
+            # zero assignees still skips the edit below.
+            CURRENT=$(gh issue view "$ISSUE" --json assignees -q '.assignees[].login' 2>/dev/null | tr '\n' ',') || {
+                echo "Error: could not read current assignees (provider lookup failed)" >&2
+                exit 1
+            }
             if [[ -n "$CURRENT" ]]; then
-                gh issue edit "$ISSUE" --remove-assignee "${CURRENT%,}"
+                prov_rc=0
+                gh issue edit "$ISSUE" --remove-assignee "${CURRENT%,}" || prov_rc=$?
+                [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
             fi
         fi
         if [[ -n "$LABELS" ]]; then
-            gh issue edit "$ISSUE" --add-label "$LABELS"
+            prov_rc=0
+            gh issue edit "$ISSUE" --add-label "$LABELS" || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         fi
         if [[ -n "$MILESTONE" ]]; then
-            gh issue edit "$ISSUE" --milestone "$MILESTONE"
+            prov_rc=0
+            gh issue edit "$ISSUE" --milestone "$MILESTONE" || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         fi
         echo "Issue #$ISSUE updated successfully"
         ;;
@@ -131,7 +158,9 @@ case "$PLATFORM" in
         fi
 
         if [[ "$NEEDS_EDIT" == true ]]; then
-            "${CMD[@]}"
+            prov_rc=0
+            "${CMD[@]}" || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
             echo "Issue #$ISSUE updated successfully"
         else
             echo "No changes specified"
diff --git a/packages/mosaic/framework/tools/git/issue-close.sh b/packages/mosaic/framework/tools/git/issue-close.sh
index 3d014a59..78d92384 100755
--- a/packages/mosaic/framework/tools/git/issue-close.sh
+++ b/packages/mosaic/framework/tools/git/issue-close.sh
@@ -1,6 +1,7 @@
 #!/bin/bash
 # issue-close.sh - Close an issue on GitHub or Gitea
-# Usage: issue-close.sh -i <issue_number> [-c <comment>]
+# Usage: issue-close.sh -i <issue_number> [-b <comment>]
+# (-c/--comment is a backward-compatible alias for -b/--body; R1/R4 2026-08-28)
 
 set -e
 
@@ -12,35 +13,49 @@ source "$SCRIPT_DIR/detect-platform.sh"
 ISSUE_NUMBER=""
 COMMENT=""
 
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1), so a
+# caller or stop gate can tell an invocation defect from a delivery blocker.
+usage_error() {
+    echo "Error: $*" >&2
+    echo "Usage: issue-close.sh -i <issue_number> [-b <comment>] (see --help)" >&2
+    exit 2
+}
+
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
-        -c|--comment)
+        -b|--body|-c|--comment)
+            # R1 (2026-08-28): --body is the canonical flag; -c/--comment stays
+            # a backward-compatible alias.
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
         -h|--help)
-            echo "Usage: issue-close.sh -i <issue_number> [-c <comment>]"
+            echo "Usage: issue-close.sh -i <issue_number> [-b <comment>]"
             echo ""
             echo "Options:"
             echo "  -i, --issue    Issue number (required)"
-            echo "  -c, --comment  Comment to add before closing (optional)"
+            echo "  -b, --body     Comment to add before closing (optional; canonical)"
+            echo "  -c, --comment  Alias for --body"
             echo "  -h, --help     Show this help"
+            echo ""
+            echo "Exit codes: 0 success; 2 usage error (stderr); 1 provider/credential/verification failure."
             exit 0
             ;;
         *)
-            echo "Unknown option: $1"
-            exit 1
+            usage_error "unknown option: $1"
             ;;
     esac
 done
 
 if [[ -z "$ISSUE_NUMBER" ]]; then
-    echo "Error: Issue number is required (-i)"
-    exit 1
+    usage_error "issue number is required (-i/--issue)"
 fi
 
 # Detect platform and close issue
@@ -82,10 +97,22 @@ gitea_issue_close_api() {
 }
 
 if [[ "$PLATFORM" == "github" ]]; then
+    # R4: normalize provider failures to exit 1 (gh's own usage errors exit 2
+    # and would collide with the reserved usage-error status).
     if [[ -n "$COMMENT" ]]; then
-        gh issue comment "$ISSUE_NUMBER" --body "$COMMENT"
+        gh_rc=0
+        gh issue comment "$ISSUE_NUMBER" --body "$COMMENT" || gh_rc=$?
+        if [[ "$gh_rc" -ne 0 ]]; then
+            echo "Error: GitHub comment before close failed (gh exit $gh_rc)" >&2
+            exit 1
+        fi
+    fi
+    gh_rc=0
+    gh issue close "$ISSUE_NUMBER" || gh_rc=$?
+    if [[ "$gh_rc" -ne 0 ]]; then
+        echo "Error: GitHub issue close failed (gh exit $gh_rc)" >&2
+        exit 1
     fi
-    gh issue close "$ISSUE_NUMBER"
     echo "Closed GitHub issue #$ISSUE_NUMBER"
 elif [[ "$PLATFORM" == "gitea" ]]; then
     GITEA_LOGIN_NAME=$(get_gitea_login || true)
@@ -107,7 +134,9 @@ elif [[ "$PLATFORM" == "gitea" ]]; then
                 exit 1
             }
         fi
-        tea issue close "$ISSUE_NUMBER" --repo "$OWNER/$REPO" --login "$GITEA_LOGIN_NAME"
+        prov_rc=0
+        tea issue close "$ISSUE_NUMBER" --repo "$OWNER/$REPO" --login "$GITEA_LOGIN_NAME" || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
     else
         echo "No tea login configured for $(get_remote_host); using authenticated Gitea API fallback." >&2
         if [[ -n "$COMMENT" ]]; then
diff --git a/packages/mosaic/framework/tools/git/issue-comment.sh b/packages/mosaic/framework/tools/git/issue-comment.sh
index e5858b35..d5b74028 100755
--- a/packages/mosaic/framework/tools/git/issue-comment.sh
+++ b/packages/mosaic/framework/tools/git/issue-comment.sh
@@ -46,7 +46,7 @@ usage_error() {
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
-            [[ $# -ge 2 ]] || usage_error "option $1 requires a value"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
@@ -54,12 +54,12 @@ while [[ $# -gt 0 ]]; do
             # R1 (2026-08-28): --body is the canonical flag, matching
             # issue-create/issue-edit/pr-create/pr-edit; -c/--comment stays a
             # backward-compatible alias.
-            [[ $# -ge 2 ]] || usage_error "option $1 requires a value"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
         -l|--login)
-            [[ $# -ge 2 ]] || usage_error "option $1 requires a value"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LOGIN_OVERRIDE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/issue-create.sh b/packages/mosaic/framework/tools/git/issue-create.sh
index d9c0bc24..e0b061a6 100755
--- a/packages/mosaic/framework/tools/git/issue-create.sh
+++ b/packages/mosaic/framework/tools/git/issue-create.sh
@@ -74,26 +74,39 @@ Examples:
     $(basename "$0") -t "Fix login bug" -l "bug,priority-high"
     $(basename "$0") -t "Add dark mode" -b "Implement theme switching" -m "0.2.0"
     $(basename "$0") -i
+
+Exit codes: 0 success; 2 usage error (stderr); 1 provider/credential failure.
 EOF
-    exit "${1:-1}"
+    exit "${1:-2}"
 }
 
 # Parse arguments
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    usage >&2
+}
+
 while [[ $# -gt 0 ]]; do
     case $1 in
         -t|--title)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
         -b|--body)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             BODY="$2"
             shift 2
             ;;
         -l|--labels)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABELS="$2"
             shift 2
             ;;
         -m|--milestone)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
@@ -131,7 +144,9 @@ case "$PLATFORM" in
         [[ -n "$BODY" ]] && CMD+=(--body "$BODY")
         [[ -n "$LABELS" ]] && CMD+=(--label "$LABELS")
         [[ -n "$MILESTONE" ]] && CMD+=(--milestone "$MILESTONE")
-        "${CMD[@]}"
+        prov_rc=0
+        "${CMD[@]}" || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         ;;
     gitea)
         if command -v tea >/dev/null 2>&1; then
diff --git a/packages/mosaic/framework/tools/git/issue-edit.sh b/packages/mosaic/framework/tools/git/issue-edit.sh
index 865af4fc..20465de9 100755
--- a/packages/mosaic/framework/tools/git/issue-edit.sh
+++ b/packages/mosaic/framework/tools/git/issue-edit.sh
@@ -14,25 +14,39 @@ BODY=""
 LABELS=""
 MILESTONE=""
 
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1), so a
+# caller or stop gate can tell an invocation defect from a delivery blocker.
+usage_error() {
+    echo "Error: $*" >&2
+    echo "Usage: issue-edit.sh -i <issue_number> [-t <title>] [-b <body>] [-l <labels>] [-m <milestone>] (see --help)" >&2
+    exit 2
+}
+
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
         -t|--title)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
         -b|--body)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             BODY="$2"
             shift 2
             ;;
         -l|--labels)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABELS="$2"
             shift 2
             ;;
         -m|--milestone)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
@@ -46,18 +60,18 @@ while [[ $# -gt 0 ]]; do
             echo "  -l, --labels     Labels (comma-separated, replaces existing)"
             echo "  -m, --milestone  Milestone name"
             echo "  -h, --help       Show this help"
+            echo ""
+            echo "Exit codes: 0 success; 2 usage error (stderr); 1 provider/credential/verification failure."
             exit 0
             ;;
         *)
-            echo "Unknown option: $1"
-            exit 1
+            usage_error "unknown option: $1"
             ;;
     esac
 done
 
 if [[ -z "$ISSUE_NUMBER" ]]; then
-    echo "Error: Issue number is required (-i)"
-    exit 1
+    usage_error "issue number is required (-i/--issue)"
 fi
 
 detect_platform >/dev/null
@@ -68,7 +82,9 @@ if [[ "$PLATFORM" == "github" ]]; then
     [[ -n "$BODY" ]] && CMD+=(--body "$BODY")
     [[ -n "$LABELS" ]] && CMD+=(--add-label "$LABELS")
     [[ -n "$MILESTONE" ]] && CMD+=(--milestone "$MILESTONE")
-    "${CMD[@]}"
+    prov_rc=0
+    "${CMD[@]}" || prov_rc=$?
+    [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
     echo "Updated GitHub issue #$ISSUE_NUMBER"
 elif [[ "$PLATFORM" == "gitea" ]]; then
     REPO_SLUG=$(get_repo_slug) || {
@@ -84,7 +100,9 @@ elif [[ "$PLATFORM" == "gitea" ]]; then
     [[ -n "$BODY" ]] && CMD+=(--description "$BODY")
     [[ -n "$LABELS" ]] && CMD+=(--add-labels "$LABELS")
     [[ -n "$MILESTONE" ]] && CMD+=(--milestone "$MILESTONE")
-    "${CMD[@]}"
+    prov_rc=0
+    "${CMD[@]}" || prov_rc=$?
+    [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
     echo "Updated Gitea issue #$ISSUE_NUMBER"
 else
     echo "Error: Unknown platform"
diff --git a/packages/mosaic/framework/tools/git/issue-list.sh b/packages/mosaic/framework/tools/git/issue-list.sh
index 4e59d3d9..54ca1ce8 100755
--- a/packages/mosaic/framework/tools/git/issue-list.sh
+++ b/packages/mosaic/framework/tools/git/issue-list.sh
@@ -36,33 +36,46 @@ Examples:
     $(basename "$0") -m "0.2.0"               # Issues in milestone 0.2.0
     $(basename "$0") --repo ddk/ai-bma         # List issues from anywhere
 EOF
-    exit "${1:-1}"
+    exit "${1:-2}"
 }
 
 # Parse arguments
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    usage >&2
+}
+
 while [[ $# -gt 0 ]]; do
     case $1 in
         -s|--state)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             STATE="$2"
             shift 2
             ;;
         -l|--label)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABEL="$2"
             shift 2
             ;;
         -m|--milestone)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
         -a|--assignee)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ASSIGNEE="$2"
             shift 2
             ;;
         -n|--limit)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LIMIT="$2"
             shift 2
             ;;
         -r|--repo)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             REPO_OVERRIDE="$2"
             shift 2
             ;;
@@ -95,7 +108,9 @@ case "$PLATFORM" in
         [[ -n "$LABEL" ]] && CMD+=(--label "$LABEL")
         [[ -n "$MILESTONE" ]] && CMD+=(--milestone "$MILESTONE")
         [[ -n "$ASSIGNEE" ]] && CMD+=(--assignee "$ASSIGNEE")
-        "${CMD[@]}"
+        prov_rc=0
+        "${CMD[@]}" || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         ;;
     gitea)
         if [[ -n "$REPO_OVERRIDE" ]]; then
@@ -114,7 +129,9 @@ case "$PLATFORM" in
         [[ -n "$MILESTONE" ]] && CMD+=(--milestones "$MILESTONE")
         # Note: tea may not support assignee filter directly in all versions.
         [[ -n "$ASSIGNEE" ]] && echo "Note: Assignee filtering may require manual review for Gitea" >&2
-        "${CMD[@]}"
+        prov_rc=0
+        "${CMD[@]}" || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         ;;
     *)
         echo "Error: Could not detect git platform" >&2
diff --git a/packages/mosaic/framework/tools/git/issue-reopen.sh b/packages/mosaic/framework/tools/git/issue-reopen.sh
index cb92acdc..d1011035 100755
--- a/packages/mosaic/framework/tools/git/issue-reopen.sh
+++ b/packages/mosaic/framework/tools/git/issue-reopen.sh
@@ -1,6 +1,7 @@
 #!/bin/bash
 # issue-reopen.sh - Reopen a closed issue on GitHub or Gitea
-# Usage: issue-reopen.sh -i <issue_number> [-c <comment>]
+# Usage: issue-reopen.sh -i <issue_number> [-b <comment>]
+# (-c/--comment is a backward-compatible alias for -b/--body; R1/R4 2026-08-28)
 
 set -e
 
@@ -11,35 +12,49 @@ source "$SCRIPT_DIR/detect-platform.sh"
 ISSUE_NUMBER=""
 COMMENT=""
 
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1), so a
+# caller or stop gate can tell an invocation defect from a delivery blocker.
+usage_error() {
+    echo "Error: $*" >&2
+    echo "Usage: issue-reopen.sh -i <issue_number> [-b <comment>] (see --help)" >&2
+    exit 2
+}
+
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
-        -c|--comment)
+        -b|--body|-c|--comment)
+            # R1 (2026-08-28): --body is the canonical flag; -c/--comment stays
+            # a backward-compatible alias.
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
         -h|--help)
-            echo "Usage: issue-reopen.sh -i <issue_number> [-c <comment>]"
+            echo "Usage: issue-reopen.sh -i <issue_number> [-b <comment>]"
             echo ""
             echo "Options:"
             echo "  -i, --issue    Issue number (required)"
-            echo "  -c, --comment  Comment to add when reopening (optional)"
+            echo "  -b, --body     Comment to add when reopening (optional; canonical)"
+            echo "  -c, --comment  Alias for --body"
             echo "  -h, --help     Show this help"
+            echo ""
+            echo "Exit codes: 0 success; 2 usage error (stderr); 1 provider/credential/verification failure."
             exit 0
             ;;
         *)
-            echo "Unknown option: $1"
-            exit 1
+            usage_error "unknown option: $1"
             ;;
     esac
 done
 
 if [[ -z "$ISSUE_NUMBER" ]]; then
-    echo "Error: Issue number is required (-i)"
-    exit 1
+    usage_error "issue number is required (-i/--issue)"
 fi
 
 detect_platform >/dev/null
@@ -80,18 +95,34 @@ gitea_issue_reopen_api() {
 }
 
 if [[ "$PLATFORM" == "github" ]]; then
+    # R4: normalize provider failures to exit 1 (gh's own usage errors exit 2
+    # and would collide with the reserved usage-error status).
     if [[ -n "$COMMENT" ]]; then
-        gh issue comment "$ISSUE_NUMBER" --body "$COMMENT"
+        gh_rc=0
+        gh issue comment "$ISSUE_NUMBER" --body "$COMMENT" || gh_rc=$?
+        if [[ "$gh_rc" -ne 0 ]]; then
+            echo "Error: GitHub comment before reopen failed (gh exit $gh_rc)" >&2
+            exit 1
+        fi
+    fi
+    gh_rc=0
+    gh issue reopen "$ISSUE_NUMBER" || gh_rc=$?
+    if [[ "$gh_rc" -ne 0 ]]; then
+        echo "Error: GitHub issue reopen failed (gh exit $gh_rc)" >&2
+        exit 1
     fi
-    gh issue reopen "$ISSUE_NUMBER"
     echo "Reopened GitHub issue #$ISSUE_NUMBER"
 elif [[ "$PLATFORM" == "gitea" ]]; then
     REPO_ARGS=$(get_gitea_repo_args || true)
     if [[ -n "$REPO_ARGS" ]]; then
         if [[ -n "$COMMENT" ]]; then
-            tea issue comment "$ISSUE_NUMBER" "$COMMENT" $REPO_ARGS
+            prov_rc=0
+            tea issue comment "$ISSUE_NUMBER" "$COMMENT" $REPO_ARGS || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         fi
-        tea issue reopen "$ISSUE_NUMBER" $REPO_ARGS
+        prov_rc=0
+        tea issue reopen "$ISSUE_NUMBER" $REPO_ARGS || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
     else
         echo "No tea login configured for $(get_remote_host); using authenticated Gitea API fallback." >&2
         if [[ -n "$COMMENT" ]]; then
diff --git a/packages/mosaic/framework/tools/git/issue-view.sh b/packages/mosaic/framework/tools/git/issue-view.sh
index da15bc10..dd0364f5 100755
--- a/packages/mosaic/framework/tools/git/issue-view.sh
+++ b/packages/mosaic/framework/tools/git/issue-view.sh
@@ -8,6 +8,14 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/detect-platform.sh"
 
 # Parse arguments
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    echo "Usage: issue-view.sh -i <issue_number> (see --help)" >&2
+    exit 2
+}
+
 ISSUE_NUMBER=""
 
 # get_remote_host and get_gitea_token are provided by detect-platform.sh
@@ -74,6 +82,7 @@ if comments:
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
@@ -88,21 +97,21 @@ while [[ $# -gt 0 ]]; do
             exit 0
             ;;
         *)
-            echo "Unknown option: $1"
-            exit 1
+            usage_error "unknown option: $1"
             ;;
     esac
 done
 
 if [[ -z "$ISSUE_NUMBER" ]]; then
-    echo "Error: Issue number is required (-i)"
-    exit 1
+    usage_error "Issue number is required"
 fi
 
 detect_platform >/dev/null
 
 if [[ "$PLATFORM" == "github" ]]; then
-    gh issue view "$ISSUE_NUMBER"
+    prov_rc=0
+    gh issue view "$ISSUE_NUMBER" || prov_rc=$?
+    [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
 elif [[ "$PLATFORM" == "gitea" ]]; then
     if command -v tea >/dev/null 2>&1; then
         # --comments is what makes tea print the comment bodies (#1357 F3).
diff --git a/packages/mosaic/framework/tools/git/lane-brief.sh b/packages/mosaic/framework/tools/git/lane-brief.sh
index 5a83fbe9..c8a07180 100755
--- a/packages/mosaic/framework/tools/git/lane-brief.sh
+++ b/packages/mosaic/framework/tools/git/lane-brief.sh
@@ -28,18 +28,25 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/detect-platform.sh"
 
 REPO="" MILESTONE="" LABEL="" LOGIN="" LIMIT=100
-while getopts "r:m:l:L:n:h" opt; do
-  case "$opt" in
-    r) REPO="$OPTARG" ;;
-    m) MILESTONE="$OPTARG" ;;
-    l) LABEL="$OPTARG" ;;
-    L) LOGIN="$OPTARG" ;;
-    n) LIMIT="$OPTARG" ;;
-    h) grep '^#' "$0" | sed 's/^# \?//'; exit 0 ;;
-    *) echo "see -h" >&2; exit 2 ;;
+# R2 (2026-08-28): long-flag aliases with the same usage-error contract the
+# wrapper family shares (rc 2, stderr). getopts could not take long flags.
+usage_error() {
+  echo "Error: $*" >&2
+  echo "Usage: lane-brief.sh -r <owner/repo> [-m milestone] [-l label] [-L login] [-n limit]" >&2
+  exit 2
+}
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    -r|--repo) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; REPO="$2"; shift 2 ;;
+    -m|--milestone) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; MILESTONE="$2"; shift 2 ;;
+    -l|--label|--labels) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; LABEL="$2"; shift 2 ;;
+    -L|--login) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; LOGIN="$2"; shift 2 ;;
+    -n|--limit) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; LIMIT="$2"; shift 2 ;;
+    -h|--help) grep '^#' "$0" | sed 's/^# \?//'; exit 0 ;;
+    *) usage_error "unknown option: $1" ;;
   esac
 done
-[[ -n "$REPO" ]] || { echo "FATAL: -r <owner/repo> required" >&2; exit 2; }
+[[ -n "$REPO" ]] || usage_error "-r/--repo <owner/repo> required"
 
 # Resolve login: explicit -L, then $GITEA_LOGIN, then owner inference, then the
 # shared default-login resolver. Owner inference comes before the shared fallback
@@ -72,7 +79,7 @@ if [[ -z "$LOGIN" ]]; then
     fi
   fi
 fi
-[[ -n "$LOGIN" ]] || { echo "FATAL: could not resolve a Gitea login for $REPO (pass -L or set GITEA_LOGIN)" >&2; exit 2; }
+[[ -n "$LOGIN" ]] || { echo "FATAL: could not resolve a Gitea login for $REPO (pass -L or set GITEA_LOGIN)" >&2; exit 1; }
 
 command -v tea >/dev/null || { echo "FATAL: tea not found" >&2; exit 1; }
 command -v jq  >/dev/null || { echo "FATAL: jq not found" >&2; exit 1; }
diff --git a/packages/mosaic/framework/tools/git/milestone-close.sh b/packages/mosaic/framework/tools/git/milestone-close.sh
index f57e6cc3..9f31b542 100755
--- a/packages/mosaic/framework/tools/git/milestone-close.sh
+++ b/packages/mosaic/framework/tools/git/milestone-close.sh
@@ -8,11 +8,20 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/detect-platform.sh"
 
 # Parse arguments
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    echo "Usage: milestone-close.sh -t <title> (see --help)" >&2
+    exit 2
+}
+
 TITLE=""
 
 while [[ $# -gt 0 ]]; do
     case $1 in
         -t|--title)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
@@ -25,28 +34,30 @@ while [[ $# -gt 0 ]]; do
             exit 0
             ;;
         *)
-            echo "Unknown option: $1"
-            exit 1
+            usage_error "unknown option: $1"
             ;;
     esac
 done
 
 if [[ -z "$TITLE" ]]; then
-    echo "Error: Milestone title is required (-t)"
-    exit 1
+    usage_error "Milestone title is required"
 fi
 
 detect_platform >/dev/null
 
 if [[ "$PLATFORM" == "github" ]]; then
-    gh api -X PATCH "/repos/{owner}/{repo}/milestones/$(gh api "/repos/{owner}/{repo}/milestones" --jq ".[] | select(.title==\"$TITLE\") | .number")" -f state=closed
+    prov_rc=0
+    gh api -X PATCH "/repos/{owner}/{repo}/milestones/$(gh api "/repos/{owner}/{repo}/milestones" --jq ".[] | select(.title==\"$TITLE\") | .number")" -f state=closed || prov_rc=$?
+    [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
     echo "Closed GitHub milestone: $TITLE"
 elif [[ "$PLATFORM" == "gitea" ]]; then
     REPO_ARGS=$(get_gitea_repo_args) || {
         echo "Error: Could not resolve Gitea repo/login for remote host" >&2
         exit 1
     }
-    tea milestone close "$TITLE" $REPO_ARGS
+    prov_rc=0
+    tea milestone close "$TITLE" $REPO_ARGS || prov_rc=$?
+    [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
     echo "Closed Gitea milestone: $TITLE"
 else
     echo "Error: Unknown platform"
diff --git a/packages/mosaic/framework/tools/git/milestone-create.sh b/packages/mosaic/framework/tools/git/milestone-create.sh
index 72d8f299..c21acfce 100755
--- a/packages/mosaic/framework/tools/git/milestone-create.sh
+++ b/packages/mosaic/framework/tools/git/milestone-create.sh
@@ -3,6 +3,7 @@
 # Usage: milestone-create.sh -t "Title" [-d "Description"] [--due "YYYY-MM-DD"]
 
 set -e
+set -o pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/detect-platform.sh"
@@ -37,21 +38,31 @@ Examples:
     $(basename "$0") -t "0.0.1" -d "Pre-MVP Foundation Sprint"
     $(basename "$0") -t "0.1.0" -d "MVP Release" --due "2025-03-01"
 EOF
-    exit "${1:-1}"
+    exit "${1:-2}"
 }
 
 # Parse arguments
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    usage >&2
+}
+
 while [[ $# -gt 0 ]]; do
     case $1 in
         -t|--title)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
         -d|--desc)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             DESCRIPTION="$2"
             shift 2
             ;;
         --due)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             DUE_DATE="$2"
             shift 2
             ;;
@@ -74,14 +85,18 @@ PLATFORM=$(detect_platform)
 if [[ "$LIST_ONLY" == true ]]; then
     case "$PLATFORM" in
         github)
-            gh api repos/:owner/:repo/milestones --jq '.[] | "\(.number)\t\(.title)\t\(.state)\t\(.open_issues)/\(.closed_issues) issues"'
+            prov_rc=0
+            gh api repos/:owner/:repo/milestones --jq '.[] | "\(.number)\t\(.title)\t\(.state)\t\(.open_issues)/\(.closed_issues) issues"' || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
             ;;
         gitea)
             REPO_ARGS=$(get_gitea_repo_args) || {
                 echo "Error: Could not resolve Gitea repo/login for remote host" >&2
                 exit 1
             }
-            tea milestones list $REPO_ARGS
+            prov_rc=0
+            tea milestones list $REPO_ARGS || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
             ;;
         *)
             echo "Error: Could not detect git platform" >&2
@@ -92,8 +107,7 @@ if [[ "$LIST_ONLY" == true ]]; then
 fi
 
 if [[ -z "$TITLE" ]]; then
-    echo "Error: Title is required (-t) for creating milestones" >&2
-    usage
+    usage_error "Title is required (-t) for creating milestones"
 fi
 
 case "$PLATFORM" in
@@ -109,7 +123,9 @@ case "$PLATFORM" in
              + (if $d != "" then {"description": $d} else {} end)
              + (if $due != "" then {"due_on": ($due + "T00:00:00Z")} else {} end)')
 
-        gh api repos/:owner/:repo/milestones --method POST --input - <<< "$JSON_PAYLOAD"
+        prov_rc=0
+        gh api repos/:owner/:repo/milestones --method POST --input - <<< "$JSON_PAYLOAD" || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         echo "Milestone '$TITLE' created successfully"
         ;;
     gitea)
@@ -120,7 +136,9 @@ case "$PLATFORM" in
         CMD=(tea milestones create --title "$TITLE")
         [[ -n "$DESCRIPTION" ]] && CMD+=(--description "$DESCRIPTION")
         [[ -n "$DUE_DATE" ]] && CMD+=(--deadline "$DUE_DATE")
-        "${CMD[@]}" $REPO_ARGS
+        prov_rc=0
+        "${CMD[@]}" $REPO_ARGS || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         echo "Milestone '$TITLE' created successfully"
         ;;
     *)
diff --git a/packages/mosaic/framework/tools/git/milestone-list.sh b/packages/mosaic/framework/tools/git/milestone-list.sh
index 3b46c3d5..2704cc9d 100755
--- a/packages/mosaic/framework/tools/git/milestone-list.sh
+++ b/packages/mosaic/framework/tools/git/milestone-list.sh
@@ -8,11 +8,20 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/detect-platform.sh"
 
 # Parse arguments
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    echo "Usage: milestone-list.sh [-s <state>] (see --help)" >&2
+    exit 2
+}
+
 STATE="open"
 
 while [[ $# -gt 0 ]]; do
     case $1 in
         -s|--state)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             STATE="$2"
             shift 2
             ;;
@@ -25,8 +34,7 @@ while [[ $# -gt 0 ]]; do
             exit 0
             ;;
         *)
-            echo "Unknown option: $1"
-            exit 1
+            usage_error "unknown option: $1"
             ;;
     esac
 done
@@ -34,13 +42,17 @@ done
 detect_platform >/dev/null
 
 if [[ "$PLATFORM" == "github" ]]; then
-    gh api "/repos/{owner}/{repo}/milestones?state=$STATE" --jq '.[] | "\(.title) (\(.state)) - \(.open_issues) open, \(.closed_issues) closed"'
+    prov_rc=0
+    gh api "/repos/{owner}/{repo}/milestones?state=$STATE" --jq '.[] | "\(.title) (\(.state)) - \(.open_issues) open, \(.closed_issues) closed"' || prov_rc=$?
+    [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
 elif [[ "$PLATFORM" == "gitea" ]]; then
     REPO_ARGS=$(get_gitea_repo_args) || {
         echo "Error: Could not resolve Gitea repo/login for remote host" >&2
         exit 1
     }
-    tea milestone list $REPO_ARGS
+    prov_rc=0
+    tea milestone list $REPO_ARGS || prov_rc=$?
+    [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
 else
     echo "Error: Unknown platform"
     exit 1
diff --git a/packages/mosaic/framework/tools/git/pr-close.sh b/packages/mosaic/framework/tools/git/pr-close.sh
index 9fcb00f4..9a9dbdf7 100755
--- a/packages/mosaic/framework/tools/git/pr-close.sh
+++ b/packages/mosaic/framework/tools/git/pr-close.sh
@@ -1,6 +1,7 @@
 #!/bin/bash
 # pr-close.sh - Close a pull request without merging on GitHub or Gitea
-# Usage: pr-close.sh -n <pr_number> [-c <comment>]
+# Usage: pr-close.sh -n <pr_number> [-b <comment>]
+# (-c/--comment is a backward-compatible alias for -b/--body; R1/R4 2026-08-28)
 
 set -e
 
@@ -11,50 +12,80 @@ source "$SCRIPT_DIR/detect-platform.sh"
 PR_NUMBER=""
 COMMENT=""
 
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1), so a
+# caller or stop gate can tell an invocation defect from a delivery blocker.
+usage_error() {
+    echo "Error: $*" >&2
+    echo "Usage: pr-close.sh -n <pr_number> [-b <comment>] (see --help)" >&2
+    exit 2
+}
+
 while [[ $# -gt 0 ]]; do
     case $1 in
         -n|--number)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             PR_NUMBER="$2"
             shift 2
             ;;
-        -c|--comment)
+        -b|--body|-c|--comment)
+            # R1 (2026-08-28): --body is the canonical flag; -c/--comment stays
+            # a backward-compatible alias.
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
         -h|--help)
-            echo "Usage: pr-close.sh -n <pr_number> [-c <comment>]"
+            echo "Usage: pr-close.sh -n <pr_number> [-b <comment>]"
             echo ""
             echo "Options:"
             echo "  -n, --number   PR number (required)"
-            echo "  -c, --comment  Comment before closing (optional)"
+            echo "  -b, --body     Comment before closing (optional; canonical)"
+            echo "  -c, --comment  Alias for --body"
             echo "  -h, --help     Show this help"
+            echo ""
+            echo "Exit codes: 0 success; 2 usage error (stderr); 1 provider/credential/verification failure."
             exit 0
             ;;
         *)
-            echo "Unknown option: $1"
-            exit 1
+            usage_error "unknown option: $1"
             ;;
     esac
 done
 
 if [[ -z "$PR_NUMBER" ]]; then
-    echo "Error: PR number is required (-n)"
-    exit 1
+    usage_error "PR number is required (-n/--number)"
 fi
 
 detect_platform >/dev/null
 
 if [[ "$PLATFORM" == "github" ]]; then
+    # R4: normalize provider failures to exit 1 (gh's own usage errors exit 2
+    # and would collide with the reserved usage-error status).
     if [[ -n "$COMMENT" ]]; then
-        gh pr comment "$PR_NUMBER" --body "$COMMENT"
+        gh_rc=0
+        gh pr comment "$PR_NUMBER" --body "$COMMENT" || gh_rc=$?
+        if [[ "$gh_rc" -ne 0 ]]; then
+            echo "Error: GitHub PR comment before close failed (gh exit $gh_rc)" >&2
+            exit 1
+        fi
+    fi
+    gh_rc=0
+    gh pr close "$PR_NUMBER" || gh_rc=$?
+    if [[ "$gh_rc" -ne 0 ]]; then
+        echo "Error: GitHub PR close failed (gh exit $gh_rc)" >&2
+        exit 1
     fi
-    gh pr close "$PR_NUMBER"
     echo "Closed GitHub PR #$PR_NUMBER"
 elif [[ "$PLATFORM" == "gitea" ]]; then
     if [[ -n "$COMMENT" ]]; then
-        tea pr comment "$PR_NUMBER" "$COMMENT" $(get_gitea_repo_args)
+        prov_rc=0
+        tea pr comment "$PR_NUMBER" "$COMMENT" $(get_gitea_repo_args) || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
     fi
-    tea pr close "$PR_NUMBER" $(get_gitea_repo_args)
+    prov_rc=0
+    tea pr close "$PR_NUMBER" $(get_gitea_repo_args) || prov_rc=$?
+    [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
     echo "Closed Gitea PR #$PR_NUMBER"
 else
     echo "Error: Unknown platform"
diff --git a/packages/mosaic/framework/tools/git/pr-create.sh b/packages/mosaic/framework/tools/git/pr-create.sh
index 31a8dfa9..2226b091 100755
--- a/packages/mosaic/framework/tools/git/pr-create.sh
+++ b/packages/mosaic/framework/tools/git/pr-create.sh
@@ -135,37 +135,51 @@ Examples:
     $(basename "$0") -i 42 -b "Implements the feature described in #42"
     $(basename "$0") -t "WIP: New feature" --draft
 EOF
-    exit "${1:-1}"
+    exit "${1:-2}"
+}
+
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    usage >&2
 }
 
 # Parse arguments
 while [[ $# -gt 0 ]]; do
     case $1 in
         -t|--title)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
         -b|--body)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             BODY="$2"
             shift 2
             ;;
         -B|--base)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             BASE_BRANCH="$2"
             shift 2
             ;;
         -H|--head)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             HEAD_BRANCH="$2"
             shift 2
             ;;
         -l|--labels)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABELS="$2"
             shift 2
             ;;
         -m|--milestone)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
         -i|--issue)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE="$2"
             shift 2
             ;;
@@ -266,7 +280,9 @@ case "$PLATFORM" in
         [[ -n "$LABELS" ]] && CMD+=(--label "$LABELS")
         [[ -n "$MILESTONE" ]] && CMD+=(--milestone "$MILESTONE")
         [[ "$DRAFT" == true ]] && CMD+=(--draft)
-        "${CMD[@]}"
+        prov_rc=0
+        "${CMD[@]}" || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         ;;
     gitea)
         # tea pull create syntax. Always pass --repo because tea repo inference
diff --git a/packages/mosaic/framework/tools/git/pr-edit.sh b/packages/mosaic/framework/tools/git/pr-edit.sh
index 47a12d8e..db520f7d 100755
--- a/packages/mosaic/framework/tools/git/pr-edit.sh
+++ b/packages/mosaic/framework/tools/git/pr-edit.sh
@@ -50,38 +50,45 @@ Options:
     -H, --host HOST        Explicit Gitea host (required with --repo off-host)
     -h, --help             Show this help message
 EOF
-    exit "${1:-1}"
+    exit "${1:-2}"
+}
+
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    usage >&2
 }
 
 while [[ $# -gt 0 ]]; do
     case "$1" in
-        -n|--number) PR_NUMBER="${2:-}"; shift 2 ;;
-        -t|--title) TITLE="${2:-}"; shift 2 ;;
-        -b|--body) BODY="${2:-}"; shift 2 ;;
-        -B|--base) BASE_BRANCH="${2:-}"; shift 2 ;;
+        -n|--number) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; PR_NUMBER="${2:-}"; shift 2 ;;
+        -t|--title) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; TITLE="${2:-}"; shift 2 ;;
+        -b|--body) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; BODY="${2:-}"; shift 2 ;;
+        -B|--base) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; BASE_BRANCH="${2:-}"; shift 2 ;;
         --draft)
-            [[ "$DRAFT_MODE" != "ready" ]] || { echo "Error: --draft and --ready are mutually exclusive" >&2; exit 1; }
+            [[ "$DRAFT_MODE" != "ready" ]] || { echo "Error: --draft and --ready are mutually exclusive" >&2; exit 2; }
             DRAFT_MODE="draft"; shift ;;
         --ready)
-            [[ "$DRAFT_MODE" != "draft" ]] || { echo "Error: --draft and --ready are mutually exclusive" >&2; exit 1; }
+            [[ "$DRAFT_MODE" != "draft" ]] || { echo "Error: --draft and --ready are mutually exclusive" >&2; exit 2; }
             DRAFT_MODE="ready"; shift ;;
-        -l|--login) LOGIN_OVERRIDE="${2:-}"; shift 2 ;;
-        -r|--repo) REPO_OVERRIDE="${2:-}"; shift 2 ;;
-        -H|--host) HOST_OVERRIDE="${2:-}"; shift 2 ;;
+        -l|--login) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; LOGIN_OVERRIDE="${2:-}"; shift 2 ;;
+        -r|--repo) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; REPO_OVERRIDE="${2:-}"; shift 2 ;;
+        -H|--host) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; HOST_OVERRIDE="${2:-}"; shift 2 ;;
         -h|--help) usage 0 ;;
         *) echo "Unknown option: $1" >&2; usage ;;
     esac
 done
 
-[[ -n "$PR_NUMBER" ]] || { echo "Error: Pull request number is required (-n)" >&2; exit 1; }
-[[ "$PR_NUMBER" =~ ^[1-9][0-9]*$ ]] || { echo "Error: Pull request number must be a positive integer" >&2; exit 1; }
+[[ -n "$PR_NUMBER" ]] || { echo "Error: Pull request number is required (-n)" >&2; exit 2; }
+[[ "$PR_NUMBER" =~ ^[1-9][0-9]*$ ]] || { echo "Error: Pull request number must be a positive integer" >&2; exit 2; }
 if [[ -z "$TITLE" && -z "$BODY" && -z "$BASE_BRANCH" && -z "$DRAFT_MODE" ]]; then
     echo "Error: At least one edit option is required" >&2
-    exit 1
+    exit 2
 fi
 [[ -z "$REPO_OVERRIDE" || "$REPO_OVERRIDE" =~ ^[^/[:space:]]+/[^/[:space:]]+$ ]] || {
     echo "Error: --repo must be OWNER/REPO" >&2
-    exit 1
+    exit 2
 }
 
 if [[ -n "$HOST_OVERRIDE" || -n "$REPO_OVERRIDE" ]]; then
@@ -92,18 +99,24 @@ fi
 
 case "$PLATFORM" in
     github)
-        [[ -z "$LOGIN_OVERRIDE" ]] || { echo "Error: --login is only valid for Gitea" >&2; exit 1; }
+        [[ -z "$LOGIN_OVERRIDE" ]] || { echo "Error: --login is only valid for Gitea" >&2; exit 2; }
         if [[ -n "$TITLE" || -n "$BODY" || -n "$BASE_BRANCH" ]]; then
             CMD=(gh pr edit "$PR_NUMBER")
             [[ -n "$TITLE" ]] && CMD+=(--title "$TITLE")
             [[ -n "$BODY" ]] && CMD+=(--body "$BODY")
             [[ -n "$BASE_BRANCH" ]] && CMD+=(--base "$BASE_BRANCH")
-            "${CMD[@]}"
+            prov_rc=0
+            "${CMD[@]}" || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         fi
         if [[ "$DRAFT_MODE" == "draft" ]]; then
-            gh pr ready "$PR_NUMBER" --undo
+            prov_rc=0
+            gh pr ready "$PR_NUMBER" --undo || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         elif [[ "$DRAFT_MODE" == "ready" ]]; then
-            gh pr ready "$PR_NUMBER"
+            prov_rc=0
+            gh pr ready "$PR_NUMBER" || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         fi
         ;;
     gitea)
diff --git a/packages/mosaic/framework/tools/git/pr-review.sh b/packages/mosaic/framework/tools/git/pr-review.sh
index b131f385..e468222d 100755
--- a/packages/mosaic/framework/tools/git/pr-review.sh
+++ b/packages/mosaic/framework/tools/git/pr-review.sh
@@ -43,60 +43,92 @@ LOGIN_OVERRIDE=""
 REPO_OVERRIDE=""
 HOST_OVERRIDE=""
 
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1), so a
+# caller or stop gate can tell an invocation defect from a delivery blocker.
+usage_error() {
+    echo "Error: $*" >&2
+    echo "Usage: pr-review.sh -n <pr_number> -a <action> [-b <comment>] (see --help)" >&2
+    exit 2
+}
+
 while [[ $# -gt 0 ]]; do
     case $1 in
         -n|--number)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             PR_NUMBER="$2"
             shift 2
             ;;
         -a|--action)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ACTION="$2"
             shift 2
             ;;
-        -c|--comment)
+        -b|--body|-c|--comment)
+            # R1 (2026-08-28): --body is the canonical flag; -c/--comment stays
+            # a backward-compatible alias.
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
         -l|--login)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LOGIN_OVERRIDE="$2"
             shift 2
             ;;
         -r|--repo)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             REPO_OVERRIDE="$2"
             shift 2
             ;;
         -H|--host)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             HOST_OVERRIDE="$2"
             shift 2
             ;;
         -h|--help)
-            echo "Usage: pr-review.sh -n <pr_number> -a <action> [-c <comment>] [--login <name>] [-r owner/repo] [-H host]"
+            echo "Usage: pr-review.sh -n <pr_number> -a <action> [-b <comment>] [--login <name>] [-r owner/repo] [-H host]"
             echo ""
             echo "Options:"
             echo "  -n, --number   PR number (required)"
             echo "  -a, --action   Review action: approve, request-changes, comment (required)"
-            echo "  -c, --comment  Review comment (required for request-changes)"
+            echo "  -b, --body     Review comment (required for request-changes; canonical)"
+            echo "  -c, --comment  Alias for --body"
             echo "  -l, --login    Override the detected Gitea tea login (approve/request-changes only)"
             echo "  -r, --repo     Explicit owner/repo slug (skips git-remote slug inference)"
             echo "  -H, --host     Explicit Gitea host (skips remote-host inference)"
             echo "  -h, --help     Show this help"
+            echo ""
+            echo "Exit codes: 0 success; 2 usage error (stderr); 1 provider/credential/verification failure."
             exit 0
             ;;
         *)
-            echo "Unknown option: $1"
-            exit 1
+            usage_error "unknown option: $1"
             ;;
     esac
 done
 
 if [[ -z "$PR_NUMBER" ]]; then
-    echo "Error: PR number is required (-n)"
-    exit 1
+    usage_error "PR number is required (-n/--number)"
 fi
 
 if [[ -z "$ACTION" ]]; then
-    echo "Error: Action is required (-a): approve, request-changes, comment"
-    exit 1
+    usage_error "Action is required (-a/--action): approve, request-changes, comment"
+fi
+
+# Validate the action BEFORE any provider contact (codex review of PR #1464:
+# an unsupported --action previously reached platform detection and could
+# touch the provider before failing with a provider-class status).
+case "$ACTION" in
+    approve|request-changes|comment) ;;
+    *) usage_error "unknown action '$ACTION': approve, request-changes, comment" ;;
+esac
+
+# Body-required actions fail fast too (codex follow-up on PR #1464):
+# request-changes and comment both require a body; validate before any
+# provider contact.
+if [[ ( "$ACTION" == "request-changes" || "$ACTION" == "comment" ) && -z "$COMMENT" ]]; then
+    usage_error "comment required for $ACTION (-b/--body)"
 fi
 
 if [[ -n "$REPO_OVERRIDE" ]]; then
@@ -679,15 +711,18 @@ PY
 if [[ "$PLATFORM" == "github" ]]; then
     case $ACTION in
         approve)
-            gh pr review "$PR_NUMBER" --approve ${COMMENT:+--body "$COMMENT"}
+            gh_rc=0
+            gh pr review "$PR_NUMBER" --approve ${COMMENT:+--body "$COMMENT"} || gh_rc=$?
+            [[ "$gh_rc" -eq 0 ]] || { echo "Error: GitHub approve failed (gh exit $gh_rc; provider failure, not a usage error)" >&2; exit 1; }
             echo "Approved GitHub PR #$PR_NUMBER"
             ;;
         request-changes)
             if [[ -z "$COMMENT" ]]; then
-                echo "Error: Comment required for request-changes"
-                exit 1
+                usage_error "comment required for request-changes (-b/--body)"
             fi
-            gh pr review "$PR_NUMBER" --request-changes --body "$COMMENT"
+            gh_rc=0
+            gh pr review "$PR_NUMBER" --request-changes --body "$COMMENT" || gh_rc=$?
+            [[ "$gh_rc" -eq 0 ]] || { echo "Error: GitHub request-changes failed (gh exit $gh_rc; provider failure, not a usage error)" >&2; exit 1; }
             echo "Requested changes on GitHub PR #$PR_NUMBER"
             ;;
         comment)
@@ -695,12 +730,13 @@ if [[ "$PLATFORM" == "github" ]]; then
                 echo "Error: Comment required"
                 exit 1
             fi
-            gh pr review "$PR_NUMBER" --comment --body "$COMMENT"
+            gh_rc=0
+            gh pr review "$PR_NUMBER" --comment --body "$COMMENT" || gh_rc=$?
+            [[ "$gh_rc" -eq 0 ]] || { echo "Error: GitHub review comment failed (gh exit $gh_rc; provider failure, not a usage error)" >&2; exit 1; }
             echo "Added review comment to GitHub PR #$PR_NUMBER"
             ;;
         *)
-            echo "Error: Unknown action: $ACTION"
-            exit 1
+            usage_error "unknown action: $ACTION"
             ;;
     esac
 elif [[ "$PLATFORM" == "gitea" ]]; then
@@ -738,8 +774,7 @@ elif [[ "$PLATFORM" == "gitea" ]]; then
             ;;
         request-changes)
             if [[ -z "$COMMENT" ]]; then
-                echo "Error: Comment required for request-changes"
-                exit 1
+                usage_error "comment required for request-changes (-b/--body)"
             fi
             # Best-effort host for credential resolution only (gitea_resolve_api_for_login
             # below re-derives the real host from HOST_OVERRIDE/remote independently and
@@ -794,8 +829,7 @@ elif [[ "$PLATFORM" == "gitea" ]]; then
             echo "Added and verified comment on Gitea PR #$PR_NUMBER (comment ID $comment_id)"
             ;;
         *)
-            echo "Error: Unknown action: $ACTION"
-            exit 1
+            usage_error "unknown action: $ACTION"
             ;;
     esac
 else
diff --git a/packages/mosaic/framework/tools/git/test-issue-assign-usage-contract.sh b/packages/mosaic/framework/tools/git/test-issue-assign-usage-contract.sh
new file mode 100755
index 00000000..5c73537c
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-issue-assign-usage-contract.sh
@@ -0,0 +1,154 @@
+#!/usr/bin/env bash
+# Usage-error contract for issue-assign.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/issue-assign-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/issue-assign.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/issue-assign.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: issue-assign.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -i exits 2"
+expect_stderr "Issue number is required" "missing -i message on stderr"
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -i -a -l -m --issue --assignee --labels --milestone; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -i 5 -a --help
+expect_rc 2 "short flag value rejected" -i 5 -a -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -a; do
+    rc=0
+    run_wrapper_sandboxed -i 5 "$flag" "value" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+# 6b. Provider-exit normalization (codex PR #1464): a provider stub exiting
+# 2 (its own usage-error status) must surface as wrapper exit 1, never 2.
+GH_REPO="$WORK_DIR/repo-gh"
+mkdir -p "$GH_REPO"
+git -C "$GH_REPO" init -q
+git -C "$GH_REPO" remote add origin https://github.com/acme/widgets.git
+cat > "$BIN_DIR/gh" <<GHSTUB
+#!/usr/bin/env bash
+echo "gh \$*" >> "$PROBE_LOG"
+if [[ "\$1 \$2" == "issue edit" ]]; then exit 2; fi
+exit 0
+GHSTUB
+chmod +x "$BIN_DIR/gh"
+rc=0
+(
+    cd "$GH_REPO"
+    PATH="$BIN_DIR:$PATH" MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+        "$SCRIPT_DIR/issue-assign.sh" -i 5 -a someone >"$OUT_FILE" 2>"$ERR_FILE"
+) || rc=$?
+[[ "$rc" -eq 1 ]] || fail "GitHub path: gh exit 2 must normalize to wrapper exit 1 (got $rc)"
+grep -q "provider" "$ERR_FILE" || fail "GitHub path: normalized provider error missing from stderr"
+
+echo "issue-assign.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-issue-close-usage-contract.sh b/packages/mosaic/framework/tools/git/test-issue-close-usage-contract.sh
new file mode 100755
index 00000000..b0ef6ae4
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-issue-close-usage-contract.sh
@@ -0,0 +1,136 @@
+#!/usr/bin/env bash
+# Usage-error contract for issue-close.sh (R1/R4, 2026-08-28).
+#
+# R4: usage errors print to STDERR and exit 2, distinct from provider,
+# credential, and verification failures (exit 1). R1: -b/--body is the
+# canonical comment flag; -c/--comment remains a compatible alias.
+# The comment is OPTIONAL here (an issue may close without one), so unlike
+# issue-comment there is no missing-comment arm.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/issue-close-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 0
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/issue-close.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/issue-close.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: issue-close.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "unknown option" "unknown option names itself on stderr"
+
+# 3. Missing required issue number: rc 2, stderr.
+expect_rc 2 "missing -i exits 2"
+expect_stderr "issue number is required" "missing -i message on stderr"
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -i -b -c --issue --body --comment; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -i 5 -b --help
+expect_rc 2 "short flag value rejected" -i 5 -b -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -b -c; do
+    rc=0
+    run_wrapper_sandboxed -i 5 "$flag" "closing note" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Sandbox arms may issue DETECTION reads only (tea login list via the
+# stub); no gh/curl write or read may occur.
+if grep -Ev '^(gh|tea|curl) login list' "$PROBE_LOG" | grep -q .; then
+    echo "FAIL: a sandbox arm performed a non-detection provider request:" >&2
+    grep -Ev '^(gh|tea|curl) login list' "$PROBE_LOG" >&2
+    exit 1
+fi
+if grep -qE '^(gh|curl)' "$PROBE_LOG"; then
+    echo "FAIL: gh or curl was invoked during a sandbox arm:" >&2
+    grep -E '^(gh|curl)' "$PROBE_LOG" >&2
+    exit 1
+fi
+
+echo "issue-close.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-issue-comment-usage-contract.sh b/packages/mosaic/framework/tools/git/test-issue-comment-usage-contract.sh
index a1be441a..d80a89a4 100755
--- a/packages/mosaic/framework/tools/git/test-issue-comment-usage-contract.sh
+++ b/packages/mosaic/framework/tools/git/test-issue-comment-usage-contract.sh
@@ -97,7 +97,7 @@ expect_rc() { # expect_rc <want> <desc> <args...>
 }
 
 expect_stderr() { # expect_stderr <pattern> <desc>
-    grep -q "$1" "$ERR_FILE" || fail "$desc: stderr missing '$1'"
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
 }
 
 # 1. Help exits 0 and prints usage on stdout.
@@ -124,6 +124,13 @@ for flag in -i -b -c -l --issue --body --comment --login; do
     expect_stderr "requires a value" "value-less $flag message on stderr"
 done
 
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -i 5 -b --help
+expect_rc 2 "short flag value rejected" -i 5 -b -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
 # 6. Alias acceptance at parse level: both -b and -c carry a value past
 # parsing; the wrapper then fails at platform detection (not a git repo)
 # nonzero but NOT as a usage error (rc must not be 2).
diff --git a/packages/mosaic/framework/tools/git/test-issue-create-usage-contract.sh b/packages/mosaic/framework/tools/git/test-issue-create-usage-contract.sh
new file mode 100755
index 00000000..1cdbfc7a
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-issue-create-usage-contract.sh
@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# Usage-error contract for issue-create.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/issue-create-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/issue-create.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/issue-create.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: issue-create.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -t exits 2"
+expect_stderr "Title is required" "missing -t message on stderr"
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -t -b -l -m --title --body --labels --milestone; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -t smoke -b --help
+expect_rc 2 "short flag value rejected" -t smoke -b -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -b; do
+    rc=0
+    run_wrapper_sandboxed -t "smoke" "$flag" "value" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "issue-create.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-issue-edit-usage-contract.sh b/packages/mosaic/framework/tools/git/test-issue-edit-usage-contract.sh
new file mode 100755
index 00000000..0f939f9d
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-issue-edit-usage-contract.sh
@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# Usage-error contract for issue-edit.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/issue-edit-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/issue-edit.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/issue-edit.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: issue-edit.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "unknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -i exits 2"
+expect_stderr "issue number is required" "missing -i message on stderr"
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -i -t -b -l -m --issue --title --body --labels --milestone; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -i 5 -b --help
+expect_rc 2 "short flag value rejected" -i 5 -b -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -b; do
+    rc=0
+    run_wrapper_sandboxed -i 5 "$flag" "value" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "issue-edit.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-issue-list-usage-contract.sh b/packages/mosaic/framework/tools/git/test-issue-list-usage-contract.sh
new file mode 100755
index 00000000..75aaae46
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-issue-list-usage-contract.sh
@@ -0,0 +1,130 @@
+#!/usr/bin/env bash
+# Usage-error contract for issue-list.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/issue-list-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/issue-list.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/issue-list.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: issue-list.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -s -l -m -a -n -r --state --label --milestone --assignee --limit --repo; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -s --help
+expect_rc 2 "short flag value rejected" -s -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -s; do
+    rc=0
+    run_wrapper_sandboxed -s open >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "issue-list.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-issue-reopen-usage-contract.sh b/packages/mosaic/framework/tools/git/test-issue-reopen-usage-contract.sh
new file mode 100755
index 00000000..ff7e7343
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-issue-reopen-usage-contract.sh
@@ -0,0 +1,136 @@
+#!/usr/bin/env bash
+# Usage-error contract for issue-reopen.sh (R1/R4, 2026-08-28).
+#
+# R4: usage errors print to STDERR and exit 2, distinct from provider,
+# credential, and verification failures (exit 1). R1: -b/--body is the
+# canonical comment flag; -c/--comment remains a compatible alias.
+# The comment is OPTIONAL here (an issue may close without one), so unlike
+# issue-comment there is no missing-comment arm.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/issue-reopen-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 0
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/issue-reopen.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/issue-reopen.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: issue-reopen.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "unknown option" "unknown option names itself on stderr"
+
+# 3. Missing required issue number: rc 2, stderr.
+expect_rc 2 "missing -i exits 2"
+expect_stderr "issue number is required" "missing -i message on stderr"
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -i -b -c --issue --body --comment; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -i 5 -b --help
+expect_rc 2 "short flag value rejected" -i 5 -b -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -b -c; do
+    rc=0
+    run_wrapper_sandboxed -i 5 "$flag" "closing note" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Sandbox arms may issue DETECTION reads only (tea login list via the
+# stub); no gh/curl write or read may occur.
+if grep -Ev '^(gh|tea|curl) login list' "$PROBE_LOG" | grep -q .; then
+    echo "FAIL: a sandbox arm performed a non-detection provider request:" >&2
+    grep -Ev '^(gh|tea|curl) login list' "$PROBE_LOG" >&2
+    exit 1
+fi
+if grep -qE '^(gh|curl)' "$PROBE_LOG"; then
+    echo "FAIL: gh or curl was invoked during a sandbox arm:" >&2
+    grep -E '^(gh|curl)' "$PROBE_LOG" >&2
+    exit 1
+fi
+
+echo "issue-reopen.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-issue-view-usage-contract.sh b/packages/mosaic/framework/tools/git/test-issue-view-usage-contract.sh
new file mode 100755
index 00000000..d2ff9182
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-issue-view-usage-contract.sh
@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# Usage-error contract for issue-view.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/issue-view-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/issue-view.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/issue-view.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: issue-view.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -i exits 2"
+expect_stderr "Issue number is required" "missing -i message on stderr"
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -i --issue; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -i --help
+expect_rc 2 "short flag value rejected" -i -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -i; do
+    rc=0
+    run_wrapper_sandboxed -i 5 >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "issue-view.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-lane-brief-pr-linkage.sh b/packages/mosaic/framework/tools/git/test-lane-brief-pr-linkage.sh
old mode 100644
new mode 100755
diff --git a/packages/mosaic/framework/tools/git/test-lane-brief-usage-contract.sh b/packages/mosaic/framework/tools/git/test-lane-brief-usage-contract.sh
new file mode 100755
index 00000000..64c08ebc
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-lane-brief-usage-contract.sh
@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# Usage-error contract for lane-brief.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/lane-brief-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/lane-brief.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/lane-brief.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "owner/repo" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -r exits 2"
+expect_stderr "required" "missing -r message on stderr"
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -r -m -l -L -n --repo --milestone --label --login --limit; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -r owner/repo -m --help
+expect_rc 2 "short flag value rejected" -r owner/repo -m -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -r; do
+    rc=0
+    run_wrapper_sandboxed -r owner/repo >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "lane-brief.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-milestone-close-usage-contract.sh b/packages/mosaic/framework/tools/git/test-milestone-close-usage-contract.sh
new file mode 100755
index 00000000..c7f38771
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-milestone-close-usage-contract.sh
@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# Usage-error contract for milestone-close.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/milestone-close-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/milestone-close.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/milestone-close.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: milestone-close.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -t exits 2"
+expect_stderr "Milestone title is required" "missing -t message on stderr"
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -t --title; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -t --help --help
+expect_rc 2 "short flag value rejected" -t --help -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -t; do
+    rc=0
+    run_wrapper_sandboxed -t "smoke" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "milestone-close.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-milestone-create-usage-contract.sh b/packages/mosaic/framework/tools/git/test-milestone-create-usage-contract.sh
new file mode 100755
index 00000000..e267f9dc
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-milestone-create-usage-contract.sh
@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# Usage-error contract for milestone-create.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/milestone-create-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/milestone-create.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/milestone-create.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: milestone-create.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -t exits 2"
+expect_stderr "Title is required" "missing -t message on stderr"
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -t -d --due --title --desc; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -t smoke -d --help
+expect_rc 2 "short flag value rejected" -t smoke -d -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -t; do
+    rc=0
+    run_wrapper_sandboxed -t "smoke" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "milestone-create.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-milestone-list-usage-contract.sh b/packages/mosaic/framework/tools/git/test-milestone-list-usage-contract.sh
new file mode 100755
index 00000000..e2456405
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-milestone-list-usage-contract.sh
@@ -0,0 +1,153 @@
+#!/usr/bin/env bash
+# Usage-error contract for milestone-list.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/milestone-list-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/milestone-list.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/milestone-list.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: milestone-list.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -s --state; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -s --help
+expect_rc 2 "short flag value rejected" -s -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -s; do
+    rc=0
+    run_wrapper_sandboxed -s open >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+# 6b. Provider-exit normalization (codex PR #1464): a provider stub exiting
+# 2 (its own usage-error status) must surface as wrapper exit 1, never 2.
+GH_REPO="$WORK_DIR/repo-gh"
+mkdir -p "$GH_REPO"
+git -C "$GH_REPO" init -q
+git -C "$GH_REPO" remote add origin https://github.com/acme/widgets.git
+cat > "$BIN_DIR/gh" <<GHSTUB
+#!/usr/bin/env bash
+echo "gh \$*" >> "$PROBE_LOG"
+if [[ "\$1" == "api" ]]; then exit 2; fi
+exit 0
+GHSTUB
+chmod +x "$BIN_DIR/gh"
+rc=0
+(
+    cd "$GH_REPO"
+    PATH="$BIN_DIR:$PATH" MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+        "$SCRIPT_DIR/milestone-list.sh" >"$OUT_FILE" 2>"$ERR_FILE"
+) || rc=$?
+[[ "$rc" -eq 1 ]] || fail "GitHub path: gh exit 2 must normalize to wrapper exit 1 (got $rc)"
+grep -q "provider" "$ERR_FILE" || fail "GitHub path: normalized provider error missing from stderr"
+
+echo "milestone-list.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-pr-close-usage-contract.sh b/packages/mosaic/framework/tools/git/test-pr-close-usage-contract.sh
new file mode 100755
index 00000000..6d380e59
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-pr-close-usage-contract.sh
@@ -0,0 +1,133 @@
+#!/usr/bin/env bash
+# Usage-error contract for pr-close.sh (R1/R4, 2026-08-28).
+#
+# R4: usage errors print to STDERR and exit 2, distinct from provider,
+# credential, and verification failures (exit 1). R1: -b/--body is the
+# canonical comment flag; -c/--comment remains a compatible alias.
+# The comment is OPTIONAL here (an issue may close without one), so unlike
+# issue-comment there is no missing-comment arm.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/pr-close-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/pr-close.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/pr-close.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: pr-close.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "unknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -n exits 2"
+expect_stderr "PR number is required" "missing -n message on stderr"
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -n -b -c --number --body --comment; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -n 5 -b --help
+expect_rc 2 "short flag value rejected" -n 5 -b -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -b -c; do
+    rc=0
+    run_wrapper_sandboxed -n 5 "$flag" "closing note" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "pr-close.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-pr-create-usage-contract.sh b/packages/mosaic/framework/tools/git/test-pr-create-usage-contract.sh
new file mode 100755
index 00000000..ad23472c
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-pr-create-usage-contract.sh
@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# Usage-error contract for pr-create.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/pr-create-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/pr-create.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/pr-create.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: pr-create.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -t exits 2"
+expect_stderr "Title is required" "missing -t message on stderr"
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -t -b -B -H -l -m -i --title --body --base --head --labels --milestone --issue; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -t smoke -b --help
+expect_rc 2 "short flag value rejected" -t smoke -b -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -b; do
+    rc=0
+    run_wrapper_sandboxed -t "smoke" "$flag" "value" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "pr-create.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-pr-edit-usage-contract.sh b/packages/mosaic/framework/tools/git/test-pr-edit-usage-contract.sh
new file mode 100755
index 00000000..71448ca9
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-pr-edit-usage-contract.sh
@@ -0,0 +1,140 @@
+#!/usr/bin/env bash
+# Usage-error contract for pr-edit.sh (R4, 2026-08-28).
+#
+# issue-edit already uses long-flag-first parsing (-i/--issue, -t/--title,
+# -b/--body, -l/--labels, -m/--milestone); this adds the rc=2 usage-error
+# contract, value checks, and the no-provider-contact proof. Required: -i.
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/pr-edit-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/pr-edit.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/pr-edit.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: pr-edit.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "[Uu]nknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -n exits 2"
+expect_stderr "Pull request number is required" "missing -n message on stderr"
+expect_rc 2 "no edit option exits 2" -n 5
+expect_stderr "At least one edit option is required" "no-edit-option message on stderr"
+expect_rc 2 "non-integer PR number exits 2" -n abc -t x
+expect_stderr "positive integer" "integer check on stderr"
+expect_rc 2 "mutually exclusive draft/ready exits 2" -n 5 --draft --ready
+expect_stderr "mutually exclusive" "mutual exclusion on stderr"
+expect_rc 2 "bad repo format exits 2" -n 5 -t x -r not-a-slug
+expect_stderr "OWNER/REPO" "repo format on stderr"
+
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -n -t -b -B -l -r -H --number --title --body --base --login --repo --host; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -n 5 -t smoke -b --help
+expect_rc 2 "short flag value rejected" -n 5 -t smoke -b -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -b; do
+    rc=0
+    run_wrapper_sandboxed -n 5 "$flag" "value" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "pr-edit.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/framework/tools/git/test-pr-review-gitea-comment.sh b/packages/mosaic/framework/tools/git/test-pr-review-gitea-comment.sh
old mode 100644
new mode 100755
diff --git a/packages/mosaic/framework/tools/git/test-pr-review-repo-host-override.sh b/packages/mosaic/framework/tools/git/test-pr-review-repo-host-override.sh
index f5699ce4..789fa410 100755
--- a/packages/mosaic/framework/tools/git/test-pr-review-repo-host-override.sh
+++ b/packages/mosaic/framework/tools/git/test-pr-review-repo-host-override.sh
@@ -218,7 +218,7 @@ if grep -q 'Unknown option' "$OUTPUT_FILE"; then
     cat "$OUTPUT_FILE" >&2
     exit 1
 fi
-grep -q 'Unknown action: bogus-action' "$OUTPUT_FILE"
+grep -q "unknown action 'bogus-action'" "$OUTPUT_FILE"
 
 # --- Case 2: -h/--help documents both overrides.
 HELP_TEXT="$("$SCRIPT_DIR/pr-review.sh" -h)"
diff --git a/packages/mosaic/framework/tools/git/test-pr-review-usage-contract.sh b/packages/mosaic/framework/tools/git/test-pr-review-usage-contract.sh
new file mode 100755
index 00000000..13dbf50b
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-pr-review-usage-contract.sh
@@ -0,0 +1,148 @@
+#!/usr/bin/env bash
+# Usage-error contract for pr-review.sh (R1/R4, 2026-08-28).
+#
+# R4: usage errors print to STDERR and exit 2, distinct from provider,
+# credential, and verification failures (exit 1). R1: -b/--body is the
+# canonical comment flag; -c/--comment remains a compatible alias.
+# Required: -n AND -a. The comment is required only for the
+# request-changes action (semantic usage check, also rc 2).
+#
+# Arms:
+#   1. --help and -h exit 0 and print usage.
+#   2. Unknown option exits 2 with the message on stderr.
+#   3. Missing required -i exits 2 (stderr).
+#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
+#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
+#      at credential resolution, nonzero and NOT 2) — no real token is
+#      ever read and no provider is contacted.
+#   6. No arm performs any provider request (PATH shims record every
+#      invocation; the probe log must stay empty).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/pr-review-usage}"
+BIN_DIR="$WORK_DIR/bin"
+PROBE_LOG="$WORK_DIR/provider-probes.log"
+OUT_FILE="$WORK_DIR/out.log"
+ERR_FILE="$WORK_DIR/err.log"
+
+cleanup() {
+    rm -rf "$WORK_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$BIN_DIR"
+: > "$PROBE_LOG"
+
+# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
+# API fallback that treats a successful curl as a closed PR, so exit-0
+# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
+for tool in gh tea curl; do
+    cat > "$BIN_DIR/$tool" <<STUB
+#!/usr/bin/env bash
+echo "$tool \$*" >> "$PROBE_LOG"
+exit 99
+STUB
+    chmod +x "$BIN_DIR/$tool"
+done
+
+run_wrapper() {
+    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/pr-review.sh" "$@" )
+}
+
+# Hermetic variant: neutralizes every identity/credential source the wrapper
+# consults so parse-acceptance arms fail at credential resolution in ANY cwd
+# repo (see test-issue-comment-usage-contract.sh for the measured incident).
+run_wrapper_sandboxed() {
+    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
+    (
+        cd "$WORK_DIR"
+        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
+            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
+            "$SCRIPT_DIR/pr-review.sh" "$@"
+    )
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    echo "--- stderr ---" >&2
+    cat "$ERR_FILE" >&2
+    exit 1
+}
+
+expect_rc() { # expect_rc <want> <desc> <args...>
+    local want="$1" desc="$2" rc=0
+    shift 2
+    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
+}
+
+expect_stderr() { # expect_stderr <pattern> <desc>
+    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
+}
+
+# 1. Help exits 0 and prints usage.
+expect_rc 0 "--help exits 0" --help
+grep -q "Usage: pr-review.sh" "$OUT_FILE" || fail "--help did not print usage"
+expect_rc 0 "-h exits 0" -h
+
+# 2. Unknown option: rc 2, stderr.
+expect_rc 2 "unknown option exits 2" --bogus
+expect_stderr "unknown option" "unknown option names itself on stderr"
+
+# 3. Missing required PR number: rc 2, stderr.
+expect_rc 2 "missing -n exits 2"
+expect_stderr "PR number is required" "missing -n message on stderr"
+expect_rc 2 "missing -a exits 2" -n 5
+expect_stderr "Action is required" "missing -a message on stderr"
+expect_rc 2 "request-changes without comment exits 2" -n 5 -a request-changes
+expect_stderr "comment required for request-changes" "request-changes message on stderr"
+expect_rc 2 "comment without body exits 2 pre-detection" -n 5 -a comment
+expect_stderr "comment required for comment" "comment-without-body message on stderr"
+expect_rc 2 "invalid action exits 2 pre-detection" -n 5 -a bogus
+expect_stderr "unknown action" "invalid action message on stderr"
+# Invalid-action arms must not contact any provider (validation precedes
+# detect_platform): probe log empty at this point.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: an invalid-action arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 4. Value-less flags: rc 2 with "requires a value" on stderr.
+for flag in -n -a -b -c -l -r --number --action --body --comment --login --repo; do
+    expect_rc 2 "value-less $flag exits 2" "$flag"
+    expect_stderr "requires a value" "value-less $flag message on stderr"
+done
+
+# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
+# -b --help previously consumed --help as the body and performed the write).
+expect_rc 2 "option-like value rejected" -n 5 -a comment -b --help
+expect_rc 2 "short flag value rejected" -n 5 -a comment -b -h
+expect_stderr "requires a value" "short flag value message on stderr"
+expect_stderr "requires a value" "option-like value message on stderr"
+
+# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
+if [[ -s "$PROBE_LOG" ]]; then
+    echo "FAIL: a parser-failure arm contacted a provider:" >&2
+    cat "$PROBE_LOG" >&2
+    exit 1
+fi
+
+# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
+#    parsing; the run fails at credential resolution nonzero and NOT 2.
+for flag in -b -c; do
+    rc=0
+    run_wrapper_sandboxed -n 5 -a comment "$flag" "review note" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
+    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
+    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
+done
+
+# 6. Post-sandbox provider assertions are intentionally NOT applied here:
+# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
+# comment parses, then falls back to the API. Hermeticity for this
+# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
+# the arm above proves only parse acceptance and non-usage classification.
+# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).
+
+echo "pr-review.sh usage-contract regression passed (R1/R4)"
diff --git a/packages/mosaic/package.json b/packages/mosaic/package.json
index ce1a3740..b047a4e8 100644
--- a/packages/mosaic/package.json
+++ b/packages/mosaic/package.json
@@ -25,7 +25,7 @@
     "lint": "eslint src",
     "typecheck": "tsc --noEmit",
     "test": "vitest run --passWithNoTests && pnpm run test:framework-shell",
-    "test:framework-shell": "bash framework/tools/quality/scripts/check-test-enumeration.sh && bash framework/tools/quality/scripts/test-check-test-enumeration.sh && python3 framework/tools/quality/scripts/test-framework-drift-check.py && bash framework/tools/quality/scripts/test-framework-drift-doctor.sh && bash framework/systemd/user/test-fleet-units.sh && python3 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_unittest.py && python3 src/lease-broker/promotion_binding_unittest.py && python3 src/lease-broker/promotion_trigger_unittest.py && python3 src/lease-broker/receipt_challenge_unittest.py && python3 src/lease-broker/context_recovery_unittest.py && python3 src/lease-broker/recovery_runtime_unittest.py && python3 src/lease-broker/recovery_b1_adversarial_unittest.py && python3 src/lease-broker/receipt_observer_client_unittest.py && python3 src/lease-broker/invariant_r_unittest.py && python3 src/lease-broker/framework_skill_portability_unittest.py && python3 src/lease-broker/revoke_noop_unittest.py && python3 src/mutator-gate/runtime_tools_unittest.py && python3 src/mutator-gate/runtime_launch_guard_unittest.py && python3 src/mutator-gate/version_coupling_unittest.py && python3 framework/tools/lease-broker/check-runtime-launches.py --root ../.. && bash framework/tools/codex/test-pr-diff-context.sh && bash framework/tools/qa/test-deps-preflight.sh && bash framework/tools/git/test-pr-edit.sh && bash framework/tools/git/test-pr-create-fallback-default-base.sh && bash framework/tools/git/test-repo-decl-consumption.sh && bash framework/tools/git/test-pr-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.sh && bash framework/tools/git/test-ci-queue-wait-no-status.sh && bash framework/tools/git/test-ci-queue-wait-branch-absent.sh && bash framework/tools/git/test-ci-queue-wait-tristate.sh && bash framework/tools/git/test-ci-queue-wait-github-checks.sh && bash framework/tools/git/test-ci-queue-wait-no-ci-expected.sh && bash framework/tools/git/test-pr-merge-queue-branch.sh && bash framework/tools/git/test-pr-merge-no-ci-expected.sh && bash framework/tools/git/test-pr-merge-fork-ci-status.sh && bash framework/tools/git/test-pr-merge-head-pin.sh && bash framework/tools/git/test-pr-merge-message-field.sh && bash framework/tools/git/test-git-credential-mosaic.sh && bash framework/tools/git/test-gitea-token-identity.sh && bash framework/tools/git/test-issue-comment-usage-contract.sh && bash framework/tools/git/test-issue-comment-readback.sh && bash framework/tools/git/test-explain-diagnostic-status-neutral.sh && bash framework/tools/git/test-detect-platform-outside-repo.sh && bash framework/tools/woodpecker/test-terminal-green-contract.sh && bash framework/tools/_scripts/test-install-ordering-guard.sh && bash framework/tools/_scripts/test-mosaic-init-rce.sh && bash framework/tools/tmux/agent-send.test.sh && bash framework/tools/wake/test-wake-store-ack.sh && bash framework/tools/wake/test-wake-store-enqueue-race.sh && bash framework/tools/wake/test-wake-digest-hmac.sh && bash framework/tools/wake/test-wake-digest-quarantine.sh && bash framework/tools/wake/test-wake-detector.sh && bash framework/tools/wake/test-wake-fn-oracle.sh && bash framework/tools/wake/test-wake-reconcile.sh && bash framework/tools/wake/test-wake-beacon.sh && bash framework/tools/wake/test-wake-preimage.sh && bash framework/tools/wake/test-wake-install.sh && bash framework/tools/glpi/test-list-http-status.sh && bash framework/tools/orchestrator/test-board-roll.sh && bash framework/tools/woodpecker/test-ci-wait-exit-matrix.sh && bash framework/tools/_scripts/test-fleet-transport-check.sh && bash framework/tools/_scripts/test-brain-home-check.sh && bash framework/tools/_scripts/test-structure-anchor-check.sh && bash framework/tools/fleet/test-agent-session-broker-preflight.sh && bash framework/tools/fleet/test-agent-session-legacy-socket-guard.sh && bash framework/tools/git/test-grant-reviewer.sh"
+    "test:framework-shell": "bash framework/tools/quality/scripts/check-test-enumeration.sh && bash framework/tools/quality/scripts/test-check-test-enumeration.sh && python3 framework/tools/quality/scripts/test-framework-drift-check.py && bash framework/tools/quality/scripts/test-framework-drift-doctor.sh && bash framework/systemd/user/test-fleet-units.sh && python3 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_unittest.py && python3 src/lease-broker/promotion_binding_unittest.py && python3 src/lease-broker/promotion_trigger_unittest.py && python3 src/lease-broker/receipt_challenge_unittest.py && python3 src/lease-broker/context_recovery_unittest.py && python3 src/lease-broker/recovery_runtime_unittest.py && python3 src/lease-broker/recovery_b1_adversarial_unittest.py && python3 src/lease-broker/receipt_observer_client_unittest.py && python3 src/lease-broker/invariant_r_unittest.py && python3 src/lease-broker/framework_skill_portability_unittest.py && python3 src/lease-broker/revoke_noop_unittest.py && python3 src/mutator-gate/runtime_tools_unittest.py && python3 src/mutator-gate/runtime_launch_guard_unittest.py && python3 src/mutator-gate/version_coupling_unittest.py && python3 framework/tools/lease-broker/check-runtime-launches.py --root ../.. && bash framework/tools/codex/test-pr-diff-context.sh && bash framework/tools/qa/test-deps-preflight.sh && bash framework/tools/git/test-pr-edit.sh && bash framework/tools/git/test-pr-create-fallback-default-base.sh && bash framework/tools/git/test-repo-decl-consumption.sh && bash framework/tools/git/test-pr-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.sh && bash framework/tools/git/test-ci-queue-wait-no-status.sh && bash framework/tools/git/test-ci-queue-wait-branch-absent.sh && bash framework/tools/git/test-ci-queue-wait-tristate.sh && bash framework/tools/git/test-ci-queue-wait-github-checks.sh && bash framework/tools/git/test-ci-queue-wait-no-ci-expected.sh && bash framework/tools/git/test-pr-merge-queue-branch.sh && bash framework/tools/git/test-pr-merge-no-ci-expected.sh && bash framework/tools/git/test-pr-merge-fork-ci-status.sh && bash framework/tools/git/test-pr-merge-head-pin.sh && bash framework/tools/git/test-pr-merge-message-field.sh && bash framework/tools/git/test-git-credential-mosaic.sh && bash framework/tools/git/test-gitea-token-identity.sh && bash framework/tools/git/test-issue-comment-usage-contract.sh && bash framework/tools/git/test-issue-comment-readback.sh && bash framework/tools/git/test-issue-close-usage-contract.sh && bash framework/tools/git/test-issue-reopen-usage-contract.sh && bash framework/tools/git/test-pr-close-usage-contract.sh && bash framework/tools/git/test-pr-review-usage-contract.sh && bash framework/tools/git/test-issue-edit-usage-contract.sh && bash framework/tools/git/test-issue-create-usage-contract.sh && bash framework/tools/git/test-pr-edit-usage-contract.sh && bash framework/tools/git/test-pr-create-usage-contract.sh && bash framework/tools/git/test-issue-assign-usage-contract.sh && bash framework/tools/git/test-milestone-close-usage-contract.sh && bash framework/tools/git/test-milestone-list-usage-contract.sh && bash framework/tools/git/test-issue-view-usage-contract.sh && bash framework/tools/git/test-issue-list-usage-contract.sh && bash framework/tools/git/test-milestone-create-usage-contract.sh && bash framework/tools/git/test-lane-brief-usage-contract.sh && bash framework/tools/git/test-explain-diagnostic-status-neutral.sh && bash framework/tools/git/test-detect-platform-outside-repo.sh && bash framework/tools/woodpecker/test-terminal-green-contract.sh && bash framework/tools/_scripts/test-install-ordering-guard.sh && bash framework/tools/_scripts/test-mosaic-init-rce.sh && bash framework/tools/tmux/agent-send.test.sh && bash framework/tools/wake/test-wake-store-ack.sh && bash framework/tools/wake/test-wake-store-enqueue-race.sh && bash framework/tools/wake/test-wake-digest-hmac.sh && bash framework/tools/wake/test-wake-digest-quarantine.sh && bash framework/tools/wake/test-wake-detector.sh && bash framework/tools/wake/test-wake-fn-oracle.sh && bash framework/tools/wake/test-wake-reconcile.sh && bash framework/tools/wake/test-wake-beacon.sh && bash framework/tools/wake/test-wake-preimage.sh && bash framework/tools/wake/test-wake-install.sh && bash framework/tools/glpi/test-list-http-status.sh && bash framework/tools/orchestrator/test-board-roll.sh && bash framework/tools/woodpecker/test-ci-wait-exit-matrix.sh && bash framework/tools/_scripts/test-fleet-transport-check.sh && bash framework/tools/_scripts/test-brain-home-check.sh && bash framework/tools/_scripts/test-structure-anchor-check.sh && bash framework/tools/fleet/test-agent-session-broker-preflight.sh && bash framework/tools/fleet/test-agent-session-legacy-socket-guard.sh && bash framework/tools/git/test-grant-reviewer.sh"
   },
   "dependencies": {
     "@mosaicstack/brain": "workspace:*",
diff --git a/packages/mosaic/src/cli.ts b/packages/mosaic/src/cli.ts
index f38e64a7..7d82480c 100644
--- a/packages/mosaic/src/cli.ts
+++ b/packages/mosaic/src/cli.ts
@@ -11,6 +11,9 @@ import { registerQualityRails } from '@mosaicstack/quality-rails';
 import { registerQueueCommand } from '@mosaicstack/queue';
 import { registerStorageCommand } from '@mosaicstack/storage';
 import { registerTelemetryCommand } from './commands/telemetry.js';
+import { registerCommsCommand } from './commands/comms.js';
+import { registerQCommand } from './commands/q.js';
+import { registerWatchCommand } from './commands/watch.js';
 import { registerAgentCommand } from './commands/agent.js';
 import { registerInteractionCommand } from './commands/interaction.js';
 import { registerConfigCommand } from './commands/config.js';
@@ -428,6 +431,9 @@ registerSkillCommand(program);
 // ─── telemetry ───────────────────────────────────────────────────────────────
 
 registerTelemetryCommand(program);
+registerWatchCommand(program);
+registerQCommand(program);
+registerCommsCommand(program);
 
 // ─── update ─────────────────────────────────────────────────────────────
 
diff --git a/packages/mosaic/src/commands/brain-dispatch.ts b/packages/mosaic/src/commands/brain-dispatch.ts
new file mode 100644
index 00000000..4a6c6fe5
--- /dev/null
+++ b/packages/mosaic/src/commands/brain-dispatch.ts
@@ -0,0 +1,67 @@
+import { spawnSync } from 'node:child_process';
+import { accessSync, constants } from 'node:fs';
+import { join } from 'node:path';
+
+import { resolveBrainHome } from '../fleet/brain-home.js';
+
+/**
+ * Shared brain-tool dispatch (fleet CLI integration, Jason ruling
+ * 2026-08-28): the npm package embeds the COMMAND SURFACE; operator-owned
+ * implementations stay in the brain (tools/). Commands resolve the brain
+ * home (MOSAIC_BRAIN_HOME wins — see brain-home.ts) and exec the tool
+ * there. Nothing operator-specific ships inside the package.
+ *
+ * Pass-through contract: arguments, stdout/stderr, and the exit code belong
+ * to the tool. The CLI adds nothing on success; absent tools fail loudly
+ * with the resolved path (127) instead of guessing.
+ */
+
+/** Absolute path of a brain-relative tool. */
+export function resolveBrainTool(mosaicHome: string, relPath: string): string {
+  return join(resolveBrainHome(mosaicHome), ...relPath.split('/'));
+}
+
+/** Map a spawnSync result + tool existence to the CLI exit status. */
+export function exitStatusFor(
+  result: { status: number | null; error?: NodeJS.ErrnoException },
+  toolExists: boolean,
+): number {
+  if (!toolExists) return 127;
+  if (result.status !== null) return result.status;
+  return 125; // killed by signal / could not run
+}
+
+export function brainToolExists(tool: string): boolean {
+  try {
+    accessSync(tool, constants.X_OK);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * Exec a brain tool with full pass-through. `interpreter` runs the tool
+ * through e.g. python3 (renderers); omit it for executable scripts.
+ * Returns the process exit status; callers assign it to process.exitCode.
+ */
+export function execBrainTool(
+  mosaicHome: string,
+  relPath: string,
+  args: string[],
+  interpreter?: string,
+): number {
+  const tool = resolveBrainTool(mosaicHome, relPath);
+  if (!brainToolExists(tool)) {
+    console.error(
+      `mosaic: brain tool not found (expected ${tool}). ` +
+        'Tool suites live in the brain tree under tools/; ' +
+        'check MOSAIC_BRAIN_HOME or the brain checkout.',
+    );
+    return 127;
+  }
+  const result = interpreter
+    ? spawnSync(interpreter, [tool, ...args], { stdio: 'inherit', env: process.env })
+    : spawnSync(tool, args, { stdio: 'inherit', env: process.env });
+  return exitStatusFor(result, true);
+}
diff --git a/packages/mosaic/src/commands/comms.spec.ts b/packages/mosaic/src/commands/comms.spec.ts
new file mode 100644
index 00000000..a20a85aa
--- /dev/null
+++ b/packages/mosaic/src/commands/comms.spec.ts
@@ -0,0 +1,143 @@
+import {
+  chmodSync,
+  existsSync,
+  mkdirSync,
+  mkdtempSync,
+  writeFileSync,
+  readFileSync,
+} from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+
+import { Command } from 'commander';
+import { afterEach, describe, expect, it } from 'vitest';
+
+import { fleetCommsSendArgs, registerCommsCommand, tmuxSendArgs } from './comms.js';
+
+describe('arg translation', () => {
+  it('tmux path: -s/-C/-L/-f/-m per agent-send.sh getopts', () => {
+    expect(tmuxSendArgs('orch-01', 'hello', {})).toEqual(['-s', 'orch-01', '-m', 'hello']);
+    expect(
+      tmuxSendArgs('orch-01', 'unused', {
+        class: 'actionable',
+        socket: 'mosaic-fleet',
+        file: '/tmp/body.txt',
+      }),
+    ).toEqual(['-s', 'orch-01', '-C', 'actionable', '-L', 'mosaic-fleet', '-f', '/tmp/body.txt']);
+  });
+
+  it('fleet-comms path: -t site/agent and -c class', () => {
+    expect(fleetCommsSendArgs('usc', 'fred', 'hi', {})).toEqual(['-t', 'usc/fred', '-m', 'hi']);
+    expect(fleetCommsSendArgs('usc', 'fred', 'hi', { class: 'human' })).toEqual([
+      '-t',
+      'usc/fred',
+      '-c',
+      'human',
+      '-m',
+      'hi',
+    ]);
+  });
+});
+
+describe('registerCommsCommand routing', () => {
+  const savedBrain = process.env['MOSAIC_BRAIN_HOME'];
+  const savedRepo = process.env['MOSAIC_FLEET_COMMS_REPO'];
+  const savedAgent = process.env['MOSAIC_AGENT_NAME'];
+  afterEach(() => {
+    for (const [k, v] of [
+      ['MOSAIC_BRAIN_HOME', savedBrain],
+      ['MOSAIC_FLEET_COMMS_REPO', savedRepo],
+      ['MOSAIC_AGENT_NAME', savedAgent],
+    ] as const) {
+      if (v === undefined) delete process.env[k];
+      else process.env[k] = v;
+    }
+    process.exitCode = undefined;
+  });
+
+  function fixture(): { brain: string; repo: string; tmuxLog: string; commsLog: string } {
+    const brain = mkdtempSync(join(tmpdir(), 'comms-brain-'));
+    const repo = mkdtempSync(join(tmpdir(), 'comms-repo-'));
+    mkdirSync(join(brain, 'tools', 'tmux'), { recursive: true });
+    mkdirSync(join(repo, 'tools'), { recursive: true });
+    const tmuxLog = join(brain, 'tmux.log');
+    const commsLog = join(repo, 'comms.log');
+    writeFileSync(
+      join(brain, 'tools', 'tmux', 'agent-send.sh'),
+      `#!/usr/bin/env bash\nprintf '%s\\n' "$*" >> ${JSON.stringify(tmuxLog)}\nexit 7\n`,
+    );
+    writeFileSync(
+      join(repo, 'tools', 'comms-send.sh'),
+      `#!/usr/bin/env bash\nprintf '%s\\n' "$*" >> ${JSON.stringify(commsLog)}\nprintf 'FLEET_COMMS_REPO=%s FLEET_COMMS_SITE=%s\\n' "$FLEET_COMMS_REPO" "$FLEET_COMMS_SITE" >> ${JSON.stringify(commsLog)}\nexit 5\n`,
+    );
+    chmodSync(join(brain, 'tools', 'tmux', 'agent-send.sh'), 0o755);
+    chmodSync(join(repo, 'tools', 'comms-send.sh'), 0o755);
+    process.env['MOSAIC_BRAIN_HOME'] = brain;
+    process.env['MOSAIC_FLEET_COMMS_REPO'] = repo;
+    process.env['MOSAIC_AGENT_NAME'] = 'tester';
+    return { brain, repo, tmuxLog, commsLog };
+  }
+
+  it('default routes same-host via agent-send with translated flags and passes rc through', async () => {
+    const f = fixture();
+    const program = new Command();
+    registerCommsCommand(program);
+    await program.parseAsync(
+      [
+        'comms',
+        'send',
+        'orch-01',
+        '--class',
+        'actionable',
+        '--socket',
+        'mosaic-fleet',
+        'verdict',
+        'landed',
+      ],
+      { from: 'user' },
+    );
+    expect(process.exitCode).toBe(7);
+    expect(readFileSync(f.tmuxLog, 'utf8').trim()).toBe(
+      '-s orch-01 -C actionable -L mosaic-fleet -m verdict landed',
+    );
+    expect(existsSync(f.commsLog)).toBe(false); // inter-site tool never invoked
+  });
+
+  it('--site routes inter-site via comms-send with site-prefixed target and passes rc through', async () => {
+    const f = fixture();
+    const program = new Command();
+    registerCommsCommand(program);
+    await program.parseAsync(
+      ['comms', 'send', 'fred', '--site', 'usc', '--class', 'human', 'hello', 'there'],
+      { from: 'user' },
+    );
+    expect(process.exitCode).toBe(5);
+    expect(readFileSync(f.commsLog, 'utf8').split('\n')[0]?.trim()).toBe(
+      '-t usc/fred -c human -m hello there',
+    );
+    // The sender must bind comms-send.sh to the SELECTED repo (codex 9c8b6ebf).
+    expect(readFileSync(f.commsLog, 'utf8')).toContain(
+      `FLEET_COMMS_REPO=${f.repo} FLEET_COMMS_SITE=usc`,
+    );
+    expect(existsSync(f.tmuxLog)).toBe(false); // same-host tool never invoked
+  });
+
+  it('inter-site without MOSAIC_AGENT_NAME is an invocation defect (exit 2)', async () => {
+    const f = fixture();
+    delete process.env['MOSAIC_AGENT_NAME'];
+    const program = new Command();
+    registerCommsCommand(program);
+    await program.parseAsync(['comms', 'send', 'fred', '--site', 'usc', 'hi'], { from: 'user' });
+    expect(process.exitCode).toBe(2);
+    expect(existsSync(f.commsLog)).toBe(false); // inter-site tool never invoked
+  });
+
+  it('missing fleet-comms repo fails 127 naming the expected path', async () => {
+    fixture();
+    process.env['MOSAIC_FLEET_COMMS_REPO'] = '/nonexistent-comms-repo';
+    const program = new Command();
+    registerCommsCommand(program);
+    await program.parseAsync(['comms', 'send', 'fred', '--site', 'usc', 'hi'], { from: 'user' });
+    expect(process.exitCode).toBe(127);
+  });
+});
diff --git a/packages/mosaic/src/commands/comms.ts b/packages/mosaic/src/commands/comms.ts
new file mode 100644
index 00000000..cb6cada7
--- /dev/null
+++ b/packages/mosaic/src/commands/comms.ts
@@ -0,0 +1,135 @@
+import type { Command } from 'commander';
+import { spawnSync } from 'node:child_process';
+import { accessSync, constants } from 'node:fs';
+import { homedir } from 'node:os';
+import { join } from 'node:path';
+
+import { DEFAULT_MOSAIC_HOME } from '../constants.js';
+import { execBrainTool } from './brain-dispatch.js';
+
+/**
+ * `mosaic comms send` — routed agent messaging (FLEET-COMMS.md doctrine).
+ *
+ * Same-host (default): brain tools/tmux/agent-send.sh. Inter-site
+ * (--site <site>): the fleet-comms repo's comms-send.sh — never for
+ * local traffic (a git round trip per message; Jason 2026-08-28).
+ *
+ * Exit codes pass through BOTH paths. rc=2 (text in pane, still draft) is
+ * a CONTRACT, not a failure: never retry, confirm with capture-pane.
+ */
+export interface CommsSendOptions {
+  readonly class?: string;
+  readonly file?: string;
+  readonly socket?: string;
+  readonly site?: string;
+  readonly commsRepo?: string;
+}
+
+export function defaultCommsRepo(): string {
+  return process.env['MOSAIC_FLEET_COMMS_REPO'] ?? join(homedir(), 'src', 'fleet-comms');
+}
+
+/** Build the agent-send.sh argv for the same-host path. */
+export function tmuxSendArgs(target: string, message: string, opts: CommsSendOptions): string[] {
+  const args = ['-s', target];
+  if (opts.class) args.push('-C', opts.class);
+  if (opts.socket) args.push('-L', opts.socket);
+  if (opts.file) args.push('-f', opts.file);
+  else args.push('-m', message);
+  return args;
+}
+
+/** Build the comms-send.sh argv for the inter-site path. */
+export function fleetCommsSendArgs(
+  site: string,
+  target: string,
+  message: string,
+  opts: CommsSendOptions,
+): string[] {
+  const args = ['-t', `${site}/${target}`];
+  if (opts.class) args.push('-c', opts.class);
+  args.push('-m', message);
+  return args;
+}
+
+export function registerCommsCommand(program: Command): void {
+  const cmd: Command = program
+    .command('comms')
+    .description(
+      'Routed agent messaging: tmux same-host (default), fleet-comms inter-site (--site)',
+    )
+    .command('send')
+    .description('send <target> [message...] — same-host tmux unless --site is given')
+    .option('--class <class>', 'terminal-log | actionable | human | reaction | digest')
+    .option('--file <path>', 'message body from file (same-host path only)')
+    .option('--socket <name>', 'tmux socket for the same-host send (e.g. mosaic-fleet)')
+    .option('--site <site>', 'route via fleet-comms to <site>/<target>')
+    .option('--comms-repo <path>', 'fleet-comms checkout', defaultCommsRepo())
+    .argument('<target>', 'destination seat (session name)')
+    .argument('[message...]', 'message text (joined; or use --file)')
+    .action(
+      async (
+        target: string,
+        messageWords: string[],
+        opts: CommsSendOptions & Record<string, unknown>,
+        command: Command,
+      ) => {
+        let mosaicHome: string | undefined;
+        for (let anc: Command | null = command; anc; anc = anc.parent) {
+          const v = (anc.opts() as Record<string, string | undefined>)['mosaicHome'];
+          if (v !== undefined) {
+            mosaicHome = v;
+            break;
+          }
+        }
+        const home = mosaicHome ?? DEFAULT_MOSAIC_HOME;
+        const message = messageWords.join(' ');
+
+        if (opts.site) {
+          const repo = opts.commsRepo ?? defaultCommsRepo();
+          const tool = join(repo, 'tools', 'comms-send.sh');
+          try {
+            accessSync(tool, constants.X_OK);
+          } catch {
+            console.error(
+              `mosaic comms: fleet-comms sender not found (expected ${tool}). ` +
+                'Clone the fleet-comms repo or point --comms-repo at it.',
+            );
+            process.exitCode = 127;
+            return;
+          }
+          if (!process.env['MOSAIC_AGENT_NAME']) {
+            console.error(
+              'mosaic comms: inter-site sends require MOSAIC_AGENT_NAME (sending identity).',
+            );
+            process.exitCode = 2; // invocation defect: fixable by the caller
+            return;
+          }
+          // comms-send.sh locates its working repo via FLEET_COMMS_REPO
+          // (default $HOME/src/fleet-comms); without this, --comms-repo
+          // would select the executable but not the repository it operates
+          // on (codex review of 9c8b6ebf).
+          const env = { ...process.env, FLEET_COMMS_SITE: opts.site, FLEET_COMMS_REPO: repo };
+          const result = spawnSync(tool, fleetCommsSendArgs(opts.site, target, message, opts), {
+            stdio: 'inherit',
+            env,
+          });
+          process.exitCode = result.status ?? 125;
+          return;
+        }
+
+        // Same-host: the brain tool owns validation (bad class -> its rc 3)
+        // and absence (execBrainTool -> 127 with the resolved path).
+        process.exitCode = execBrainTool(
+          home,
+          'tools/tmux/agent-send.sh',
+          tmuxSendArgs(target, message, opts),
+        );
+      },
+    );
+
+  cmd.addHelpText(
+    'after',
+    '\nExit codes pass through. rc=2 means the text reached the pane but is still a draft: NEVER retry (double-send); confirm with tmux capture-pane.',
+  );
+}
diff --git a/packages/mosaic/src/commands/q.spec.ts b/packages/mosaic/src/commands/q.spec.ts
new file mode 100644
index 00000000..e86a7550
--- /dev/null
+++ b/packages/mosaic/src/commands/q.spec.ts
@@ -0,0 +1,91 @@
+import { mkdirSync, mkdtempSync, writeFileSync, chmodSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+
+import { Command } from 'commander';
+import { afterEach, describe, expect, it } from 'vitest';
+
+import { registerQCommand, resolveQuestionTool } from './q.js';
+import { exitStatusFor, resolveBrainTool } from './brain-dispatch.js';
+
+describe('resolveBrainTool', () => {
+  const saved = process.env['MOSAIC_BRAIN_HOME'];
+  afterEach(() => {
+    if (saved === undefined) delete process.env['MOSAIC_BRAIN_HOME'];
+    else process.env['MOSAIC_BRAIN_HOME'] = saved;
+  });
+
+  it('joins brain home with the relative tool path', () => {
+    const tmp = mkdtempSync(join(tmpdir(), 'dispatch-resolve-'));
+    process.env['MOSAIC_BRAIN_HOME'] = tmp;
+    expect(resolveBrainTool('/nonexistent/mosaic-home', 'tools/questions/q-new.sh')).toBe(
+      join(tmp, 'tools', 'questions', 'q-new.sh'),
+    );
+  });
+});
+
+describe('resolveQuestionTool', () => {
+  const saved = process.env['MOSAIC_BRAIN_HOME'];
+  afterEach(() => {
+    if (saved === undefined) delete process.env['MOSAIC_BRAIN_HOME'];
+    else process.env['MOSAIC_BRAIN_HOME'] = saved;
+  });
+
+  it('maps new/render subcommands to their brain tools', () => {
+    const tmp = mkdtempSync(join(tmpdir(), 'q-resolve-'));
+    process.env['MOSAIC_BRAIN_HOME'] = tmp;
+    expect(resolveQuestionTool(tmp, 'new')).toBe(join(tmp, 'tools', 'questions', 'q-new.sh'));
+    expect(resolveQuestionTool(tmp, 'render')).toBe(join(tmp, 'tools', 'questions', 'render.py'));
+    expect(resolveQuestionTool(tmp, 'bogus')).toBeUndefined();
+  });
+});
+
+describe('registerQCommand usage + dispatch', () => {
+  const saved = process.env['MOSAIC_BRAIN_HOME'];
+  afterEach(() => {
+    if (saved === undefined) delete process.env['MOSAIC_BRAIN_HOME'];
+    else process.env['MOSAIC_BRAIN_HOME'] = saved;
+    process.exitCode = undefined;
+  });
+
+  it('exit 2 with the subcommand list when no/unknown subcommand', async () => {
+    process.env['MOSAIC_BRAIN_HOME'] = mkdtempSync(join(tmpdir(), 'q-usage-'));
+    const program = new Command();
+    registerQCommand(program);
+    await program.parseAsync(['q'], { from: 'user' });
+    expect(process.exitCode).toBe(2);
+    process.exitCode = undefined;
+    await program.parseAsync(['q', 'bogus'], { from: 'user' });
+    expect(process.exitCode).toBe(2);
+    process.exitCode = undefined;
+    // Reserved property names must not leak through the record lookup.
+    await program.parseAsync(['q', 'toString'], { from: 'user' });
+    expect(process.exitCode).toBe(2);
+  });
+
+  it('execs the brain tool with pass-through args and exit code', async () => {
+    const tmp = mkdtempSync(join(tmpdir(), 'q-live-'));
+    process.env['MOSAIC_BRAIN_HOME'] = tmp;
+    mkdirSync(join(tmp, 'tools', 'questions'), { recursive: true });
+    const stub = join(tmp, 'tools', 'questions', 'q-new.sh');
+    writeFileSync(stub, '#!/usr/bin/env bash\necho "called with: $*"\nexit 7\n');
+    chmodSync(stub, 0o755);
+
+    const program = new Command();
+    registerQCommand(program);
+    await program.parseAsync(['q', 'new', '--slug', 'x', '--question', 'why'], { from: 'user' });
+    expect(process.exitCode).toBe(7);
+  });
+});
+
+describe('exitStatusFor (shared dispatch contract)', () => {
+  it('maps absent tool to 127', () => {
+    expect(exitStatusFor({ status: 0 }, false)).toBe(127);
+  });
+  it('passes tool status through', () => {
+    expect(exitStatusFor({ status: 7 }, true)).toBe(7);
+  });
+  it('maps signal death to 125', () => {
+    expect(exitStatusFor({ status: null }, true)).toBe(125);
+  });
+});
diff --git a/packages/mosaic/src/commands/q.ts b/packages/mosaic/src/commands/q.ts
new file mode 100644
index 00000000..0bcfb8bb
--- /dev/null
+++ b/packages/mosaic/src/commands/q.ts
@@ -0,0 +1,63 @@
+import type { Command } from 'commander';
+
+import { DEFAULT_MOSAIC_HOME } from '../constants.js';
+import { execBrainTool, resolveBrainTool } from './brain-dispatch.js';
+
+/**
+ * `mosaic q` — tracked decision questions (brain tools/questions).
+ * `new` files a question file (one FILE per question, merge-conflict
+ * impossible by construction); `render` regenerates the
+ * docs/OPEN-QUESTIONS.md index (id allocation happens in the renderer).
+ */
+const SUBCOMMANDS: Record<string, { path: string; interpreter?: string; help: string }> = {
+  new: {
+    path: 'tools/questions/q-new.sh',
+    help: 'file a question (--question, --slug, --owed-by, ...)',
+  },
+  render: {
+    path: 'tools/questions/render.py',
+    interpreter: 'python3',
+    help: 'regenerate docs/OPEN-QUESTIONS.md (owns Q-id allocation)',
+  },
+};
+
+export function resolveQuestionTool(mosaicHome: string, sub: string): string | undefined {
+  const entry = SUBCOMMANDS[sub];
+  return entry ? resolveBrainTool(mosaicHome, entry.path) : undefined;
+}
+
+export function registerQCommand(program: Command): void {
+  const cmd: Command = program
+    .command('q')
+    .description('Tracked decision questions: file and render (brain tools/questions)')
+    .allowUnknownOption()
+    .argument('[args...]', 'subcommand + args passed through to the question tools')
+    .action(async (args: string[], _opts: unknown, command: Command) => {
+      let mosaicHome: string | undefined;
+      for (let anc: Command | null = command; anc; anc = anc.parent) {
+        const v = (anc.opts() as Record<string, string | undefined>)['mosaicHome'];
+        if (v !== undefined) {
+          mosaicHome = v;
+          break;
+        }
+      }
+      const home = mosaicHome ?? DEFAULT_MOSAIC_HOME;
+
+      const sub = args[0];
+      if (!sub || !Object.hasOwn(SUBCOMMANDS, sub)) {
+        console.error('mosaic q: expected a subcommand:');
+        for (const [name, entry] of Object.entries(SUBCOMMANDS)) {
+          console.error(`  mosaic q ${name}   ${entry.help}`);
+        }
+        process.exitCode = 2; // usage error contract: invocation defect
+        return;
+      }
+      const entry = SUBCOMMANDS[sub]!;
+      process.exitCode = execBrainTool(home, entry.path, args.slice(1), entry.interpreter);
+    });
+
+  cmd.addHelpText(
+    'after',
+    '\nEverything after the subcommand is passed through verbatim (args, output, exit code).',
+  );
+}
diff --git a/packages/mosaic/src/commands/watch.spec.ts b/packages/mosaic/src/commands/watch.spec.ts
new file mode 100644
index 00000000..489ef8c2
--- /dev/null
+++ b/packages/mosaic/src/commands/watch.spec.ts
@@ -0,0 +1,72 @@
+import { mkdirSync, mkdtempSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+
+import { Command } from 'commander';
+import { afterEach, describe, expect, it } from 'vitest';
+
+import { exitStatusFor, registerWatchCommand, resolveAgentWatchTool } from './watch.js';
+
+// The dispatch command execs a real process with inherited stdio; the spec
+// covers the pure resolution and exit-mapping surfaces plus the absent-tool
+// path (which exits without spawning). Live pass-through is exercised by the
+// fleet smoke test against the real brain tool.
+
+describe('resolveAgentWatchTool', () => {
+  const saved = process.env['MOSAIC_BRAIN_HOME'];
+  afterEach(() => {
+    if (saved === undefined) delete process.env['MOSAIC_BRAIN_HOME'];
+    else process.env['MOSAIC_BRAIN_HOME'] = saved;
+  });
+
+  it('honors MOSAIC_BRAIN_HOME over the canonical brain', () => {
+    const tmp = mkdtempSync(join(tmpdir(), 'watch-resolve-'));
+    process.env['MOSAIC_BRAIN_HOME'] = tmp;
+    expect(resolveAgentWatchTool('/nonexistent/mosaic-home')).toBe(
+      join(tmp, 'tools', 'agent-watch', 'agent-watch.sh'),
+    );
+  });
+
+  it('resolves inside the brain tools tree', () => {
+    const tmp = mkdtempSync(join(tmpdir(), 'watch-resolve-'));
+    process.env['MOSAIC_BRAIN_HOME'] = tmp;
+    const tool = resolveAgentWatchTool(tmp);
+    expect(tool.endsWith(join('tools', 'agent-watch', 'agent-watch.sh'))).toBe(true);
+  });
+});
+
+describe('exitStatusFor', () => {
+  it('maps absent tool to 127', () => {
+    expect(exitStatusFor({ status: 0 }, false)).toBe(127);
+  });
+
+  it('passes the tool exit status through', () => {
+    expect(exitStatusFor({ status: 2 }, true)).toBe(2);
+    expect(exitStatusFor({ status: 78 }, true)).toBe(78);
+  });
+
+  it('maps signal death / null status to 125', () => {
+    expect(exitStatusFor({ status: null }, true)).toBe(125);
+  });
+});
+
+describe('registerWatchCommand absent-tool path', () => {
+  const saved = process.env['MOSAIC_BRAIN_HOME'];
+  afterEach(() => {
+    if (saved === undefined) delete process.env['MOSAIC_BRAIN_HOME'];
+    else process.env['MOSAIC_BRAIN_HOME'] = saved;
+    process.exitCode = undefined;
+  });
+
+  it('sets exitCode 127 with the resolved path when the tool is missing', async () => {
+    const tmp = mkdtempSync(join(tmpdir(), 'watch-missing-'));
+    // The suite directory exists but the tool file does not.
+    mkdirSync(join(tmp, 'tools', 'agent-watch'), { recursive: true });
+    process.env['MOSAIC_BRAIN_HOME'] = tmp;
+
+    const program = new Command();
+    registerWatchCommand(program);
+    await program.parseAsync(['watch', 'list'], { from: 'user' });
+    expect(process.exitCode).toBe(127);
+  });
+});
diff --git a/packages/mosaic/src/commands/watch.ts b/packages/mosaic/src/commands/watch.ts
new file mode 100644
index 00000000..a507b011
--- /dev/null
+++ b/packages/mosaic/src/commands/watch.ts
@@ -0,0 +1,68 @@
+import type { Command } from 'commander';
+
+import { DEFAULT_MOSAIC_HOME } from '../constants.js';
+import {
+  brainToolExists,
+  execBrainTool,
+  exitStatusFor,
+  resolveBrainTool,
+} from './brain-dispatch.js';
+
+export { exitStatusFor };
+
+/**
+ * `mosaic watch` — dispatch to the brain's agent-watch suite.
+ * See brain-dispatch.ts for the architecture and pass-through contract.
+ */
+export function resolveAgentWatchTool(mosaicHome: string): string {
+  return resolveBrainTool(mosaicHome, 'tools/agent-watch/agent-watch.sh');
+}
+
+export function registerWatchCommand(program: Command): void {
+  const cmd: Command = program
+    .command('watch')
+    .description('Wake-me-when watchers (agent-watch): start, list, stop')
+    // allowUnknownOption + variadic = full ordered pass-through: unknown
+    // options (--name, --when, ...) and their values land in args verbatim
+    // (commander 13 measured behavior), so the tool owns its own flag
+    // surface without the CLI needing passThroughOptions (which would
+    // force enablePositionalOptions fleet-wide on the root program).
+    .allowUnknownOption()
+    // The tool owns help too: without this, commander would intercept
+    // --help and answer with wrapper help instead of agent-watch's own
+    // (codex review of 18f3dd49).
+    .helpOption(false)
+    .argument('[args...]', 'args passed through to agent-watch.sh')
+    .action(async (args: string[], _opts: unknown, command: Command) => {
+      // --mosaic-home is not global in this CLI; walk parents for it and
+      // fall back to the default. MOSAIC_BRAIN_HOME (seat launchers export
+      // it) wins inside resolveBrainHome regardless.
+      let mosaicHome: string | undefined;
+      for (let anc: Command | null = command; anc; anc = anc.parent) {
+        const v = (anc.opts() as Record<string, string | undefined>)['mosaicHome'];
+        if (v !== undefined) {
+          mosaicHome = v;
+          break;
+        }
+      }
+      const home = mosaicHome ?? DEFAULT_MOSAIC_HOME;
+
+      const tool = resolveAgentWatchTool(home);
+      if (!brainToolExists(tool)) {
+        console.error(
+          `mosaic watch: agent-watch not found (expected ${tool}). ` +
+            'The watcher suite lives in the brain tree under tools/agent-watch/; ' +
+            'check MOSAIC_BRAIN_HOME or the brain checkout.',
+        );
+        process.exitCode = 127;
+        return;
+      }
+
+      process.exitCode = execBrainTool(home, 'tools/agent-watch/agent-watch.sh', args);
+    });
+
+  cmd.addHelpText(
+    'after',
+    '\nEverything after `mosaic watch` is passed through to agent-watch.sh verbatim (args, output, exit code).',
+  );
+}