diff --git a/packages/mosaic/framework/tools/git/issue-close.sh b/packages/mosaic/framework/tools/git/issue-close.sh
index 05788e6d..3d014a59 100755
--- a/packages/mosaic/framework/tools/git/issue-close.sh
+++ b/packages/mosaic/framework/tools/git/issue-close.sh
@@ -91,13 +91,18 @@ elif [[ "$PLATFORM" == "gitea" ]]; then
     GITEA_LOGIN_NAME=$(get_gitea_login || true)
     if [[ -n "$GITEA_LOGIN_NAME" ]]; then
         if [[ -n "$COMMENT" ]]; then
-            # `tea issue comment` is NOT a subcommand (tea 0.11.x lists only
-            # list/create/edit/reopen/close); comments are the top-level `tea comment`.
-            # The call therefore always failed, was unchecked, and the script proceeded
-            # to close the issue anyway -- losing the record of WHY it was closed.
-            # Route through the authenticated API helper: it is login-independent and is
-            # already the mechanism used by the no-login branch below.
-            gitea_issue_comment_api || {
+            # `tea issue comment` is NOT a subcommand -- tea 0.11.x lists only
+            # list/create/edit/reopen/close under `tea issue`. Comments are the
+            # TOP-LEVEL `tea comment`, which takes the same --repo/--login flags.
+            # The old call therefore always failed, was unchecked, and the script
+            # closed the issue anyway, losing the record of WHY.
+            #
+            # Use `tea comment` rather than the API helper so the comment and the
+            # close are made by the SAME principal ($GITEA_LOGIN_NAME). Routing the
+            # comment through the token-authenticated helper here would attribute the
+            # comment to the token holder and the close to the tea login -- two
+            # principals for one operation.
+            tea comment "$ISSUE_NUMBER" "$COMMENT" --repo "$OWNER/$REPO" --login "$GITEA_LOGIN_NAME" || {
                 echo "Error: failed to post comment on #$ISSUE_NUMBER -- NOT closing (fail closed)." >&2
                 exit 1
             }
diff --git a/packages/mosaic/framework/tools/git/test-issue-close-fail-closed.sh b/packages/mosaic/framework/tools/git/test-issue-close-fail-closed.sh
new file mode 100755
index 00000000..44f190f0
--- /dev/null
+++ b/packages/mosaic/framework/tools/git/test-issue-close-fail-closed.sh
@@ -0,0 +1,79 @@
+#!/usr/bin/env bash
+# Regression: issue-close.sh must NOT close an issue when the closing comment
+# could not be posted, and comment+close must be made by ONE principal.
+#
+# Guards two defects fixed together (see #1081):
+#   1. `tea issue comment` is not a subcommand -- tea exposes comments as the
+#      TOP-LEVEL `tea comment`. The old call always failed, was unchecked, and
+#      the issue closed anyway, losing the record of WHY it was closed.
+#   2. Routing the comment through the token-authenticated API helper while the
+#      close used --login would attribute one operation to two principals.
+#
+# Fully offline: `tea` and `curl` are mocked onto PATH, the repo is a throwaway
+# `git init`, everything lives under $SANDBOX, removed on EXIT.
+set -uo pipefail
+
+WORK_ROOT="${AGENT_WORK_ROOT:-${TMPDIR:-/tmp}}"
+SANDBOX="$WORK_ROOT/issue-close-fail-closed-test-$$"
+MOCK_BIN="$SANDBOX/bin"; REPO_DIR="$SANDBOX/repo"; CALLS="$SANDBOX/calls.log"
+cleanup() { rm -rf "$SANDBOX"; }
+trap cleanup EXIT
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+TARGET="$SCRIPT_DIR/issue-close.sh"
+[ -f "$TARGET" ] || { echo "FAIL: issue-close.sh not found beside this test"; exit 1; }
+fail() { echo "FAIL: $*"; exit 1; }
+
+mkdir -p "$MOCK_BIN" "$REPO_DIR"; : > "$CALLS"
+cd "$REPO_DIR"; git init -q
+git remote add origin https://git.mosaicstack.dev/mosaicstack/stack.git
+export PATH="$MOCK_BIN:$PATH" CALLS
+export GITEA_LOGIN="git.mosaicstack.dev"
+export GITEA_URL="https://git.mosaicstack.dev"
+export GITEA_TOKEN="redacted-test-token"
+
+cat > "$MOCK_BIN/curl" <<'EOF'
+#!/bin/bash
+printf 'curl %q ' "$@" >> "$CALLS"; printf '\n' >> "$CALLS"; exit 0
+EOF
+chmod +x "$MOCK_BIN/curl"
+
+mk_tea() {  # $1 = exit code for `tea comment`
+  cat > "$MOCK_BIN/tea" <<EOF
+#!/bin/bash
+printf 'tea %s\n' "\$*" >> "$CALLS"
+if [[ "\$*" == *"login list"* ]]; then
+    echo '[{"name":"git.mosaicstack.dev","url":"https://git.mosaicstack.dev"}]'; exit 0
+fi
+# Fail ANY comment attempt -- both the correct top-level \`tea comment\` and the
+# broken \`tea issue comment\` -- so the test exercises the DEFECT on an unfixed
+# script rather than failing on a setup assertion.
+if [[ "\$1" == "comment" || ( "\$1" == "issue" && "\$2" == "comment" ) ]]; then exit $1; fi
+exit 0
+EOF
+  chmod +x "$MOCK_BIN/tea"
+}
+
+# ── 1. NEGATIVE (the regression): comment fails => must NOT close, must exit non-zero
+mk_tea 1; : > "$CALLS"
+bash "$TARGET" -i 42 -c "closing note" >/dev/null 2>&1; rc=$?
+grep -qE 'tea (issue )?comment' "$CALLS" || fail "no comment attempt at all -- setup did not reach the tea branch"
+grep -q 'tea issue close' "$CALLS" && fail "ISSUE CLOSED AFTER THE COMMENT FAILED -- the regression"
+[ "$rc" -ne 0 ] || fail "comment failed but issue-close exited 0 -- FAIL-OPEN"
+
+# ── 2. POSITIVE (rule MET must pass): comment succeeds => close proceeds, exit 0
+mk_tea 0; : > "$CALLS"
+bash "$TARGET" -i 42 -c "closing note" >/dev/null 2>&1; rc=$?
+[ "$rc" -eq 0 ] || fail "comment succeeded but issue-close exited $rc"
+grep -q 'tea issue close' "$CALLS" || fail "issue not closed even though the comment succeeded"
+
+# ── 3. must use top-level `tea comment`, never `tea issue comment`
+grep -q 'tea issue comment' "$CALLS" && fail "used 'tea issue comment' -- not a valid subcommand"
+
+# ── 4. ONE PRINCIPAL: comment and close must carry the SAME --login
+c=$(grep -m1 '^tea comment'    "$CALLS" | grep -o -- '--login [^ ]*' | awk '{print $2}')
+k=$(grep -m1 '^tea issue close' "$CALLS" | grep -o -- '--login [^ ]*' | awk '{print $2}')
+[ -n "$c" ] || fail "comment carried no --login"
+[ "$c" = "$k" ] || fail "MIXED PRINCIPALS: comment=$c close=$k"
+
+echo "issue-close.sh fail-closed + single-principal regression passed"