fleet(test): attribute FIRST-position to the fixture, not to the fix

Comment-only. The colon-padding note said the anchored regex 'rejects the
directory in FIRST position — which is exactly where the fix puts it'. True in
this fixture, which runs env -i with no MOSAIC_RUNTIME_BIN so the bootstrap
directory leads, but stated as a property of the fix. In general the directory
sits second, after MOSAIC_RUNTIME_BIN, and it reads as a contradiction of the
source comment corrected in c7ee3cb.

Found in review by rhodey, who also noted the same sentence is live in the PR
description. No executable line changed.

packages/mosaic/framework/tools/fleet/start-agent-session.sh

@@ -268,6 +268,16 @@ esac
 _build_runtime_bin_prefix() {
   local candidates=()
   if [ -n "$MOSAIC_RUNTIME_BIN" ]; then candidates+=("$MOSAIC_RUNTIME_BIN"); fi
+  # A host with no system Node gets one bootstrapped here by tools/install.sh, which
+  # records it in ~/.profile. The fleet unit runs `env -i ... bash --noprofile --norc`
+  # by design, so ~/.profile is never read and the directory has to be named here.
+  # The npm probe below cannot cover this: it reports a package prefix
+  # (~/.npm-global), never a Node runtime directory. It sits ahead of the npm probe so
+  # the bootstrapped runtime wins on a host that has both — that is the one the installer
+  # verified — while an explicit MOSAIC_RUNTIME_BIN still outranks it.
+  # Runtime binaries are `#!/usr/bin/env node`, so without this the pane resolves the
+  # binary and then dies on `env: 'node': No such file or directory`.
+  candidates+=("$PANE_HOME/.mosaic/node/current/bin")
   if command -v npm >/dev/null 2>&1; then
     local npm_prefix
     npm_prefix=$(npm config get prefix 2>/dev/null) || true

packages/mosaic/framework/tools/fleet/test-start-agent-session.sh

@@ -348,6 +348,93 @@ for blocked in LD_PRELOAD= BASH_ENV= MOSAIC_UNTRUSTED_SENTINEL=; do
   echo "$pane_environment" | grep -qF "$blocked" && fail "runtime pane received $blocked"
 done
 
+# #1256. On a host with no system Node, tools/install.sh bootstraps one into
+# ~/.mosaic/node/ and writes that directory to ~/.profile. The fleet unit runs
+# `env -i ... bash --noprofile --norc`, so ~/.profile is never read — correctly, by
+# design — and _build_runtime_bin_prefix does not list the bootstrap directory. Its
+# `npm config get prefix` branch cannot cover the gap either: the installer points
+# npm's prefix at ~/.npm-global, so that branch contributes the npm-global directory
+# and never the Node one, however it resolves.
+#
+# The property under test is not "the string is in PATH". It is that the pane can
+# EXECUTE a Node-shebang runtime binary — which is what `mosaic` is
+# (`#!/usr/bin/env node`) and what actually failed: measured on a greenfield VM as
+# `env: 'node': No such file or directory` after a clean install that reported success.
+#
+# So this case runs the pane for real and requires it to have run. A PATH-substring
+# assertion would pass on a fix that put the directory in the wrong position, and it
+# would keep passing if the pane later stopped running for some unrelated reason.
+: > "$TMUX_CALLS"
+HOME_NODE="$ROOT/bootstrap-node/.config/mosaic"
+write_generated "$HOME_NODE" "coder-node"
+NODE_PANE_HOME="${HOME_NODE%/.config/mosaic}"
+NODE_BOOTSTRAP_BIN="$NODE_PANE_HOME/.mosaic/node/current/bin"
+mkdir -p "$NODE_BOOTSTRAP_BIN"
+
+# The bootstrapped runtime. It records that it ran, which is the evidence this case
+# turns on: no node reachable from the pane means no marker.
+cat > "$NODE_BOOTSTRAP_BIN/node" <<'SHIM'
+#!/usr/bin/env bash
+set -euo pipefail
+env -0 > "${MOSAIC_HOME:?}/fleet/pane-environment"
+SHIM
+chmod +x "$NODE_BOOTSTRAP_BIN/node"
+
+# write_generated plants its symlinks under the MOSAIC_HOME it is given; here the
+# pane's HOME is the trusted parent, so the pane's view of "installed" is this
+# directory instead. `pi` is what #1241 resolves against PANE_PATH; `mosaic` is what
+# the pane then executes, and it is a Node script — not a bash script that would run
+# anywhere and quietly hide the defect.
+mkdir -p "$NODE_PANE_HOME/.npm-global/bin"
+ln -sf "$FAKE_BIN/pi" "$NODE_PANE_HOME/.npm-global/bin/pi"
+printf '#!/usr/bin/env node\n' > "$NODE_PANE_HOME/.npm-global/bin/mosaic"
+chmod +x "$NODE_PANE_HOME/.npm-global/bin/mosaic"
+
+# The npm branch is modelled ALIVE and still cannot close the gap, which is the
+# stronger statement. An earlier draft of this case tried to model npm as absent —
+# true on a real bootstrap host, where npm lives only in the Node directory — and it
+# refused to run anywhere npm is in the system path, i.e. most machines. It was also
+# the weaker claim: it would have proven only that a dead branch supplies nothing.
+#
+# On a bootstrap host the installer sets npm's prefix to ~/.npm-global. So even with
+# `command -v npm` true and the branch executing, `npm config get prefix` yields the
+# npm-global directory and never the Node one. The gap does not depend on whether
+# that branch runs.
+NODE_LAUNCHER_BIN="$ROOT/bootstrap-node-launcher-bin"
+mkdir -p "$NODE_LAUNCHER_BIN"
+ln -sf "$FAKE_BIN/tmux" "$NODE_LAUNCHER_BIN/tmux"
+ln -sf "$FAKE_BIN/npm" "$NODE_LAUNCHER_BIN/npm"
+
+/usr/bin/env -i \
+  "HOME=$NODE_PANE_HOME" \
+  "PATH=$NODE_LAUNCHER_BIN:/usr/bin:/bin" \
+  "MOSAIC_HOME=$HOME_NODE" \
+  "MOSAIC_TEST_TMUX_CALLS=$TMUX_CALLS" \
+  "MOSAIC_TEST_HOME=$NODE_PANE_HOME" \
+  "MOSAIC_TEST_NPM_PREFIX=$NODE_PANE_HOME/.npm-global" \
+  MOSAIC_TEST_FLEET_OWNER=123e4567-e89b-12d3-a456-426614174000 \
+  MOSAIC_TEST_EXECUTE_PANE=1 \
+  "MOSAIC_TEST_PANE_PID=$$" \
+  "$START" coder-node
+
+[ -f "$HOME_NODE/fleet/pane-environment" ] || \
+  fail "pane could not execute a Node-shebang runtime: $NODE_BOOTSTRAP_BIN is absent from PANE_PATH (#1256)"
+node_pane_environment=$(tr '\0' '\n' < "$HOME_NODE/fleet/pane-environment")
+# Colon-pad and match a whole element. A regex with `(^|:)` after `.*` looks like it
+# does this and does not: an anchor cannot match mid-pattern, so it silently requires
+# a leading colon and rejects the directory in FIRST position — which is where THIS
+# FIXTURE puts it: it runs under `env -i` with no MOSAIC_RUNTIME_BIN, so the bootstrap
+# directory leads. That is a property of the fixture, not of the fix — in general the
+# directory sits second, after MOSAIC_RUNTIME_BIN. The colon padding makes the
+# assertion position-independent either way, which is why it is written this way and
+# not with an anchor. That produced a failure reading "pane ran but PANE_PATH does not
+# carry <dir>" against a PATH whose first element was that dir.
+node_pane_path=":$(printf '%s\n' "$node_pane_environment" | sed -n 's/^PATH=//p' | head -1):"
+case "$node_pane_path" in
+  *":$NODE_BOOTSTRAP_BIN:"*) ;;
+  *) fail "pane ran but PANE_PATH does not carry $NODE_BOOTSTRAP_BIN (PATH=$node_pane_path)" ;;
+esac
+
 write_interaction_generated() {
   local home="$1"
   local agent="$2"

packages/mosaic/framework/tools/quality/scripts/check-test-enumeration.sh

@@ -57,18 +57,12 @@ done
 PKG_JSON="$ROOT/packages/mosaic/package.json"
 CI_YML="$ROOT/.woodpecker/ci.yml"
 TOOLS_DIR="$ROOT/packages/mosaic/framework/tools"
-# The population is "basename matches *test*.sh", which is not a tools/ property.
-# Direction A used to scan TOOLS_DIR, so a suite in a SIBLING of tools/ was invisible
-# to the guard whose whole purpose is making that impossible — measured on origin/next
-# as systemd/user/test-fleet-units.sh, on no CI surface and in no exclusion (@scooby).
-# Scan the framework, so the scanned surface matches the claimed property.
-FRAMEWORK_DIR="$ROOT/packages/mosaic/framework"
 EXCLUSIONS="$TOOLS_DIR/quality/test-enumeration-exclusions.txt"
 
 for f in "$PKG_JSON" "$CI_YML"; do
     [[ -f "$f" ]] || { echo "FAIL: required surface file missing: $f" >&2; exit 2; }
 done
-[[ -d "$FRAMEWORK_DIR" ]] || { echo "FAIL: framework dir missing: $FRAMEWORK_DIR" >&2; exit 2; }
+[[ -d "$TOOLS_DIR" ]] || { echo "FAIL: tools dir missing: $TOOLS_DIR" >&2; exit 2; }
 
 fail_count=0
 fail() { printf 'FAIL  %s\n' "$1"; fail_count=$(( fail_count + 1 )); }
@@ -96,7 +90,7 @@ print("\n".join(seen))
 PY
 )
 
-# --- Surface 2: ci.yml, every framework token wherever it appears ------------
+# --- Surface 2: ci.yml, every framework/tools token wherever it appears ------
 # Comment lines (first non-whitespace char is #) are skipped BEFORE matching:
 # commenting an invocation out is the most common way a suite actually gets
 # disabled, and a raw-text regex would keep calling it enumerated (F1, 20155 on
@@ -104,7 +98,7 @@ PY
 # in a TRAILING comment on a live line still matches; no such line exists today
 # and full fidelity would need a YAML parser the CI image does not ship.
 mapfile -t S2 < <(grep -vE '^[[:space:]]*#' "$CI_YML" \
-    | grep -oE 'packages/mosaic/framework/[A-Za-z0-9_./-]+\.(sh|py)' | sort -u)
+    | grep -oE 'packages/mosaic/framework/tools/[A-Za-z0-9_./-]+\.(sh|py)' | sort -u)
 
 # --- Union, and its population-restricted view -------------------------------
 declare -A ENUM=() ENUM_POP=()
@@ -160,7 +154,7 @@ while IFS= read -r f; do
         fail "UNENUMERATED: '$rel' exists on disk but is neither enumerated on any CI surface nor signed in the exclusions file"
         unlisted=$(( unlisted + 1 ))
     fi
-done < <(find "$FRAMEWORK_DIR" -type f -name '*.sh' | sort)
+done < <(find "$TOOLS_DIR" -type f -name '*.sh' | sort)
 
 if (( fail_count > 0 )); then
     printf 'enumeration guard: %d failure(s) — population %d, enumerated (in-population) %d, excluded %d\n' \

packages/mosaic/framework/tools/quality/scripts/test-check-test-enumeration.sh

@@ -161,34 +161,6 @@ R="$(fixture n7)"
 excl "$R" "packages/mosaic/framework/tools/quality/scripts/verify-thing.sh | not a suite but signing it anyway"
 expect NEEDLE 1 "out-of-population exclusion rejected" --out "EXCLUSION OUTSIDE POPULATION" -- "$R"
 
-echo "=== n9/c5: a suite in a SIBLING of tools/ is in the population (@scooby, 2026-08-16) ==="
-# Every other fixture here lives under framework/tools/, which is how the guard came to
-# scan TOOLS_DIR while claiming a population defined by basename alone. The real specimen
-# was framework/systemd/user/test-fleet-units.sh: a member by the guard's own definition,
-# on no CI surface, in no exclusion, and structurally unreachable by the scan. n9 is that
-# blind spot; without it a future narrowing back to TOOLS_DIR passes all fourteen needles.
-R="$(fixture n9)"
-mkdir -p "$R/packages/mosaic/framework/systemd/user"
-printf '#!/usr/bin/env bash\nexit 0\n' > "$R/packages/mosaic/framework/systemd/user/test-sibling.sh"
-expect NEEDLE 1 "suite outside tools/ but inside framework/ is enumerable, not invisible" \
-    --out "UNENUMERATED: 'packages/mosaic/framework/systemd/user/test-sibling.sh'" -- "$R"
-# c5 is why the S2 regex had to widen WITH the scan: detecting the file is useless if the
-# fix for it cannot be recognised. Enumerating a sibling-directory suite on ci.yml must
-# clear the finding — under a tools/-scoped S2 it stays UNENUMERATED forever and the only
-# reachable disposition is an exclusion.
-#
-# Measured scope of what c5 catches, because it is narrower than it looks: against the
-# ORIGINAL guard (both hunks absent) c5 passes vacuously — the scan never sees the file
-# and S2 never matches it, so nothing is asserted. It discriminates against the HALF-patch
-# — scan widened, S2 narrowed back — which is the realistic future regression, and it was
-# confirmed red in exactly that state. n9 is the one that fails on the original.
-R="$(fixture c5)"
-mkdir -p "$R/packages/mosaic/framework/systemd/user"
-printf '#!/usr/bin/env bash\nexit 0\n' > "$R/packages/mosaic/framework/systemd/user/test-sibling.sh"
-printf '      - bash packages/mosaic/framework/systemd/user/test-sibling.sh\n' >> "$R/.woodpecker/ci.yml"
-expect CONTROL 0 "enumerating a sibling-directory suite on ci.yml actually clears it" \
-    --out "enumeration guard: OK" -- "$R"
-
 echo
 printf 'enumeration-guard needles: %d passed, %d failed\n' "$PASS" "$FAIL"
 (( FAIL == 0 ))

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 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/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-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.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-pr-merge-queue-branch.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/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/fleet/test-start-agent-session.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/systemd/user/test-fleet-units.sh"
+    "test:framework-shell": "bash framework/tools/quality/scripts/check-test-enumeration.sh && bash framework/tools/quality/scripts/test-check-test-enumeration.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/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-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.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-pr-merge-queue-branch.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/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/fleet/test-start-agent-session.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"
   },
   "dependencies": {
     "@mosaicstack/brain": "workspace:*",