Diagnose Cloud Run deployment failures for Your Project (and any python-on-Cloud-Run service). Also load for RUNTIME failures when the deployed revision is serving and `/health` returns 200 but the user-facing feature is broken — the proxy may be masquerading the upstream provider (e.g. `Cerebras API error: 402` returning OpenRouter's billing wedge). See `references/2026-07-30-proxy-provider-masquerade-402.md` for the recipe. v2.5.0 (2026-07-24) refines the auth-cookie-TTL sibling class — the original v1.0 hypothesis (cookie TTL is the problem; add `max_age` to the proxy) was wrong for the actual iOS symptom; the real root cause is iOS WebKit localStorage eviction of the Firebase Auth persisted user record. See `references/auth-cookie-ttl-class-2026-07-24.md` v1.1.0 and Pitfall #15.
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Diagnose Cloud Run deployment failures for Your Project (and any python-on-Cloud-Run service). Also load for RUNTIME failures when the deployed revision is serving and `/health` returns 200 but the user-facing feature is broken — the proxy may be masquerading the upstream provider (e.g. `Cerebras API error: 402` returning OpenRouter's billing wedge). See `references/2026-07-30-proxy-provider-masquerade-402.md` for the recipe. v2.5.0 (2026-07-24) refines the auth-cookie-TTL sibling class — the original v1.0 hypothesis (cookie TTL is the problem; add `max_age` to the proxy) was wrong for the actual iOS symptom; the real root cause is iOS WebKit localStorage eviction of the Firebase Auth persisted user record. See `references/auth-cookie-ttl-class-2026-07-24.md` v1.1.0 and Pitfall #15.
Load first when ANY of these fire in the $GITHUB_REPOSITORY repo (or any python-on-Cloud-Run project with a similar shape):
Email: "❌ FAILED: dev Deployment - mvp-site-app-dev" sent via the send-deploy-notification action (dawidd6/action-send-mail).
Auto-Deploy Dev workflow (or any Cloud Run deploy workflow) shows a red gcloud step with output like:
ERROR: (gcloud.run.deploy) The user-provided container failed to start
and listen on the port defined provided by the PORT=8080 environment variable
within the allocated timeout.
New Cloud Run revision shows Ready=False and 0% traffic in gcloud run services describe <service>.
gh pr checks shows the deploy step failed but earlier steps (build, push) passed.
User reports "the deploy says it succeeded but the service is broken" — the visible green hides the real failure.
User reports "I have to log in again after a day or two" / "the cookie expires too soon" / "session doesn't last" on the deployed Cloud Run URL — auth-cookie-TTL class (sibling to deploy failures; same GCP project, same client_diag log surface, different fix surface). The v1.0 hypothesis (cookie TTL is the failure mode; add max_age to the proxy) is WRONG for the actual symptom on iOS — see references/auth-cookie-ttl-class-2026-07-24.md v1.1.0. The real root cause is iOS WebKit localStorage eviction of the Firebase Auth persisted user record; the right fix is server-side session restore from the __session cookie + silent client re-bootstrap, NOT a cookie TTL override.
User reports "the app shows <provider-X> API error: 402 but the key should be fine" / "the deploy is green but the chat is broken" / "the spinner just shows <provider-X> error for every model" — proxy-chain provider-masquerade class (the runtime sibling). The deployed revision is serving, /health returns 200, but the proxy upstream is denying calls. The displayed provider name in the UI may NOT match the actual upstream the proxy hits. See references/2026-07-30-proxy-provider-masquerade-402.md for the recipe (SPA-bundle inspection + curl repro + gcloud run services describe + secret fingerprint cross-reference).
PRECOMPUTE_FAILED in the deploy step BEFORE gcloud is called — pip install in setup-precompute-deps succeeded (log shows Successfully installed ... fastembed-0.8.0 ...) but deploy.sh's interpreter probe can't find the interpreter on a self-hosted Mac runner. The deploy step exits 1 at the probe, the failure-email step fires, but gcloud run deploy never ran. The fix surface is the composite action's VPYTHON env-export, NOT the deploy script's revision log. See Mode 7 below.
The Iron Law of Cloud Run deploy debugging
THE BUILD/IMAGE IS NOT THE DEPLOY.
THE REVISION STARTUP LOGS ARE.
gcloud builds submit exiting 0 only proves the image built and pushed. Cloud Run then pulls that image, creates a NEW revision, runs its CMD, and starts probing TCP port 8080 — ANY of those four steps can fail independently of the build. The Auto-Deploy workflow only checks the gcloud exit code; a deployment that quietly rolls back the failed revision still counts as "Auto-Deploy Dev ✅" on the commit. Operators reading PR status see green and stop. The failure ships to production quietly the next time someone redeploys from this base.
The Iron Law 2 — the script-level probe (added 2026-07-13, PR #8380)
THE PIP INSTALL CAN SUCCEED WHILE THE DEPLOY SCRIPT PROBE FAILS.
THE COMPOSITE ACTION'S ENV-EXPORT IS THE BRIDGE.
The setup-precompute-deps action runs actions/setup-python@v5.0.0 then pip install fastembed numpy google-cloud-storage jsonschema pydantic cachetools. The pip install succeeds (Successfully installed ... fastembed-0.8.0 ... in the GH Actions log). But on a self-hosted Mac runner, the interpreter lands in the GitHub-Actions-hosted toolcache ($RUNNER_TOOL_CACHE/python/3.11.x/bin/python) — NOT on $PATH and NOT named python3 (system Python). deploy.sh's interpreter probe iterates ${VPYTHON:-} ./vpython vpython python3 and finds none of those candidates point at the just-installed interpreter. The probe exits 1 at deploy.sh:466 BEFORE gcloud run deploy is invoked. The failure-email step fires. The deploy job looks like a hard failure but the image build still succeeded and earlier sibling runs may have actually deployed the same commit to dev — the recurring email is masking the fact that the user's PR likely DID ship.
The bridge: composite actions that install runtime dependencies MUST export an env var pointing at the interpreter they just installed (e.g. echo "VPYTHON=$pythonPath" >> $GITHUB_ENV) AND prepend the interpreter's bin dir to $GITHUB_PATH. deploy.sh then reads the env var as an absolute path ([ -x "${VPYTHON}" ], not command -v) — the absolute path check is the load-bearing part because the toolcache path may not be on $PATH at the point the deploy step runs.
Diagnosing Iron Law 2 vs Iron Law 1:
Question
Iron Law 1 (revision start)
Iron Law 2 (script probe)
Where does it fail?
gcloud run deploy step, Cloud Run revision logs
deploy.sh step, before gcloud run deploy runs
What's the symptom?
latestCreatedRevisionName != latestReadyRevisionName OR revision logs show can't open, SIGKILL, ModuleNotFoundError
Deploy step exit code 1 with PRECOMPUTE_FAILED: in stdout; no new revision created since the failure
Is the old revision still serving?
Yes (old revision serves until new one is Ready)
Yes (no new revision was attempted)
Does the user's PR show up on the live service?
Possibly — depends on whether a sibling deploy succeeded
Probably yes — sibling deploys in the same push window may have shipped it; verify with gcloud run services describe + commit-sha-full label
TypeError: Metaclasses with custom tp_new are not supported. in google._upb._message during firebase_admin → google.cloud.firestore import chain
Pin protobuf>=5.27.0 in requirements.txt, OR use python:3.11-slim/python:3.12-slim base instead of Chainguard :latest-dev
7
Script-level probe failure (PRECOMPUTE_FAILED family — pre-gcloud) — composite action installs deps but never exports the interpreter path; downstream deploy.sh probe can't find fastembed/numpy/jsonschema in any of its candidate interpreters; deploy exits 1 BEFORE gcloud run deploy. Verified 2026-07-13 PR #8380 v1
Deploy step stdout shows PRECOMPUTE_FAILED: no interpreter with fastembed+numpy+google-cloud-storage+mvp_site.agent_prompts found; aborting deploy; pip install in the action step earlier in the same job succeeded (look for Successfully installed ... jsonschema-X.X.X ... fastembed-X.X.X ...)
Composite action MUST write echo "VPYTHON=$pythonPath" >> $GITHUB_ENV AND echo "$binDir" >> $GITHUB_PATH so deploy.sh's ${VPYTHON:-} candidate resolves. deploy.sh MUST read VPYTHON as an absolute path ([ -x "${VPYTHON}" ], not command -v).
8
Over-strict probe (PRECOMPUTE_FAILED v2 — post-#8380) — composite action exports VPYTHON + the install puts fastembed into a clean toolcache Python, but the probe in deploy.sh (and the action's probe-precompute step) checks import mvp_site.agent_prompts which transitively pulls in flask/fpdf2/etc. — deps the action does NOT install. Probe always fails even when the install succeeded. Verified 2026-07-13 PR #8381 (run 29292726556) → fixed by PR #8381
Deploy step stdout shows WARNING: VPYTHON='/home/runner/_work/_tool/Python/3.11.15/x64/bin/python' set but failed import probe — falling through to PATH lookup followed by PRECOMPUTE_FAILED; pip install in the earlier action step already succeeded. The action's precompute-ready=false is emitted but does NOT block the deploy (deploy.sh runs its own probe).
Three-step diagnostic: (a) confirm the action's install-depspip install completed successfully (look for Successfully installed ... fastembed-0.8.0 ...); (b) confirm VPYTHON IS set in the env dump of the deploy step (VPYTHON: /home/runner/_work/_tool/Python/3.11.x/<arch>/bin/python); (c) trace the import chain failure: if VPYTHON -c 'import fastembed, ...' succeeds but import mvp_site.X fails, the chain has a transitive dep the action didn't install. Fix: (i) pip install flask (or whichever transitive dep the chain needs) in install-deps; (ii) reduce the probe to ONLY the deps the install step actually pip-installs (NO import mvp_site.X in the probe — let the script surface transitive-dep failures as a clear ModuleNotFoundError at runtime); (iii) verify with a local repro venv: python3 -m venv /tmp/repro && /tmp/repro/bin/pip install <dep-list> && /tmp/repro/bin/python scripts/precompute_prompt_embeddings.py --help must exit 0 before merging. See Pitfall #14.
9
Silent breaking-major-version bumper on unbounded pip pin — requirements.txt pins e.g. mcp>=1.0.0, the upstream package publishes a new major (e.g. mcp 2.0.0) that removes public API surface still decorated in app code (@server.list_tools(), @server.call_tool()), the image builds cleanly, the revision is created and reported Ready, BUT every gunicorn worker immediately crashes at module-import time with AttributeError: 'Server' object has no attribute 'list_tools'. The revision is "Ready" because gunicorn master binds :8080; it's just serving a worker death-restart loop. Cloud Run's proxy returns 503 to every request. Prod is unaffected because its image predates the upstream major release. Verified 2026-07-28 mcp 2.0.0 release / PR #8657 (pin mcp>=1.0.0,<2.0.0).
curl <service>/health returns HTTP 503 with body Service Unavailable; gcloud run services describe shows latestReadyRevisionName == latestCreatedRevisionName (i.e. the revision IS Ready — disambiguates from Mode 1-6 startup failures); gcloud logging read resource.type=cloud_run_revision ... severity>=ERROR shows a recurring worker-loop: Booting worker with pid: N → Worker (pid:N) exited with code 3 → Shutting down: Master → Reason: Worker failed to boot. every ~10s; the traceback terminates at the app's first use of the removed API (e.g. $PROJECT_ROOT/mcp_api.py:69 @server.list_tools()).
Five-step fix recipe (the "mcp-style silent-major-bump" recipe): (a) python3 -m venv /tmp/probe && /tmp/probe/bin/pip install '<package>==<current-used-version>' and reproduce the missing-attribute error in 3 lines; (b) pip index versions <package> to see the latest; (c) repeat the probe with the latest published version to confirm the API surface was removed/replaced (e.g. mcp 2.0.0); (d) check the app's decorators/imports against the broken surface (`grep -rnE '@server\.(list_tools
10
Runtime proxy-chain provider-masquerade (sibling class — added 2026-07-30, verified on consensus-ml.ai → ai-universe-consulting-v2 in worldarchitecture-ai). The deployed revision is serving, /health returns 200, but the user-facing feature is broken with <UI-label> API error: 402 style messages from the proxy. The displayed provider name in the UI may NOT match the actual upstream the proxy hits. The proxy re-emits the upstream's raw error body to the browser unchanged; the browser wraps it with the UI-side model label. Verified on consensus-ml.ai: the SPA bundle contained zero outbound fetches to any LLM provider (only /_log and /api/contact), the Cloud Run revision logs showed clean startup with POST /v1/chat/completions 200 1700 style access lines, but the response body returned OpenRouter's {"code":402,"metadata":{"limit_source":"openrouter_credits"}} payload which the SPA re-rendered as Cerebras API failed: Cerebras API error: 402.
Cloud Run revision logs show clean startup + standard access lines for POST /v1/chat/completions; NO upstream stack traces in the log stream (the error lives in the response body, not the log stream). The gcloud run services describe label commit-sha-full matches the latest deploy; /health returns 200. The 402 / 5xx only appears when hitting the LLM endpoint with the same body the browser sends.
Five-step recipe: (a) curl -fsS https://<site>/assets/index-*.js | grep -aoE 'fetch\\([^)]{0,300}\\)' | sort -u — if no provider hostname appears inside any fetch(...), the LLM call is server-side; (b) gcloud run services list --project=<each-project> to find the backend serving the public URL; (c) curl -X POST https://<site>/v1/chat/completions -d '{"model":"<displayed-model-name>","messages":[…]}' to reproduce the upstream's actual error body; (d) probe each candidate key against the real upstream with the displayed model name — a 404 on qwen-3-235b-a22b-instruct-2507 doesn't mean the key is dead, it means that model isn't available on that key. The 4 keys the user provided all worked for gpt-oss-120b / gemma-4-31b / zai-glm-4.7 but ALL returned {"code":"model_not_found"} for the displayed qwen-3-235b-a22b-instruct-2507. (A) top up the OpenRouter account that owns the stored key (smallest, fastest — is in the error body itself); (B) repoint the proxy to direct Cerebras / another provider — requires editing the deployed image and shipping a new revision. Full recipe, worked transcript, and the 4-key probe matrix in .
Mode 1a and 1b are the SAME root cause broken in two distinct ways. A bare CMD ["gunicorn", ...] fails immediately because Docker prepends python and tries to open gunicorn as a file. The "obvious" fix — CMD ["python", "-m", "gunicorn", ...] — ALSO fails because Docker still prepends the inherited python entrypoint, giving python python -m gunicorn ..., and Python tries to open the first arg python as a script file. The only correct fix is ENTRYPOINT [] + CMD ["python", "-m", ...]. See references/2026-07-06-entrypoint-override-mandatory.md.
The Phase 1 loop (run these in order; don't skip)
Step 1 — Find the failing revision name
gh api "repos/$GITHUB_REPOSITORY/actions/runs/<RUN_ID>/jobs" \
--jq '.jobs[] | select(.conclusion=="failure") | "\(.name) | \(.id)"'# Note: <RUN_ID> = the `Auto-Deploy Dev` run from the email body or# gh run list --workflow="Auto-Deploy Dev" --limit=1
The failing job's log URL is in the email and gh run view <id> --web.
Step 2 — Pull the revision logs (not the build logs)
gcloud logging read \
'resource.type=cloud_run_revision
AND resource.labels.service_name=mvp-site-app-dev
AND timestamp>="<30 min before failure>Z"
AND timestamp<="<30 min after failure>Z"' \
--project=worldarchitecture-ai \
--limit=100 \
--format=json
The build log (in deploy / deploy job output) shows the IMAGE BUILD succeeded. The REVISION LOGS (in Cloud Logging, queried above) show the actual container start failure. Most operators stop at the build log. Don't.
Step 3 — Sanity-check "what does the current prod run?"
gcloud run services describe mvp-site-app-stable \
--region=us-central1 --project=worldarchitecture-ai --format=json
If prod was last deployed BEFORE the breaking change, prod still runs the old image and is not the regression source — dev failed only because it recently redeployed from the same base. This is what happened 2026-07-05: prod's revision was 2026-06-28, base swap was 2026-07-02, dev failed every push since.
Step 4 — Find the Dockerfile base + diff the base change
git log --oneline -10 -- $PROJECT_ROOT/Dockerfile
# Then read the commit that last touched $PROJECT_ROOT/Dockerfile
git show <SHA> --stat
Look for FROM ... python ... line. Chainguard's :latest-dev has ENTRYPOINT=["python"] (verified). python:3.11-slim does NOT have any ENTRYPOINT.
Step 5 — Verify the fix locally
# Reproduce the EXACT CMD the Dockerfile ships:
docker build -t wa-debug -f $PROJECT_ROOT/Dockerfile .
docker run --rm -p 8093:8080 -e PORT=8080 -e TESTING_AUTH_BYPASS=true wa-debug
# OR without docker (works in the repo venv):cd mvp_site && python -m gunicorn -c gunicorn.conf.py main:create_app() \
--bind 127.0.0.1:8093 --workers 1 --preload
# Then:
curl http://127.0.0.1:8093/health
# Expected: HTTP 200, body JSON {"status":"healthy","service":"worldarchitect-ai",...}
The macOS fork+objc gotcha:--preload is local-mac-only. Production Linux / Cloud Run doesn't see the objc[pid]: +[NSMutableString initialize] may have been in progress in another thread when fork() crash; the production gunicorn.conf.py defaults (gthread, no --preload) are unchanged. Use --preload for the smoke test ONLY on macOS; document the reason in the PR.
Step 5.5 — Sanity-check "is the deploy actually live despite the failure?" (added 2026-07-13)
This step applies whenever the failing job's exit code masks the live deploy state — especially Mode 7 (PRECOMPUTE_FAILED, the deploy step exits 1 BEFORE gcloud run deploy is invoked) and any sibling-run-cancellation case (Pitfall 10). The recurring failure email is alarming but the user's PR may have shipped hours ago.
# 1. What's the latest revision actually serving?
gcloud run services describe mvp-site-app-dev \
--region=us-central1 --project=worldarchitecture-ai \
--format='value(status.latestReadyRevisionName, status.latestCreatedRevisionName, metadata.labels.commit-sha-full)'# Expected interpretation:# - latestReadyRevisionName == latestCreatedRevisionName AND# commit-sha-full == <PR_HEAD_SHA>: the PR is live and healthy# - latestReadyRevisionName != latestCreatedRevisionName: a NEW revision was# attempted but isn't ready (Mode 1-6 territory — pull revision logs)# - commit-sha-full != <PR_HEAD_SHA>: the live revision is from a PRIOR deploy;# the failing run failed before it could deploy anything new# 2. Is /health returning 200 from the live revision?
URL=$(gcloud run services describe mvp-site-app-dev \
--region=us-central1 --project=worldarchitecture-ai \
--format='value(status.url)')
curl -fsS "${URL}/health"# Expected: HTTP 200, body JSON {"status":"healthy","service":"worldarchitect-ai",...}# 3. (Optional) What time was the current revision created?
gcloud run revisions describe <latestReadyRevisionName> \
--region=us-central1 --project=worldarchitecture-ai \
--format='value(metadata.creationTimestamp)'
Decision matrix:
Live state vs PR HEAD
Action
Live revision == PR HEAD AND /health returns 200
Tell the user "your PR is live and healthy — the failing deploy step is a CI infra issue, not your PR's fault." Diagnose the CI infra failure separately (Mode 7 territory).
Live revision == PR HEAD AND /health returns 5xx
Mode 1-6 territory. Pull the revision logs from the current revision (Step 2, but point at the LIVE revision not the failing one).
Live revision != PR HEAD
The failing run actually did try to deploy. Compare timestamps to determine whether the live revision was deployed by an earlier sibling run or by an earlier successful push.
No new revision since PR HEAD timestamp
The failing run never reached gcloud run deploy (Mode 7 or Pitfall 10). The user's PR code may still be live via an earlier deploy — verify with #1.
Verified recipe for PR #8380 / cc7ec0a:latestReadyRevisionName == latestCreatedRevisionName == mvp-site-app-dev-03841-ftq, commit-sha-full=cc7ec0a06a47ddfa497dc2af1ee1b1677b0efe96, /health returns 200 → the user's PR #8337 shipped via a sibling run at 20:00:18 UTC; the 20:00:20 run failed at Mode 7 (PRECOMPUTE_FAILED) and the failure-email step fired. The right user-facing answer was "your PR is fine, this is a CI infra bug" — NOT "we need to roll back."
The Phase 2 fix recipe (for ENTRYPOINT/CMD mismatches)
Why ENTRYPOINT [] AND not just CMD ["python", "-m", ...]:
Docker's exec form runs <ENTRYPOINT> <CMD-as-args>. If the parent image sets ENTRYPOINT=["python"] (Chainguard cgr.dev/chainguard/python:latest-dev does), then:
Dockerfile
What runs in container
Result
CMD ["gunicorn", ...]
python /app/$PROJECT_ROOT/gunicorn
can't open file '/app/$PROJECT_ROOT/gunicorn'
CMD ["python", "-m", "gunicorn", ...]
python python -m gunicorn ...
can't open file '/app/$PROJECT_ROOT/python' (the first arg is interpreted as a script, not as -m's module)
ENTRYPOINT [] + CMD ["python", "-m", ...]
python -m gunicorn ...
✅ gunicorn module found via Python's import system, listens on PORT=8080
The "obvious" fix in the row 2 — CMD ["python", "-m", ...] without ENTRYPOINT override — DOES NOT WORK. This was the trap that PR #8180 (this session's first attempt) fell into. The advisor who reviewed v1 missed the ENTRYPOINT detail. Only the Phase 1 revision-log inspection AFTER merge revealed the same-family failure with a different can't open file path. Always set ENTRYPOINT [] first, THEN exec-form CMD.
Why this works in the third row:ENTRYPOINT [] clears the inherited entrypoint, so the exec-form CMD runs as written. python -m gunicorn resolves the module via Python's import system — no $PATH lookup, no /app/$PROJECT_ROOT/<tool> file interpretation. Portable across python:3.11-slim (no ENTRYPOINT — the [] is a no-op there), Chainguard, distroless, and any future base.
Shell form as alternative (NOT preferred):CMD python -m gunicorn ... (no JSON list) also works because shell-form CMD bypasses the ENTRYPOINT wrap. But shell form loses PID 1 signal handling that some bases rely on. Stick with ENTRYPOINT [] + CMD ["exec-form", ...].
Generalize: Any time a Dockerfile CMD references a tool, ask "what ENTRYPOINT does the parent image set?" If the answer is "python" (Chainguard, many minimal bases), BOTH CMD ["tool", ...] AND CMD ["python", "-m", ...] break — only ENTRYPOINT [] + CMD ["python", "-m", ...] survives. The fix surface is one line longer than the obvious fix. Don't stop at the obvious fix; ship the override.
The Phase 2 fix recipe for Mode 7 v2 (composite-action env-export + install/probe scope match, verified PR #8381)
This is the contract that makes the "install then probe" pattern work. A composite action that installs Python deps in step N must produce an env var pointing at the interpreter it just installed, AND its install list must include every dep the downstream probe will check; the deploy step in step N+1 must consume that env var as an absolute path.
The scope-match invariant (added 2026-07-14, after PR #8380 v1 shipped an over-strict probe): the probe MUST import ONLY what the install step actually pip-installs. If the probe adds import mvp_site.X and X's transitive chain pulls in flask/fpdf2/etc., the probe ALWAYS fails even on a healthy install — because the toolcache venv will never have those transitive deps. The actual mvp_site.X import happens inside the precompute script itself at runtime, where cwd-based path injection finds the source tree and surfaces a clear ModuleNotFoundError: No module named '<transitive-dep>' if anything is missing. Verified by PR #8381 run 29294984874 (success) — the toolcache Python now has flask installed (added to the action's pip install list), the probe checks only the 7 deps the action installs, the precompute script imports mvp_site.agent_prompts successfully at runtime via cwd-based path injection, no PRECOMPUTE_FAILED anywhere in the log.
Composite action side (.github/actions/setup-precompute-deps/action.yml):
runs:using:'composite'steps:-name:SetupPythonforembeddingprecomputeid:setup-pythonuses:actions/setup-python@<pinned-sha># v5.0.0continue-on-error:truewith:python-version:'3.11'# Capture the setup-python interpreter path so the deploy step can# hand it to deploy.sh's VPYTHON slot.-name:ExportprecomputeinterpretertoVPYTHONid:set-python-pathshell:bashif:always()run:|
set -u
python_path="${{ steps.setup-python.outputs.python-path }}"
if [ -n "$python_path" ] && [ -x "$python_path" ]; then
echo "VPYTHON=$python_path" >> "$GITHUB_ENV"
echo "$(dirname "$python_path")" >> "$GITHUB_PATH"
echo "python-path=$python_path" >> "$GITHUB_OUTPUT"
fi
# pip-install ONLY the deps the downstream probe will check (NOT mvp_site# — that's the script's job, see Pitfall #14). Add transitive deps the# precompute script's mvp_site import chain actually needs (flask was# the one missing dep for mvp_site.agent_prompts via# mvp_site.llm_providers.provider_gateway → from flask import g).-name:Installembeddingprecomputedepsid:install-depscontinue-on-error:trueshell:bashrun:|
python -m pip install --no-cache-dir \
fastembed numpy google-cloud-storage jsonschema pydantic cachetools flask || true
# Run the probe AFTER install. Import ONLY the 7 deps the step above just# installed — do NOT add `import mvp_site.X` (see Pitfall #14).-name:Verifyprecomputeinterpretercanimporttheembed-depstheactionjustinstalledid:probe-precomputeshell:bashif:always()run:|
set -u
ready="false"
python_path="${VPYTHON:-}"
if [ -z "$python_path" ] || [ ! -x "$python_path" ]; then
command -v python >/dev/null 2>&1 && python_path="$(command -v python)"
fi
if [ -z "$python_path" ] || [ ! -x "$python_path" ]; then
echo "WARNING: no interpreter available (precompute-ready=false)"
echo "precompute-ready=false" >> "$GITHUB_OUTPUT"; exit 0
fi
if "$python_path" -c 'import fastembed, numpy, google.cloud.storage, jsonschema, pydantic, cachetools, flask' >/dev/null 2>&1; then
ready="true"
echo "Precompute interpreter passed import probe ($python_path)"
else
echo "WARNING: precompute interpreter failed import probe" >&2
"$python_path" -c 'import fastembed, numpy, google.cloud.storage, jsonschema, pydantic, cachetools, flask' 2>&1 | head -5 || true
fi
echo "precompute-ready=$ready" >> "$GITHUB_OUTPUT"
Deploy script side (deploy.sh) — store the probe target in a single _EMBED_PROBE variable so it stays in sync between the VPYTHON branch and the PATH-fallback loop:
# Probe ONLY the deps the install step actually pip-installs. Do NOT# add `import mvp_site.X` here — the toolcache venv can't satisfy that# chain (see Pitfall #14).
_EMBED_PROBE='import fastembed, numpy, google.cloud.storage, jsonschema, pydantic, cachetools, flask'if [ -n "${VPYTHON:-}" ] && [ -x "${VPYTHON}" ]; thenif"${VPYTHON}" -c "${_EMBED_PROBE}" >/dev/null 2>&1; then
_EMBED_PY="${VPYTHON}"elseecho"WARNING: VPYTHON='${VPYTHON}' set but failed import probe — falling through to PATH lookup" >&2
fifiif [ -z "$_EMBED_PY" ]; thenfor _cand in ./vpython vpython python; docommand -v "$_cand" >/dev/null 2>&1 || continueif"$_cand" -c "${_EMBED_PROBE}" >/dev/null 2>&1; then
_EMBED_PY="$_cand"; breakfidonefi
The three load-bearing details:
[ -x "${VPYTHON}" ] instead of command -v "${VPYTHON}" — the absolute path check is the contract that makes the toolcache path work. command -v only finds executables on $PATH; the toolcache path is not on $PATH at the point the deploy step runs.
python not python3 in the fallback loop — system python3 lacks fastembed; python is what actions/setup-python prepends to $PATH when $GITHUB_PATH is honored. On a GitHub-hosted runner both work; on a self-hosted Mac runner only python works.
Probe scope == install scope (Pitfall #14, added 2026-07-14): the probe imports exactly fastembed numpy google.cloud.storage jsonschema pydantic cachetools flask (7 deps) — the same list the install step just pip-installed. If the probe is broader than the install (e.g. adds import mvp_site.agent_prompts), the probe always fails because mvp_site.agent_prompts's transitive chain includes flask AND other deps the action does not install. The actual mvp_site import happens inside the precompute script itself via cwd-based path injection (scripts/precompute_prompt_embeddings.py:35 adds os.path.dirname(os.path.dirname(os.path.abspath(__file__))) to sys.path, then imports mvp_site.* from the source tree at runtime).
Diagnostic message discipline (the FAIL-LOUD contract):
When the probe fails, the script's error message MUST list every candidate it tried AND whether VPYTHON was set. Without that, the next failure is debuggable only by reading source. The v2 contract (PR #8381) drops mvp_site.agent_prompts from both the probe and the message to prevent the operator-facing "no interpreter with ... mvp_site.agent_prompts found" message from masking an otherwise-correct deploy. See references/2026-07-14-precompute-fla[REDACTED_OPENAI_KEY] for the verified 6-line diagnostic block + the full session transcript of run 29294984874 (the SUCCESSFUL live verification).
Pitfalls — DO NOT do these
Don't trust "gcloud builds submit exit 0" as deploy success. The image built, but the revision may still fail to start. Always pull the Cloud Run revision logs.
Don't compare revisions to a previous deployment's logs if the Docker base changed between then and now — the ENTRYPOINT may have changed too.
Don't assume "it works locally" means "it works in Cloud Run". The reverse is also true: a local failure that's macOS-specific (objc fork) does NOT mean Cloud Run will fail. Pin down the actual root cause in the revision logs, then test the FIX not the build.
Don't silently merge the fix. Per the your-project.com repo rule (~/.cursor/rules/pr-hyperlink.mdc + MERGE APPROVED gate), always open a PR and wait for explicit MERGE APPROVED before merging. The user reviews.
Don't bundle "while I'm here" refactors into the deploy-fix PR. Per simplify-code and requesting-code-review skills, the PR must be one logical change — the Dockerfile CMD. No formatting-only edits, no opportunistic test additions, no doc-string rewrites. Pure root-cause fix.
Don't ignore evidence/gunicorn_es_evidence.log if you produce a smoke-test log during Phase 1 — commit it to the PR branch so the failure → fix → proof chain is auditable. Evidence Staleness Tolerance (~/.claude/skills/evidence-standards) applies, but a 60-line gunicorn log for a Dockerfile CMD fix is permanent evidence.
Don't ship CMD ["python", "-m", ...] as the ENTRYPOINT-mismatch fix. The "obvious" fix breaks because Docker still prepends the inherited python entrypoint, giving python python -m gunicorn ... and the same can't open file family of errors with python instead of gunicorn in the path. ONLY ENTRYPOINT [] + CMD ["python", "-m", ...] works against an ENTRYPOINT=python base. This is the #1 reason the v1 fix in this session's PR #8180 had to be followed by a v2 fix in PR #8182.
Don't accept an /advice approval from the start of a PR as binding once the PR's fix surface has evolved. When a follow-up commit changes the actual change-set materially (different Dockerfile lines, different config keys, different module), the original review's reasoning may no longer match what's being merged. This session: /advice returned "Approve and merge as-is, confidence high" against v1, and v2 turned out to be insufficient for the same root cause — the reviewer's "Verify Chainguard python base has ENTRYPOINT=python" claim was correct but the "use python -m gunicorn instead" recommendation was incomplete. Re-run advisory review on the actual FINAL form of the fix before merging, especially when two+ approaches were considered and one was rejected post-review. See the related advice skill.
Don't assume fixing one failure layer exhausts the root cause. A single base-image swap (e.g. python:3.11-slim → cgr.dev/chainguard/python:latest-dev) can introduce MULTIPLE independent failure layers that only surface sequentially as you fix each one: (Layer 1) ENTRYPOINT mismatch → can't open file '/app/.../gunicorn', (Layer 2) ENTRYPOINT mismatch with python -m → can't open file '/app/.../python', (Layer 3) Python 3.14 + protobuf metaclass → TypeError: Metaclasses with custom tp_new are not supported. Each layer masks the next — you can't see Layer 3 until Layers 1+2 are fixed because gunicorn never boots far enough to import firebase_admin. After fixing the visible failure, re-pull the revision logs for the NEW revision deployed from your fix and check for the next layer. Don't claim "fixed" until latestReadyRevisionName == latestCreatedRevisionName AND /health returns 200 from the new revision.
Don't assume Auto-Deploy Dev actually deployed just because a run was created. The workflow uses concurrency: cancel-in-progress: ${{ github.event_name != 'release' }} — rapid successive pushes to main cancel earlier deploy runs before the deploy job (reusable workflow call) starts. A cancelled run shows only smoke-tests (skipped) in its job list and has 0 log lines. To actually deploy after a merge, trigger manually: gh workflow run deploy-dev.yml --repo $GITHUB_REPOSITORY --ref main, then watch with gh run list --workflow=deploy-dev.yml --limit=1.
Don't ship a composite action that installs runtime deps without exporting the interpreter path (Mode 7 anti-pattern, added 2026-07-13). The setup-precompute-deps action runs actions/setup-python@v5.0.0 then pip install fastembed ... into the GitHub-Actions-hosted toolcache. Without an explicit echo "VPYTHON=$pythonPath" >> $GITHUB_ENV step, the interpreter lives at $RUNNER_TOOL_CACHE/python/3.11.x/bin/python which is NOT on $PATH of subsequent steps AND not named python3 on self-hosted Mac runners. deploy.sh's probe loop iterated ${VPYTHON:-} ./vpython vpython python3 and silently fell through to system python3 (no fastembed) every time. The fix is two-pronged: (a) the action MUST echo "VPYTHON=$pythonPath" >> $GITHUB_ENV AND echo "$binDir" >> $GITHUB_PATH after the install, AND (b) deploy.sh MUST trust VPYTHON as an absolute path ([ -x "${VPYTHON}" ]) instead of command -v. Verified: PR #8380 (action) + deploy.sh probe loop rewrite. WARNING: fixing the VPYTHON export is NOT ENOUGH — see Pitfall #14. Without adding the transitive deps the downstream import mvp_site.X chain needs (flask was the missing dep for mvp_site.agent_prompts via mvp_site.llm_providers.provider_gateway) AND reducing the probe to ONLY the deps the install step actually pip-installs, the recurring PRECOMPUTE_FAILED persists. PR #8381 is the v3 fix that makes the deploy infra actually green; PR #8380 v1 was insufficient on its own.
Don't write a single-line PRECOMPUTE_FAILED: no interpreter ... found error message. The deploy script's failure-email fires every push to main until fixed; the email body is the operator's first debugging surface. A 1-line "set SKIP_PROMPT_EMBEDDINGS_PRECOMPUTE=true to bypass" is the operator's worst-case starting point — they have to read source to know what was tried. The verified diagnostic block (PR #8380) lists the candidates tried in order AND reports VPYTHON='...' (exists: yes/no) AND points at the action that should have set VPYTHON. Future failures are debuggable from the failure email alone, no source dive.
Don't put the interpreter probe in the same composite-action step as the setup-python install (Mode 7 v2 anti-pattern, added 2026-07-13 PR #8380 review). The v1 fix in PR #8380 inlined the precompute-ready probe inside the set-python step — which runs BEFORE install-deps. That meant precompute-ready=false was always emitted even on a perfectly healthy install, because the probe ran against empty site-packages. The fixed action order is 4 separate steps: setup-python → set-python-path (export python-path + VPYTHON + GITHUB_PATH; NO probe) → install-deps → probe-precompute (runs AFTER pip install + emits precompute-ready). The probe MUST be a separate id: probe-precompute step that runs after install-deps. Verified contract test in tests/test_precompute_deps_self_hosted.py::TestPrecomputeProbeStepOrder pins the step-ordering invariant — if a future refactor reintroduces the v1 ordering (probe inside set-python), test_probe_step_runs_after_install_step fails-fast with the exact diff. Caveat: the step-ordering fix alone is NOT sufficient — PR #8381 further fixed the probe's import mvp_site.agent_prompts clause (Pitfall #14), which the action COULD satisfy even with proper step ordering.
The contract: in any composite action that follows the "setup-python → install-deps → probe" pattern, the probe step MUST run AFTER the install step. The precompute-ready output's value is only meaningful when its step depends on install-deps.outcome == success (or always() after the install). The reverse order reports false for a healthy install — a silent-but-deadly CI infra bug.
Recipe to verify the order is correct in any composite action under review:
# Get the steps in declaration order
python3 -c "
import yaml
action = yaml.safe_load(open('<action.yml>'))
for step in action['runs']['steps']:
print(step.get('id', '(no-id)'), '|', step.get('name', ''))
"# Confirm: install step comes BEFORE probe step, not after.
Verified correct order (PR #8380 v2):
setup-python | Set up Python for embedding precompute
set-python-path | Export precompute interpreter to VPYTHON (no probe!)
install-deps | Install embedding precompute deps (pip install)
probe-precompute | Verify precompute interpreter can import fastembed+numpy+GCS+mvp_site (probe AFTER install)
Verified WRONG order (PR #8380 v1, caught by CodeRabbit):
setup-python | Set up Python for embedding precompute
set-python | Export precompute interpreter to VPYTHON + run probe (probe INLINE, runs BEFORE install)
install-deps | Install embedding precompute deps
If a future refactor puts the probe inline with set-python, the regression test fails-fast before the bug ships.
Don't put import mvp_site.X in a probe that runs against a Python the install step doesn't actually pre-install (added 2026-07-14, post-#8380). PR #8380 v1's deploy.sh probe checked import mvp_site.agent_prompts even though the setup-precompute-deps action only pip installs fastembed numpy google-cloud-storage jsonschema pydantic cachetools. mvp_site.agent_prompts's import chain transitively pulls in flask via mvp_site.llm_providers.provider_gateway → from flask import g, and the action does NOT pip-install flask. Result: the probe ALWAYS fails on self-hosted Mac runners even on a healthy install. Verified by deploy run 29292726556 — WARNING: precompute interpreter failed import probe (fastembed+numpy+google-cloud-storage+mvp_site.agent_prompts) immediately followed by deploy.sh's WARNING: VPYTHON='...' set but failed import probe — falling through to PATH lookup. The fix in PR #8381 has two halves:
a. Make the install list match the probe list — add any transitive dep the probe actually needs to the action's pip install. For PR #8381 that was just flask. To find which transitive deps you need: python3 -m venv /tmp/repro && /tmp/repro/bin/pip install <installed-deps> && /tmp/repro/bin/python -c "import mvp_site.X" — the failing ModuleNotFoundError tells you which dep the action needs to add. Repeat until the import succeeds. The probe and the install must stay in lockstep forever — tests/test_precompute_deps_self_hosted.py's TestInstallDepsPinsFlaskForToolcacheUsability.test_install_deps_pip_installs_flask pins the install list.
b. Remove the over-strict probe imports — the probe should import ONLY what the install step just pip-installed (i.e. exactly fastembed numpy google.cloud.storage jsonschema pydantic cachetools flask post-#8381). Do NOT add import mvp_site.X. The precompute script (scripts/precompute_prompt_embeddings.py:35) injects the repo root onto sys.path via os.path.dirname(os.path.dirname(os.path.abspath(__file__))), then imports mvp_site.X at runtime. If a transitive dep is genuinely missing, the script surfaces a ModuleNotFoundError: No module named '<X>' at the actual import site — which is a far clearer debug signal than the probe gate's silent false.
Generalize: any time a deploy-time probe tries to validate "the script can run", check what the install step ACTUALLY pip-installs, then probe only that. Script-side imports (which may pull in transitive deps not in any install list) belong at script-runtime, not probe-time. If the probe is more permissive than the install (e.g. checks mvp_site.chain when only mvp_site itself isn't installed), the probe becomes a useless gate that always reports failure — the deploy infra is wired correctly, the probe is over-strict. tests/test_precompute_deps_self_hosted.py::TestDeployShProbeNoMvpSiteAgentPrompts::test_deploy_sh_probe_does_not_check_mvp_site.agent_prompts pins the contract via _EMBED_PROBE='...' regex.
Don't propose fix options before proving the root cause (added 2026-07-24, verified on iOS auth-cookie symptom). The session that produced this v2.5.0 revision had the user push back on a 4-option fix menu (A/B/C/D) for "the cookie expires after 1-2 days" with "Let's first root cause why it's expired versus all these speculative fixes. It has not been 30 days." The pushback was correct — the proposed fixes (server-side max_age override, etc.) were a no-op for the actual symptom on iOS. The diagnostic order is: (1) confirm user-agent, (2) compute sign-in interval, (3) check Firebase project config for any cookie TTL config, (4) read the JS persistence code path, (5) only then propose fixes. Phase 1 takes 2 minutes; the fixes are wrong if Phase 1 is skipped. The v1.0 reference for references/auth-cookie-ttl-class-2026-07-24.md is the canonical example of this pitfall — it shipped 4 fix options before proving the cause, and the v1.1.0 reference revision documents why the v1.0 fixes would not have worked. Future investigators of "I have to log in again after a day or two" must read the v1.1.0 reference and run Phase 1 before proposing any fix.
Verification before claiming "fixed"
Gate
How to verify
Block if red
Local smoke test
curl http://127.0.0.1:8093/health returns 200 with the JSON body
gh pr checks <N> all green (or at least no relevant-to-this-PR failures)
Don't merge
Cloud Run revision actually serving
gcloud run revisions list --service=<name> shows the new SHA as latestReadyRevisionName (not just latestCreatedRevisionName); gcloud run services describe <name> shows 100% traffic on it
Don't close the bead — re-investigate (see Pitfall 7)
Live deploy matches PR HEAD (Mode 7 sanity check)
gcloud run services describe <name> --format='value(metadata.labels.commit-sha-full)' returns the PR's head SHA AND curl <service-url>/health returns 200
Don't claim "fixed" — see Step 5.5 above
Post-merge: next dev deploy succeeds
Watch gh run list --workflow="Auto-Deploy Dev" --limit=1 after the next push
Don't close the bead
The fourth row is new and is the one that caught this skill's first version. latestCreatedRevisionName ≠ latestReadyRevisionName. The created-but-not-ready state is exactly what happens when the v1 fix shipped but the v1-only change still failed the startup probe.
The fifth row (added 2026-07-13) catches the opposite failure mode: the deploy step fails BEFORE gcloud run deploy is invoked (Mode 7), but a sibling run in the same push window may have shipped the PR. The live service IS the source of truth — verify before claiming "fixed."
Cross-references
references/2026-07-05-chainguard-entrypoint.md — full session evidence: failing revision mvp-site-app-dev-03646-k8w, gcloud logging query, PR #8180, the silent 4-day outage pattern. (Note: this reference documents the v1 fix. The v1 fix was incomplete — see the addendum below. Read both files together for the complete story.)
references/2026-07-06-entrypoint-override-mandatory.md — the v1→v2 patch lesson: CMD ["python", "-m", ...] is NOT sufficient when the base image sets ENTRYPOINT=["python"]. Documents the failing revision from PR #8180's merge (mvp-site-app-dev-03647-68m), the second-stage can't open file '/app/$PROJECT_ROOT/python' error, and the canonical fix ENTRYPOINT [] + CMD ["python", "-m", ...]. MUST READ before advising anyone on a Chainguard ENTRYPOINT/CMD fix.
references/2026-07-13-precompute-deps-self-hosted-mac.md — Mode 7 evidence: failing GHA run 29280658965, the setup-precompute-deps toolcache architecture, the deploy.sh probe loop's python3 blind spot, the PR #8380 fix (action exports VPYTHON + deploy.sh reads it as absolute path), and the "your PR is fine, only the deploy CI is broken" diagnostic that landed via Step 5.5. MUST READ before assuming the user's PR is broken when a deploy failure email lands — the failure may be at the script probe, NOT at the deployed revision.
references/2026-07-14-precompute-fla[REDACTED_OPENAI_KEY] — Mode 8 (v2 PR #8381) evidence: the post-#8380 deploy run 29292726556 that kept failing despite #8380 v2's step-ordering fix; the transitive-dep trace (mvp_site.agent_prompts → mvp_site.dice_strategy → mvp_site.llm_providers.provider_gateway → from flask import g → ModuleNotFoundError); the PR #8381 fix (action now pip install flask; probe reduced to the 7 deps the install step actually installs; deploy.sh stores the probe target in a single _EMBED_PROBE variable); the live verification by dev-deploy run 29294984874 (success + revision mvp-site-app-dev-03844-8t2 serving PR HEAD + /health HTTP 200); and the local repro recipe that proves the red-state-then-green pattern (simulated toolcache venv with the install list; probe exits 0; scripts/precompute_prompt_embeddings.py --help exits 0; the full mvp_site chain imports successfully). MUST READ before diagnosing any "PRECOMPUTE_FAILED but install log shows Successfully installed ..." scenario.
references/2026-07-30-proxy-provider-masquerade-402.md — the runtime sibling class (verified 2026-07-30 on consensus-ml.ai → ai-universe-consulting-v2 in worldarchitecture-ai): when the deployed revision is serving and /health returns 200 but the user-facing feature is broken with a Cerebras API error: 402 / OpenRouter 402 style message, the proxy is masquerading the upstream. Recipes: SPA-bundle-inspection (grep -aoE 'fetch\([^)]{0,300}\)' <bundle>), gcloud run services list cross-reference to find the serving backend, curl -X POST to reproduce the upstream's actual error body, and the 4-key probe matrix showing all 4 keys worked for gpt-oss-120b / gemma-4-31b / zai-glm-4.7 but ALL returned {"code":"model_not_found"} for the displayed qwen-3-235b-a22b-instruct-2507. Two fix options: top up OpenRouter credits (smallest, fastest) or repoint the proxy to direct Cerebras (durable, requires a new revision). MUST READ before diagnosing any "the app shows error 402 but says the key is fine" symptom.
references/auth-cookie-ttl-class-2026-07-24.md — v1.1.0 (REFINED 2026-07-24): the original v1.0 hypothesis (cookie TTL is the failure mode, fix is server-side max_age override on the proxy at $PROJECT_ROOT/main.py:1692) was WRONG for the actual iOS user-visible symptom. The real root cause is iOS WebKit ITP evicting the Firebase Auth client's persisted user record (forced to localStorage by auth.js:75-99 iOS WebKit IndexedDB neutralization); the right fix is server-side session restore from __session cookie + silent client re-bootstrap, NOT a cookie TTL override. Verified symptom: campaign wc2BBcSgOljiU3vJ160A on mvp-site-app-dev-03980-l7l from iPhone iOS 26.5.2 / Chrome mobile, sign-in interval 2d 18h. MUST READ before treating "the cookie expired / I have to log in again" as either a deploy failure (it's not), a client-side bug (it's not), or a cookie-TTL issue (it's not — the cookie survives fine; the persisted user record is what gets evicted).
~/.claude/skills/systematic-debugging/SKILL.md — the umbrella Phase 1 protocol this skill is a domain-specific instance of.
~/.hermes/skills/skills/workflow/drive-pr-to-green/SKILL.md — for driving the resulting PR through to merge.
~/.claude/skills/evidence-standards/SKILL.md — for /es evidence requirements and Staleness Tolerance.
~/.claude/skills/advice/SKILL.md — the /advice second-opinion slash skill; relevant here because advisor approval was scoped to the v1 fix surface, not to the eventual v2 (Pitfall 8 captures the lesson).
~/.cursor/rules/pr-hyperlink.mdc — for the PR-hyperlink rule when reporting status to the user.
The repo's CLAUDE.md "Merge safety" section — for the MERGE APPROVED gate on your-project.com PRs.
One-line summary
Three Iron Laws: (1) the build log lies; the revision log tells the truth — pull the Cloud Run cloud_run_revision resource logs for the failing revision, find the actual container-startup error, fix that, smoke-test locally, then open a PR — don't merge without MERGE APPROVED. (2) the pip install can succeed while the script probe fails — when the deploy step exits 1 BEFORE gcloud run deploy is invoked, the user's PR may already be live via a sibling run; verify with gcloud run services describe before claiming "your PR is broken." (3) the auth-cookie-TTL class's v1.0 hypothesis was wrong — for "I have to log in again after a day or two" on iPhone, the failure is iOS WebKit localStorage eviction of the Firebase Auth persisted user record, NOT a cookie TTL issue. See references/auth-cookie-ttl-class-2026-07-24.md v1.1.0. (4) the proxy-chain provider-masquerade class — for " API error: 402" on a Cloud Run app, the displayed provider name and the actual upstream are often different; the proxy re-emits the upstream's raw error body wrapped with the UI label. grep -aoE 'fetch\([^)]{0,300}\)' <spa-bundle-url> + curl -X POST to reproduce + gcloud run services describe to find the backend is the recipe. See references/2026-07-30-proxy-provider-masquerade-402.md.
