---
name: fix-vercel-deployment-protection-in-ci
classification: convoy
success_metric: |
  `Playwright smoke` and `Screenshot diff` workflows reach their actual
  smoke / capture step on every PR (no more 401-from-Vercel-SSO 10-min
  timeouts). Both workflows complete in < 5 minutes. Failures, when they
  occur, are real assertion failures — not auth failures against the
  preview URL.
skip:
  - role-design-system-auditor   # CI infra only
  - role-a11y-auditor            # no a11y surface
  - role-ux-reviewer             # no UX surface
  - role-ia-architect            # no IA surface
  - browser-smoke                # the convoy IS the smoke pipeline
status: in-progress
created: 2026-05-24
parent: ship-readiness
addresses: P0 #7 (CI infrastructure side-effect)
depends_on:
  - fix-layout-default-user (shipped — PR #15, ca302a8)
  - PR #16 fix(ci) scoped permissions (shipped — 7e97254)
---

# Fix Vercel Deployment Protection in CI

Plumb `VERCEL_AUTOMATION_BYPASS_SECRET` into the `Playwright smoke` and
`Screenshot diff` workflows so anonymous GitHub Actions runners can
actually GET the preview URL without hitting Vercel's SSO 401 challenge.
Without this, both workflows permanently red on every PR — just slower
red than before PR #16.

## Why now

PR #16 (`fix(ci): scoped permissions`, squash commit `7e97254`) added
minimal scoped `permissions:` blocks to `.github/workflows/preview-smoke.yml`
and `.github/workflows/visual-diff.yml`. That fixed the 5-second 403
"Resource not accessible by integration" failure both workflows hit when
trying to call the GitHub deployments API. **However**, with permissions
correct, both workflows now reach the actual deployment check and fail
with a different error: a 10-minute timeout from
`patrickedqvist/wait-for-vercel-preview@v1.3.2`'s subsequent HTTP GET
against the preview URL, which Vercel returns 401 for because Deployment
Protection is on (anonymous GitHub-runner request → Vercel SSO challenge).
Cost: ~10 minutes of runner time per workflow per PR — and zero signal,
since neither workflow ever reaches its smoke step. This blocks PR #15's
recurring follow-up convoys (visual-regression baselines, Playwright smoke
for `adopt-playwright-smoke`) from getting any CI feedback.

The bypass token already exists locally as `VERCEL_AUTOMATION_BYPASS_SECRET`
in `.env.local` (Protection Bypass for Automation, configured in the
Vercel project). Documented in `AGENTS.md` § 7 — Deployment. The work here
is plumbing it from operator-supplied repo secret → workflow env →
`wait-for-vercel-preview`'s `path:` input + the eventual Playwright
`BASE_URL` so anonymous runner requests bypass the SSO challenge.

## Operator action required (BEFORE this convoy can run)

This convoy CANNOT proceed without the operator first seeding the secret
into GitHub Actions. The implementer has nothing to wire up if the
secret isn't visible to the workflows.

1. **Seed the secret:**
   ```bash
   gh secret set VERCEL_AUTOMATION_BYPASS_SECRET --body "<value from local .env.local>"
   ```
   (The value is whatever `VERCEL_AUTOMATION_BYPASS_SECRET=…` says in
   `.env.local`. Do not paste it anywhere logged. Do not echo it from a
   workflow step.)
2. **Confirm visibility:**
   ```bash
   gh secret list
   ```
   Expect to see `VERCEL_AUTOMATION_BYPASS_SECRET` listed alongside the
   existing repo secrets. Note: `gh secret list` shows names only — never
   values — by design.
3. **Notify the next agent** that steps 1 + 2 are done. The convoy file's
   frontmatter `status:` should flip from `queued` to `in-progress` only
   after this notification.

This is the same pattern `npm run setup-db`'s `ADMIN_INITIAL_PASSWORD`
established (`drop-public-setup` Brief 1, commit `ff80753`): CI / scripts
that need a secret get an actionable fail-loud error when the secret is
missing, and the operator seeds it once per environment.

## Decisions to ratify with operator

Queued; do not pre-decide.

1. **Bypass via query param vs. request header.**
   - **Option A — query param.** Append `?x-vercel-protection-bypass=...&x-vercel-set-bypass-cookie=true`
     to the wait-action's `path:` input AND to the Playwright `BASE_URL`.
     The first request sets a `_vercel_jwt` cookie on the runner's
     ephemeral browser context; subsequent same-origin requests reuse it.
     Pro: works with any HTTP client, no custom config in Playwright.
     Con: the bypass token shows up in workflow run logs if any step
     echoes the URL (mitigation: never `echo` or `cat` a URL containing
     the token; log `${{ steps.wait.outputs.url }}` only after stripping
     the query string).
   - **Option B — request header (`x-vercel-protection-bypass: <secret>`).**
     Cleaner — the token never appears in any URL. But requires custom
     HTTP-client config in `playwright.config.js` (`extraHTTPHeaders`)
     AND in `wait-for-vercel-preview` (the action's docs need confirming —
     header support may not be exposed via inputs).
2. **CI assertion that bypass actually works.** Should we add a step
   that explicitly asserts `200` on the preview URL during the wait-
   action's healthcheck phase, before handing off to Playwright /
   screenshot capture? This would surface bypass-misconfiguration as a
   fast-fail step instead of letting Playwright time out 8 minutes
   later on a different error. Cost: ~5 lines of YAML; benefit: clearer
   failure signal for the next operator-touch event.
3. **Workflow concurrency cancellation.** The workflows already use
   `concurrency:` keyed on `github.ref`. Confirm that the bypass-token
   wiring doesn't inadvertently break the cancel-stale behavior (e.g.
   if the `secrets.VERCEL_AUTOMATION_BYPASS_SECRET` reference is in a
   `concurrency:` expression, that's a syntax error and the implementer
   should pull it into a job-level `env:` instead).

## Scope

**In scope:**

- `.github/workflows/preview-smoke.yml` — wire the bypass into the
  `wait-for-vercel-preview` step's `path:` input (Option A) OR add the
  bypass header via the action's input shape (Option B, pending
  confirmation that the action exposes header inputs).
- `.github/workflows/visual-diff.yml` — same treatment as preview-smoke
  (the two workflows have similar shapes; whatever pattern works for one
  should land in both).
- `playwright.config.js` (when it exists — the `adopt-playwright-smoke`
  convoy ships it) — add `use: { extraHTTPHeaders: { 'x-vercel-protection-bypass': process.env.VERCEL_AUTOMATION_BYPASS_SECRET } }`
  if Decision #1 picks Option B; OR build the BASE_URL with the query
  param (Option A).
- Any test-setup file or helper that constructs the preview URL for
  `screenshot-diff`-style workflows.

**Out of scope:**

- Writing new Playwright tests. Test authoring lives in
  `adopt-playwright-smoke`. This convoy only makes the existing smoke
  pipeline reachable.
- Broadening workflow `permissions:` blocks. PR #16 already landed the
  minimal scope; this convoy should not need to touch them again.
- Replacing `patrickedqvist/wait-for-vercel-preview` with a different
  action. The action retrieves the URL successfully (confirmed in PR #16's
  run logs); the failure is the subsequent HTTP GET, which is a
  configuration issue, not an action choice. A wholesale action swap is
  a deeper rewrite — separate convoy if/when it's needed.
- Authoring new visual-regression baselines. The screenshot diff workflow
  has nothing meaningful to compare against today; baseline authoring is
  its own convoy.
- Disabling Vercel Deployment Protection on the project. Operator may
  prefer to keep protected previews (cheap defense-in-depth against
  preview-URL leakage); this fix lets CI work _around_ the protection
  without weakening it.

## Known constraints

- **`wait-for-vercel-preview@v1.3.2` `path:` input is supported.** PR
  #16's run logs confirm the action retrieves the URL successfully — the
  subsequent HTTP GET is what fails. The action's `path:` input accepts a
  full path including query string, so Option A (`?x-vercel-protection-bypass=...`)
  is mechanically straightforward. Whether the action exposes a way to
  inject custom request headers (Option B) needs to be confirmed by
  reading the action's source / README before the implementer commits to
  it.
- **The same secret will need to be plumbed into Playwright's `BASE_URL`
  or into a request header in `playwright.config.js`** when the
  `adopt-playwright-smoke` convoy ships. Coordinating shape now (this
  convoy) vs. shape later (when Playwright lands) saves churn — the
  implementer should pick whichever option keeps both call sites
  consistent.
- **`npm run setup-db`'s `ADMIN_INITIAL_PASSWORD` is a parallel
  precedent** for "CI needs a secret the operator must seed." Same
  pattern applies: secret is repo-scoped, fail-loud (or fail-noisy) when
  unset, never echoed to logs. See `drop-public-setup` Brief 1
  (commit `ff80753`).
- **Token rotation.** The Vercel bypass token can be rotated from the
  Vercel dashboard. If/when that happens, the operator must re-seed the
  GitHub secret (`gh secret set ...`). No automation here — this is a
  human responsibility per the same pattern as `JWT_SECRET` rotation.

## Acceptance criteria

The convoy is shippable when ALL of the following hold:

1. `Playwright smoke` workflow reaches its actual smoke step on a fresh
   PR. It either passes (smoke green) OR fails on a real assertion
   (Playwright reports a test failure or a runtime error from the
   smoke spec). It does NOT fail with a 10-min timeout from the
   `wait-for-vercel-preview` step or with a 401 from the preview URL.
2. `Screenshot diff` workflow reaches its screenshot capture step and
   posts the "Visual Diff" comment to the PR (even if the diff itself
   is empty / first-run / null-baseline). Same constraint: no 10-min
   timeout, no 401.
3. Both workflows complete in < 5 minutes on a typical PR (the
   pre-PR-16 baseline was ~30 seconds for the workflow body; adding a
   bypass query string or header shouldn't materially affect runtime).
4. The bypass token does not appear in any workflow run log. Verify by
   downloading the raw log of a passing run and grepping for the token's
   first 8 chars.
5. Workflow YAML still passes basic actionlint review (`actionlint .github/workflows/*.yml`
   exits 0). PR #16's permissions blocks remain unchanged.
6. `AGENTS.md` § 7 deployment paragraph (the "Preview protection bypass
   for automation" line) still reflects reality after the change. May
   need a one-sentence update if the implementer picks Option B
   (`x-vercel-protection-bypass` header) vs. Option A (query string).

## Anything flagged but not acted on (in advance)

These are real findings that the architect / implementer should NOT try
to solve in this convoy. Each is queued separately if it warrants a fix.

- **The `wait-for-vercel-preview` action is no longer maintained** (last
  release Mar 2024; no v2). Could be replaced with a few lines of
  `gh api` + `curl`-loop in the workflow itself. Not in scope here —
  this convoy needs to fix the immediate auth failure, not rewrite the
  wait logic. Queue as `replace-wait-for-vercel-preview` if the action
  ages out further or has a security advisory.
- **Playwright config doesn't exist yet.** `playwright.config.js`,
  `tests/smoke/`, and `@playwright/test` all land in
  `adopt-playwright-smoke` (P1 #10 step 2 / launch sequence step 10).
  Until that convoy ships, the only `Playwright smoke` workflow body is
  a no-op. This convoy can pre-wire the bypass infrastructure (env var,
  workflow secrets) so `adopt-playwright-smoke` only needs to add the
  test files and the Playwright config — but it can't ship a real
  smoke-pass without that follow-up.
- **`Screenshot diff` baseline authoring.** Even after this convoy lands,
  the visual-diff workflow has nothing to compare against on its first
  run. That's expected and orthogonal — baseline authoring is a separate
  scope.
- **Operator-rotation hygiene for `VERCEL_AUTOMATION_BYPASS_SECRET`.**
  Vercel's bypass tokens don't auto-expire. If the team wants a periodic
  rotation policy, that's an ops-runbook concern outside this convoy.
- **`AGENTS.md` § 7 wording.** The current "Smoke/visual-diff workflows
  pass this header (`x-vercel-protection-bypass`)" line in § 7 is
  aspirational — it describes intent, not what was actually wired. After
  this convoy ships, that line becomes accurate. The doc-writer pass at
  convoy close should reword to past-tense reality. **Also: § 7 says
  "header"; the architect recommendation in Decision A below is the query
  param (the wait-action has no input for custom headers). The doc-writer
  pass MUST correct the noun.**

## Decisions (post-IA round)

Each decision below routes back to the operator for ratification at
human gate 1 (per the architect contract). Recommendations are based on
fresh-checkout evidence the architect gathered before drafting the brief.

### A — 2026-05-24: Use query-param-on-`path:` for the wait-action; reserve `extraHTTPHeaders` for the Playwright config that lands in `adopt-playwright-smoke`

> Resolves convoy file § "Decisions to ratify with operator" #1 (query
> param vs. header).

**Context.** The convoy file framed this as a clean either/or between
Option A (query param on `path:`) and Option B (request header via the
action's input shape). Boot-the-brief revealed the choice is forced for
the wait step but free for Playwright:

- `patrickedqvist/wait-for-vercel-preview@v1.3.2`'s `action.yml`
  exposes inputs `token`, `max_timeout`, `environment`,
  `allow_inactive`, `check_interval`, `vercel_password`, and `path` —
  and **nothing else**. There is no input for custom request headers.
  Option B is mechanically impossible for the wait step without
  forking the action.
- `action.js:42` consumes `path` via `new URL(path, url)`. Anything
  parseable as a URL path is fine; query strings work verbatim. So
  `path: '/?x-vercel-protection-bypass=…&x-vercel-set-bypass-cookie=true'`
  becomes the URL `https://<deployment>/?x-vercel-protection-bypass=…`
  that axios then GETs.
- Crucially, the action only echoes `targetUrl` (the bare deployment
  URL — `status.target_url`) in its logs (`action.js:357`, `:363`) and
  sets it as `outputs.url` at `:360`. The `path:` query string is
  **never appended to anything that is logged or set as an output.**
  So passing the secret via `path:` does NOT leak it to workflow logs
  or to downstream steps that consume `${{ steps.vercel.outputs.url }}`.
- Vercel's docs explicitly support both shapes; the "header is
  recommended" guidance is about URL-in-log leak risk in callers, not
  Vercel's acceptance. For the wait-action the leak risk is structurally
  absent (see above).
- The future `playwright.config.js` (owned by `adopt-playwright-smoke`)
  CAN and SHOULD use `extraHTTPHeaders` per Vercel's own snippet — the
  config controls its own request shape and the header is cleaner.

**Recommendation (needs operator ratification).** Option A for the
wait-action. Pass the secret to Playwright through `env:` (this convoy
plumbs the env var; the actual Playwright config is `adopt-playwright-smoke`'s
job).

**If operator prefers Option B uniformly** (i.e. headers everywhere),
the cost is forking `wait-for-vercel-preview` or replacing it with a
hand-rolled `gh api` + `curl` poll. That's a larger rewrite and was
flagged as out-of-scope in the convoy file (§ "Anything flagged but not
acted on" → `replace-wait-for-vercel-preview`). Recommend keeping it
out of scope for now.

**Routing.** Operator ratifies at gate 1. Default to A unless rejected.

### B — 2026-05-24: No extra healthcheck assertion step; tighten `max_timeout` from 600 → 120 instead

> Resolves convoy file § "Decisions to ratify with operator" #2 (CI
> assertion that bypass actually works).

**Context.** The convoy file asked whether to add an explicit step that
asserts `200` on the preview URL before handing off to Playwright /
screenshot capture.

- The wait-action's healthcheck loop (`action.js:25-66`) already does
  exactly this: `axios.get` against `new URL(path, url)`, retry on
  non-2xx, exit on first 2xx, fail the step on timeout. If the bypass
  is misconfigured, the action will time out at `max_timeout` and
  call `core.setFailed('Timeout reached: Unable to connect to <url>')`.
  An extra `curl` step would duplicate this signal.
- The real ergonomics problem is `max_timeout: 600` (10 minutes). At
  2-second polling intervals (the action's default — confirmed in PR
  #16's run logs: "Attempt N of 300"), a misconfigured bypass burns
  10 minutes of runner time before failing. Vercel preview builds
  typically complete in 30-90s; the deployment is normally already up
  by the time GitHub triggers the workflow.

**Recommendation (architect-self-ratifiable; flagging for awareness).**
No additional assertion step. Lower `max_timeout` from `600` to `120`
in both workflows. This makes a misconfigured bypass fail in ~2 minutes
instead of ~10, well inside the convoy's "< 5 minutes" success metric,
and gives the deployment plenty of headroom for slow builds.

**Routing.** Architect ratifies. Operator may override at gate 1 if
preview builds in this project are known to exceed 120s — observed
behavior in PR #16's logs (deployment URL retrieved within 1 second of
job start) suggests the deployment is up well before the wait step
starts, so 120s is comfortable.

### C — 2026-05-24: Confirmed — `concurrency:` block contains no secret reference and stays unchanged

> Resolves convoy file § "Decisions to ratify with operator" #3
> (workflow concurrency cancellation).

**Context.** The convoy file flagged the risk that a secret-reference
inside a `concurrency:` group expression would be a YAML syntax error.

- Current `concurrency:` groups: `preview-smoke-${{ github.event.pull_request.number }}`
  and `visual-diff-${{ github.event.pull_request.number }}`. No secret
  reference today.
- The implementer's plumb-the-secret work lands in: (a) the wait-action
  step's `with: path: ...` input, and (b) the Playwright smoke step's
  `env: VERCEL_AUTOMATION_BYPASS_SECRET: ...` for forward-compat with
  `adopt-playwright-smoke`. Neither location intersects `concurrency:`.
- Brief acceptance criterion #3 explicitly forbids placing the secret in
  the `concurrency:` group expression.

**Recommendation (architect-self-ratifiable).** No change to the
`concurrency:` blocks; the cancel-stale behavior is preserved as-is.

**Routing.** Architect ratifies. No operator action needed.

### D — 2026-05-24: Skip Playwright smoke + Screenshot diff on fork PRs (extend `gate:` job) — NEW decision surfaced by Boot-the-brief

> Not in the original convoy file's "Decisions to ratify" list. Surfaced
> by the architect's Boot-the-brief check ("Empty / unset secret" case).

**Context.** GitHub Actions silently omits repo secrets on
`pull_request`-event runs that originate from a fork. The wait-action
would receive `${{ secrets.VERCEL_AUTOMATION_BYPASS_SECRET }}` as an
empty string, build the URL `https://<deployment>/?x-vercel-protection-bypass=&x-vercel-set-bypass-cookie=true`,
get 401 (empty bypass value is not a valid bypass), and time out at
`max_timeout`. After Decision B (120s timeout), that's still ~2 minutes
of wasted runner time per fork PR per workflow — net 4 minutes per fork
PR. The failure signal is "the convoy's fix didn't work" instead of "the
PR is from a fork and can't access secrets" — a misleading red.

tcg-vault is single-maintainer with occasional collaborators (all with
write access, so their PRs aren't from forks today). Fork PRs are rare.
But the cost of a one-line gate-job extension is zero, and the value
is "fork PRs get a clear skip message instead of a 2-minute wait + red."

**Recommendation (needs operator ratification).** Extend the existing
`gate:` step in both workflows to check `github.event.pull_request.head.repo.fork`
first, BEFORE the existing `pipeline:.*skip.*\bsmoke\b` / `\bvisual\b`
body-directive check. When `fork == true`, emit a `::notice::`
explaining why, and `should_run=false`. The actual `smoke` /
`visual` job stays guarded by `if: needs.gate.outputs.should_run == 'true'`
unchanged — it just doesn't fire for forks.

Verbatim shape baked into the brief:

```bash
if [[ "${{ github.event.pull_request.head.repo.fork }}" == "true" ]]; then
  echo "should_run=false" >> $GITHUB_OUTPUT
  echo "::notice::Smoke skipped on fork PR (bypass secret unavailable to forks)"
elif echo "${{ github.event.pull_request.body }}" | grep -qE 'pipeline:.*skip.*\bsmoke\b'; then
  ...
```

**Alternative (rejected):** add the fork check as an `if:` on the
`smoke` and `visual` jobs directly. Same effect, but loses the
`::notice::` annotation that surfaces in the GitHub Actions UI summary —
silent skip is worse UX than annotated skip.

**Side effect.** Until `adopt-playwright-smoke` ships, this convoy's
fork-PR skip applies to a workflow that already does nothing useful
(no Playwright config, no `@playwright/test`). The skip is forward-
looking — once the smoke pipeline becomes real, fork PRs gracefully opt
out instead of failing.

**Routing.** Operator ratifies at gate 1. Default to "yes, skip on
forks" unless rejected. If rejected, the brief drops the fork check and
the recommendation in `AGENTS.md` § 7 (the doc-writer pass) should
document the fork-PR failure mode.

## Architecture

### File plan

| File | Action | Purpose |
| --- | --- | --- |
| `.github/workflows/preview-smoke.yml` | modified | Inject bypass-secret query into `path:` of the wait-for-vercel-preview step (Decision A); lower `max_timeout` 600 → 120 (Decision B); extend `gate:` step to skip fork PRs (Decision D); add `VERCEL_AUTOMATION_BYPASS_SECRET` to the Playwright smoke step's `env:` for forward-compat with `adopt-playwright-smoke` |
| `.github/workflows/visual-diff.yml` | modified | Same shape as preview-smoke: bypass query on `path:`, `max_timeout` 600 → 120, fork-PR gate, `VERCEL_AUTOMATION_BYPASS_SECRET` in the screenshot-capture step's `env:` |

### API surface

N/A — this convoy modifies CI workflow YAML only. No HTTP routes are
added, modified, or removed.

### Schema diff

N/A — no database changes.

### Test plan

- **No new unit tests.** The change is workflow YAML; vitest does not
  exercise GitHub Actions. The existing 16-test auth-surface suite stays
  green and is unaffected.
- **Manual validation in the brief's "Manual verification" section:**
  - Acceptance criterion #1 (wait-action exits successfully on the
    convoy's own PR): observe by reading the workflow's run log after
    pushing the convoy branch. Expect `Received success status code`
    within the first few attempts and total wait-step duration < 90s.
  - Acceptance criterion #4 (no bypass secret in workflow logs):
    `gh run download <run-id> -n logs && rg "<first-8-chars-of-secret>"
    logs/` (locally only — never paste the chars into a script or
    commit). Expect zero matches.
  - Acceptance criterion #5 (actionlint validation): document the
    one-line `brew install actionlint` install OR a hermetic Docker
    one-liner; recommended-not-required (no actionlint binary in CI
    today, and gating on it would expand scope). The brief includes the
    exact command.
- **Smoke / visual jobs themselves still fail** after the brief lands,
  because `@playwright/test` is not installed and `playwright.config.js`
  does not exist — the failure mode shifts from "401 timeout in the
  wait step" (this convoy's target) to "playwright not installed" (the
  `adopt-playwright-smoke` convoy's target). That is the **correct,
  expected end state of this convoy.** Brief acceptance criterion #1
  explicitly accepts a real downstream failure as success, as long as
  the wait-action reaches `Received success status code` first.

### Risk list

- **R1 — Secret leaks via workflow log.** Even though the wait-action
  itself doesn't echo `path:` (verified — `action.js:357,360,363` only
  emit `targetUrl`, which does NOT include the query string the action
  appended internally), any added `echo "$BASE_URL"` or `run: |` step
  with `set -x` in the same job could expose the secret. Brief calls
  this out and prohibits echoing constructed URLs. Mitigation: keep the
  bypass *only* in `path:` and `env:` — never built into a shell
  variable that a step might print.
- **R2 — `outputs.url` is the bare deployment URL (already verified) —
  Playwright will need its own injection.** Confirmed via `action.js:360`:
  `core.setOutput('url', targetUrl)` where `targetUrl = status.target_url`.
  The `path:` query is NOT appended. So the BASE_URL Playwright receives
  via `${{ steps.vercel.outputs.url }}` is clean — Playwright must inject
  the bypass itself (via `extraHTTPHeaders` per Vercel's docs). This
  convoy plumbs `VERCEL_AUTOMATION_BYPASS_SECRET` as an env var on the
  step so `adopt-playwright-smoke` can read it from `process.env`.
- **R3 — `path:` parsing requires leading `/`.** `action.js:42`:
  `new URL(path, url)`. If the implementer writes
  `path: '?x-vercel-protection-bypass=...'` (no leading `/`), the URL
  resolver will combine relative-to-current-document which can drop the
  origin. Brief acceptance criterion explicitly mandates `path: '/?...'`.
- **R4 — `max_timeout: 120` may be too aggressive for very slow Vercel
  builds.** PR #16's run log evidence (deployment URL retrieved within
  1 second of job start) suggests the deployment is already up by the
  time the workflow triggers. 120s gives ~60 polls at the default 2s
  interval. If a cold-start build legitimately takes > 120s, the
  workflow will time out. Mitigation: operator may override at gate 1
  if recent Vercel build times have been long. Easy revert.
- **R5 — Fork-PR gate misclassification.** GitHub's
  `github.event.pull_request.head.repo.fork` is a boolean but is
  rendered as the string `"true"` / `"false"` in expression context.
  The brief's shell check uses `[[ ... == "true" ]]`, which is the
  safe comparison.
- **R6 — Token rotation invalidates CI silently.** If the operator
  rotates the bypass token in the Vercel dashboard but forgets to
  re-seed the GitHub secret, the workflow will start failing with the
  same 401 + timeout it does today. This is documented in convoy file
  § Known constraints; not preventable from workflow YAML. The doc-
  writer pass should add a one-line note to `AGENTS.md` § 7 listing
  the secret-rotation runbook.
- **R7 — Concurrency-group cancellation interacts with the bypass URL?
  Confirmed: no.** `concurrency:` uses only `github.event.pull_request.number`;
  no secret reference. Decision C covers this.
- **R8 — actionlint not in CI.** No workflow validator runs on PRs
  today. The brief recommends a local `actionlint` install for the
  implementer; CI integration is its own scope (queueable as
  `adopt-actionlint`).

### Decomposition

| Brief # | Title | Files | Depends on | Estimated PR size |
| --- | --- | --- | --- | --- |
| 1 | Inject `VERCEL_AUTOMATION_BYPASS_SECRET` into preview-smoke + visual-diff workflows | `.github/workflows/preview-smoke.yml`, `.github/workflows/visual-diff.yml` | none | ~50 LOC YAML diff total |

**Why 1 brief and not 2** (one per workflow):

- Both files take the **identical shape change** (same wait-action step,
  same `max_timeout` reduction, same gate-job extension, same
  forward-compat env var). The diffs are parallel and best reviewed
  together — PR #16 set the precedent of touching both workflow files
  in a single PR for this exact reason.
- Splitting into 2 briefs would force two PRs into the same review
  surface, two implementer runs, two convoy-cycle bookings, with zero
  reviewer benefit: the files are independently reverte-able at the
  file level inside a single PR.
- Total brief LOC is well under the 400-LOC architect ceiling.
- No cross-brief commitments are needed.

If the implementer surfaces a reason the two files must diverge mid-
flight (e.g. visual-diff needs a different `path:` because it captures
a deeper page), that's a Decision-letter scope expansion documented in
this file, not a re-decomposition.

### Slice dependencies (multitask-ready)

```yaml
slice_dependencies:
  - brief: 1
    depends_on: []
    files:
      - .github/workflows/preview-smoke.yml
      - .github/workflows/visual-diff.yml
```

Single brief — no parallelization opportunity. Conductor dispatches
serially.

Architecture complete. 1 brief created. Estimated PRs: 1. Awaiting
human gate 1 (Decisions A + B + D ratification + brief approval) before
the implementer runs.