Diagnose Integration Failure

---
name: diagnose-integration-failure
description: Diagnose a failing TMDb integration-test run — summarise the failure, rank the likely cause, and suggest a concrete fix
---

# Diagnose an integration-test failure

The TMDb integration tests hit the **live** TMDb API. The suite runs on three
triggers — **`pull_request` / `push`** (where it *gates* the change) and
**`schedule`** (the weekly live-API canary). **Which run failed flips the most
likely cause, so determine the trigger first** (step 0):

- **PR / push-triggered** → this run is the gate for a code change, so a
  **regression in the diff is a real candidate** — weigh it alongside backend/data
  drift. This is the common case when invoked from `/watch-pr` or `/fix-pr-checks`.
- **Scheduled** → no code changed, so a regression is **unlikely**; the cause is
  almost certainly a backend change, drifted test data, or a transient error.

> **Wrong suite?** If a **CI** check failed instead (lint, markdown, build, or
> unit tests from `ci.yml`), use `/diagnose-ci-failure`. That one leads with the
> opposite assumption: a CI failure is almost always caused by the change under
> review.

## Agent Behaviour Contract

Do these by default, without being reminded.

1. **Observe before you theorise.** The log tells you *what broke*; only a live
   call tells you *what the API returns today*. So a cause that claims the API
   changed shape, or that a test's baseline drifted, must be backed by a live
   observation — **`mcp__tmdb__*`** (CLAUDE.md's standing instruction).
2. **Every such cause carries an `observed:` line** naming the tool called and
   the shape that came back. **A cause with no `observed:` line is not
   reportable as ranked** — demote it and mark it `unverified`. This is what
   makes the rule checkable by the consumer instead of trusting the
   diagnostician.
3. **Only causes 1 and 2 can be observed.** A transient/rate-limit (cause 3) and
   an in-diff regression (cause 0) cannot be confirmed by a live call — the
   endpoint being healthy *now* says nothing about either. Do not manufacture an
   `observed:` line for them; the requirement does not apply.
4. **Never publish a secret.** An `observed:` line records the **tool and the
   shape**, never a URL, command, or header carrying `TMDB_API_KEY`. TMDb takes
   `api_key` as a *query item*, so a pasted `curl` leaks it — and this analysis
   is published verbatim into an issue on a **public** repo. Say
   `mcp__tmdb__movie_details(550) → runtime: Int, present`, not the command.
5. **Headless runs cannot probe.** The scheduled `integration-failure.yml` job
   mounts no MCP. There, write `observed: unavailable (headless)` and mark the
   cause `unverified` — **do not** fall back to `curl`, which would put the key
   in the text (rule 4). Attended runs have the MCP; use it.

Produce a concise markdown analysis with exactly these three sections:

**Summary:** one or two sentences on what failed — name the failing
suite/test where visible.

**Likely cause:** the most probable root cause, ranked most-likely first —
**ranked by the trigger** (step 0). Each cause 1 or 2 carries its `observed:`
line, or is marked `unverified`:

- **If PR / push-triggered**, add as a **top candidate**:
  0. **A regression in the changed code** — read the diff (`git diff main...HEAD`).
     A new/renamed request path or query item, a changed model/`CodingKeys`, or a
     decoder tweak can break a live call. This run is the gate, so the diff is a
     prime suspect — but still weigh causes 1–3 below, since the live API can drift
     independently of your change.
- **If scheduled**, do **NOT** lead with "a code bug" (nothing changed); go
  straight to 1–3.

1. **A TMDb backend change** — a response field was added, removed, renamed, or
   became nullable, breaking a model's `Decodable`. **Call the endpoint via
   `mcp__tmdb__*` and record what came back** (`observed:`); confirm against the
   OpenAPI spec (see step 3) for the documented shape.
2. **Stale assumed data in an integration test** — the test asserts a specific
   live value (a title, count, id, date, or ordering) that the API now returns
   differently. The code is fine; the test's baseline has drifted. **Fetch the
   value the test asserts and record it** (`observed:`) — drift is only a fact
   once you have seen today's value.
3. **A transient API error, rate limiting (HTTP 429), or a timeout** — the
   Integration Test job has a 30-minute `timeout-minutes`, and a cancelled
   (timed-out) run still surfaces as a workflow `failure`. A truncated log with
   no assertion failure, or a run that ran the full 30 minutes, points here.

Cite the specific HTTP status codes, error messages, or failing assertions from
the log that point to your conclusion.

**Suggested fix:** the concrete next step — which Swift model or JSON fixture to
update for an API change, which integration-test assertion to relax or refresh
for drifted data, or (only for case 3) re-run the job / wait out rate limiting /
investigate the slow run if it timed out.

Keep it under ~150 words.

## Steps

0. **Determine the trigger** (it sets the cause ranking above). If the caller told
   you (e.g. `/watch-pr` / `/fix-pr-checks` diagnose a **PR** run), use that.
   Otherwise read it from the run with `mcp__github__actions_get` method
   `get_workflow_run` (owner/repo from the `origin` remote, `resource_id: <id>`) →
   `event` is `pull_request`, `push`, or `schedule` (headless / no MCP:
   `gh run view <id> --json event,displayTitle`). If you can't tell, assume
   **PR/push** when a local diff vs `main` exists, else scheduled.

1. **Locate the failure log**, in this order — use the first that exists:
   - A path the caller handed you (e.g. `failure-log.txt` in the working
     directory, used by the CI alert workflow).
   - `.build/last-integration-test.log` — written by the `/integration-test`
     skill. If you (or the user) haven't run the tests yet locally, run
     `/integration-test` first, then read this log.
   - Otherwise, find the failing run with the **GitHub MCP** (owner/repo from
     `origin`): `mcp__github__actions_list` method `list_workflow_runs`
     (`resource_id: integration.yml`, `workflow_runs_filter: { status: completed }`,
     then filter to `conclusion == "failure"`), and read its log with
     `mcp__github__get_job_logs` (`run_id: <id>`, `failed_only: true`,
     `return_content: true`). Headless / no MCP:
     `gh run list --workflow Integration --status failure --limit 1` then
     `gh run view <id> --log-failed`.

2. **Read the failing portion** — focus on the assertion failures and error
   messages, which surface near the end. Read the specific test, model, and
   fixture files the log points to so your suggested fix names real symbols.

3. **Check the OpenAPI spec when the failure looks like a decode/shape error.**
   The live spec is the source of truth for the current response shape, but it
   is **~3 MB of minified JSON on a single line** — NEVER `grep`, `cat`, or
   `Read` it whole; that dumps the entire file into context. Extract only the
   one endpoint you need with `jq` (requires `jq`, which is present in CI and
   installable via Homebrew locally; if `jq` is unavailable, skip this step and
   say so):
   - Use `tmdb-openapi.json` in the working directory if present; otherwise
     fetch it (best-effort):
     `curl -fsSL --max-time 30 https://developer.themoviedb.org/openapi/tmdb-api.json -o tmdb-openapi.json`
   - The spec is OpenAPI 3.1 with response schemas **inlined per endpoint**
     (there is no reusable `components.schemas`). Find the endpoint, then pull
     just its 200-response schema:
     - List endpoints (cheap, ~5 KB): `jq -r '.paths | keys[]' tmdb-openapi.json`
     - Pull one schema (~5 KB): `jq '.paths."/3/movie/{movie_id}".get.responses."200".content."application/json".schema' tmdb-openapi.json`
       (swap in the path + HTTP method for the failing request)
     - Even cheaper, just the field names:
       `… .schema.properties | keys[]`
   - Compare the live schema against the failing model/fixture to confirm
     whether a field changed, became nullable, or was removed — then point at
     the specific Swift model or JSON fixture that needs updating.
   - If the spec can't be fetched or `jq` is unavailable, say so and proceed
     without it.

4. **Output the analysis.** If the caller asked you to write it to a file (e.g.
   `claude-analysis.md`), write the three-section markdown there and nothing
   else. Otherwise present it directly in your reply.