investigation-mode

---
name: investigation-mode
description: "Orchestrated debugging coordinator. Triggers on frustration signals (stuck, hung, broken, waiting) and systematically triages: runtime logs → workflow status → browser verify → deploy/env. Reports findings at every step."
summary: "Debug stuck/hung apps: check logs → workflow runs → browser → deployment"
metadata:
  priority: 8
  docs:
    - "https://docs.anthropic.com/en/docs/claude-code/sub-agents"
  pathPatterns:
    - "**/middleware.{ts,js,mjs}"
    - "**/lib/logger.{ts,js}"
    - "**/utils/logger.{ts,js}"
    - "**/instrumentation.{ts,js}"
    - "**/*.log"
    - "**/error.{tsx,ts,js,jsx}"
    - "**/global-error.{tsx,ts,js,jsx}"
    - "**/not-found.{tsx,ts,js,jsx}"
  bashPatterns:
    - '\bvercel\s+logs?\b'
    - '\bvercel\s+inspect\b'
    - '\btail\s+-f\b.*\.log'
    - '\bworkflow\s+runs?\b'
    - '\bvercel\s+ls\b'
    - '\bcurl\s+-[vI]'
  importPatterns: []
  promptSignals:
    phrases:
      - "nothing happened"
      - "still waiting"
      - "it's stuck"
      - "it's hung"
      - "nothing is happening"
      - "not responding"
      - "just sitting there"
      - "just sits there"
      - "seems frozen"
      - "is it frozen"
      - "frozen"
      - "why is it hanging"
      - "check the logs"
      - "check logs"
      - "where are the logs"
      - "how do I debug"
      - "how to debug"
      - "white screen"
      - "blank page"
      - "spinning forever"
      - "timed out"
      - "keeps timing out"
      - "no response"
      - "no output"
      - "not loading"
      - "debug this"
      - "investigate why"
      - "what went wrong"
      - "why did it fail"
      - "why is it failing"
      - "something is broken"
      - "something broke"
      - "seems broken"
      - "check what happened"
      - "check the status"
      - "where is the error"
      - "where did it fail"
      - "find the error"
      - "show me the error"
      - "why is it slow"
      - "taking forever"
      - "still loading"
      - "not finishing"
      - "seems dead"
      - "been waiting"
      - "waiting forever"
      - "stuck on"
      - "hung up"
      - "not progressing"
      - "stalled out"
      - "is it running"
      - "did it crash"
      - "keeps failing"
      - "why no response"
      - "where did it go"
      - "lost connection"
      - "never finishes"
      - "pending forever"
      - "queue stuck"
      - "job stuck"
      - "build stuck"
      - "request hanging"
      - "api not responding"
    allOf:
      - [stuck, workflow]
      - [stuck, deploy]
      - [stuck, loading]
      - [stuck, build]
      - [stuck, queue]
      - [stuck, job]
      - [hung, request]
      - [hung, api]
      - [frozen, page]
      - [frozen, app]
      - [check, why]
      - [check, broken]
      - [check, error]
      - [check, status]
      - [check, logs]
      - [debug, workflow]
      - [debug, deploy]
      - [debug, api]
      - [debug, issue]
      - [investigate, error]
      - [logs, error]
      - [logs, check]
      - [slow, response]
      - [slow, loading]
      - [timeout, api]
      - [timeout, request]
      - [waiting, response]
      - [waiting, forever]
      - [waiting, deploy]
      - [not working, why]
      - [not, responding]
      - [hanging, for]
      - [been, hanging]
      - [been, stuck]
      - [been, waiting]
      - [why, slow]
      - [why, failing]
      - [why, stuck]
      - [why, hanging]
      - [job, failing]
      - [queue, processing]
    anyOf:
      - "stuck"
      - "hung"
      - "frozen"
      - "broken"
      - "failing"
      - "timeout"
      - "slow"
      - "debug"
      - "investigate"
      - "check"
      - "logs"
      - "error"
      - "hanging"
      - "waiting"
      - "stalled"
      - "pending"
      - "processing"
      - "loading"
      - "unresponsive"
    noneOf:
      - "css stuck"
      - "sticky position"
      - "position: sticky"
      - "z-index"
      - "sticky nav"
      - "sticky header"
      - "sticky footer"
      - "overflow: hidden"
      - "add a button"
      - "create a button"
      - "style the button"
    minScore: 4
retrieval:
  aliases:
    - debug helper
    - troubleshooter
    - stuck helper
    - problem solver
  intents:
    - debug issue
    - fix stuck app
    - investigate error
    - triage problem
  entities:
    - runtime logs
    - workflow status
    - browser verify
    - triage
chainTo:
  -
    pattern: 'createWorkflow|use workflow|use step|@workflow/'
    targetSkill: workflow
    message: 'Workflow code detected during investigation — loading Workflow DevKit guidance for debugging durable execution, step replay, and hook state.'
  -
    pattern: 'VERCEL_URL|DEPLOYMENT_ID|vercel\.app|VERCEL_ENV'
    targetSkill: deployments-cicd
    message: 'Deployment context detected — loading Deployments guidance for inspecting builds, preview URLs, and production promotion.'
    skipIfFileContains: 'vercel\s+inspect|vercel\s+logs'
  -
    pattern: '@vercel/analytics|@vercel/speed-insights|otel|OpenTelemetry|instrumentation\.(ts|js)'
    targetSkill: observability
    message: 'Observability instrumentation detected — loading Observability guidance for log queries, tracing, and monitoring setup.'

---

# Investigation Mode — Orchestrated Debugging

When a user reports something stuck, hung, broken, or not responding, you are the **diagnostic coordinator**. Do not guess. Follow the triage order, report what you find at every step, and stop when you have a high-confidence root cause.

## Reporting Contract

Every investigation step MUST follow this pattern:

1. **Tell the user what you are checking** — "I'm checking the runtime logs for errors…"
2. **Share the evidence you found** — paste the relevant log line, status, error, or screenshot
3. **Explain the next step** — "The logs show a timeout on the DB call. I'll check the connection pool next."

Never silently move between steps. The user is already frustrated — silence makes it worse.

## Triage Order

Work through these in order. Stop as soon as you find the root cause.

### 1. Runtime Logs (check first — most issues leave traces here)

- **Dev server**: Check terminal output for errors, warnings, unhandled rejections
- **Vercel logs**: `vercel logs --follow` (production) or `vercel logs <deployment-url>`
- **Browser console**: Open DevTools → Console tab for client-side errors
- **If no logs exist**: This is the problem. Add logging before continuing (see "Add Logging" below)

Tell the user: "Checking runtime logs…" → share what you found → explain next step.

### 2. Workflow / Background Job Status

If the app uses workflows, queues, or cron jobs:

- Run `vercel workflow runs list` to check recent run statuses
- Look for runs stuck in `running` state — likely a missing `await` or unresolved promise
- Check individual run details: `vercel workflow runs get <run-id>`
- Look for failed steps, retry exhaustion, or timeout errors

Tell the user: "Checking workflow run status…" → share the run state → explain next step.

### 3. Browser Verification

Use agent-browser to visually verify what the user sees:

- Take a screenshot of the current page state
- Check the browser console for JavaScript errors
- Check the Network tab for failed requests (4xx/5xx, CORS errors, hanging requests)
- Look for hydration mismatches or React error boundaries

Tell the user: "Taking a browser screenshot to see the current state…" → share the screenshot → explain what you see.

### 4. Deploy / Environment Status

- `vercel inspect <deployment-url>` — check build output, function regions, environment
- `vercel ls` — verify the latest deployment succeeded
- Check for environment variable mismatches between local and production
- Verify the correct branch/commit is deployed

Tell the user: "Checking deployment status…" → share the deployment state → explain findings.

## Stop Condition

**Stop investigating when:**
- You find a high-confidence root cause (specific error, missing env var, failed step, etc.)
- Two consecutive triage steps produce no signal — report what you checked and that you found no evidence, then ask the user for more context

**Do not** keep cycling through steps hoping something appears. If logs are empty and workflows look fine, say so and ask the user what they expected to happen.

## Common Hang Causes

When logs point to code issues, check for these frequent culprits:

- **Missing `await`**: Async functions called without await cause silent failures
- **Infinite loops**: `while(true)` without break conditions, recursive calls without base cases
- **Unresolved promises**: `new Promise()` that never calls `resolve()` or `reject()`
- **Missing env vars**: `process.env.X` returning `undefined` causing silent auth/DB failures
- **Connection pool exhaustion**: Database connections not being released
- **Middleware chains**: A middleware that never calls `next()` or returns a response
- **Timeout misconfigs**: Function timeout too short for the operation (check `vercel.json` maxDuration)

## Add Logging (If Missing)

If the investigation reveals insufficient observability, **add structured logging immediately** — you cannot debug what you cannot see.

```typescript
// API routes — wrap handlers with try/catch + logging
export async function POST(request: Request) {
  console.log('[api/route] incoming request', { method: 'POST', url: request.url });
  try {
    const result = await doWork();
    console.log('[api/route] success', { resultId: result.id });
    return Response.json(result);
  } catch (error) {
    console.error('[api/route] failed', { error: String(error), stack: (error as Error).stack });
    return Response.json({ error: 'Internal error' }, { status: 500 });
  }
}
```

```typescript
// Workflow steps — log entry/exit of every step
const result = await step.run('process-data', async () => {
  console.log('[workflow:process-data] step started');
  const data = await fetchData();
  console.log('[workflow:process-data] step completed', { count: data.length });
  return data;
});
```

**Key principle**: Every async boundary, every external call, every step entry/exit should have a log line. When something hangs, the last log line tells you exactly where it stopped.

> **Cross-reference**: For comprehensive logging setup (OpenTelemetry, log drains, Sentry, Vercel Analytics), see the **observability** skill. For workflow-specific debugging, see the **workflow** skill.