## What
Adds `next experimental-diagnose` and an MCP `get_request_insights` tool
so agents and local users can inspect Request Insights without opening
the DevTools overlay.
Stack:
1. request insights: record local framework spans (1/5)
2. request insights: derive request history and fetch data (2/5)
3. request insights: expose dev snapshots to tools and HMR (3/5)
4. request insights: add agent diagnosis access (4/5) ← current
5. request insights: add DevTools request panel (5/5)
## Review Focus
- CLI error handling and raw JSON output.
- MCP gating when Request Insights is unavailable.
- Telemetry registration for the new MCP tool name.
## Proof In This PR
- `pnpm jest packages/next/src/telemetry/events/mcp-telemetry.test.ts
--runInBand`
- `pnpm --filter=next types`
- Stack-tip smoke verifies `next experimental-diagnose --url
http://localhost:3003 --json` against a real dev server.
## Deferred Coverage
- A more curated agent summary format is intentionally deferred until
the raw private snapshot contract settles.
<!-- NEXT_JS_LLM_PR -->
---------
Co-authored-by: Tim Neutkens <[email protected]>
