--- name: claude-api-probe description: Generate a paste-into-DevTools snippet that probes a Claude.ai internal API endpoint and downloads the response as JSON. Use when the user wants to test an unknown Claude internal endpoint, verify a response shape, or capture data for fixtures. Output is a single self-contained async IIFE the user pastes into the DevTools console on claude.ai. The downloaded filename includes the HTTP status so 200 vs 404 is visible at a glance. disable-model-invocation: true --- # claude-api-probe Codifies the paste-into-DevTools pattern we use repeatedly when reverse-engineering Claude's internal API surface during Mayia development. ## When to use - Probing a new endpoint path (e.g. `/projects/{id}/docs`, `/organizations/{id}/recent`, etc.) - Verifying a response shape after Claude ships a UI change - Capturing real responses to use as test fixtures in `packages/shared` - Quick "does this endpoint exist?" checks before committing to an adapter implementation ## Inputs the user provides - **Endpoint path** (relative, e.g. `/api/organizations/${orgId}/projects/${projectId}/docs`) - Optional: **method** (default `GET`) - Optional: **body** (for POST/PATCH) - Optional: **a specific project/conversation/user UUID** to substitute ## Output A single self-contained snippet shaped like: ```js (async () => { const orgId = document.cookie.match(/lastActiveOrg=([^;]+)/)?.[1]; if (!orgId) { console.error('no lastActiveOrg cookie'); return; } const path = `/api/organizations/${orgId}/`; const res = await fetch(path, { method: '', credentials: 'include', headers: { 'Content-Type': 'application/json' }, // body: JSON.stringify(), }); const body = await res.text(); console.log('status', res.status, 'bytes', body.length); let pretty = body; try { pretty = JSON.stringify(JSON.parse(body), null, 2); } catch {} const blob = new Blob([pretty], { type: 'application/json' }); const a = document.createElement('a'); a.href = URL.createObjectURL(blob); a.download = `claude_probe__${res.status}.json`; document.body.appendChild(a); a.click(); a.remove(); URL.revokeObjectURL(a.href); })(); ``` ## Behavior rules - **Filename always includes HTTP status** (`_200`, `_404`, etc.) so the user knows what they got without opening the file. - **Always downloads** — even on 4xx/5xx. The body of an error response often reveals API shape (e.g. the `not_found_error` envelope Claude uses). - **`credentials: 'include'`** is non-negotiable. Cookies (`lastActiveOrg`, session) flow because the script runs on `claude.ai`. - **No try/catch swallowing.** Log the status and bytes count to console so the user sees what happened. - **Prefer console.log over console.table** for raw API output — the data is rarely tabular. ## Related context - Memory: `~/.claude/projects/-home-arctux-mayia/memory/claude_api_surface.md` for the confirmed endpoint catalog - Phase 0 spike: `phase-0-spike/fetch_claude_*.js` for canonical examples ## Anti-patterns - Don't generate a snippet that uses Node's `fetch` — it must be browser DevTools code with `credentials: 'include'`. - Don't add jQuery or any library. Pure browser APIs only. - Don't add user prompts (`prompt()`, etc.) — paste-and-run, no interaction. - Don't auto-download multiple files in one snippet — one probe per run.