---
description: "Fetch current library docs via Context7 MCP instead of training data. Use when user asks about frameworks, APIs, setup, or code examples for React, Next.js, Prisma, etc."
alwaysApply: false
---

# Context7 MCP

> **HARD GATE** — Max **3** Context7 tool calls per user question (`resolve-library-id` + `query-docs` count toward the cap). On quota/rate-limit errors, emit an explicit **CONTEXT7_UNAVAILABLE** block — do NOT silently answer from training data.
>
> **HARD GATE** — Before HTTP fetch, check `bash scripts/lib/doc-fetch-cache.sh get "<libraryId>:<query>"`. Cache hit within TTL → use cached body (no round-trip). On ETag mismatch after conditional refresh, replace cache entry.

## When to Use

- Setup/configuration questions ("How do I configure Next.js middleware?")
- Code involving libraries ("Write a Prisma query for…")
- API references ("What are the Supabase auth methods?")
- User mentions specific frameworks (React, Vue, Svelte, Express, Tailwind, etc.)

## Bounded Retry (max 3x)

| Attempt | Action |
|---------|--------|
| 1 | `resolve-library-id` → pick best match |
| 2 | `query-docs` with selected `libraryId` |
| 3 | Retry `query-docs` once with refined query (narrower scope) |

After 3 failures, stop and print:

```
CONTEXT7_UNAVAILABLE
Reason: <quota|rate-limit|no-match|timeout>
Action: Ask user to retry later, paste official docs URL, or run `bts docs <lib>`.
Do NOT substitute training-data answers without labeling them UNVERIFIED.
```

## Fetch Cache (ETag-revalidated)

1. **Cache key:** `"<libraryId>:<normalized-query>"` (lowercase, trimmed).
2. **Read:** `bash scripts/lib/doc-fetch-cache.sh get "<key>"` — exit 0 → use cached body.
3. **Miss / stale:** call `query-docs`; store via `doc-fetch-cache.sh put`.
4. **TTL:** 300s default (`DOC_CACHE_TTL`). Stale entries refresh on next fetch; honor `ETag` when MCP returns it.

`bts docs <lib>` shares the same cache helper when invoked from this skill.

## Process

1. `resolve-library-id` with `libraryName` + full user `query`.
2. Select match: name similarity, reputation, benchmark score; prefer version-specific IDs when user names a version.
3. `query-docs` with `libraryId` + specific question (one concept per call).
4. Answer using fetched docs; cite library/version when relevant.

## Verify

→ verify: `test -f scripts/lib/doc-fetch-cache.sh`