---
name: devrites-source-driven
description: Verify uncertain framework or library behavior against official docs or installed source before relying on it, then record the source in `evidence.md` / `decisions.md`. Use when the user says "check the docs", "is this still the API", "don't guess", "cite the source", "verify this assumption", or build encounters an unfamiliar framework call. Not for project-internal code or trivial stdlib calls.
user-invocable: false
---

# devrites-source-driven — verify, don't guess

A confident wrong assumption about a library is a bug waiting to ship. When behavior
matters and isn't certain, check the source of truth.

## When to trigger
- You're about to rely on an API signature, default, config key, or behavior you're not
  sure of.
- The docs in memory might be stale (the project pins a different version).
- Tests can't easily prove the assumption, but it drives the implementation.
- An error message points at framework behavior you don't fully understand.

## How
1. **Find the version** the project actually uses (lockfile, manifest) — behavior is
   version-specific.
2. **Consult the source of truth**, in order: the installed package's own source/types
   in `node_modules`/gem/site-packages; official docs for *that version*; the project's
   existing usage of the same API.
3. **Confirm the specific fact** — the signature, the default, the edge behavior — not a
   general impression.
4. **Record it** in `decisions.md` (or `evidence.md`): the fact, the version, and the
   source (path or URL). Future phases trust the record instead of re-checking.

## Rules
- Prefer the **installed** source over remembered docs — it can't be out of date.
- Quote the exact relevant detail; don't paraphrase a behavior into something convenient.
- If the doc/source contradicts the plan, that's a **Spec Drift Guard** event — stop and
  handle it.
- Don't rabbit-hole: confirm the one fact you need, record it, return.