name: reference-registry description: > [STATUS: review] [CONFIDENCE: high] [REVIEWED: 2026-03-17] Systematic external reference lookup. Reads project references.md, suggests relevant URLs for current task, fetches on demand. Triggers: reference, check external, how others solve, compare with, look up, competitor, alternative implementation, benchmark.

Skill: Reference Registry

Project References (auto-injected)

!`cat .claude/memory/references.md 2>/dev/null | head -50`

When to Load

• User mentions "check how X does it", "compare with", "look up"
• Task involves design decisions that benefit from external examples
• User explicitly says "check references" or "what do our refs say"

How It Works

Each project can have a references.md file in .claude/memory/ with structured external links. This skill teaches Claude to use them systematically.

Workflow

1. Check if references exist

Read .claude/memory/references.md (project-level)
  OR ~/.claude/memory/references.md (global)

2. Match current task to reference entries

Each entry has a WHEN: field — match it against the current task context.

3. Fetch only what's needed

Use WebFetch with a specific LOOK FOR: prompt from the entry. Do NOT fetch entire repos — fetch specific files/sections.

4. Report with evidence markers

[EXTERNAL-REF] From <source>: <finding>
[EXTERNAL-DIFF] Our approach differs: <comparison>

references.md Format

# External References

## Category Name

- [Short Name](https://url/to/specific/file)
  WHEN: <conditions when this reference is relevant>
  LOOK FOR: <what to extract from the URL>
  NOTES: <optional context, caveats, last verified date>

Example

## Architecture Patterns

- [Circuit Breaker in Polly](https://github.com/App-vNext/Polly/blob/main/src/Polly.Core/CircuitBreaker/README.md)
  WHEN: modifying circuit breaker logic, adding new states
  LOOK FOR: state transition rules, half-open behavior, success threshold
  NOTES: .NET implementation but patterns are universal

## Competitor Configs

- [Trail of Bits Claude Config](https://github.com/trailofbits/are-we-right)
  WHEN: comparing security approaches, hook architecture
  LOOK FOR: how they handle prompt injection, what hooks they use
  NOTES: Security-focused team, good baseline for comparison

Rules

1. Never fetch without purpose — always have a LOOK FOR goal
2. Cache mentally — if you fetched a URL this session, don't re-fetch
3. Prefer specific files over repo roots (.../blob/main/src/X.py > .../tree/main)
4. Mark findings with [EXTERNAL-REF] so user knows the source
5. Don't assume freshness — URLs may be outdated. Note last verified date if available

Anti-Patterns

Gotchas

• References older than 6 months may be outdated — always check version
• Prefer official docs over blog posts — blogs drift from reality