Agent skill
knowledge-retrieval
(ePost) Use when you need prior art, past decisions, or existing patterns — checks docs/, skills, and RAG before external sources
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/knowledge-retrieval
Metadata
Additional technical details for this skill
- keywords
-
retrieve search knowledge context rag lookup prior-art
- triggers
-
[ "what do we know about", "check knowledge", "prior art", "previous decision" ] - platforms
-
[ "all" ] - connections
-
{ "enhances": [ "research", "plan" ] } - agent affinity
-
[ "epost-planner", "epost-fullstack-developer", "epost-debugger", "epost-researcher", "epost-code-reviewer" ]
SKILL.md
Knowledge Retrieval Skill
Purpose
Internal-first knowledge retrieval protocol. Each piece of knowledge lives in exactly ONE tier. Search sources in order, stop when sufficient context found.
Three Knowledge Tiers
| Tier | Type | Owner | Updated |
|---|---|---|---|
| Procedural | How to do things (methodology, pipelines, decision frameworks) | Skills | Versioned releases |
| Codebase | What exists in the code (components, tokens, patterns, implementations) | RAG system | Automatic (file watcher) |
| Project | What we decided & learned (ADRs, findings, conventions) | docs/ |
Organic (captured during work) |
Rule: Each piece of knowledge lives in exactly ONE tier. Other systems reference it, never copy it.
When Active
- Starting implementation (check for existing patterns)
- Debugging (check for similar findings)
- Making decisions (check for prior ADRs)
- Researching libraries (check for previous evaluations)
- Reviewing code (check for conventions)
Retrieval Chain (5 Levels)
Search sources in order, stop when sufficient context found:
| Level | Source | Tool | When to Use |
|---|---|---|---|
| 1 | docs/ (multi-level) |
Glob **/docs/index.json, then filter by agentHint + tags |
Decisions, conventions, findings, patterns |
| 2 | RAG systems | MCP query |
Code, components, tokens, implementations |
| 3 | Skills | Read skill-index.json | Methodology, procedures, guidelines |
| 4 | Codebase | Grep, Glob, Read | Exact matches, files RAG missed |
| 5 | External | Context7, WebSearch | Library APIs, latest external info |
Level 1 Multi-Level Discovery
docs/index.json registries can exist at any level. Discover them all with a single glob, then read each to understand its scope from the description field:
Glob: **/docs/index.json
Use the registry closest to the files being worked on as primary. See references/search-strategy.md for query patterns.
No registry found? Prompt the user:
No
docs/index.jsonfound. Run/docsto initialize one. This enables consistent, session-persistent knowledge retrieval for all agents.
Search Protocol
Search sources in order, stop when sufficient context found. See references/search-strategy.md for full retrieval chain, query examples, and source-specific techniques.
Key principle: Start internal (docs/ index — all levels), then RAG, then skills, then codebase grep, then external (Context7/WebSearch). Stop as soon as you have sufficient context.
Decision Matrix
| Question Type | Go to | Skip |
|---|---|---|
| "What did we decide about X?" | L1 docs/decisions/ |
RAG, External |
| "How is X implemented?" | L2 RAG → L4 Codebase | Skills |
| "What components exist?" | L2 RAG | docs/ |
| "What's the token value?" | L2 RAG | Skills |
| "What's the process for X?" | L3 Skills | RAG |
| "What's our convention?" | L1 docs/conventions/ |
External |
| "Why does X break?" | L1 docs/findings/ → L2 RAG → L4 Codebase |
— |
| "How to use library X API?" | L5 External (Context7) | docs/ |
| "Should we use technology X?" | L1 docs/decisions/ → L5 External |
RAG |
| "What's the system architecture?" | L1 docs/architecture/ |
External |
| "How does feature X work?" | L1 docs/features/ → L4 Codebase |
— |
Integration with Existing Skills
docs-seeker
Handles Context7 + WebSearch (Level 5):
docs-seeker → resolve-library-id → get-library-docs
docs-seeker → WebSearch (if Context7 fails)
research
Handles deep multi-source investigation:
research → knowledge-retrieval (internal first)
research → docs-seeker (external)
research → synthesize findings
Cross-Source Bridging
docs/ (L1) and RAG (L2) complement each other. Bridge them:
| docs/ finding | RAG action |
|---|---|
| ADR mentions component path | Query RAG for current implementation state |
| PATTERN describes approach | Query RAG for usage examples across codebase |
| FINDING references file | Query RAG for related files in same module |
| Convention names a pattern | Query RAG for conformance/violations |
| RAG finding | docs/ action |
|---|---|
| Result looks like a recurring pattern | Check docs/patterns/ for documented version |
| Multiple results share an approach | Check docs/conventions/ for existing convention |
| No docs/ entry for frequently-queried topic | Flag for knowledge-capture |
Rule: Always cross-reference. An ADR without code validation is stale. A code pattern without docs is undocumented risk.
Cross-Platform RAG Coordination
When a query spans platforms, coordinate RAG queries:
| Scenario | Query strategy |
|---|---|
| Design tokens, colors, typography | Query both web (2636) + iOS (2637) RAGs |
| Component parity check | Query both, compare by concept |
| Pattern consistency | Query both, note divergences |
| Platform-specific implementation | Query single platform RAG only |
Dedup rule: Group results by concept, not file. Note platform differences. Authority rule: Definitions live in design system RAG, usage examples in platform RAG. Prefer the authoritative source.
Staleness Detection
| Source | Freshness Signal | Action |
|---|---|---|
docs/ |
updatedAt field |
Verify if >90 days old, cross-check with RAG |
| RAG code chunks | Auto-indexed on file change | Trust current code content |
| RAG sidecar metadata | stale_sidecar: true flag |
Metadata outdated but code chunks still valid |
| Skills | Manually updated | Check last commit date |
| Codebase | Always current | Trust HEAD |
| Context7 | Live docs | Trust current |
| WebSearch | Publication date | Prefer <2 years |
RAG staleness rule: When stale_sidecar: true, use code chunks for implementation details but ignore metadata fields (summary, topics, component_names). Sidecar regeneration is handled server-side automatically.
Best Practices
- Start internal: Always check
docs/index.jsonfirst - Use agentHint: Match hints against current task for relevance
- Skip irrelevant levels: No RAG server? Skip L2, go directly to L4 (Grep/Glob codebase search) — never block on RAG availability
- Stop when sufficient: Don't search all levels unnecessarily
- Attribute sources: Note where each finding came from
- Validate staleness: Check dates on knowledge entries
- Expand keywords: Try synonyms if no results
- Combine results: Merge complementary findings
- Update knowledge: If external search yields new insight, capture it
Aspect Files
| File | Purpose |
|---|---|
search-strategy.md |
How to search each source |
priority-matrix.md |
Decision table for source priority |
Related Skills
knowledge-retrieval/references/knowledge-base.md— Knowledge system structureknowledge-capture— Persist new learningsdocs-seeker— External documentation retrievalresearch— Deep multi-source investigation
References
references/search-strategy.md— Source-specific search techniquesreferences/priority-matrix.md— Decision table for source selection
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