retrieval-strategy

Retrieval Strategy

Pick a modality by what you know about the query × what you know about the corpus.

This skill is portable across GitHub Copilot, APM, and Claude Code. Each host installs it from the mbeacom/context-kit marketplace — register the marketplace (copilot plugin marketplace add, apm marketplace add, or /plugin marketplace add), then install retrieval-core@context-kit. It also ships automatically with code-search.

Decision flow

• Know the exact token / regex / filename? → lexical (rg, fd)
• Know the code shape, not the text? → structural (ast-grep, semgrep)
• Querying JSON / YAML / config by schema? → structured-data (jq, yq, gron)
• Asking when/why something changed? → history (git log -S/-G/-L)
• Tabular data at scale (CSV/Parquet)? → data files (duckdb, sqlite-utils)
• Sizing / complexity of a codebase? → metrics (tokei, scc)
• Content inside PDFs / Office docs / archives? → docs (rga, pandoc)
• Only know the meaning/intent, or corpus is huge / unfamiliar / prose? → semantic / RAG (local-rag: rag index then rag query)
• Corpus is an Obsidian vault / link graph? → graph (obsidian bridge: graph/tags → rag query --allowlist). For authoring/Bases/Canvas use kepano/obsidian-skills.

Lexical/structural/structured-data/history/metrics/docs live in code-search. Semantic and graph are available as the local-rag and obsidian plugins.

Composition (modalities are layers, not rivals)

• Hybrid rerank: narrow with lexical/structured-data or the obsidian graph → pipe candidate file paths to rag query --allowlist - (turbovec reranks only those).
• Scope then search: graph backlinks narrow to a subgraph → RAG within it.
• Find then pin: RAG surfaces candidate regions → rg pins exact lines.

Defaults

1. Start with the cheapest modality that fits (lexical is free and instant).
2. Narrow before widening; count matches (rg -c) before reading full output.
3. Escalate to semantic only when lexical/structural genuinely can't express the query (intent without known terms) or the corpus is too large/unfamiliar.
4. If a needed plugin (local-rag, obsidian) isn't installed, say so and suggest installing it — don't assume its tools exist.
5. If rtk is installed, prefix the rtk-wrapped commands (rg/git/find/ diff) for compact output — it passes other tools through unchanged. (See the code-search plugin's rtk reference.)