Chroma Patterns

Quick Guide: Use chromadb (v3.x) with @chroma-core/default-embed for automatic embedding. Chroma auto-embeds documents if no embeddings are provided -- just pass documents and ids to collection.add(). Use where for metadata filtering and whereDocument for document content filtering ($contains, $regex). Default distance metric is l2 (Euclidean); use cosine for most embedding models via configuration: { hnsw: { space: "cosine" } }. Query results return nested arrays (ids: string[][]) because queries are batched -- always access results.ids[0] for a single query. Include only the fields you need via the include parameter to reduce payload size.

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CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST install @chroma-core/default-embed alongside chromadb -- the default embedding function ships as a separate package since v3)

(You MUST access query results as nested arrays -- results.ids[0], results.documents[0] -- because Chroma batches queries and returns string[][] not string[])

(You MUST use the configuration parameter for HNSW settings -- the legacy metadata: { "hnsw:space": "cosine" } approach is deprecated)

(You MUST use flat metadata values only (string, number, boolean, typed arrays) -- nested objects are not supported and will be rejected)