Phase 2 — Chunking and indexing
- rag/chunk.py: replace template chunker with seed-variety-specific
chunks_from_variety(). One chunk per variety (varieties are small
and named-rating retrieval signal is best kept together). Output
is rebuilt deterministically from the sidecar JSON: every value is
verbatim from the source, only framing language ("Disease ratings
(1-9, 9=best):") is template glue. Anti-hallucination contract:
same sidecar in → same chunk out, never a fabricated rating.
Metadata flattened to Chroma-safe primitives (str/int/float/bool):
source, source_key, vendor, brand, crop, product_name,
product_id, source_url, rm (corn), mg (soy), wheat_class,
release_year, trait_codes_csv, rating_scale.
- rag/index.py: walks corpus/<source>/<source_key>.json sidecars
via the new chunker. Default PRODUCT_NAME=crop_seed so the
Chroma collection is crop_seed_docs.
- rag/bm25.py: filterable columns updated to seed-domain facets
(source/vendor/brand/crop/source_key) instead of the template's
version/platform/product.
Phase 3 — MCP server tools wired up
- search_docs: hybrid dense (Chroma) + BM25 (FTS5) retrieval with
RRF fusion. Optional filters: crop, brand, vendor, source.
Variety-code prefilter pins exact source_key / product_name /
hybrid_prefix matches at the top — dense embeddings have no
semantic neighbor for tokens like "DKC62-08RIB" and RRF can let
noise float to #1 without this pin. Each response carries the
variety's source URL inline so the agent can cite.
- get_page(source, source_key): emits a structured ratings header
(verbatim from sidecar, table per characteristics group, vendor
positioning, regional listings) followed by the raw indexed body.
This is the canonical fact-check surface.
- list_versions(): facet discovery — distinct sources, vendors,
brands, crops across the corpus.
- lookup_variety(source_key, source?): returns the raw sidecar JSON
for one variety. The agent should call this BEFORE quoting any
specific rating value to a farmer — guaranteed verbatim.
Smoke tests against 475 indexed Bayer varieties:
- list_versions returns 475 varieties, 1 source, 1 vendor, 3 brands,
3 crops with correct per-brand counts (288/102/85).
- Semantic ag queries find the right candidates: short-season
drought-tolerant corn → DKC44-97RIB at RM 94 (in 90-95 band);
SCN+MG3 soybean → Asgrow XF varieties with explicit SCN R3 ratings;
Phytophthora Rps3a soy → AG07XF4 (right gene); stripe-rust
wheat → WestBred WB1376CLP (Yellow Rust 2 = best).
- Variety-code lookups work via prefilter: DKC62-08RIB, AG29XF4,
WB6430 all return as #1 hit. BM25 confirms ranking unambiguously
(top-1 score -13.2 vs -8.5 for #2 on "DKC62-08RIB ratings").
- Server boots cleanly in stdio AND streamable-http modes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
justin