Shorten and condense comments across the RAG backend, frontend, and
tests for readability. Comment text only; no code, strings, identifiers,
or logic changed. License headers and lint/type pragmas are preserved.
asg017/sqlite-vec is Apache-2.0 and OSI-approved. Replaces
qdrant-client (~30 MB) with a small SQLite extension loaded into a
dedicated rag.db file. Single file holds RAG vectors; bm25s indexes
and chat-side studio.db are unaffected.
- New core/rag/db.py owns the rag.db connection and sqlite-vec load.
Extension load runs once at first open. Process-wide singleton
protected by a lock; check_same_thread=False + WAL handles the
FastAPI thread pool.
- core/rag/vector_store.py keeps the same public API
(ensure_collection / upsert_chunks / search / collection_exists /
delete_scope / delete_document) so callers in routes/rag.py,
core/rag/ingestion.py, core/rag/tool.py, and core/rag/retrieval.py
don't change. ensure_collection is now a no-op; collection_exists
returns True iff the scope has at least one indexed vector.
- search uses sqlite-vec's vec_distance_cosine and converts distance
to similarity in [0, 1] so the per-scope min_score threshold
semantics stay identical.
- Mixed-dim scopes coexist behind WHERE scope = ? — the per-scope
embedder resolver guarantees one embedder per scope.
- requirements/rag.txt swaps qdrant-client for sqlite-vec.
- utils/paths/storage_roots.py drops rag_vectordb_root() (the old
qdrant directory); rag.db lives directly under rag_root().
- Rewritten tests/python/test_rag_vector_store.py for the new
semantics (collection_exists tracks populated scopes; new tests
for filtered search and upsert conflict resolution).
Python build requirement: connection.enable_load_extension(True)
must be available. install.sh creates the venv via uv-managed
python-build-standalone, which is compiled with
--enable-loadable-sqlite-extensions, so this works on standard
installs. core/rag/db.py raises an actionable error on the rare
custom-interpreter case.
