Dense vectors don't preserve numbers (BGE-small treats 'Figure 1' and
'Figure 10' as nearly identical), so a query like 'what does Figure 1
show' got out-ranked by chunks describing other figures that share more
vocabulary with the question — even after the figure-boundary chunker
ensured Figure 1's chunk started with the literal caption.
Detect 'Figure N' / 'Table N' (numbered, decimal, appendix-style)
references in the query, look up chunks that start with those captions
directly, and feed the result as a third RRF source. RRF gives them
rank-0 in the third ranking and the fused score lifts them above the
dense-vocabulary noise. No-ops when the query has no figure ref.
Dense embedders mean-pool over a whole chunk, so a 'Figure 1:' caption
buried at the end of a 500-token body chunk gets washed out by the
surrounding theory text and never surfaces for queries about that
figure. Pre-split each page's markdown at the start of every
Figure/Table caption line so the caption anchors its own chunk, which
gives both BM25 and the dense vector a focused, figure-dominated
target. Handles numbered, decimal, and appendix-style labels
(Figure 1, Figure 1.2, Figure B.1, Table 4, Fig./Tab. abbreviations).
Reasoning models (gemma-4, qwen3-thinking) burn the entire max_tokens
budget on <thinking> output and return empty visible content, so the
captioner produced zero captions for every image. Pass
chat_template_kwargs={enable_thinking: false} per-request to skip the
reasoning phase, and bump max_tokens 120 -> 200 as headroom.
Both modules used stdlib logging.getLogger which is not bridged to the
project's structlog config, so every probe / captioner log was silently
dropped. Switch to loggers.get_logger and convert %-format calls to
structlog kwargs so the captioning path becomes observable.
Four valid review comments from gemini-code-assist[bot] on #5759:
1. core/rag/bm25.py:_load — wrap bm25s.BM25.load + json.loads with
specific exception handlers (FileNotFoundError, OSError,
JSONDecodeError, ValueError) and log a warning instead of
propagating a 500. Corrupt/partial bm25 dirs now degrade to
empty-search rather than crashing the request.
2. core/rag/tool.py was importing _resolve_scope_embedder from
routes/rag.py — a layering violation (core depending on
routes). Move the resolver into a new core/rag/scope.py module
along with the chat-settings key constants; routes/rag.py
now re-imports it under the same name. Same behaviour, no
cycle, one source of truth for the resolution logic.
3. core/rag/bm25.py:rebuild_index — call delete_scope before saving
the new index so stale files from a previous build (or a
bm25s naming change) never coexist with current files. The
library's save() doesn't unlink files it doesn't write.
4. routes/rag.py:_save_upload was running f.write() synchronously
inside an async def. Switch to anyio.open_file() so each chunk
write runs in a worker thread instead of blocking the event
loop on multi-MB uploads. Cleanup unlink happens after the
async-with closes the handle so Windows is happy.
Skipped one (vector_store.py:133 'hasattr query_points' redundancy)
— that comment was on the pre-rewrite Qdrant code; the file is
now sqlite-vec backed and the hasattr check is gone.
core/rag/db.py, vector_store.py, tool.py, bm25.py, and reranker.py
all run only in the FastAPI parent process. Switch their loggers
from Python stdlib to studio's structlog get_logger so their output
shows up in the same JSON stream as the rest of the backend (the
request_completed / RAG search lines).
embeddings.py and ingestion.py stay on stdlib because they execute
inside the mp.spawn ingestion subprocess, which doesn't inherit the
parent's structlog configuration.
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.
The query was always going through the default text embedder
(bge-small, 384-d) regardless of how the scope was ingested. A
multimodal thread indexed by Qwen3-VL (2048-d) crashed at cosine
similarity with 'shapes (104,2048) and (384,) not aligned'.
Resolve the scope's embedder at search time:
- kb_<id> -> rag_knowledge_bases.embedding_model column
- thread_<id> -> thread settings (with fallback to defaults +
RAG_EMBEDDER_MATRIX matrix lookup)
Pass it through retrieve_hybrid/retrieve_dense to embeddings.encode
so the query lands in the same vector space as the docs. Both the
/api/rag/search route and the search_knowledge_base tool use the
same resolver.
BGE-VL inherits CLIP's 77-token text positional embedding table —
longer chunks crash inside the text model with a shape mismatch.
Pre-tokenize with truncation=True, max_length=77 and call
get_text_features directly so the high-level encode() (which does
not truncate) is bypassed. Log when truncation happens — text
chunks beyond the cap are silently cut, so multimodal mode is
lossy on the text channel. Image channel is unaffected.
BGE-VL's sentence-transformers shim (bge_vl_clip_transformer.py)
is coupled to specific ST internals and broke across both the 5.2
and 5.3 pin attempts. The canonical load path documented at
bge-model.com is transformers.AutoModel with trust_remote_code +
model.set_processor() + model.encode(text=/images=).
- Wrap that path in _BGEVLAdapter exposing the slice of
SentenceTransformer API the ingester uses (encode for text or PIL
images, get_sentence_embedding_dimension, best-effort tokenize).
- Restore BAAI/BGE-VL-base in RAG_EMBEDDER_MATRIX.
- Revert sentence_transformers pin to 5.2.0 — no longer relevant
since the multimodal path no longer touches ST.
BGE-VL (multimodal) and nomic-embed-text-v1.5 (late chunking) both
ship custom modeling code in their model repos; sentence-transformers
refuses to import the referenced module (e.g. bge_vl_clip_transformer)
without trust_remote_code=True. Safe to enable because the embedder
matrix is config-pinned — users don't supply arbitrary names.
client.search() was removed/renamed to query_points() in
qdrant-client 1.10+. Use the new API when available and fall back
to search() for older pinned versions.
- chat-adapter pre-fetches retrieval on every turn when RAG is on,
regardless of provider. Users no longer have to phrase queries as
'the document I attached' for retrieval to fire. Local tool models
still get search_knowledge_base registered as a refinement path.
- New per-thread ragMinScore slider (Min relevance, 0..1) gates
retrieved hits by dense cosine similarity. Hits below the floor
(and BM25-only hits with no dense signal) are dropped server-side
so unrelated docs don't get injected when the user's query is
off-topic from what's indexed.
- Backend logs at search start (scope, top_k, min_score, query
preview), after retrieval (retrieved vs met_threshold counts),
and on return (final hit count) for both /api/rag/search and the
search_knowledge_base tool path.
- System-prompt nudge prepended when pre-fetch returns hits so the
model knows to cite [1], [2] rather than paraphrase silently.
Promotes RAG to a first-class composer toggle alongside Think / Web
Search / Code, with tool-use semantics on local models that support
tools and a pre-fetch fallback on external providers. The model
decides when to call `search_knowledge_base` on local inference; on
external providers retrieval still fires before each message (the
existing pre-fetch path), gated on the same button.
Backend
- core/rag/tool.py (new): search_knowledge_base handler + JSON-schema
tool spec. Resolves scope (kb_id wins over thread_id) from the
request's rag_scope, runs retrieve_hybrid + optional rerank, then
hydrates filename / page_number / text from sqlite and formats as
numbered Markdown citations ('[1] file.pdf (page 5): ...') for the
LLM to cite. Empty scope returns a user-facing hint; empty results
return a clear no-match message instead of an empty string.
- core/inference/tools.py: SEARCH_KNOWLEDGE_BASE_TOOL added to
ALL_TOOLS (lazy import keeps tools.py importable on inference
paths that never touch RAG). execute_tool() gains a tool_context
parameter that carries per-request extras the LLM doesn't see
(currently just rag_scope). The new 'search_knowledge_base' branch
dispatches to the handler with scope unpacked from tool_context.
- core/inference/llama_cpp.py + safetensors_agentic.py +
orchestrator.py: thread tool_context through generate_chat_completion_
with_tools / run_safetensors_tool_loop / execute_tool. Both local
backends (GGUF llama-server and safetensors agentic) carry the same
context object.
- models/inference.py: ChatCompletionRequest gains optional
rag_scope: dict ({kb_id?, thread_id?, enable_rerank?, default_top_k?,
reranker_model?}). Ignored unless 'search_knowledge_base' is in
enabled_tools.
- routes/inference.py: both the GGUF and safetensors call sites for
generate_chat_completion_with_tools forward payload.rag_scope into
tool_context.
Frontend
- chat-runtime-store.ts: global ragToolEnabled boolean + setter +
CHAT_RAG_TOOL_ENABLED_KEY localStorage, mirroring toolsEnabled /
codeToolsEnabled. Settings-hydration migration auto-flips
ragToolEnabled=true for pre-Phase-4 users who already had ragSource
set, so existing RAG users don't silently lose retrieval on upgrade.
- shared-composer.tsx: new 'RAG' pill button after Images (uses
lucide BookOpenIcon, composer-pill-btn style, data-active toggle).
Disabled when no model is loaded. Toggling on from ragSource='off'
auto-flips source to 'thread' so the sidebar lands ready-to-go.
- chat-adapter.ts:
* The existing pre-fetch block is now gated on ragToolEnabled AND
only fires when the tool path isn't viable (external provider OR
local model without tool-use support). Tool-capable local models
skip pre-fetch and let the LLM decide.
* The local-model body assembly adds 'search_knowledge_base' to
enabled_tools and packs ragSource + enableRerank + ragTopK into a
rag_scope object the backend tool handler consumes.
- chat-settings-sheet.tsx: entire Retrieval CollapsibleSection is
wrapped in {ragToolEnabled && ...} so it hides when the button is
off — the button is now the single on/off control. The 'Off'
option is removed from the Source dropdown (the button handles
that). Default open when shown so settings are one click away.
Tests
- test_rag_tool_handler.py: handler covers empty query, missing
scope, kb_id > thread_id precedence, thread-only path, citation
formatting (numbered + page numbers + unknown source); tool spec
shape (function/name/required); execute_tool dispatch with and
without tool_context; ALL_TOOLS includes the new spec without
dropping the existing ones.
Verification scope
- Local GGUF with tools: toggle button on, upload doc, ask about
doc content → assistant emits a search_knowledge_base tool call
card (rendered by the existing ToolFallback component since no
custom UI exists yet — that's a v2 nice-to-have).
- External provider (Anthropic / OpenAI / etc.): same button, same
UX, but uses the pre-fetch path under the hood.
- Migration: pre-existing ragSource != off → button initializes ON
so retrieval keeps working.
When a KB has mode = 'multimodal', ingestion extracts images alongside
text and embeds both into a shared 512-d vector space via BGE-VL-base.
Image hits become first-class search results — useful for slides,
reports, and diagrams where text-only retrieval loses ~30-50% of the
content.
Backend
- embeddings.py: new encode_images(image_bytes_list) — opens bytes via
PIL and routes to the SentenceTransformer (BGE-VL accepts PIL images
in the same encode call as text).
- ingestion.py: _subprocess_worker gains document_id arg and a new
_stream_image_chunks() helper. For multimodal KBs the standard text
chunking runs first, then images are saved to
rag_uploads_root() / 'images' / <document_id> / img-NNNN.<ext> and
embedded; for each image with an adjacent caption, both an
'image'-kind chunk (vector = encoded image) and a 'caption'-kind
chunk (vector = encoded caption text) are streamed back with a
shared pair_group field.
- ingestion.py parent: _insert_chunks_and_collect_for_bm25 now reads
kind / image_path / pair_group from the subprocess message,
populates the new rag_chunks columns, and runs a second pass that
sets linked_chunk_id for each image ↔ caption pair. BM25 indexes
text + caption chunks only — image chunks have no tokenisable body.
- retrieval.py: Hit gains a `kind` field plumbed through bm25, dense,
RRF, and rerank paths.
- reranker.py: image-kind hits skip CrossEncoder rerank (text-only
model) but are appended back in their original relative position
rather than dropped.
- routes/rag.py: new GET /api/rag/images/{document_id}/{filename}
static-file route with realpath containment check. SearchHit gains
`kind` and `image_url` fields so the chat UI can render image
thumbnails alongside text hits. KB-doc upload threads kind/mode
through to ingestion.
Frontend
- rag-api.ts: SearchHit gains optional `kind` and `image_url`.
- kb-create-dialog.tsx: new Mode select (Text / Multimodal) alongside
the existing Chunking strategy select. The forbidden
(multimodal + late) combo is enforced in the UI — each side
disables the conflicting option on the other side with a tooltip
explaining why. Embedding-model placeholder cycles through the
three valid defaults (bge-small / nomic / BGE-VL).
- kb-list.tsx + chat-settings-sheet.tsx: 🖼️ MM badge alongside the
⚡ Late one so multimodal KBs are obvious at a glance.
Tests
- test_rag_multimodal.py: parser returns images when want_images=True
and skips them when False; _validate_mode_combo rejects the
forbidden (multimodal, late) pair with 400; RAG_EMBEDDER_MATRIX
contains the three valid combos and excludes the forbidden one;
image URL construction shape is verified. A server-marked test
loads BGE-VL-base end-to-end and confirms image + text vectors
share the same dimension.
Phase 3 of the plan is now feature-complete on the backend; the
remaining items (re-ingest UX for changing strategy on existing KBs)
are tracked under "Backfill UX" and can land separately.
When a KB has chunking_strategy = 'late', ingestion takes a separate
code path that embeds the full document in a single forward pass and
mean-pools token embeddings per chunk span. Each chunk vector carries
full-document context via the encoder's bidirectional attention —
Jina's published technique, ~+6.5 nDCG@10 on long docs.
Backend
- chunking.py: new chunk_pages_with_spans() that joins all pages into a
single full_doc, runs the existing recursive splitter, and returns
per-chunk (char_start, char_end) offsets. Page-number metadata is
recovered by overlap with the original page ranges so PDF citations
still work. Existing chunk_pages() unchanged.
- embeddings.py: new late_chunk_encode(doc_text, char_spans). Tokenizes
the doc with return_offsets_mapping, runs the underlying transformer
to get per-token last_hidden_state, then mean-pools per chunk span.
When the doc exceeds the embedder's context, falls back to windowed
late chunking with a 512-token overlap so cross-window context is
partially preserved.
- ingestion.py _subprocess_worker: branches on chunking_strategy.
'late' path: chunk_pages_with_spans -> late_chunk_encode -> one big
chunks_batch message. 'standard' path unchanged. Both reuse the same
parent-side pump.
- ingestion.enqueue_ingestion: new chunking_strategy + mode kwargs;
defaults to 'standard' / 'text' for legacy callers. embedder model
resolved via resolve_embedder() from the (mode, strategy) matrix.
- routes/rag.py: KB-doc upload reads chunking_strategy + mode from the
KB row (defensive .get for pre-Phase-3 schemas) and threads them
through _start_ingestion.
Frontend
- kb-create-dialog.tsx: new "Chunking strategy" select with Standard /
Late options. Embedding-model placeholder switches to nomic when
Late is picked. createKB request now carries chunking_strategy.
- kb-list.tsx + chat-settings-sheet.tsx: small "⚡ Late" badge next to
late-chunking KB names in the settings KB list and the chat sidebar
dropdown so users see the mode at a glance.
Tests
- test_rag_late_chunking.py: pure-python tests for chunk_pages_with_spans
(chunks index back into full_doc; page numbers inherited by overlap;
pages joined with blank line). A server-marked test loads
all-MiniLM-L6-v2 to exercise late_chunk_encode end-to-end.
No multimodal yet; that's Phase 3B-multimodal (next PR).
Replace bare-pypdf/python-docx/BeautifulSoup extraction with Markdown-
preserving parsers so the chunker can split on real heading boundaries
instead of running paragraphs together.
Parsers
- pdf.py: pymupdf + pymupdf4llm.to_markdown() per page; pypdf kept as
fallback when pymupdf can't open the file.
- docx.py: mammoth.convert_to_html() + markdownify, with an explicit
style_map so Title/Heading 1..6 become h1..h6 in the output.
- html.py: BeautifulSoup pre-scrub (drop script/style) then markdownify
so <h*>, <table>, <ul> convert faithfully.
- text.py: signature update only; TXT/MD pass through unchanged.
- parsers/__init__.py: new ParsedImage + ParseResult dataclass; parse()
signature is now parse(path, *, want_images=False) -> ParseResult.
ParseResult is iterable over .pages for backward compat.
Chunker
- chunking.py: prepend Markdown heading separators ("\n# " .. "\n#### ")
to the priority list so heading-aware splits happen for free once the
parsers emit Markdown.
Ingestion
- ingestion.py: single call site updated to consume ParseResult.pages.
Deps (no-torch-runtime.txt)
+ pymupdf>=1.24, pymupdf4llm>=0.0.17, mammoth>=1.7, markdownify>=0.13
- pypdf kept as a fallback path.
Tests
- test_rag_parsers.py asserts Markdown headings survive PDF/DOCX/HTML
extraction; also exercises ParseResult iteration backward-compat.
- test_rag_chunking.py: new case verifying chunks start at Markdown
heading boundaries when the input is Markdown.
Foundation for Phase 3B-late (heading-aware spans for late chunking)
and Phase 3B-multimodal (want_images=True enables image extraction in
the same parser layer). No schema or opt-in flags in this commit.
