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.
Snapshot taken before fast-forwarding feature/rag to origin and merging main.
Bundles in-flight work so the merge has a clean tree:
Frontend
- PDF preview panel (preview-panel, preview-pdf-view, preview-text-view,
preview-unavailable) with lazy-rendered page thumbnail rail
- Resizable preview slot via useResizablePanelWidth hook (drag handle,
localStorage persistence, viewport clamping)
- Neutral scrollbar + Source Excerpt card restyle (no brand-coloured rail)
- Preview-store + chat-adapter / rag-api / kb-detail wiring
- Frontend test harness (vitest.config, setupTests, biome update) and the
paired __tests__ suites for preview, sources, document-row, chat-adapter,
rag-api, knowledge-bases-tab, search-knowledge-base-tool-ui
Backend
- RAG locator + authorization modules with chunking / retrieval / tool /
vector_store / studio_db updates
- Paired test_rag_* suites (authorization, locators, locator_backfill,
locator_migration, preview_routes, preview_target_locators, source_identity)
Other
- tests/fixtures/rag-preview for preview route fixtures (sample.pdf,
sample.txt, make_fixture_pdf.py)
- .gitignore + package(-lock).json adjustments for the new test runner
Will be squashed/reworked via interactive rebase after main is merged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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).
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.
