Two related bugs surfaced in production while viewing chunks from the
Astrolabe frontend on the AWS-hosted MCP server:
1. PyMuPDF document closed: in _fetch_document_text the fallback path
referenced pdf_doc.page_count after pdf_doc.close(), raising
"document closed" and returning None. The slow PDF re-parse already
completed but its result was discarded. Capture page_count into a
local before close().
2. Slow/fragile chunk lookup: get_chunk_with_context filtered Qdrant by
(chunk_start_offset, chunk_end_offset). Those fields are not part of
the always-indexed payload schema, and with strict_mode enabled they
yield 400 errors. Even with manually-added indexes the filter is
fragile if a doc is re-chunked. Switch to chunk_index (always
indexed) as the primary lookup key, falling back to offset-based
lookup when callers don't supply it.
Plumb chunk_index/total_chunks through both the management API
(api/visualization.py) and the OAuth viz route (auth/viz_routes.py).
Apply the same change to the highlighted-image lookup so all four
chunk-context Qdrant queries prefer the indexed field.
Skip the slow PDF re-parse fallback entirely for files: when both the
chunk_index and offset Qdrant lookups miss, re-downloading and
re-parsing the source PDF won't find the chunk either, and routinely
exceeds 30s on large documents - which is the proxy timeout in
Astrolabe. Notes/cards keep the document-fetch fallback (cheap).
Removes dead code (_get_file_path_from_qdrant) that was only used by
the now-unreachable file fallback path.
Companion change in the Astrolabe app passes chunk_index from search
results through to the new endpoint params.
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_This PR was generated with the help of AI, and reviewed by a Human_
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
