perf(search): fetch Lucid page regions concurrently on a live read

[waleedlatif1]

Summary

• A Lucid live read made about 11 MCP calls one after another: metadata, a metadata-only manifest, one fetch per page region (up to 8), then metadata again. At 1–2 s per call, reads ran past the 15 s live read deadline and failed with MCP error -32001: TimeoutError.
• The first metadata call and the manifest now run together, and region fetches run four at a time. That's three rounds of latency instead of up to 11.
• Validation still walks the responses in page and region order, and the before/after document-change checks and the content size cap are unchanged.

Test plan

• New lucid-mcp.test.ts: region fetches overlap and are assembled in page and region order even when they finish in reverse. It fails on the old code (max in-flight = 1).
• CI

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1 Skipped Deployment

Project	Deployment	Actions	Updated
docs	Skipped		Oct 10, 2026 9:03pm UTC

[cubic-dev-ai]

All reported issues were addressed across 2 files

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[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; no new actionable issue was found.

Summary

Lucid live reads fetch metadata and the manifest together, then fetch regions through a four-call window.

• Lucid reads fetch page regions four at a time.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  A[Read metadata and manifest together] --> B[Check identity and coverage]
  B --> C[Start up to four region reads]
  C --> D[Await next region in document order]
  D --> E{Response valid and content within limit?}
  E -->|No| F[Reject without scheduling more]
  E -->|Yes| G[Start next queued region]
  G --> H{More regions?}
  H -->|Yes| D
  H -->|No| I[Read metadata again]
  I --> J{Document unchanged?}
  J -->|Yes| K[Return complete content]
  J -->|No| F

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_{Reviews (2) · Last reviewed commit: "fix(search): stop scheduling Lucid regio..." · Reviewed by Greptile}

[waleedlatif1]

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[waleedlatif1]

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[cubic-dev-ai]

No issues found across 3 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

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