ADE-104 External session import: Codex project-scope discovery can truncate at the 2000-file scan ceiling -> Primary

[arul28]

Fixes ADE-104

Linked Linear issues

• ADE-104: External session import: Codex project-scope discovery can truncate at the 2000-file scan ceiling - closes on merge

  Open in ADE  ·  ade-104-external-session-import-codex-project-scope-discovery-can-truncate-at-the-2000-file-scan-ceiling branch  ·  PR #892

Summary by CodeRabbit

• Bug Fixes

  • Improved project-scoped Codex session discovery, including projects with many newer sessions outside the selected project.
  • Excluded Codex subagent rollouts from discovered sessions.
  • Improved session metadata handling for titles, working directories, creation times, and import eligibility.

• Performance

  • Added caching to make repeated project-scoped Codex session discovery faster and more reliable.

Greptile Summary

This PR improves Codex external session discovery for project-scoped imports. The main changes are:

• Adds a rebuildable cwd/importability index for Codex rollout metadata.
• Removes the fixed project-scope scan limit that could hide older in-scope sessions.
• Excludes structured-source Codex subagent rollouts from importable sessions.
• Adds tests for large rollout inventories, index rewrite batching, and subagent filtering.
• Updates external session import docs for the new Codex discovery behavior.

Confidence Score: 5/5

Safe to merge with low risk.

The changes are localized to Codex external-session discovery, add targeted tests for the previous truncation failure and cache behavior, and preserve existing non-scoped discovery paths.

No files require special attention.

T-Rex Logs

What T-Rex did

• The pre-proof environment state was captured from Ade104-01-before.log, showing 2,001 outside sessions and 1 project session.
• The real targeted Vitest run was validated against Ade104-02-after.log, which shows the run completed successfully with 1 test file passed, 2 tests passed, 14 skipped, and exit code 0.
• The test source used for validation was copied to Ade104-used-discoverProviders.test.ts and the copy was logged in Ade104-used-test-copy.log.

_{Ran code and verified through T-Rex}

Important Files Changed

Filename	Overview
apps/desktop/src/main/services/externalSessions/discoverCodex.ts	Replaces the fixed project-scope scan limit with a rebuildable Codex cwd/importability index and excludes object-shaped subagent source metadata.
apps/desktop/src/main/services/externalSessions/discoverProviders.test.ts	Adds coverage for project-scoped discovery beyond 2,000 newer rollouts, index rewrite batching, and subagent rollout exclusion.
docs/features/terminals-and-sessions/external-session-import.md	Updates external session import documentation to describe the Codex scope index and stricter source/importability behavior.

Sequence Diagram

sequenceDiagram
  participant Caller as External session list
  participant Discover as discoverCodexSessions
  participant FS as Codex sessions dir
  participant Index as ADE cwd/importability index

  Caller->>Discover: request Codex sessions with scopeRoots
  Discover->>Index: load cached scope index
  Discover->>FS: stat rollout inventory
  loop each rollout file
    alt missing or changed index entry
      Discover->>FS: read session_meta prefix
      Discover->>Index: refresh mtime/size/meta entry
    else unchanged
      Index-->>Discover: reuse cached meta
    end
  end
  Discover->>Discover: filter importable sessions in scope
  Discover->>Index: write immediately or schedule batched rewrite
  Discover-->>Caller: sorted Codex session summaries

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_{Reviews (2): Last reviewed commit: "Refs ADE-104: ship: iteration 1 — batch ..." | Re-trigger Greptile}

[linear-code]

ADE-104

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
ade	Ignored	Preview	Jul 24, 2026 7:15am

[coderabbitai]

📝 Walkthrough

Walkthrough

Codex discovery now parses session metadata directly, derives importability from payload fields, and uses cached per-directory indexes for project-scoped rollouts. Discovery processing and tests cover indexed scope filtering and exclusion of object-shaped subagent sources.

Changes

Codex discovery

Layer / File(s)	Summary
Metadata parsing and importability apps/desktop/src/main/services/externalSessions/discoverCodex.ts	Adds bounded binary session_meta parsing, explicit importability evaluation, and candidate collection separated from mtime sorting.
Project-scoped indexing apps/desktop/src/main/services/externalSessions/discoverCodex.ts	Adds validated on-disk scope indexes with in-memory caching, changed-file refreshes, deduplication, and atomic-style writes.
Discovery integration and tests apps/desktop/src/main/services/externalSessions/discoverCodex.ts, apps/desktop/src/main/services/externalSessions/discoverProviders.test.ts	Uses metadata for JSONL filtering and fields, preserves JSONLZST handling, and tests scoped indexing plus subagent exclusion.

Estimated code review effort: 4 (Complex) | ~45 minutes

Possibly related PRs

• arul28/ADE#797: Also changes Codex session discovery logic in discoverCodex.ts.

Suggested labels: desktop, docs

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the Codex project-scope discovery fix and matches the PR’s main change.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch ade-104-external-session-import-codex-project-scope-discovery-can-truncate-at-the-2000-file-scan-ceiling

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[coderabbitai]

🧹 Nitpick comments (1)

apps/desktop/src/main/services/externalSessions/discoverCodex.ts (1)

605-611: 🚀 Performance & Scalability | 🔵 Trivial

Full-index rewrite on any single-file change may amplify writes on large Codex dirs.

indexChanged flips whenever one rollout's mtimeMs/size differs — which happens on every discovery while the current-day session is still being appended to. Each such run re-serializes and rewrites the entire index (all entries), so on a directory with thousands of rollouts this becomes a large JSON write on nearly every scoped discovery. Consider debouncing writes, batching, or only rewriting past a change threshold if this path runs frequently.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@apps/desktop/src/main/services/externalSessions/discoverCodex.ts` around
lines 605 - 611, Reduce full-index rewrites in the discovery flow around
indexChanged and writeCodexScopeIndex: avoid serializing and writing the entire
index for every single rollout mtimeMs/size update during active sessions.
Implement a scoped batching, debounce, or change-threshold policy while
preserving index updates and ensuring accumulated changes are eventually
persisted.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@apps/desktop/src/main/services/externalSessions/discoverCodex.ts`:
- Around line 605-611: Reduce full-index rewrites in the discovery flow around
indexChanged and writeCodexScopeIndex: avoid serializing and writing the entire
index for every single rollout mtimeMs/size update during active sessions.
Implement a scoped batching, debounce, or change-threshold policy while
preserving index updates and ensuring accumulated changes are eventually
persisted.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 8c51085d-2750-434b-b0d6-3129a0e8c1ce

📥 Commits

Reviewing files that changed from the base of the PR and between bcd019d and d3c3023.

⛔ Files ignored due to path filters (1)

• docs/features/terminals-and-sessions/external-session-import.md is excluded by !docs/**

📒 Files selected for processing (2)

• apps/desktop/src/main/services/externalSessions/discoverCodex.ts
• apps/desktop/src/main/services/externalSessions/discoverProviders.test.ts

[arul28]

@codex review

[chatgpt-codex-connector]

Codex Review: Something went wrong. Try again later by commenting “@codex review”.

Unknown error

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[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. More of your lovely PRs please.

Reviewed commit: 16f8a535c0

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".