fix(server): isolate Cursor metadata generation

[saphid]

Cursor generates titles, branch names, commit messages, and PR text from a prompt that already contains everything it needs. Starting those ACP requests in the real project directory exposes them to project files and instructions they do not need.

Each Cursor metadata request now starts in an empty temporary workspace, and the prompt tells Cursor to use only the supplied input. This follows #4169, which did the same for Claude. Relative configured binary paths still resolve from the original project. Endpoint, environment, and model settings are unchanged. The workspace is removed after the ACP child closes, on success, failure, or cancellation. Cleanup errors are logged and ignored so they don't discard generated output. This is also why the code uses an explicit acquireRelease instead of makeTempDirectoryScoped, whose finalizer calls orDie.

This isolates the workspace; it is not an OS sandbox. Only the Cursor implementation, its tests, and the mock ACP agent's prompt-started receipt change.

Verification

Rebased onto main at 4d06156dd; no conflicts.

• vp test run src/textGeneration/CursorTextGeneration.test.ts: 6 passed. Covers temp-workspace cwd, relative binary resolution, cleanup on success, failure, and cancellation, and output surviving a failed cleanup.
• tsc --noEmit for apps/server: passed.
• vp lint on the three touched files: passed.

Tests use the repo's mock ACP agent. No live Cursor run was done.

Coordination trace: T3 thread a837405b-3eae-403f-882c-f585e66419e5

Rebased and verified by Claude Opus 5 in Claude Code (via T3 Code).

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — The PR changes existing Cursor ACP behavior across four metadata-generation operations by introducing temporary workspaces, relative-binary resolution, prompt restrictions, and scoped cleanup. It also adds a line-level static-analysis suppression in the test suite, so the runtime changes and diagnostic override warrant human verification.

No code changes detected at 04bfcb7. Prior analysis still applies.

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[macroscopeapp]

Macroscope has since reviewed this pull request. An earlier review was skipped by a cost limit; a review has now completed, so that notice no longer applies.

[cursor]

This PR is too large for Bugbot to review. It changes 99,173 lines and 4,020,811 characters. Split the change into smaller pull requests to get a review.

[coderabbitai]

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Team

Run ID: 909d0378-ce6d-4ef2-8004-f9ce50801ece

📥 Commits

Reviewing files that changed from the base of the PR and between 08c715e and de8aa56.

📒 Files selected for processing (3)

• apps/server/scripts/acp-mock-agent.ts
• apps/server/src/textGeneration/CursorTextGeneration.test.ts
• apps/server/src/textGeneration/CursorTextGeneration.ts

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📝 Walkthrough

Walkthrough

Cursor ACP generation now runs in isolated temporary metadata workspaces, resolves relative binaries from the source directory, uses stricter JSON prompts, and validates cleanup during cancellation and cleanup failures.

Changes

Cursor metadata isolation

Layer / File(s)	Summary
Metadata workspace lifecycle apps/server/src/textGeneration/CursorTextGeneration.ts	runCursorJson creates and releases a temporary metadata workspace. Relative Cursor binaries resolve against the source directory. All generation call sites use sourceCwd.
Prompt contract and workspace assertions apps/server/src/textGeneration/CursorTextGeneration.ts, apps/server/src/textGeneration/CursorTextGeneration.test.ts	The prompt requires input-only processing and JSON-only output. Tests verify the isolated cwd, relative binary handling, ACP options, and prompt ordering.
Cancellation and cleanup validation apps/server/scripts/acp-mock-agent.ts, apps/server/src/textGeneration/CursorTextGeneration.test.ts	The mock agent atomically records prompt start. Tests verify workspace removal after cancellation and metadata preservation when cleanup fails.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Sequence Diagram(s)

sequenceDiagram
  participant TextGeneration
  participant FileSystem
  participant CursorACP
  TextGeneration->>FileSystem: Create metadata workspace
  TextGeneration->>CursorACP: Start with isolated cwd and JSON prompt
  CursorACP-->>TextGeneration: Return generated metadata
  TextGeneration->>FileSystem: Remove workspace on release

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Suggested reviewers: juliusmarminge, t3dotgg

Merge Risk: ⚪ Minimal · up to de8aa

Cursor metadata generation now uses an isolated temporary workspace while preserving source-relative binary configuration and cleaning up after completion, failure, or cancellation. No concrete merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
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.
Title check	✅ Passed	The title clearly and concisely identifies the main change: isolating Cursor metadata generation.
Description check	✅ Passed	The description explains what changed, why the change is needed, implementation details, scope limits, verification results, and the absence of UI changes. It does not use every template heading or in…

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[saphid]

Independent automated first-pass review (Amp/Astra agent mode) of head de8aa56 against upstream/main: no findings. Correctness, invariants, edge cases, Effect conventions, and performance all checked; temp-workspace scoping, relative binary-path resolution, and cleanup-on-failure semantics verified sound against the source. Nothing to address, no commits pushed.

[saphid]

Friendly review nudge @juliusmarminge @maria-rcks — this is mergeable and hasn't had a maintainer pass yet. Independent bot/agent reviews have run with findings triaged in-commit (see receipts in earlier comments). Full queue context and status: #10688.