[Fix] Architect mode fails to save plans with EROFS when creating /plans at filesystem root

[zoomote]

Opened on behalf of Toray Altas. View the task or mention @zoomote for follow-up asks.

Related GitHub Issue

Closes: #965

Description

In Architect mode, Zoo attempted to create a plans directory at the absolute filesystem root (/plans) and failed with EROFS: read-only file system, mkdir '/plans'.

Root cause: the Architect mode customInstructions in packages/types/src/mode.ts ended with "if you want to save a plan file, put it in the /plans directory". The leading slash leads models to interpret /plans as an absolute path instead of a workspace-relative one, so write_to_file / execute_command (mkdir /plans) targeted the real filesystem root.

The instruction now reads "put it in the ./plans directory (a directory named "plans" relative to the workspace root, not the absolute filesystem path /plans)". A repo-wide search confirmed this prompt text was the only place an absolute /plans path was instructed. The 10 affected system-prompt snapshot files were regenerated/updated to match.

Test Procedure

• pnpm test (full turbo run, forced uncached): all 10 tasks successful — 414 test files / 6786 tests passed in the main package, including the system-prompt snapshot tests that assert the Architect mode instructions.
• Pre-commit hooks ran lint and check-types across all packages: all green.
• Reviewers can verify by inspecting the Architect mode system prompt (e.g., via the snapshot src/core/prompts/__tests__/__snapshots__/add-custom-instructions/architect-mode-prompt.snap) and confirming it references ./plans relative to the workspace root.

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Testing: New and/or updated tests have been added to cover my changes (if applicable).
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Screenshots / Videos

N/A — prompt-text change only; no UI surface is affected.

Documentation Updates

• No documentation updates are required. The docs site does not document the /plans behavior; this restores the intended workspace-relative behavior.

Additional Notes

Optional future hardening (out of scope here): normalizing or rejecting workspace-escaping absolute paths in write_to_file so an absolute /plans path resolves inside the workspace or is rejected with a clear error.

Linked work items

Closes #965

[zoomote]

No code issues found. See task

Verified in context: the /plans → ./plans prompt rewording in packages/types/src/mode.ts:185 is the only place the absolute path was instructed (repo-wide search), all 10 system-prompt snapshots were regenerated consistently with no stale copies remaining, the existing .gitignore entry plans/ matches the workspace-relative directory, and the file passes the repo's Prettier config. The write_to_file path-hardening idea is already noted in the PR description as explicit future scope.

_{Reviewed f2f5e62}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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