Detect Bun-managed Codex CLI

[jagadhis]

What changed

MonoCode now checks ~/.bun/bin/codex when resolving the Codex CLI.

Why

Apps such as T3 can provision Codex in ~/.bun/bin, while GUI processes may not inherit that directory through PATH. MonoCode could therefore report an existing Codex installation as unavailable.

This is the discovery-only slice of #81. Downloading and executing an installer from the application is intentionally excluded and will require a separate review covering Windows support, integrity and update behavior, failure recovery, and the security boundary.

UI

No UI changes.

Checklist

• I ran npm run check:rust
• This PR is small and focused
• I did not mix unrelated changes

Summary by CodeRabbit

• Bug Fixes
  • Codex CLI detection now also supports installations located in the user’s ~/.bun/bin directory.

[hardbeat920]

Could we split this into two PRs?
Detecting ~/.bun/bin/codex is a small, safe fix we can land now.

Downloading and executing an installer from the application needs a separate review covering Windows support, integrity/update behavior, failure recovery, and the security boundary.

[jagadhis]

Split as requested. This PR now contains only the ~/.bun/bin/codex discovery change, rebased onto current main. The in-app installer, UI, bridge, and documentation changes have been removed and remain separate pending the broader Windows, integrity/update, recovery, and security review.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Advanced

Run ID: 2dd93e2f-0a9a-4a62-a0ed-549a2b7a2226

📥 Commits

Reviewing files that changed from the base of the PR and between 36d6d28 and e776fbb.

📒 Files selected for processing (1)

• src-tauri/src/harness.rs

Included review availability: Your plan provides up to 4 included reviews per hour; 3 remain after this review.

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📝 Walkthrough

Walkthrough

The Codex resolver now checks ~/.bun/bin/codex in addition to its existing candidate paths.

Changes

Codex resolution

Layer / File(s)	Summary
Bun-managed Codex path src-tauri/src/harness.rs	resolve_codex now includes ~/.bun/bin/codex among the paths it checks.

Priority: ➖ Normal

Estimated code review effort: 1 (Trivial) | ~2 minutes

Change: Bug fix · Severity of issue fixed: Medium

Suggested reviewers: hardbeat920

Merge Risk: ⚪ Minimal · up to e776f

This change safely expands Codex discovery to Bun-managed installations without altering other provider behavior.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	The change satisfies the discovery objective in issue #81. src-tauri/src/harness.rs adds ~/.bun/bin/codex to resolve_codex candidates. The issue also requires an explicit Install Codex action, t…	Implement or include the remaining #81 provider setup changes: the confirmed installer action, the specified installer environment, post-install provider and model refresh, and user-owned authentication guidance. If the work is intentionall…
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 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: detecting Codex installations managed by Bun.
Description check	✅ Passed	The description includes the required What changed, Why, UI, and Checklist sections. It explains the scope and confirms that installer work is excluded. The checklist records npm run check:rust instea…
Out of Scope Changes check	✅ Passed	The only reviewed change adds home.join(".bun/bin/codex") to the existing Codex CLI discovery candidates. This directly supports the existing-installation objective in issue #81. The summary reports…

Full details: Linked Issues check

Explanation

The change satisfies the discovery objective in issue #81. src-tauri/src/harness.rs adds ~/.bun/bin/codex to resolve_codex candidates. The issue also requires an explicit Install Codex action, the official installer flow with CODEX_INSTALL_DIR=~/.monocode/bin and CODEX_NON_INTERACTIVE=1, availability and model-catalog refresh after installation, and user-owned authentication. The PR summary states that installer, UI, authentication, and refresh changes remain outside this PR. Therefore, the complete coding requirements of #81 are not met by this PR.

Resolution

Implement or include the remaining #81 provider setup changes: the confirmed installer action, the specified installer environment, post-install provider and model refresh, and user-owned authentication guidance. If the work is intentionally split, link the follow-up implementation that completes these requirements.

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[nulljosh]

Correct and safe — adds ~/.bun/bin/codex as a candidate path alongside the existing npm-global/cargo/n entries in resolve_codex(). Matches the existing pattern exactly, no conflicts.