Include claude attach in claude_builtin_command_name

[sjiang647]

Problem

claude attach <id> is a real Claude Code subcommand — the attach door printed for --bg background sessions — but it's hidden from claude --help, so it never made it into claude_builtin_command_name in cmux-claude-wrapper. Inside a cmux surface the wrapper therefore classifies it as a session entrypoint and execs the real CLI as:

claude --session-id <fresh-uuid> --settings '{...hooks...}' attach <id>

The CLI eats the injected flags and reads attach as the [prompt] positional: instead of attaching to the running background session, it mints a brand-new session with "attach" pre-filled in the composer.

Repro (any cmux surface, Claude Code ≥ 2.1.x): claude attach <any-id> → new session with "attach" in the prompt box, instead of No job matching '<any-id>' / attaching.

Fix

Add attach to the builtin-command list so it passes through untouched, like agents/mcp/etc. Hook injection is meaningless for attach anyway — hooks live in the already-running background writer process, and a fresh --session-id on an attach invocation is exactly the bug.

Two-commit structure per the regression-test policy: commit 1 adds the failing test (test_hidden_attach_subcommand_bypasses_hook_injection in tests/test_claude_wrapper_hooks.py), commit 2 the one-word fix. Full wrapper suite passes locally.

Supersedes #10115 (same change, reopened from the right account).

🤖 Generated with Claude Code

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Summary by cubic

Passes the hidden claude attach <id> subcommand through the cmux-claude-wrapper so attaches work inside cmux surfaces. Previously the wrapper injected --session-id/--settings, the CLI treated "attach" as the prompt, and created a new session; now argv is forwarded unchanged and no hook or NODE_OPTIONS injection occurs.

Review notes

• Add attach to the builtin command list in claude_builtin_command_name, matching other pass-through subcommands.
• Add regression test test_hidden_attach_subcommand_bypasses_hook_injection to assert raw argv and absence of injected flags.
• No migration required; hooks are irrelevant for attach because they run in the existing background writer process.

^{Written for commit 8157248. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes

  • Preserved the behavior of the hidden claude attach <id> command so it runs without unintended hook settings, session identifiers, or NODE_OPTIONS changes.

• Tests

  • Added regression coverage to verify attach commands pass through unchanged.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: e00c6903-12e5-4bfc-a859-41e95105557d

📥 Commits

Reviewing files that changed from the base of the PR and between 3ee68ba and 8157248.

📒 Files selected for processing (2)

• Resources/bin/cmux-claude-wrapper
• tests/test_claude_wrapper_hooks.py

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📝 Walkthrough

Walkthrough

The change adds regression coverage for hidden claude attach <id> commands. The test verifies raw argument passthrough without hook settings, session ID, or NODE_OPTIONS injection. The wrapper command list remains unchanged.

Changes

Claude attach passthrough

Layer / File(s)	Summary
Attach passthrough coverage Resources/bin/cmux-claude-wrapper, tests/test_claude_wrapper_hooks.py	The test suite verifies hidden attach commands preserve raw arguments and bypass hook, session, and NODE_OPTIONS injection. The test is registered in main().

Estimated code review effort: 1 (Trivial) | ~5 minutes

Mergeability Score: ⚪ Minimal · up to 81572

The PR makes the hidden attach command bypass wrapper-only session setup and adds regression coverage; no actionable merge-blocking risk remains after normal checks and review.

Possibly related PRs

• manaflow-ai/cmux#10115: Adds the same claude attach passthrough change and regression test.

Suggested reviewers: azooz2003-bit

🚥 Pre-merge checks | ✅ 25

✅ Passed checks (25 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.
Cmux Swift Actor Isolation	✅ Passed	The two-commit diff changes only a shell wrapper and a Python test; it introduces no production Swift code or Swift actor-isolation behavior.
Cmux Swift Blocking Runtime	✅ Passed	The PR changes only a shell wrapper and a Python regression test; it introduces no production Swift code or blocking/timing synchronization primitives.
Cmux Browser Automation Off-Main	✅ Passed	The two-commit PR changes only the Claude wrapper and its Python regression test; it adds no browser socket command or WebKit/AppKit routing change in the policy scope.
Cmux Expensive Synchronous Load	✅ Passed	The PR changes only a shell wrapper and Python tests; both commit diffs contain no Swift files or synchronous agent-history loads on interactive paths.
Cmux Cache Substitution Correctness	✅ Passed	The diff changes only a Bash wrapper and a Python test. It contains no production Swift, TypeScript, or JavaScript change, so this cache-substitution check is inapplicable.
Cmux No Hacky Sleeps	✅ Passed	The diff adds only attach to the shell command list and a deterministic regression test; it introduces no fixed sleeps, timers, polling, or wall-clock synchronization.
Cmux Algorithmic Complexity	✅ Passed	The PR adds one entry to a fixed case command list and a regression test; it introduces no scalable collection scan, nested loop, sort, filter, join, or slower algorithm.
Cmux Swift Concurrency	✅ Passed	The PR changes only the shell wrapper and a Python regression test; the two-commit diff contains no Swift paths or Swift concurrency changes.
Cmux Swift @Concurrent	✅ Passed	The cumulative PR diff changes only the shell wrapper and Python test; it contains no .swift paths or Swift concurrency annotations, so this check is inapplicable.
Cmux Swift Package Boundaries	✅ Passed	The complete PR diff changes only a shell wrapper and a Python test; it introduces no production Swift code, so the Swift package-boundary rule does not apply.
Cmux Swiftpm Lockfiles	✅ Passed	The PR diff changes only the Claude wrapper and its Python regression test; it contains no Package.swift, Package.resolved, Xcode project, .gitignore, workflow, or dependency changes covered by thi...
Cmux Swift Logging	✅ Passed	The complete diff changes only the shell wrapper and its Python test; it adds no Swift code or logging, so the Swift logging rule is not applicable.
Cmux User-Facing Error Privacy	✅ Passed	The diff only adds attach to command passthrough logic and adds regression test code/comments; it adds no user-facing error, alert, command output, or recovery text.
Cmux Full Internationalization	✅ Passed	The diff adds only the literal attach command token and regression-test code; no Swift, web, catalog, locale, or metadata files changed. Command tokens and tests are allowed.
Cmux Swiftui State Layout	✅ Passed	The full PR diff changes only a shell wrapper and a Python test; it adds no SwiftUI files, state, GeometryReader, lazy rows, or render-time mutation.
Cmux Architecture Rethink	✅ Passed	The diff changes only a shell wrapper and Python regression test; no Swift files or listed architecture symptom patches are introduced.
Cmux Swift Auxiliary Window Close Shortcuts	✅ Passed	The diff changes only a shell wrapper and Python tests; it adds no Swift-owned window code, so the auxiliary-window shortcut rule is not applicable.
Cmux Source Artifacts	✅ Passed	The two-commit diff changes only the hand-written wrapper script and its regression test; no logs, caches, build output, scratch directories, or copied artifacts are added.
Cmux No Test Or Debug Seam In Production Source	✅ Passed	PASS: The PR diff changes only Resources/bin/cmux-claude-wrapper and tests/test_claude_wrapper_hooks.py; it changes no Swift file under a production Sources/ path.
Cmux No Ambient Global State	✅ Passed	The PR changes only a shell wrapper and Python tests; the two-commit diff contains no production Swift changes, so this check is inapplicable.
Title check	✅ Passed	The title clearly identifies the main change: adding the hidden claude attach subcommand to the builtin-command list.
Description check	✅ Passed	The description clearly explains the problem, fix, regression test, and local test result, but it omits several template sections.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[sjiang647]

small fix @lawrencecchen PTAL, ty!