[Kuddev]

Result

Fixes #540. Interactive Claude hooks started without a controlling terminal can return their authenticated OSC event through the supported terminalSequence JSON field instead of silently losing failure and permission notifications.

This isolates the notification-delivery fix proposed by @wyr-zal in #542. Automatic continuation from #541 is a separate feature and is not included.

Scope and compatibility

Only Claude and ENXIO from opening /dev/tty use this fallback, before any terminal bytes have been written. Existing frame authentication, ordering, bounded payloads, provider isolation and partial-write cancellation remain. No dependency, setting, credential, real hook installation or retry-policy changes.

The official Claude Code changelog documents terminalSequence in version 2.1.141. Older clients and non-interactive/SDK modes that ignore this field are not covered. The causal note records the decision and attribution.

Validation

• A real detached subprocess running the production bridge first failed on the previous implementation with empty stdout, then passed for permission/failure events and invalid-token rejection.
• python3 -m unittest scripts.tests.test_remote_hooks -v: 14 passed on Linux, including real PTY delivery, normal-TTY single delivery, provider/error isolation and partial-frame cancellation without stdout retry.
• GPUI product cargo check --locked -p nebula --bin pebrel --features gpui-shell --tests --config .github/ci-profile.toml --profile ci: passed.
• Architecture, Python compilation, prohibited-name and whitespace checks passed. No physical WSL/Claude acceptance is claimed by the detached Linux process test; required current-head CI remains separate.