fix: keep an agent name through a process-exit observation

[caner-akca]

Summary

• free a pane's agent name when the agent is confirmed gone rather than on a
  single process-exit observation
• keep the name through a false exit that the next probe clears, matching how
  detection uncertainty is already handled
• leave the pane.agent_detected { released: true } event unchanged

This fixes the failure reported in the #3225 comment thread: a named pane stops
resolving by its name while its process keeps running, with a rename as the only
recovery. It does not address the failure in the issue body, so #3225 should stay
open.

Validation

• just check
• API-boundary reproduction of the reported agent_not_found, plus state-layer
  tests pinning both directions — a false exit keeps the name, a confirmed exit
  frees it
• two live_handoff tests fail identically on master and this branch on macOS
  26.2, before reaching changed code: their fake agent execs /bin/sleep, and
  KERN_PROCARGS2 there returns an empty environment section, so HERDR_AGENT
  is invisible to process_agent_hint. Those run in CI.

refs #3225

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Team

Run ID: 0ae282b2-53a9-45fb-b0bd-02f7f30c4d4c

📥 Commits

Reviewing files that changed from the base of the PR and between 9a2a7af and 065026e.

📒 Files selected for processing (3)

• src/app/api.rs
• src/app/api/agents.rs
• src/terminal/state.rs

Included review availability: Your plan provides up to 10 included reviews per hour; 8 remain after this review.

---

📝 Walkthrough

Walkthrough

The change updates agent name handling after process-exit observations. Names remain associated with terminals when the agent is still detected or is detected again. A subsequent no-agent observation after a process exit still releases the name. Tests cover terminal state transitions, named live agents, idle agents, and hook-owned agent registrations.

Suggested reviewers: ogulcancelik

Merge Risk: ⚪ Minimal · up to 06502

This change preserves agent names through false process-exit observations while still releasing names after a later no-agent observation confirms exit. The covered state and API scenarios indicate no current merge-blocking risk.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	Docstring coverage is 80.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 10 functions across 3 files.
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 summarizes the main change: preserving an agent name through a single process-exit observation.
Description check	✅ Passed	The description directly explains the agent-name release behavior, test coverage, validation, and scope of the fix.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[kangal-bot]

@coderabbitai review
@greptileai

[coderabbitai]

@kangal-bot I will review the changes in #3574.

✅ Action performed

Review finished.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

[greptile-apps]

Greptile Summary

This PR delays clearing an assigned agent name until process-exit evidence is followed by a no-agent observation, preserving name-based API targeting when an exit observation proves false.

• Keeps the agent name through an initial process-exit observation while retaining the existing release event.
• Clears the name after a subsequent observation confirms that no agent remains.
• Adds state-level and API-level regression coverage for false and confirmed exits.

Confidence Score: 5/5

The PR appears safe to merge, with the revised cleanup transition preserving name reachability while retaining confirmed-exit cleanup.

The changed state transition is consistent with the production detection sequence: a renewed agent observation clears the exit marker, while a confirmed no-agent observation releases the name, and no concrete blocking failure remains.

Important Files Changed

Filename	Overview
src/terminal/state.rs	Changes agent-name cleanup to require both recorded exit evidence and a subsequent no-agent observation, with focused state-machine regression tests.
src/app/api/agents.rs	Adds API-boundary coverage proving that a falsely reported exit does not make a re-detected live agent unreachable by its assigned name.
src/app/api.rs	Updates release-event tests to reflect that registration release no longer immediately clears the assigned agent name.

Sequence Diagram

sequenceDiagram
    participant D as Agent detection
    participant T as TerminalState
    participant API as Agent API
    D->>T: Exit observation with agent present
    T->>T: Record recent process exit
    T->>T: Preserve assigned name
    alt Agent detected again
        D->>T: AgentProcessDetected
        T->>T: Clear exit marker, retain name
        API->>T: Resolve assigned name
        T-->>API: Named live agent
    else No agent confirmed
        D->>T: "StateChanged(agent=None)"
        T->>T: Clear assigned name
    end

Loading

_{Reviews (1): Last reviewed commit: "fix: keep an agent name through a proces..." | Re-trigger Greptile}