Fix stale sidebar agent status refresh

[austinywang]

Summary

• add a regression for a structured agent status becoming visible after a PID ownership update
• move agent PID ownership and lifecycle maps behind a focused @Observable runtime model with an AsyncStream change signal
• have sidebar rows refresh their existing value snapshot from that runtime stream, so status visibility changes update independently per workspace without broadcasting Workspace.objectWillChange

Fixes #6799

Testing

• python3 scripts/normalize-pbxproj.py cmux.xcodeproj/project.pbxproj && scripts/check-pbxproj.sh && git diff --check
• Not run locally per issue instructions: the cmux app test target launches the app; relying on CI for app-host tests.

Demo Video

N/A. This is an intermittent state-observation race; the deterministic regression test is the useful proof, and the issue instructions say not to build or launch the app before CI is green.

Review Trigger

Please focus on the sidebar observation path for agent runtime visibility: hook/status metadata can already exist while PID ownership/lifecycle state changes later, and each workspace must refresh independently without broad workspace invalidation.

Checklist

• Regression test committed before the fix commit.
• PR body includes Fixes #6799.
• No local app build or app-host test run.

Summary by CodeRabbit

• New Features

  • Sidebar workspace status now updates more reliably when agent runtime activity changes.
  • Hidden sidebar entries can become visible automatically when related agent activity is recorded.

• Bug Fixes

  • Improved refresh behavior so workspace rows stay in sync with agent process and lifecycle changes.
  • Reduced unnecessary UI change notifications while keeping displayed state current.

[vercel]

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Project	Deployment	Actions	Updated (UTC)
cmux	Ready	Preview, Comment	Jun 27, 2026 6:11am
cmux-staging	Building	Preview, Comment	Jun 27, 2026 6:11am

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro

Run ID: e730d697-d99d-485b-a339-73a703767908

📥 Commits

Reviewing files that changed from the base of the PR and between 0efdb77 and 75f392c.

📒 Files selected for processing (7)

• Sources/ContentView.swift
• Sources/Workspace+PanelLifecycle.swift
• Sources/Workspace.swift
• Sources/WorkspaceSidebarAgentRuntimeObservationModel.swift
• Sources/WorkspaceSidebarObservation.swift
• cmux.xcodeproj/project.pbxproj
• cmuxTests/WorkspaceSidebarObservationTests.swift

📝 Walkthrough

Walkthrough

Workspace agent runtime tracking now flows through a shared observation model, sidebar observation state includes the runtime fields, the tab row refreshes from runtime changes, and tests were migrated to Testing with a new agent-PID visibility case.

Changes

Sidebar agent runtime observation

Layer / File(s)	Summary
Runtime model and wiring Sources/WorkspaceSidebarAgentRuntimeObservationModel.swift, cmux.xcodeproj/project.pbxproj	A new main-actor observation model stores agent runtime maps, exposes change streams, and is added to the Xcode project.
Workspace forwards runtime maps Sources/Workspace.swift	Workspace replaces stored agent runtime dictionaries with computed accessors that delegate reads and writes to the sidebar agent runtime observation model.
Sidebar observation and refresh Sources/WorkspaceSidebarObservation.swift, Sources/ContentView.swift	Sidebar observation state gains agent runtime fields, the observation publisher combines those fields with listening ports, and the tab row refresh task reacts to runtime observation updates.
Sidebar observation tests cmuxTests/WorkspaceSidebarObservationTests.swift	The sidebar observation tests move to the Testing framework, update assertions, and add a case that records an agent PID and checks visibility, change generation, and object-will-change behavior.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• manaflow-ai/cmux#5662: Both PRs change Sources/WorkspaceSidebarObservation.swift’s sidebar observation publisher/state construction and update tests around publisher emissions.
• manaflow-ai/cmux#5855: Both PRs touch the same sidebar agent-runtime coupling state and update WorkspaceSidebarObservationTests around agent PID ownership affecting sidebar visibility.
• manaflow-ai/cmux#6460: Both PRs revolve around the agentPIDs and related runtime state used to drive sidebar updates.

Poem

I’m a rabbit with a hoppy grin,
I watched the agent lights turn in.
PIDs twinkle, panels wake,
Sidebar dots no longer fake.
🐇✨

🚥 Pre-merge checks | ✅ 24 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 5.56% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (24 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly matches the main change: fixing stale sidebar agent status refresh behavior.
Description check	✅ Passed	The PR description follows the template well with Summary, Testing, Demo Video, Review Trigger, and Checklist sections.
Linked Issues check	✅ Passed	The changes address #6799 by making sidebar rows observe agent runtime updates and adding a regression test for the stale status case.
Out of Scope Changes check	✅ Passed	The added model, sidebar refresh wiring, test updates, and project file changes all support the stated stale status fix.
Cmux Swift Actor Isolation	✅ Passed	PASS: the new runtime model and Workspace are @MainActor, and all added accesses occur on the main actor or via the main-actor mutation bus.
Cmux Swift Blocking Runtime	✅ Passed	PASS: The new runtime model is @MainActor+AsyncStream; the changed files add no semaphores, sleeps, asyncAfter, sync, or locks, and the only Task hop is onTermination cleanup.
Cmux Browser Automation Off-Main	✅ Passed	PR only updates submodule pointers; ghostty hunks add screen-row selection/clipboard APIs, not browser.* routing, waits, or mainActor/processV2Command changes.
Cmux Expensive Synchronous Load	✅ Passed	No new synchronous agent-history load was added; the new task only listens to an AsyncStream and refreshes a cached snapshot, while load() stays in the existing cache path.
Cmux Cache Substitution Correctness	✅ Passed	PASS: the new runtime model is the authoritative store for transient sidebar UI state, and its AsyncStream yields immediately plus on updates, so no stale persistence/snapshot cache substitution ap...
Cmux No Hacky Sleeps	✅ Passed	Changed files are Swift/pbxproj only; the new row refresh uses AsyncStream, with no introduced sleeps, timers, polling, or asyncAfter in the diff.
Cmux Algorithmic Complexity	✅ Passed	No new nested scans or hot-path re-sorts; the new runtime model and per-workspace AsyncStream are linear and bounded per workspace.
Cmux Swift Concurrency	✅ Passed	Uses @Observable + AsyncStream; added Tasks are SwiftUI/onTermination boundaries, and no new DispatchQueue/Combine app-state or completion-handler APIs appear.
Cmux Swift @Concurrent	✅ Passed	The new async row observer is explicitly @MainActor UI-bound, and the added model is actor-isolated; no new nonisolated async/@concurrent mismatch appears.
Cmux Swift File And Package Boundaries	✅ Passed	The PR makes a focused sidebar-runtime extraction: a 60-line model plus tiny glue/tests; large existing app files are only incidentally touched, not mixed with new unrelated responsibilities.
Cmux Swiftpm Lockfiles	✅ Passed	Diff only bumps vendored submodules (ghostty, vendor/bonsplit); no cmux-owned .gitignore, Package.resolved, or cmux.xcodeproj package-reference changes appear.
Cmux Swift Logging	✅ Passed	The changed sidebar/runtime code adds observation plumbing and tests only; no new print/debugPrint/dump/NSLog/Logger calls appear in the diff.
Cmux User-Facing Error Privacy	✅ Passed	No production-facing error/alert/copy strings were added; the diff only changes sidebar observation/state plumbing and tests.
Cmux Full Internationalization	✅ Passed	PASS: The diff only adds runtime-observation plumbing and a DEBUG-only log; no production Swift UI text, string catalogs, or web locale files were changed.
Cmux Swiftui State Layout	✅ Passed	The PR adds a new @MainActor @Observable model; no new ObservableObject/@published state or layout-changing GeometryReader was introduced in the touched SwiftUI paths.
Cmux Architecture Rethink	✅ Passed	The agent-runtime maps now have a clear focused owner, and sidebar rows refresh from a direct per-workspace stream without sleeps, polling, or duplicate lifecycle owners.
Cmux Swift Auxiliary Window Close Shortcuts	✅ Passed	No standalone NSWindow/NSPanel/WindowGroup changes or cmuxAuxiliaryWindowIdentifiers edits; the diff only adds sidebar observation/task plumbing.
Cmux Source Artifacts	✅ Passed	Changed paths are tracked submodules (ghostty, vendor/bonsplit); diff only bumps gitlinks to source commits, with no logs/build output/temp artifacts added.
Cmux No Test Or Debug Seam In Production Source	✅ Passed	No new test-only/debug seam was added in production Sources; the new runtime model has a real production caller and the added DEBUG code is logging only.
Cmux No Ambient Global State	✅ Passed	No new file-scope funcs/vars or singleton-style namespaces were added; the new agent runtime state lives on a Workspace-owned WorkspaceSidebarAgentRuntimeObservationModel instance.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch issue-6799-sidebar-agent-status-stale

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[greptile-apps]

Greptile Summary

This PR fixes a stale sidebar agent status visibility bug by moving agent runtime maps (agentPIDs, agentPIDPanelIdsByKey, agentPIDKeysByPanelId, agentLifecycleStatesByPanelId) out of Workspace and into a new @MainActor @Observable model whose properties are all @ObservationIgnored, then fanning out change signals via per-subscriber AsyncStreams so each sidebar row can refresh independently without broadcasting Workspace.objectWillChange.

• Introduces WorkspaceSidebarAgentRuntimeObservationModel with explicit setters and an AsyncStream-based notification channel (changes()) that uses bufferingNewest(1) to coalesce rapid-fire mutations before subscribers can drain them.
• Adds a .sidebarAgentRuntimeObservation(id:model:onChange:) SwiftUI view modifier in TabItemView that subscribes each sidebar row to the new stream independently.
• Migrates the existing XCTest-based sidebar tests to Swift Testing (@Test, #expect) and adds two new regression tests: one verifying that a recordAgentPID call raises changeGeneration and makes a hidden structured status visible, and one verifying terminalAgentContext does not observe the agent runtime maps.

Confidence Score: 5/5

Safe to merge. The change is well-scoped: it encapsulates agent runtime maps in a dedicated @mainactor model, uses @ObservationIgnored to prevent broad view invalidation, and fans change signals to per-workspace AsyncStreams. The @mainactor isolation guarantees consumers always see fully-settled map state even when a single recordAgentPID call triggers multiple notifyChanged() yields.

The architecture directly addresses the root cause rather than patching symptoms. Computed property delegation in Workspace+PanelLifecycle means all existing call sites — recordAgentPID, clearAgentPID, removeAgentPIDOwnership, recordAgentPIDOwnership — route through the new equality-guarded setters without any call-site changes. The regression test is deterministic and covers both the visibility fix and the isolation from Workspace.objectWillChange. No new global state, no timing-based synchronization, and no broad invalidation path is introduced.

No files require special attention.

Important Files Changed

Filename	Overview
Sources/WorkspaceSidebarAgentRuntimeObservationModel.swift	New model class that encapsulates all four agent runtime maps, exposes them with equality-guarded setters, and fans change signals out to per-subscriber AsyncStreams. All properties are @ObservationIgnored so reads don't register in any @observable tracking context; @mainactor isolation ensures continuation yields and consumer task scheduling never interleave with a partially-updated map state.
Sources/Workspace+PanelLifecycle.swift	Adds four computed properties that delegate reads and writes to the new model, replacing the former plain vars on Workspace. All existing call sites in recordAgentPID, clearAgentPID, removeAgentPIDOwnership, and recordAgentPIDOwnership now route through the equality-guarded setters transparently.
Sources/WorkspaceSidebarObservation.swift	Adds the .sidebarAgentRuntimeObservation view extension that wires a .task(id:) loop over model.changes() to refreshWorkspaceSnapshot(); uses bufferingNewest(1) coalescing inherited from the model. Adds SwiftUI import; no changes to the Combine-based makeSidebarObservationPublisher path.
Sources/ContentView.swift	Threads the new .sidebarAgentRuntimeObservation modifier into TabItemView's modifier chain, keyed on tab.id so the AsyncStream subscription is restarted only when the workspace tab identity changes.
Sources/Workspace.swift	Replaces four plain var agent runtime maps with a single let sidebarAgentRuntimeObservation model constant. Because it's let, Workspace.objectWillChange is never triggered by agent runtime mutations — which is exactly the isolation the fix requires.
cmuxTests/WorkspaceSidebarObservationTests.swift	Migrated from XCTestCase to Swift Testing; adds agentRuntimeObservationChangesWhenAgentPIDMakesExistingStatusVisible (regression for the bug) and terminalAgentContextDoesNotObserveAgentRuntimeMaps (proves @ObservationIgnored isolation). ObservationChangeFlag uses @unchecked Sendable to satisfy the Sendable closure requirement for withObservationTracking; safe because all accesses are @mainactor.
cmux.xcodeproj/project.pbxproj	Adds WorkspaceSidebarAgentRuntimeObservationModel.swift to both the file references and the app target build phase. Entry IDs use the issue number as a mnemonic prefix (6799A001…), consistent with the existing project convention.

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    participant Hook as Agent Hook
    participant WS as Workspace
    participant Model as WorkspaceSidebarAgentRuntimeObservationModel
    participant Stream as AsyncStream<Void>
    participant Row as TabItemView (Sidebar Row)

    Hook->>WS: recordAgentPID(key:pid:panelId:)
    WS->>Model: setAgentPIDs(newValue)
    Model->>Model: "guard != newValue"
    Model->>Model: "agentPIDs = newValue, changeGeneration &+= 1"
    Model->>Stream: continuation.yield(()) [bufferingNewest(1)]
    Note over WS,Model: Additional map mutations (ownership, lifecycle) also call notifyChanged() — all synchronous on @MainActor
    Note over Stream: Task won't resume until current @MainActor turn completes — consumer always sees fully-settled map state
    Stream-->>Row: for await _ in model.changes()
    Row->>Row: refreshWorkspaceSnapshot()

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sequenceDiagram
    participant Hook as Agent Hook
    participant WS as Workspace
    participant Model as WorkspaceSidebarAgentRuntimeObservationModel
    participant Stream as AsyncStream<Void>
    participant Row as TabItemView (Sidebar Row)

    Hook->>WS: recordAgentPID(key:pid:panelId:)
    WS->>Model: setAgentPIDs(newValue)
    Model->>Model: "guard != newValue"
    Model->>Model: "agentPIDs = newValue, changeGeneration &+= 1"
    Model->>Stream: continuation.yield(()) [bufferingNewest(1)]
    Note over WS,Model: Additional map mutations (ownership, lifecycle) also call notifyChanged() — all synchronous on @MainActor
    Note over Stream: Task won't resume until current @MainActor turn completes — consumer always sees fully-settled map state
    Stream-->>Row: for await _ in model.changes()
    Row->>Row: refreshWorkspaceSnapshot()

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