Concurrent agent support with tab view

[krissetto]

Concurrent agents

Introduces an initial version of a new feature: concurrent agents.

This allows users to open multiple "tabs" with their current agent, even in separate working directories, and run them in parallel.

Includes:

• Uses the experimental renderer by default
• Tab switching works via mouse and keyboard
• Introduces a TUI store to save user TUI state (open sessions, collapsed sidebar per session, etc)
• Lets users know when a background agent is requesting a confirmation

The feature is gated behind the CAGENT_EXPERIMENTAL_CONCURRENT_AGENTS environment variable. The rest of the TUI should remain as-is, i created a separate model strongly based off of the original TUI model to touch as little of the existing code as possible until we all test things and agree on the approach

Screencast

Screencast.From.2026-02-08.16-37-05.mp4

[github-actions]

Review Summary

I found 4 concurrency-related issues in the concurrent agent implementation. These are real bugs that could cause crashes or resource leaks:

• 1 HIGH severity: Double-close panic on programReady channel (latent, unlikely with current usage)
• 3 MEDIUM severity: Race conditions and cleanup synchronization issues

All issues are in the new pkg/tui/service/supervisor/supervisor.go file. The most critical is the missing synchronization in cleanup operations, which could leave resources in inconsistent states.

Key Findings:

1. Unprotected channel close operation (potential panic)
2. Goroutine spawning s.program access without synchronization
3. Cleanup functions launched without WaitGroup or synchronization

These should be addressed before merge to ensure stability of the concurrent agents feature.

[krissetto]

/review

[github-actions]

🔍 Code Review Summary

Reviewed the concurrent agent support implementation. Found 2 issues worth addressing:

Findings:

• 1 issue with error handling in cleanup goroutines
• 1 issue with shallow copying causing shared references

Both are medium severity but could cause issues in production under specific conditions.

[krissetto]

/review

[github-actions]

Review Summary

Found 3 issues in the new concurrent agent support code that should be addressed:

1. HIGH Severity: Goroutine leak if SetProgram() is never called (could leak all subscription goroutines)
2. MEDIUM Severity: Unnecessary goroutine spawning in notifyTabsUpdated() with missing error handling
3. MEDIUM Severity: Inconsistent cleanup pattern that may cause deadlock

All issues are in the new pkg/tui/service/supervisor/supervisor.go file. The rest of the PR looks good - the concurrent agent architecture is well-designed with proper locking and context cancellation patterns.

[krissetto]

/review

[github-actions]

Code Review Summary

Found 4 issues in the concurrent agent implementation that should be addressed:

• 2 CONFIRMED bugs (configuration cloning and blocking I/O)
• 2 LIKELY coordination issues (cleanup goroutine patterns)

The concurrent agent architecture looks solid overall. The main concerns are around proper resource cleanup coordination and using appropriate contexts for I/O operations.

[krissetto]

drafting as I'm going to make this proposal fully integrated and not-gated behind an experimental flag, to not have 2 TUIs and be able to move more quickly

[krissetto]

replaced by #1695