Summary

This PR introduces the /switch-agent command, Ctrl+Shift keyboard shortcuts for agent switching, and UUID-based identifiers for sub-agents — improving usability in terminals like Windows Git Bash where Ctrl+Alt shortcuts are problematic, and enabling unambiguous identification when multiple sub-agents share the same name.

Key Changes

1. /switch-agent Command

• New command: /switch-agent <agent-name> allows users to switch between the primary agent and sub-agents by name.
• Tab completion: Auto-completes agent names including UUID prefixes for disambiguation.
• TUI interception: The /switch-agent command is intercepted in the TUI input handler and processed immediately without LLM round-tripping, ensuring instant switching.
• Non-TUI fallback: In non-TUI mode, the command sets foreground_uuid directly on the AgentService.
• Help text: Includes usage examples and tab-completion guidance.

2. UUID Identifiers for Sub-Agents

• 3-character UUID prefix: Sub-agent names in the UI now always include a 3-character UUID prefix (e.g., reviewer (a1b)) to uniquely identify agents when duplicate names exist.
• UUID prefix matching: The /switch-agent command resolves agents by:
  1. "name (uuid)" format — e.g., /switch-agent reviewer (a1b)
  2. Direct name match — e.g., /switch-agent reviewer
  3. UUID prefix match — e.g., /switch-agent a1b
• Completions always include UUID prefix: Tab-completion for /switch-agent always appends the UUID prefix to sub-agent names, making disambiguation seamless.
• Duplicate name handling in TUI: When multiple sub-agents share the same name, the TUI input container appends the UUID prefix to distinguish them.

3. Ctrl+Shift Keybindings

• The TUI now supports Ctrl+Shift+Left, Ctrl+Shift+Right, and Ctrl+Shift+Up for agent switching, providing an alternative to the existing Ctrl+Alt shortcuts that don't work well on Windows Git Bash.

4. Synchronous Linter & Command Execution

• Reverted the Linter and shell command execution from async to synchronous (using asyncio.to_thread for run_cmd). This simplifies the codebase and improves reliability in interrupt handling.
• Removed run_cmd_async and interruptible_async_generator — no longer needed.
• Linter methods (lint, py_lint, flake8_lint, run_cmd) are now synchronous, using subprocess.run directly.

5. Bug Fixes

• Resolved a circular import in cecli/commands/switch_agent.py.
• Fixed an issue where the TUI would not visually update when switching agents.
• Corrected a bug in cecli/commands/invoke_agent.py that was causing sub-agent invocation to fail (added MessageTag.CUR to the summary message).
• Fixed spawn message to show Ctrl+Alt+Right instead of dynamic key lookup that could fail.

6. Cleanup

• Removed interrupt_event parameter from Linter.__init__ and all lint-related methods.
• Removed notification cooldown logic and notify_user_input_required call from InputOutput.
• Removed stale interrupt state clearing from base_coder.py.
• Removed unused Path() conversion in SkillsManager.find_skills.

Files Changed

• cecli/commands/switch_agent.py — New /switch-agent command implementation
• cecli/commands/__init__.py — Registered SwitchAgentCommand
• cecli/commands/invoke_agent.py — Fixed sub-agent invocation, added MessageTag.CUR
• cecli/commands/spawn_agent.py — Simplified spawn message
• cecli/commands/lint.py — Synchronous lint call
• cecli/commands/run.py — Synchronous run_cmd via asyncio.to_thread
• cecli/tui/app.py — Ctrl+Shift keybindings, /switch-agent interception, switch_agent message handling
• cecli/coders/agent_coder.py — Synchronous lint, removed interruptible sleep
• cecli/coders/base_coder.py — Synchronous lint, removed interruptible formatting/streaming
• cecli/linter.py — Fully synchronous linter with subprocess.run
• cecli/run_cmd.py — Removed run_cmd_async
• cecli/helpers/coroutines.py — Removed interruptible_async_generator
• cecli/helpers/skills.py — Removed unused Path() conversion
• cecli/io.py — Removed notification cooldown and notify_user_input_required
• cecli/models.py — Removed interruptible wrapper around litellm.acompletion
• tests/commands/test_switch_agent.py — Tests for the new command

Why Needed

• Ctrl+Alt shortcuts don't work in Windows Git Bash — Ctrl+Shift provides a working alternative.
• The /switch-agent command gives users a CLI-based way to switch agents, with tab-completion for convenience.
• UUID prefixes solve the ambiguity problem when multiple sub-agents share the same name (e.g., two "reviewer" agents).
• Reverting to synchronous operations for linting and commands reduces complexity and potential race conditions in the async event loop.