Tool System

A source-aligned map of built-in tools, conditional tools, desktop automation, MCP tools, and permission boundaries.

Where tools come from

CrabCode assembles the tool pool at runtime. The current source tree confirms these sources:

Source	Description
Built-ins	File read/write/edit, shell, web, todos, planning, skills, tasks, MCP resources
Conditional tools	Feature-flagged, platform-specific, or mode-specific tools such as LSP, worktree, desktop automation, cron, PowerShell
MCP tools	Tools and resources exposed by configured MCP servers
Plugins / skills	Plugins can ship MCP servers, slash commands, hooks, and skills
GUI / App Server capabilities	Browser, cron, plugin, account, memory, local model and other local methods used by the desktop app

Default built-ins

Tool	Purpose
`Agent` / `TaskOutput`	Start sub-agents and read task output
`Bash`	Run shell commands
`Read` / `Edit` / `Write`	Read, patch, and create files
`NotebookEdit`	Edit notebook cells
`WebFetch` / `WebSearch`	Fetch URLs and search the web
`TodoWrite`	Maintain the active task list
`EnterPlanMode` / `ExitPlanMode`	Move between planning and execution
`AskUserQuestion`	Ask the user for required input
`Skill`	Discover and invoke local skills
`TaskStop`	Stop tasks
`ListMcpResources` / `ReadMcpResource`	Browse and read MCP resources

If embedded search is not available, Glob and Grep are added as fallback file-search tools.

Conditional groups

Group	Purpose
`ToolSearch`	Search a large tool set
`TerminalCapture`	Read current terminal output
`LSP`	Language-server-backed diagnostics and symbols
`EnterWorktree` / `ExitWorktree`	Isolated worktree flows
Collaboration tools	Messages, peers, teams, agent swarms
Cron tools	Create, list, and delete scheduled jobs when enabled
Remote / monitor / notification tools	Remote triggers, monitors, push notifications, PR subscriptions
`PowerShell`	Windows PowerShell execution
Debug/context tools	Context inspection and snippets

When desktop automation is enabled, the pool can include ComputerObserve, ComputerPermissions, ComputerMove, ComputerClick, ComputerDoubleClick, ComputerDrag, ComputerScroll, ComputerKey, ComputerHotkey, and ComputerTypeText.

These tools operate real local apps, so approval and operating-system permissions matter more than with plain text tools.

Minimal mode

--bare skips hooks, LSP, plugin sync, automatic memory, and other extras. Normal bare sessions keep a minimal file/command tool set, typically Bash, Read, and Edit; REPL mode swaps in the REPL tool.

Permission boundary

Tool execution is constrained by sandboxing, permission mode, allowlists/denylists, explicit --tools, MCP config, and plugin loading. Start with Sandbox and permissions, Permission modes, MCP, and Plugins and skills.