Built-in Tools

OpenWalrus gives agents access to your filesystem and shell through three built-in tools, all sandboxed to a work directory.

Sandbox

All file operations are restricted to the work directory at ~/.openwalrus/work/. Paths are automatically remapped — agents see a clean workspace without access to your full filesystem.

You can override the work directory in configuration:

work_dir = "/path/to/custom/work"

Tools

read

Read the contents of a file:

{
  "name": "read",
  "parameters": {
    "path": "src/main.rs"
  }
}

Returns the file content as a string. Paths are relative to the work directory.

write

Write content to a file:

{
  "name": "write",
  "parameters": {
    "path": "output.txt",
    "content": "Hello from OpenWalrus"
  }
}

Creates the file if it doesn't exist, or overwrites it.

bash

Execute a shell command:

{
  "name": "bash",
  "parameters": {
    "command": "ls",
    "args": ["-la"]
  }
}

The command runs inside the work directory. Paths in the command are remapped to stay within the sandbox.

Registration

These tools are registered by OsHook through the hook system. They're available to all agents by default.

What's next

• Skills — extend agents with community-contributed skills
• MCP integration — connect external tool servers
• Hooks — how tools are registered and dispatched