# `Puck.Backends.ClaudeAgentSDK`
[🔗](https://github.com/bradleygolden/puck/blob/v0.2.25/lib/puck/backends/claude_agent_sdk.ex#L2)

Backend implementation using the Claude Agent SDK.

This backend uses the Claude Code CLI (via the Elixir SDK) to run prompts.
It supports your existing Claude subscription (Pro/Max) when authenticated
via `claude login`.

## Authentication

The backend uses your Claude subscription. Make sure you're logged in:

    # In your terminal
    claude login

If `ANTHROPIC_API_KEY` is set, it will use API credits instead.

## Configuration

Backend options are passed in the client tuple:

- `:cwd` - Working directory for file operations (defaults to current directory)
- `:allowed_tools` - List of tools Claude can use (e.g., `["Read", "Glob", "Grep"]`)
- `:disallowed_tools` - List of tools to disable
- `:permission_mode` - Permission handling (`:default`, `:accept_edits`, `:bypass_permissions`)
- `:max_turns` - Maximum conversation turns
- `:model` - Model to use (e.g., `"sonnet"`, `"opus"`)
- `:output_format` - Response format (`:text`, `:json`, or schema map)
- `:sandbox` - Sandbox settings map with `:enabled`, `:root`, `:allowed_paths`, etc.

## Examples

    # Basic usage - read-only agent
    client = Puck.Client.new(
      {Puck.Backends.ClaudeAgentSDK, %{
        allowed_tools: ["Read", "Glob", "Grep"],
        permission_mode: :bypass_permissions
      }}
    )

    {:ok, response, _ctx} = Puck.call(client, "What files are in this directory?")

    # Code editing agent
    client = Puck.Client.new(
      {Puck.Backends.ClaudeAgentSDK, %{
        allowed_tools: ["Read", "Edit", "Write", "Glob", "Grep", "Bash"],
        permission_mode: :accept_edits,
        cwd: "/path/to/project"
      }}
    )

    {:ok, response, _ctx} = Puck.call(client, "Fix the bug in auth.py")

## Notes

- The Claude Agent SDK is an agentic system - it may make multiple tool calls
  before returning a final result
- For structured outputs, use the `:output_schema` option with a Zoi schema
- Streaming returns intermediate messages as Claude works

See the [claude_agent_sdk documentation](https://hexdocs.pm/claude_agent_sdk) for more details.

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*Consult [api-reference.md](api-reference.md) for complete listing*