# `ADK.Tool.ExitLoop`
[🔗](https://github.com/zeroasterisk/adk-elixir/blob/main/lib/adk/tool/exit_loop.ex#L1)

Built-in tool that allows an LLM inside a `LoopAgent` to break out of the loop.

When called, the tool returns `{:exit_loop, reason}`, which `LlmAgent`
detects and converts to an event with `actions.escalate = true`. The
`LoopAgent` sees the escalate flag and stops iterating.

This mirrors Python ADK's escalation mechanism where an agent inside a
`LoopAgent` can signal that the task is complete and the loop should exit.

## Usage

Add the exit_loop tool to any `LlmAgent` that runs inside a `LoopAgent`:

    agent = ADK.Agent.LlmAgent.new(
      name: "worker",
      model: "gemini-flash-latest",
      instruction: "Do the task. When finished, call exit_loop.",
      tools: [ADK.Tool.ExitLoop.tool()]
    )

    loop = ADK.Agent.LoopAgent.new(
      name: "loop",
      sub_agents: [agent],
      max_iterations: 10
    )

The LLM will call `exit_loop` when it considers the task done, producing an
escalation event that stops the loop immediately.

# `exit_loop?`

```elixir
@spec exit_loop?(term()) :: boolean()
```

Returns `true` if the given value is an exit_loop signal.

## Examples

    iex> ADK.Tool.ExitLoop.exit_loop?({:exit_loop, "done"})
    true
    iex> ADK.Tool.ExitLoop.exit_loop?({:ok, "result"})
    false

# `reason`

```elixir
@spec reason({:exit_loop, String.t()}) :: String.t()
```

Extract the reason from an exit_loop signal.

## Examples

    iex> ADK.Tool.ExitLoop.reason({:exit_loop, "all done"})
    "all done"

# `tool`

```elixir
@spec tool() :: ADK.Tool.FunctionTool.t()
```

Create the `exit_loop` tool as a `FunctionTool`.

The returned tool, when called by the LLM, returns `{:exit_loop, reason}`.
`LlmAgent` intercepts this signal and emits an escalation event.

## Examples

    iex> tool = ADK.Tool.ExitLoop.tool()
    iex> tool.name
    "exit_loop"

---

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