# Handoffs

Handoffs allow an agent to delegate tasks to another agent. This is particularly useful in scenarios where different agents specialize in distinct areas. For example, a customer support app might have agents that each specifically handle tasks like order status, refunds, FAQs, etc.

Handoffs are represented as tools to the LLM. So if there's a handoff to an agent named `Refund Agent`, the tool would be called `transfer_to_refund_agent`.

## Creating a handoff

All agents have a [`handoffs`][agents.agent.Agent.handoffs] param, which can either take an `Agent` directly, or a `Handoff` object that customizes the Handoff.

If you pass plain `Agent` instances, their [`handoff_description`][agents.agent.Agent.handoff_description] (when set) is appended to the default tool description. Use it to hint when the model should pick that handoff without writing a full `handoff()` object.

You can create a handoff using the [`handoff()`][agents.handoffs.handoff] function provided by the Agents SDK. This function allows you to specify the agent to hand off to, along with optional overrides and input filters.

### Basic usage

Here's how you can create a simple handoff:

```python
from agents import Agent, handoff

billing_agent = Agent(name="Billing agent")
refund_agent = Agent(name="Refund agent")

# (1)!
triage_agent = Agent(name="Triage agent", handoffs=[billing_agent, handoff(refund_agent)])
```

1. You can use the agent directly (as in `billing_agent`), or you can use the `handoff()` function.

### Customizing handoffs via the `handoff()` function

The [`handoff()`][agents.handoffs.handoff] function lets you customize things.

-   `agent`: This is the agent to which things will be handed off.
-   `tool_name_override`: By default, the `Handoff.default_tool_name()` function is used, which resolves to `transfer_to_<agent_name>`. You can override this.
-   `tool_description_override`: Override the default tool description from `Handoff.default_tool_description()`
-   `on_handoff`: A callback function executed when the handoff is invoked. This is useful for things like kicking off some data fetching as soon as you know a handoff is being invoked. This function receives the agent context, and can optionally also receive LLM generated input. The input data is controlled by the `input_type` param.
-   `input_type`: The schema for the handoff tool-call arguments. When set, the parsed payload is passed to `on_handoff`.
-   `input_filter`: This lets you filter the input received by the next agent. See below for more.
-   `is_enabled`: Whether the handoff is enabled. This can be a boolean or a function that returns a boolean, allowing you to dynamically enable or disable the handoff at runtime.
-   `nest_handoff_history`: Optional per-call override for the RunConfig-level `nest_handoff_history` setting. If `None`, the value defined in the active run configuration is used instead.

The [`handoff()`][agents.handoffs.handoff] helper always transfers control to the specific `agent` you passed in. If you have multiple possible destinations, register one handoff per destination and let the model choose among them. Use a custom [`Handoff`][agents.handoffs.Handoff] only when your own handoff code must decide which agent to return at invocation time.

```python
from agents import Agent, handoff, RunContextWrapper

def on_handoff(ctx: RunContextWrapper[None]):
    print("Handoff called")

agent = Agent(name="My agent")

handoff_obj = handoff(
    agent=agent,
    on_handoff=on_handoff,
    tool_name_override="custom_handoff_tool",
    tool_description_override="Custom description",
)
```

## Handoff inputs

In certain situations, you want the LLM to provide some data when it calls a handoff. For example, imagine a handoff to an "Escalation agent". You might want a reason to be provided, so you can log it.

```python
from pydantic import BaseModel

from agents import Agent, handoff, RunContextWrapper

class EscalationData(BaseModel):
    reason: str

async def on_handoff(ctx: RunContextWrapper[None], input_data: EscalationData):
    print(f"Escalation agent called with reason: {input_data.reason}")

agent = Agent(name="Escalation agent")

handoff_obj = handoff(
    agent=agent,
    on_handoff=on_handoff,
    input_type=EscalationData,
)
```

`input_type` describes the arguments for the handoff tool call itself. The SDK exposes that schema to the model as the handoff tool's `parameters`, validates the returned JSON locally, and passes the parsed value to `on_handoff`.

It does not replace the next agent's main input, and it does not choose a different destination. The [`handoff()`][agents.handoffs.handoff] helper still transfers to the specific agent you wrapped, and the receiving agent still sees the conversation history unless you change it with an [`input_filter`][agents.handoffs.Handoff.input_filter] or nested handoff history settings.

`input_type` is also separate from [`RunContextWrapper.context`][agents.run_context.RunContextWrapper.context]. Use `input_type` for metadata the model decides at handoff time, not for application state or dependencies you already have locally.

### When to use `input_type`

Use `input_type` when the handoff needs a small piece of model-generated metadata such as `reason`, `language`, `priority`, or `summary`. For example, a triage agent can hand off to a refund agent with `{ "reason": "duplicate_charge", "priority": "high" }`, and `on_handoff` can log or persist that metadata before the refund agent takes over.

Choose a different mechanism when the goal is different:

-   Put existing application state and dependencies in [`RunContextWrapper.context`][agents.run_context.RunContextWrapper.context]. See the [context guide](context.md).
-   Use [`input_filter`][agents.handoffs.Handoff.input_filter], [`RunConfig.nest_handoff_history`][agents.run.RunConfig.nest_handoff_history], or [`RunConfig.handoff_history_mapper`][agents.run.RunConfig.handoff_history_mapper] if you want to change what history the receiving agent sees.
-   Register one handoff per destination if there are multiple possible specialists. `input_type` can add metadata to the chosen handoff, but it does not dispatch between destinations.
-   If you want structured input for a nested specialist without transferring the conversation, prefer [`Agent.as_tool(parameters=...)`][agents.agent.Agent.as_tool]. See [tools](tools.md#structured-input-for-tool-agents).

## Input filters

When a handoff occurs, it's as though the new agent takes over the conversation, and gets to see the entire previous conversation history. If you want to change this, you can set an [`input_filter`][agents.handoffs.Handoff.input_filter]. An input filter is a function that receives the existing input via a [`HandoffInputData`][agents.handoffs.HandoffInputData], and must return a new `HandoffInputData`.

[`HandoffInputData`][agents.handoffs.HandoffInputData] includes:

-   `input_history`: the input history before `Runner.run(...)` started.
-   `pre_handoff_items`: items generated before the agent turn where the handoff was invoked.
-   `new_items`: items generated during the current turn, including the handoff call and handoff output items.
-   `input_items`: optional items to forward to the next agent instead of `new_items`, allowing you to filter model input while keeping `new_items` intact for session history.
-   `run_context`: the active [`RunContextWrapper`][agents.run_context.RunContextWrapper] at the time the handoff was invoked.

Nested handoffs are available as an opt-in beta and are disabled by default while we stabilize them. When you enable [`RunConfig.nest_handoff_history`][agents.run.RunConfig.nest_handoff_history], the runner collapses the prior transcript into a single assistant summary message and wraps it in a `<CONVERSATION HISTORY>` block that keeps appending new turns when multiple handoffs happen during the same run. You can provide your own mapping function via [`RunConfig.handoff_history_mapper`][agents.run.RunConfig.handoff_history_mapper] to replace the generated message without writing a full `input_filter`. The opt-in only applies when neither the handoff nor the run supplies an explicit `input_filter`, so existing code that already customizes the payload (including the examples in this repository) keeps its current behavior without changes. You can override the nesting behaviour for a single handoff by passing `nest_handoff_history=True` or `False` to [`handoff(...)`][agents.handoffs.handoff], which sets [`Handoff.nest_handoff_history`][agents.handoffs.Handoff.nest_handoff_history]. If you just need to change the wrapper text for the generated summary, call [`set_conversation_history_wrappers`][agents.handoffs.set_conversation_history_wrappers] (and optionally [`reset_conversation_history_wrappers`][agents.handoffs.reset_conversation_history_wrappers]) before running your agents.

If both the handoff and the active [`RunConfig.handoff_input_filter`][agents.run.RunConfig.handoff_input_filter] define a filter, the per-handoff [`input_filter`][agents.handoffs.Handoff.input_filter] takes precedence for that specific handoff.

!!! note

    Handoffs stay within a single run. Input guardrails still apply only to the first agent in the chain, and output guardrails only to the agent that produces the final output. Use tool guardrails when you need checks around each custom function-tool call inside the workflow.

There are some common patterns (for example removing all tool calls from the history), which are implemented for you in [`agents.extensions.handoff_filters`][]

```python
from agents import Agent, handoff
from agents.extensions import handoff_filters

agent = Agent(name="FAQ agent")

handoff_obj = handoff(
    agent=agent,
    input_filter=handoff_filters.remove_all_tools, # (1)!
)
```

1. This will automatically remove all tools from the history when `FAQ agent` is called.

## Recommended prompts

To make sure that LLMs understand handoffs properly, we recommend including information about handoffs in your agents. We have a suggested prefix in [`agents.extensions.handoff_prompt.RECOMMENDED_PROMPT_PREFIX`][], or you can call [`agents.extensions.handoff_prompt.prompt_with_handoff_instructions`][] to automatically add recommended data to your prompts.

```python
from agents import Agent
from agents.extensions.handoff_prompt import RECOMMENDED_PROMPT_PREFIX

billing_agent = Agent(
    name="Billing agent",
    instructions=f"""{RECOMMENDED_PROMPT_PREFIX}
    <Fill in the rest of your prompt here>.""",
)
```
