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Lifecycle

RunHooks

Bases: Generic[TContext]

A class that receives callbacks on various lifecycle events in an agent run. Subclass and override the methods you need.

on_agent_start async 

on_agent_start(
    context: RunContextWrapper[TContext],
    agent: Agent[TContext],
) -> None

Called before the agent is invoked. Called each time the current agent changes.

on_agent_end async 

on_agent_end(
    context: RunContextWrapper[TContext],
    agent: Agent[TContext],
    output: Any,
) -> None

Called when the agent produces a final output.

on_handoff async 

on_handoff(
    context: RunContextWrapper[TContext],
    from_agent: Agent[TContext],
    to_agent: Agent[TContext],
) -> None

Called when a handoff occurs.

on_tool_start async 

on_tool_start(
    context: RunContextWrapper[TContext],
    agent: Agent[TContext],
    tool: Tool,
) -> None

Called before a tool is invoked.

on_tool_end async 

on_tool_end(
    context: RunContextWrapper[TContext],
    agent: Agent[TContext],
    tool: Tool,
    result: str,
) -> None

Called after a tool is invoked.

AgentHooks

Bases: Generic[TContext]

A class that receives callbacks on various lifecycle events for a specific agent. You can set this on agent.hooks to receive events for that specific agent.

Subclass and override the methods you need.

on_start async 

on_start(
    context: RunContextWrapper[TContext],
    agent: Agent[TContext],
) -> None

Called before the agent is invoked. Called each time the running agent is changed to this agent.

on_end async 

on_end(
    context: RunContextWrapper[TContext],
    agent: Agent[TContext],
    output: Any,
) -> None

Called when the agent produces a final output.

on_handoff async 

on_handoff(
    context: RunContextWrapper[TContext],
    agent: Agent[TContext],
    source: Agent[TContext],
) -> None

Called when the agent is being handed off to. The source is the agent that is handing off to this agent.

on_tool_start async 

on_tool_start(
    context: RunContextWrapper[TContext],
    agent: Agent[TContext],
    tool: Tool,
) -> None

Called before a tool is invoked.

on_tool_end async 

on_tool_end(
    context: RunContextWrapper[TContext],
    agent: Agent[TContext],
    tool: Tool,
    result: str,
) -> None

Called after a tool is invoked.