Integration with MCP Types

MCP Type Compatibility

FastAgent is built to seamlessly integrate with the MCP SDK type system:

Conversations with assistants are based on PromptMessageMultipart - an extension the the mcp PromptMessage type, with support for multiple content sections. This type is expected to become native in a future version of MCP: https://github.com/modelcontextprotocol/specification/pull/198

Message History Transfer

FastAgent makes it easy to transfer conversation history between agents:

history_transfer.py

@fast.agent(name="haiku", model="haiku")
@fast.agent(name="openai", model="o3-mini.medium")

async def main() -> None:
    async with fast.run() as agent:
        # Start an interactive session with "haiku"
        await agent.prompt(agent_name="haiku")
        # Transfer the message history top "openai" (using PromptMessageMultipart)
        await agent.openai.generate(agent.haiku.message_history)
        # Continue the conversation
        await agent.prompt(agent_name="openai")