Pull trait definitions for Agent/Client to SDK

Author: benbrandt

package.json

@@ -22,7 +22,7 @@
   "type": "module",
   "scripts": {
     "generate:json-schema": "cd rust && cargo run --bin generate --features unstable",
-    "generate": "npm run generate:json-schema && npm run generate:ts-schema && npm run format",
+    "generate": "npm run generate:json-schema && npm run format",
     "format": "prettier --write . && cargo fmt",
     "format:check": "prettier --check . && cargo fmt -- --check",
     "spellcheck": "./scripts/spellcheck.sh",

rust/agent.rs

@@ -3,238 +3,14 @@
 //! This module defines the Agent trait and all associated types for implementing
 //! an AI coding agent that follows the Agent Client Protocol (ACP).
 
-use std::rc::Rc;
 use std::{path::PathBuf, sync::Arc};
 
-use anyhow::Result;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use serde_json::value::RawValue;
 
 use crate::ext::ExtRequest;
-use crate::{
-    ClientCapabilities, ContentBlock, Error, ExtNotification, ExtResponse, ProtocolVersion,
-    SessionId,
-};
-
-/// Defines the interface that all ACP-compliant agents must implement.
-///
-/// Agents are programs that use generative AI to autonomously modify code. They handle
-/// requests from clients and execute tasks using language models and tools.
-#[async_trait::async_trait(?Send)]
-pub trait Agent {
-    /// Establishes the connection with a client and negotiates protocol capabilities.
-    ///
-    /// This method is called once at the beginning of the connection to:
-    /// - Negotiate the protocol version to use
-    /// - Exchange capability information between client and agent
-    /// - Determine available authentication methods
-    ///
-    /// The agent should respond with its supported protocol version and capabilities.
-    ///
-    /// See protocol docs: [Initialization](https://agentclientprotocol.com/protocol/initialization)
-    async fn initialize(&self, args: InitializeRequest) -> Result<InitializeResponse, Error>;
-
-    /// Authenticates the client using the specified authentication method.
-    ///
-    /// Called when the agent requires authentication before allowing session creation.
-    /// The client provides the authentication method ID that was advertised during initialization.
-    ///
-    /// After successful authentication, the client can proceed to create sessions with
-    /// `new_session` without receiving an `auth_required` error.
-    ///
-    /// See protocol docs: [Initialization](https://agentclientprotocol.com/protocol/initialization)
-    async fn authenticate(&self, args: AuthenticateRequest) -> Result<AuthenticateResponse, Error>;
-
-    /// Creates a new conversation session with the agent.
-    ///
-    /// Sessions represent independent conversation contexts with their own history and state.
-    ///
-    /// The agent should:
-    /// - Create a new session context
-    /// - Connect to any specified MCP servers
-    /// - Return a unique session ID for future requests
-    ///
-    /// May return an `auth_required` error if the agent requires authentication.
-    ///
-    /// See protocol docs: [Session Setup](https://agentclientprotocol.com/protocol/session-setup)
-    async fn new_session(&self, args: NewSessionRequest) -> Result<NewSessionResponse, Error>;
-
-    /// Processes a user prompt within a session.
-    ///
-    /// This method handles the whole lifecycle of a prompt:
-    /// - Receives user messages with optional context (files, images, etc.)
-    /// - Processes the prompt using language models
-    /// - Reports language model content and tool calls to the Clients
-    /// - Requests permission to run tools
-    /// - Executes any requested tool calls
-    /// - Returns when the turn is complete with a stop reason
-    ///
-    /// See protocol docs: [Prompt Turn](https://agentclientprotocol.com/protocol/prompt-turn)
-    async fn prompt(&self, args: PromptRequest) -> Result<PromptResponse, Error>;
-
-    /// Cancels ongoing operations for a session.
-    ///
-    /// This is a notification sent by the client to cancel an ongoing prompt turn.
-    ///
-    /// Upon receiving this notification, the Agent SHOULD:
-    /// - Stop all language model requests as soon as possible
-    /// - Abort all tool call invocations in progress
-    /// - Send any pending `session/update` notifications
-    /// - Respond to the original `session/prompt` request with `StopReason::Cancelled`
-    ///
-    /// See protocol docs: [Cancellation](https://agentclientprotocol.com/protocol/prompt-turn#cancellation)
-    async fn cancel(&self, args: CancelNotification) -> Result<(), Error>;
-
-    /// Loads an existing session to resume a previous conversation.
-    ///
-    /// This method is only available if the agent advertises the `loadSession` capability.
-    ///
-    /// The agent should:
-    /// - Restore the session context and conversation history
-    /// - Connect to the specified MCP servers
-    /// - Stream the entire conversation history back to the client via notifications
-    ///
-    /// See protocol docs: [Loading Sessions](https://agentclientprotocol.com/protocol/session-setup#loading-sessions)
-    async fn load_session(&self, _args: LoadSessionRequest) -> Result<LoadSessionResponse, Error> {
-        Err(Error::method_not_found())
-    }
-
-    /// Sets the current mode for a session.
-    ///
-    /// Allows switching between different agent modes (e.g., "ask", "architect", "code")
-    /// that affect system prompts, tool availability, and permission behaviors.
-    ///
-    /// The mode must be one of the modes advertised in `availableModes` during session
-    /// creation or loading. Agents may also change modes autonomously and notify the
-    /// client via `current_mode_update` notifications.
-    ///
-    /// This method can be called at any time during a session, whether the Agent is
-    /// idle or actively generating a response.
-    ///
-    /// See protocol docs: [Session Modes](https://agentclientprotocol.com/protocol/session-modes)
-    async fn set_session_mode(
-        &self,
-        _args: SetSessionModeRequest,
-    ) -> Result<SetSessionModeResponse, Error> {
-        Err(Error::method_not_found())
-    }
-
-    /// **UNSTABLE**
-    ///
-    /// This capability is not part of the spec yet, and may be removed or changed at any point.
-    ///
-    /// Select a model for a given session.
-    #[cfg(feature = "unstable")]
-    async fn set_session_model(
-        &self,
-        _args: SetSessionModelRequest,
-    ) -> Result<SetSessionModelResponse, Error> {
-        Err(Error::method_not_found())
-    }
-
-    /// Handles extension method requests from the client.
-    ///
-    /// Extension methods provide a way to add custom functionality while maintaining
-    /// protocol compatibility.
-    ///
-    /// See protocol docs: [Extensibility](https://agentclientprotocol.com/protocol/extensibility)
-    async fn ext_method(&self, _args: ExtRequest) -> Result<ExtResponse, Error> {
-        Ok(RawValue::NULL.to_owned().into())
-    }
-
-    /// Handles extension notifications from the client.
-    ///
-    /// Extension notifications provide a way to send one-way messages for custom functionality
-    /// while maintaining protocol compatibility.
-    ///
-    /// See protocol docs: [Extensibility](https://agentclientprotocol.com/protocol/extensibility)
-    async fn ext_notification(&self, _args: ExtNotification) -> Result<(), Error> {
-        Ok(())
-    }
-}
-
-#[async_trait::async_trait(?Send)]
-impl<T: Agent> Agent for Rc<T> {
-    async fn initialize(&self, args: InitializeRequest) -> Result<InitializeResponse, Error> {
-        self.as_ref().initialize(args).await
-    }
-    async fn authenticate(&self, args: AuthenticateRequest) -> Result<AuthenticateResponse, Error> {
-        self.as_ref().authenticate(args).await
-    }
-    async fn new_session(&self, args: NewSessionRequest) -> Result<NewSessionResponse, Error> {
-        self.as_ref().new_session(args).await
-    }
-    async fn load_session(&self, args: LoadSessionRequest) -> Result<LoadSessionResponse, Error> {
-        self.as_ref().load_session(args).await
-    }
-    async fn set_session_mode(
-        &self,
-        args: SetSessionModeRequest,
-    ) -> Result<SetSessionModeResponse, Error> {
-        self.as_ref().set_session_mode(args).await
-    }
-    async fn prompt(&self, args: PromptRequest) -> Result<PromptResponse, Error> {
-        self.as_ref().prompt(args).await
-    }
-    async fn cancel(&self, args: CancelNotification) -> Result<(), Error> {
-        self.as_ref().cancel(args).await
-    }
-    #[cfg(feature = "unstable")]
-    async fn set_session_model(
-        &self,
-        args: SetSessionModelRequest,
-    ) -> Result<SetSessionModelResponse, Error> {
-        self.as_ref().set_session_model(args).await
-    }
-    async fn ext_method(&self, args: ExtRequest) -> Result<ExtResponse, Error> {
-        self.as_ref().ext_method(args).await
-    }
-    async fn ext_notification(&self, args: ExtNotification) -> Result<(), Error> {
-        self.as_ref().ext_notification(args).await
-    }
-}
-
-#[async_trait::async_trait(?Send)]
-impl<T: Agent> Agent for Arc<T> {
-    async fn initialize(&self, args: InitializeRequest) -> Result<InitializeResponse, Error> {
-        self.as_ref().initialize(args).await
-    }
-    async fn authenticate(&self, args: AuthenticateRequest) -> Result<AuthenticateResponse, Error> {
-        self.as_ref().authenticate(args).await
-    }
-    async fn new_session(&self, args: NewSessionRequest) -> Result<NewSessionResponse, Error> {
-        self.as_ref().new_session(args).await
-    }
-    async fn load_session(&self, args: LoadSessionRequest) -> Result<LoadSessionResponse, Error> {
-        self.as_ref().load_session(args).await
-    }
-    async fn set_session_mode(
-        &self,
-        args: SetSessionModeRequest,
-    ) -> Result<SetSessionModeResponse, Error> {
-        self.as_ref().set_session_mode(args).await
-    }
-    async fn prompt(&self, args: PromptRequest) -> Result<PromptResponse, Error> {
-        self.as_ref().prompt(args).await
-    }
-    async fn cancel(&self, args: CancelNotification) -> Result<(), Error> {
-        self.as_ref().cancel(args).await
-    }
-    #[cfg(feature = "unstable")]
-    async fn set_session_model(
-        &self,
-        args: SetSessionModelRequest,
-    ) -> Result<SetSessionModelResponse, Error> {
-        self.as_ref().set_session_model(args).await
-    }
-    async fn ext_method(&self, args: ExtRequest) -> Result<ExtResponse, Error> {
-        self.as_ref().ext_method(args).await
-    }
-    async fn ext_notification(&self, args: ExtNotification) -> Result<(), Error> {
-        self.as_ref().ext_notification(args).await
-    }
-}
+use crate::{ClientCapabilities, ContentBlock, ExtNotification, ProtocolVersion, SessionId};
 
 // Initialize