Fix missing method for experimental model selection (#107)

* Fix missing method for experimental model selection

* Update changelog

Author: benbrandt

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## 0.4.2 (2025-09-22)
+
+### Rust
+
+**Unstable** fix missing method for model selection in Rust library.
+
 ## 0.4.1 (2025-09-22)
 
 ### Protocol

Cargo.lock

@@ -1,7 +1,7 @@
 [package]
 name = "agent-client-protocol"
 authors = ["Zed <hi@zed.dev>"]
-version = "0.4.1"
+version = "0.4.2"
 edition = "2024"
 license = "Apache-2.0"
 description = "A protocol for standardizing communication between code editors and AI coding agents"

Cargo.toml

@@ -1,6 +1,6 @@
 {
   "name": "@zed-industries/agent-client-protocol",
-  "version": "0.4.1",
+  "version": "0.4.2",
   "publishConfig": {
     "access": "public"
   },

package-lock.json

@@ -242,7 +242,7 @@ impl Agent for ClientSideConnection {
         self.conn
             .request(
                 SESSION_SET_MODEL_METHOD_NAME,
-                Some(ClientRequest::ModelSelectRequest(args)),
+                Some(ClientRequest::SetSessionModelRequest(args)),
             )
             .await
     }
@@ -613,6 +613,10 @@ impl Side for AgentSide {
             SESSION_SET_MODE_METHOD_NAME => serde_json::from_str(params.get())
                 .map(ClientRequest::SetSessionModeRequest)
                 .map_err(Into::into),
+            #[cfg(feature = "unstable")]
+            SESSION_SET_MODEL_METHOD_NAME => serde_json::from_str(params.get())
+                .map(ClientRequest::SetSessionModelRequest)
+                .map_err(Into::into),
             SESSION_PROMPT_METHOD_NAME => serde_json::from_str(params.get())
                 .map(ClientRequest::PromptRequest)
                 .map_err(Into::into),
@@ -681,9 +685,9 @@ impl<T: Agent> MessageHandler<AgentSide> for T {
                 Ok(AgentResponse::SetSessionModeResponse(response))
             }
             #[cfg(feature = "unstable")]
-            ClientRequest::ModelSelectRequest(args) => {
+            ClientRequest::SetSessionModelRequest(args) => {
                 let response = self.set_session_model(args).await?;
-                Ok(AgentResponse::ModelSelectResponse(response))
+                Ok(AgentResponse::SetSessionModelResponse(response))
             }
             ClientRequest::ExtMethodRequest(args) => {
                 let response = self.ext_method(args).await?;

package.json

@@ -778,7 +778,7 @@ pub enum ClientRequest {
     SetSessionModeRequest(SetSessionModeRequest),
     PromptRequest(PromptRequest),
     #[cfg(feature = "unstable")]
-    ModelSelectRequest(SetSessionModelRequest),
+    SetSessionModelRequest(SetSessionModelRequest),
     ExtMethodRequest(ExtRequest),
 }
 
@@ -799,7 +799,7 @@ pub enum AgentResponse {
     SetSessionModeResponse(#[serde(default)] SetSessionModeResponse),
     PromptResponse(PromptResponse),
     #[cfg(feature = "unstable")]
-    ModelSelectResponse(SetSessionModelResponse),
+    SetSessionModelResponse(SetSessionModelResponse),
     ExtMethodResponse(#[schemars(with = "serde_json::Value")] Arc<RawValue>),
 }
 

rust/acp.rs

@@ -113,7 +113,7 @@
         },
         {
           "$ref": "#/$defs/SetSessionModelResponse",
-          "title": "ModelSelectResponse"
+          "title": "SetSessionModelResponse"
         },
         {
           "title": "ExtMethodResponse"
@@ -367,7 +367,7 @@
         },
         {
           "$ref": "#/$defs/SetSessionModelRequest",
-          "title": "ModelSelectRequest"
+          "title": "SetSessionModelRequest"
         },
         {
           "title": "ExtMethodRequest"

rust/agent.rs

@@ -250,7 +250,7 @@ export type AgentRequest =
   | LoadSessionRequest
   | SetSessionModeRequest
   | PromptRequest
-  | ModelSelectRequest
+  | SetSessionModelRequest
   | ExtMethodRequest1;
 /**
  * Configuration for connecting to an MCP (Model Context Protocol) server.
@@ -388,7 +388,7 @@ export type AgentResponse =
   | LoadSessionResponse
   | SetSessionModeResponse
   | PromptResponse
-  | ModelSelectResponse
+  | SetSessionModelResponse
   | ExtMethodResponse1;
 /**
  * Unique identifier for a Session Mode.
@@ -1157,7 +1157,7 @@ export interface PromptRequest {
  *
  * Request parameters for setting a session model.
  */
-export interface ModelSelectRequest {
+export interface SetSessionModelRequest {
   /**
    * Extension point for implementations
    */
@@ -1477,7 +1477,7 @@ export interface PromptResponse {
  *
  * Response to `session/set_model` method.
  */
-export interface ModelSelectResponse {
+export interface SetSessionModelResponse {
   /**
    * Extension point for implementations
    */
@@ -1876,7 +1876,7 @@ export const setSessionModeRequestSchema = z.object({
 });
 
 /** @internal */
-export const modelSelectRequestSchema = z.object({
+export const setSessionModelRequestSchema = z.object({
   _meta: z.record(z.unknown()).optional(),
   modelId: z.string(),
   sessionId: z.string(),
@@ -1929,7 +1929,7 @@ export const promptResponseSchema = z.object({
 });
 
 /** @internal */
-export const modelSelectResponseSchema = z.object({
+export const setSessionModelResponseSchema = z.object({
   _meta: z.record(z.unknown()).optional(),
 });
 
@@ -2413,7 +2413,7 @@ export const agentRequestSchema = z.union([
   loadSessionRequestSchema,
   setSessionModeRequestSchema,
   promptRequestSchema,
-  modelSelectRequestSchema,
+  setSessionModelRequestSchema,
   extMethodRequest1Schema,
 ]);
 
@@ -2425,7 +2425,7 @@ export const agentResponseSchema = z.union([
   loadSessionResponseSchema,
   setSessionModeResponseSchema,
   promptResponseSchema,
-  modelSelectResponseSchema,
+  setSessionModelResponseSchema,
   extMethodResponse1Schema,
 ]);