Agent2 Model Selector (#36028)

Release Notes:

- N/A

---------

Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>

crates/acp_thread/Cargo.toml

@@ -20,12 +20,12 @@ action_log.workspace = true
 agent-client-protocol.workspace = true
 anyhow.workspace = true
 buffer_diff.workspace = true
+collections.workspace = true
 editor.workspace = true
 futures.workspace = true
 gpui.workspace = true
 itertools.workspace = true
 language.workspace = true
-language_model.workspace = true
 markdown.workspace = true
 project.workspace = true
 serde.workspace = true
@@ -36,6 +36,7 @@ terminal.workspace = true
 ui.workspace = true
 url.workspace = true
 util.workspace = true
+watch.workspace = true
 workspace-hack.workspace = true
 
 [dev-dependencies]

crates/acp_thread/src/acp_thread.rs

@@ -694,6 +694,10 @@ impl AcpThread {
         }
     }
 
+    pub fn connection(&self) -> &Rc<dyn AgentConnection> {
+        &self.connection
+    }
+
     pub fn action_log(&self) -> &Entity<ActionLog> {
         &self.action_log
     }

crates/acp_thread/src/connection.rs

@@ -1,61 +1,14 @@
-use std::{error::Error, fmt, path::Path, rc::Rc, sync::Arc};
+use std::{error::Error, fmt, path::Path, rc::Rc};
 
 use agent_client_protocol::{self as acp};
 use anyhow::Result;
-use gpui::{AsyncApp, Entity, Task};
-use language_model::LanguageModel;
+use collections::IndexMap;
+use gpui::{AsyncApp, Entity, SharedString, Task};
 use project::Project;
-use ui::App;
+use ui::{App, IconName};
 
 use crate::AcpThread;
 
-/// Trait for agents that support listing, selecting, and querying language models.
-///
-/// This is an optional capability; agents indicate support via [AgentConnection::model_selector].
-pub trait ModelSelector: 'static {
-    /// Lists all available language models for this agent.
-    ///
-    /// # Parameters
-    /// - `cx`: The GPUI app context for async operations and global access.
-    ///
-    /// # Returns
-    /// A task resolving to the list of models or an error (e.g., if no models are configured).
-    fn list_models(&self, cx: &mut AsyncApp) -> Task<Result<Vec<Arc<dyn LanguageModel>>>>;
-
-    /// Selects a model for a specific session (thread).
-    ///
-    /// This sets the default model for future interactions in the session.
-    /// If the session doesn't exist or the model is invalid, it returns an error.
-    ///
-    /// # Parameters
-    /// - `session_id`: The ID of the session (thread) to apply the model to.
-    /// - `model`: The model to select (should be one from [list_models]).
-    /// - `cx`: The GPUI app context.
-    ///
-    /// # Returns
-    /// A task resolving to `Ok(())` on success or an error.
-    fn select_model(
-        &self,
-        session_id: acp::SessionId,
-        model: Arc<dyn LanguageModel>,
-        cx: &mut AsyncApp,
-    ) -> Task<Result<()>>;
-
-    /// Retrieves the currently selected model for a specific session (thread).
-    ///
-    /// # Parameters
-    /// - `session_id`: The ID of the session (thread) to query.
-    /// - `cx`: The GPUI app context.
-    ///
-    /// # Returns
-    /// A task resolving to the selected model (always set) or an error (e.g., session not found).
-    fn selected_model(
-        &self,
-        session_id: &acp::SessionId,
-        cx: &mut AsyncApp,
-    ) -> Task<Result<Arc<dyn LanguageModel>>>;
-}
-
 pub trait AgentConnection {
     fn new_thread(
         self: Rc<Self>,
@@ -77,8 +30,8 @@ pub trait AgentConnection {
     ///
     /// If the agent does not support model selection, returns [None].
     /// This allows sharing the selector in UI components.
-    fn model_selector(&self) -> Option<Rc<dyn ModelSelector>> {
-        None // Default impl for agents that don't support it
+    fn model_selector(&self) -> Option<Rc<dyn AgentModelSelector>> {
+        None
     }
 }
 
@@ -91,3 +44,95 @@ impl fmt::Display for AuthRequired {
         write!(f, "AuthRequired")
     }
 }
+
+/// Trait for agents that support listing, selecting, and querying language models.
+///
+/// This is an optional capability; agents indicate support via [AgentConnection::model_selector].
+pub trait AgentModelSelector: 'static {
+    /// Lists all available language models for this agent.
+    ///
+    /// # Parameters
+    /// - `cx`: The GPUI app context for async operations and global access.
+    ///
+    /// # Returns
+    /// A task resolving to the list of models or an error (e.g., if no models are configured).
+    fn list_models(&self, cx: &mut App) -> Task<Result<AgentModelList>>;
+
+    /// Selects a model for a specific session (thread).
+    ///
+    /// This sets the default model for future interactions in the session.
+    /// If the session doesn't exist or the model is invalid, it returns an error.
+    ///
+    /// # Parameters
+    /// - `session_id`: The ID of the session (thread) to apply the model to.
+    /// - `model`: The model to select (should be one from [list_models]).
+    /// - `cx`: The GPUI app context.
+    ///
+    /// # Returns
+    /// A task resolving to `Ok(())` on success or an error.
+    fn select_model(
+        &self,
+        session_id: acp::SessionId,
+        model_id: AgentModelId,
+        cx: &mut App,
+    ) -> Task<Result<()>>;
+
+    /// Retrieves the currently selected model for a specific session (thread).
+    ///
+    /// # Parameters
+    /// - `session_id`: The ID of the session (thread) to query.
+    /// - `cx`: The GPUI app context.
+    ///
+    /// # Returns
+    /// A task resolving to the selected model (always set) or an error (e.g., session not found).
+    fn selected_model(
+        &self,
+        session_id: &acp::SessionId,
+        cx: &mut App,
+    ) -> Task<Result<AgentModelInfo>>;
+
+    /// Whenever the model list is updated the receiver will be notified.
+    fn watch(&self, cx: &mut App) -> watch::Receiver<()>;
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct AgentModelId(pub SharedString);
+
+impl std::ops::Deref for AgentModelId {
+    type Target = SharedString;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl fmt::Display for AgentModelId {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct AgentModelInfo {
+    pub id: AgentModelId,
+    pub name: SharedString,
+    pub icon: Option<IconName>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct AgentModelGroupName(pub SharedString);
+
+#[derive(Debug, Clone)]
+pub enum AgentModelList {
+    Flat(Vec<AgentModelInfo>),
+    Grouped(IndexMap<AgentModelGroupName, Vec<AgentModelInfo>>),
+}
+
+impl AgentModelList {
+    pub fn is_empty(&self) -> bool {
+        match self {
+            AgentModelList::Flat(models) => models.is_empty(),
+            AgentModelList::Grouped(groups) => groups.is_empty(),
+        }
+    }
+}