Partially fix assistant onboarding (#25313)

While investigating #24896, I noticed two issues:

1. The default configuration for the `zed.dev` provider was using the
wrong string for Claude 3.5 Sonnet. This meant the provider would always
result as not configured until the user selected it from the model
picker, because we couldn't deserialize that string to a valid
`anthropic::Model` enum variant.
2. When clicking on `Open New Chat`/`Start New Thread` in the provider
configuration, we would select `Claude 3.5 Haiku` by default instead of
Claude 3.5 Sonnet.

Release Notes:

- Fixed some issues that caused AI providers to sometimes be
misconfigured.

assets/settings/default.json

@@ -581,7 +581,7 @@
       // The provider to use.
       "provider": "zed.dev",
       // The model to use.
-      "model": "claude-3-5-sonnet"
+      "model": "claude-3-5-sonnet-latest"
     }
   },
   // The settings for slash commands.

crates/assistant/src/assistant_panel.rs

@@ -978,7 +978,7 @@ impl AssistantPanel {
                             .active_provider()
                             .map_or(true, |p| p.id() != provider.id())
                         {
-                            if let Some(model) = provider.provided_models(cx).first().cloned() {
+                            if let Some(model) = provider.default_model(cx) {
                                 update_settings_file::<AssistantSettings>(
                                     this.fs.clone(),
                                     cx,

crates/assistant2/src/assistant_panel.rs

@@ -431,7 +431,7 @@ impl AssistantPanel {
                         active_provider.id() != provider.id()
                     })
                 {
-                    if let Some(model) = provider.provided_models(cx).first().cloned() {
+                    if let Some(model) = provider.default_model(cx) {
                         update_settings_file::<AssistantSettings>(
                             self.fs.clone(),
                             cx,

crates/assistant_settings/src/assistant_settings.rs

@@ -512,7 +512,7 @@ mod tests {
                 AssistantSettings::get_global(cx).default_model,
                 LanguageModelSelection {
                     provider: "zed.dev".into(),
-                    model: "claude-3-5-sonnet".into(),
+                    model: "claude-3-5-sonnet-latest".into(),
                 }
             );
         });

crates/google_ai/src/google_ai.rs

@@ -299,7 +299,7 @@ pub struct CountTokensResponse {
 }
 
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Eq, strum::EnumIter)]
+#[derive(Clone, Default, Debug, Deserialize, Serialize, PartialEq, Eq, strum::EnumIter)]
 pub enum Model {
     #[serde(rename = "gemini-1.5-pro")]
     Gemini15Pro,
@@ -308,6 +308,7 @@ pub enum Model {
     #[serde(rename = "gemini-2.0-pro-exp")]
     Gemini20Pro,
     #[serde(rename = "gemini-2.0-flash")]
+    #[default]
     Gemini20Flash,
     #[serde(rename = "gemini-2.0-flash-thinking-exp")]
     Gemini20FlashThinking,

crates/language_model/src/fake_provider.rs

@@ -46,6 +46,10 @@ impl LanguageModelProvider for FakeLanguageModelProvider {
         provider_name()
     }
 
+    fn default_model(&self, _cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        Some(Arc::new(FakeLanguageModel::default()))
+    }
+
     fn provided_models(&self, _: &App) -> Vec<Arc<dyn LanguageModel>> {
         vec![Arc::new(FakeLanguageModel::default())]
     }

crates/language_model/src/language_model.rs

@@ -247,6 +247,7 @@ pub trait LanguageModelProvider: 'static {
     fn icon(&self) -> IconName {
         IconName::ZedAssistant
     }
+    fn default_model(&self, cx: &App) -> Option<Arc<dyn LanguageModel>>;
     fn provided_models(&self, cx: &App) -> Vec<Arc<dyn LanguageModel>>;
     fn load_model(&self, _model: Arc<dyn LanguageModel>, _cx: &App) {}
     fn is_authenticated(&self, cx: &App) -> bool;

crates/language_models/src/provider/anthropic.rs

@@ -183,6 +183,17 @@ impl LanguageModelProvider for AnthropicLanguageModelProvider {
         IconName::AiAnthropic
     }
 
+    fn default_model(&self, _cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        let model = anthropic::Model::default();
+        Some(Arc::new(AnthropicModel {
+            id: LanguageModelId::from(model.id().to_string()),
+            model,
+            state: self.state.clone(),
+            http_client: self.http_client.clone(),
+            request_limiter: RateLimiter::new(4),
+        }))
+    }
+
     fn provided_models(&self, cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         let mut models = BTreeMap::default();
 

crates/language_models/src/provider/cloud.rs

@@ -272,6 +272,18 @@ impl LanguageModelProvider for CloudLanguageModelProvider {
         IconName::AiZed
     }
 
+    fn default_model(&self, cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        let llm_api_token = self.state.read(cx).llm_api_token.clone();
+        let model = CloudModel::Anthropic(anthropic::Model::default());
+        Some(Arc::new(CloudLanguageModel {
+            id: LanguageModelId::from(model.id().to_string()),
+            model,
+            llm_api_token: llm_api_token.clone(),
+            client: self.client.clone(),
+            request_limiter: RateLimiter::new(4),
+        }))
+    }
+
     fn provided_models(&self, cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         let mut models = BTreeMap::default();
 

crates/language_models/src/provider/copilot_chat.rs

@@ -89,6 +89,14 @@ impl LanguageModelProvider for CopilotChatLanguageModelProvider {
         IconName::Copilot
     }
 
+    fn default_model(&self, _cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        let model = CopilotChatModel::default();
+        Some(Arc::new(CopilotChatLanguageModel {
+            model,
+            request_limiter: RateLimiter::new(4),
+        }) as Arc<dyn LanguageModel>)
+    }
+
     fn provided_models(&self, _cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         CopilotChatModel::iter()
             .map(|model| {

crates/language_models/src/provider/deepseek.rs

@@ -163,6 +163,17 @@ impl LanguageModelProvider for DeepSeekLanguageModelProvider {
         IconName::AiDeepSeek
     }
 
+    fn default_model(&self, _cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        let model = deepseek::Model::Chat;
+        Some(Arc::new(DeepSeekLanguageModel {
+            id: LanguageModelId::from(model.id().to_string()),
+            model,
+            state: self.state.clone(),
+            http_client: self.http_client.clone(),
+            request_limiter: RateLimiter::new(4),
+        }))
+    }
+
     fn provided_models(&self, cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         let mut models = BTreeMap::default();
 

crates/language_models/src/provider/google.rs

@@ -166,6 +166,17 @@ impl LanguageModelProvider for GoogleLanguageModelProvider {
         IconName::AiGoogle
     }
 
+    fn default_model(&self, _cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        let model = google_ai::Model::default();
+        Some(Arc::new(GoogleLanguageModel {
+            id: LanguageModelId::from(model.id().to_string()),
+            model,
+            state: self.state.clone(),
+            http_client: self.http_client.clone(),
+            rate_limiter: RateLimiter::new(4),
+        }))
+    }
+
     fn provided_models(&self, cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         let mut models = BTreeMap::default();
 

crates/language_models/src/provider/lmstudio.rs

@@ -152,6 +152,10 @@ impl LanguageModelProvider for LmStudioLanguageModelProvider {
         IconName::AiLmStudio
     }
 
+    fn default_model(&self, cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        self.provided_models(cx).into_iter().next()
+    }
+
     fn provided_models(&self, cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         let mut models: BTreeMap<String, lmstudio::Model> = BTreeMap::default();
 

crates/language_models/src/provider/mistral.rs

@@ -167,6 +167,17 @@ impl LanguageModelProvider for MistralLanguageModelProvider {
         IconName::AiMistral
     }
 
+    fn default_model(&self, _cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        let model = mistral::Model::default();
+        Some(Arc::new(MistralLanguageModel {
+            id: LanguageModelId::from(model.id().to_string()),
+            model,
+            state: self.state.clone(),
+            http_client: self.http_client.clone(),
+            request_limiter: RateLimiter::new(4),
+        }))
+    }
+
     fn provided_models(&self, cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         let mut models = BTreeMap::default();
 

crates/language_models/src/provider/ollama.rs

@@ -157,6 +157,10 @@ impl LanguageModelProvider for OllamaLanguageModelProvider {
         IconName::AiOllama
     }
 
+    fn default_model(&self, cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        self.provided_models(cx).into_iter().next()
+    }
+
     fn provided_models(&self, cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         let mut models: BTreeMap<String, ollama::Model> = BTreeMap::default();
 

crates/language_models/src/provider/open_ai.rs

@@ -169,6 +169,17 @@ impl LanguageModelProvider for OpenAiLanguageModelProvider {
         IconName::AiOpenAi
     }
 
+    fn default_model(&self, _cx: &App) -> Option<Arc<dyn LanguageModel>> {
+        let model = open_ai::Model::default();
+        Some(Arc::new(OpenAiLanguageModel {
+            id: LanguageModelId::from(model.id().to_string()),
+            model,
+            state: self.state.clone(),
+            http_client: self.http_client.clone(),
+            request_limiter: RateLimiter::new(4),
+        }))
+    }
+
     fn provided_models(&self, cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         let mut models = BTreeMap::default();