Extract provider specific logic from llm crate into a codec trait

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- Provider-specific request/response handling moved out of the generic chat completions codec into per-provider codecs.
+- Remove google from active providers.
+
 ## 0.1.4 - 2026-10-4
 
 ### Added

crates/agent/src/agent/mod.rs

@@ -370,13 +370,13 @@ impl Agent {
         Ok(())
     }
 
-    pub async fn set_provider_order(&self, provider_order: Vec<String>) -> Result<(), AgentError> {
+    pub async fn set_extensions(&self, extensions: llm::Extensions) -> Result<(), AgentError> {
         let mut model = self.model.try_lock().map_err(|_| {
             AgentError::Model(providers::ModelError::Llm(llm::LlmError::Configuration(
-                "agent is busy: cannot change provider order mid-run".into(),
+                "agent is busy: cannot change request extensions mid-run".into(),
             )))
         })?;
-        model.set_provider_order(provider_order);
+        model.set_extensions(extensions);
         Ok(())
     }
 }

crates/agent/src/agent/prompt.rs

@@ -184,11 +184,13 @@ pub(super) async fn summarize(
     messages.push(Message::user(instruction));
 
     let options = RequestOptions::default();
+    let extensions = llm::Extensions::default();
     let mut stream_resp = model
         .stream(CompletionInput {
             messages: &messages,
             tools: &[],
             options: &options,
+            extensions: &extensions,
         })
         .await?;
 
@@ -217,9 +219,9 @@ pub(super) async fn stream_round(
         .collect();
 
     let messages = build_messages(context);
+    let mut extensions = llm::Extensions::default();
+    extensions.insert(llm::SessionId(session_id));
     let options = RequestOptions {
-        prompt_cache_key: Some(session_id.clone()),
-        session_id: Some(session_id),
         cache_control: Some(PromptCacheControl::one_hour()),
         ..RequestOptions::default()
     };
@@ -229,6 +231,7 @@ pub(super) async fn stream_round(
             messages: &messages,
             tools: &tools,
             options: &options,
+            extensions: &extensions,
         })
         .await?;
 

crates/alan/src/core/settings.rs

@@ -22,6 +22,7 @@ use crate::core::store::JsonStore;
 const SETTINGS_KEY: &str = "settings";
 use anyhow::Context as _;
 use llm::ReasoningEffort;
+use providers::OpenRouterOptions;
 use std::collections::BTreeMap;
 use std::path::PathBuf;
 
@@ -146,6 +147,20 @@ impl Settings {
     pub fn provider_order(&self, model: &str) -> Vec<String> {
         self.provider_orders.get(model).cloned().unwrap_or_default()
     }
+
+    /// Provider-specific request options for `model`, keyed by provider.
+    /// Only OpenRouter exposes settings today; the order is routed to its
+    /// codec via request extensions.
+    pub fn extensions(&self, model: &str) -> llm::Extensions {
+        let mut extensions = llm::Extensions::default();
+        let order = self.provider_order(model);
+        if !order.is_empty() {
+            extensions.insert(OpenRouterOptions {
+                provider_order: order,
+            });
+        }
+        extensions
+    }
 }
 
 /// Apply a PatchSettings to mutate only specified fields.

crates/alan/src/main.rs

@@ -22,7 +22,7 @@ use agent::{Agent, SessionManager, ToolPermissionManager, default_tools};
 use alan_tui::Runtime;
 use llm::ReasoningEffort;
 use providers::{
-    FileCredentialStore, GoogleProvider, LocalProvider, ModelOptions, OpenRouterProvider, Provider,
+    FileCredentialStore, LocalProvider, ModelOptions, OpenRouterProvider, Provider,
     ProviderRegistry, ZaiProvider, bind_model,
 };
 use std::path::PathBuf;
@@ -151,7 +151,8 @@ fn build_providers(
 ) -> anyhow::Result<Vec<Arc<dyn Provider>>> {
     Ok(vec![
         Arc::new(ZaiProvider::from_store(Arc::clone(credential_store)).build()?),
-        Arc::new(GoogleProvider::from_store(Arc::clone(credential_store)).build()?),
+        // until there really exists some evidence that this is needed, we can add back
+        // Arc::new(GoogleProvider::from_store(Arc::clone(credential_store)).build()?),
         Arc::new(OpenRouterProvider::from_store(Arc::clone(credential_store)).build()?),
         Arc::clone(local_provider) as Arc<dyn Provider>,
     ])
@@ -197,7 +198,7 @@ fn select_model(
         ModelOptions {
             server_tools,
             reasoning_effort: settings.reasoning.unwrap_or_default(),
-            provider_order: settings.provider_order(&model_id),
+            extensions: settings.extensions(&model_id),
         },
     )?)
 }

crates/alan/src/views/components/chat_view/models.rs

@@ -8,8 +8,8 @@ use crate::root::AlanAction;
 use alan_tui::TaskError;
 use alan_tui::context::Context;
 use providers::{
-    Model, ModelInfo, ModelOptions, Provider, ProviderId, ProviderRegistry, bind_local_model,
-    bind_model,
+    Model, ModelInfo, ModelOptions, OpenRouterOptions, Provider, ProviderId, ProviderRegistry,
+    bind_local_model, bind_model,
 };
 use std::sync::Arc;
 
@@ -63,7 +63,7 @@ pub(crate) fn open_models_picker(view: &mut ChatView, cx: &mut Context<'_, ChatV
                     let settings = settings::get_settings()
                         .await
                         .map_err(|e| TaskError(e.into()))?;
-                    options.provider_order = settings.provider_order(&model_info.id);
+                    options.extensions = settings.extensions(&model_info.id);
 
                     let model = bind_model_info(&providers, &model_info, options)?;
                     let name = model_info.name.clone();
@@ -124,8 +124,12 @@ pub(crate) fn apply_model_provider(
     cx.spawn(
         async move {
             let model_id = agent.info().await.id;
+            let mut extensions = agent.model_options().await.extensions;
+            extensions.insert(OpenRouterOptions {
+                provider_order: provider_order.clone(),
+            });
             agent
-                .set_provider_order(provider_order.clone())
+                .set_extensions(extensions)
                 .await
                 .map_err(|error| TaskError(Box::new(error)))?;
 

crates/alan/src/views/components/chat_view/profiles.rs

@@ -187,7 +187,7 @@ fn apply_profile(
         async move {
             let mut options = agent.model_options().await;
             let settings = settings::get_settings().await.map_err(super::to_task)?;
-            options.provider_order = settings.provider_order(&profile.model);
+            options.extensions = settings.extensions(&profile.model);
             options.reasoning_effort = profile.reasoning;
             options.server_tools = server_tools_for_provider(
                 &providers,