Use Canonical Models to set context window sizes (#6723)

crates/goose-cli/src/session/builder.rs

@@ -386,6 +386,7 @@ fn resolve_provider_and_model(
                 output::render_error(&format!("Failed to create model configuration: {}", e));
                 process::exit(1);
             })
+            .with_canonical_limits(&provider_name)
             .with_temperature(temperature)
     };
 

crates/goose-cli/src/session/mod.rs

@@ -1847,7 +1847,7 @@ async fn get_reasoner() -> Result<Arc<dyn Provider>, anyhow::Error> {
     };
 
     let model_config =
-        ModelConfig::new_with_context_env(model, Some("GOOSE_PLANNER_CONTEXT_LIMIT"))?;
+        ModelConfig::new_with_context_env(model, &provider, Some("GOOSE_PLANNER_CONTEXT_LIMIT"))?;
     let extensions = goose::config::extensions::get_enabled_extensions_with_config(config);
     let reasoner = create(&provider, model_config, extensions).await?;