Redesign Extensions page. Remove enable toggle in UI. Treat Extension Manager as core MCP enabler per session. (#8940)

Signed-off-by: morgmart <98432065+morgmart@users.noreply.github.com>

crates/goose/src/config/base.rs

@@ -1986,10 +1986,12 @@ extensions:
         )
         .unwrap();
 
-        // User config (higher priority / write target) disables developer and adds a new extension
+        // User config (higher priority / write target) has already migrated, then disables
+        // developer and adds a new extension.
         std::fs::write(
             local_file.path(),
             r#"
+extensions_on_demand_migration: true
 extensions:
   developer:
     enabled: false
@@ -2014,7 +2016,7 @@ extensions:
         let values = config.load()?;
         let extensions = values.get("extensions").unwrap().as_mapping().unwrap();
 
-        // developer should be disabled (user config overrides system)
+        // developer should be disabled (user config overrides system after migration)
         let dev = extensions.get("developer").unwrap().as_mapping().unwrap();
         assert!(!dev.get("enabled").unwrap().as_bool().unwrap());
         // Fields from the system config should be preserved via merge

crates/goose/src/config/extensions.rs

@@ -13,8 +13,13 @@ pub const DEFAULT_EXTENSION_DESCRIPTION: &str = "";
 pub const DEFAULT_DISPLAY_NAME: &str = "Developer";
 const EXTENSIONS_CONFIG_KEY: &str = "extensions";
 
+fn default_extension_enabled() -> bool {
+    true
+}
+
 #[derive(Debug, Deserialize, Serialize, Clone, ToSchema)]
 pub struct ExtensionEntry {
+    #[serde(default = "default_extension_enabled")]
     pub enabled: bool,
     #[serde(flatten)]
     pub config: ExtensionConfig,
@@ -210,4 +215,22 @@ mod tests {
         assert!(!is_extension_available(&unknown_platform));
         assert!(is_extension_available(&builtin));
     }
+
+    #[test]
+    fn test_extension_entry_defaults_missing_enabled_to_true() {
+        let value = serde_yaml::from_str(
+            r#"
+type: stdio
+name: github
+description: GitHub tools
+cmd: npx
+args: []
+"#,
+        )
+        .unwrap();
+
+        let entry: ExtensionEntry = serde_yaml::from_value(value).unwrap();
+
+        assert!(entry.enabled);
+    }
 }

crates/goose/src/config/migrations.rs

@@ -114,10 +114,18 @@ mod tests {
         assert!(changed);
         let extensions_key = serde_yaml::Value::String(EXTENSIONS_CONFIG_KEY.to_string());
         assert!(config.contains_key(&extensions_key));
+
+        let extensions = config.get(&extensions_key).unwrap().as_mapping().unwrap();
+        for (key, value) in extensions {
+            let key = key.as_str().unwrap();
+            let def = PLATFORM_EXTENSIONS.get(key).unwrap();
+            let entry: ExtensionEntry = serde_yaml::from_value(value.clone()).unwrap();
+            assert_eq!(entry.enabled, def.default_enabled);
+        }
     }
 
     #[test]
-    fn test_migrate_platform_extensions_preserves_enabled_state() {
+    fn test_migrate_platform_extensions_refreshes_metadata_without_changing_enabled() {
         let mut config = Mapping::new();
         let mut extensions = Mapping::new();
         let todo_entry = ExtensionEntry {
@@ -149,6 +157,105 @@ mod tests {
         let todo_entry: ExtensionEntry = serde_yaml::from_value(todo_value.clone()).unwrap();
 
         assert!(!todo_entry.enabled);
+        match todo_entry.config {
+            ExtensionConfig::Platform {
+                description,
+                display_name,
+                ..
+            } => {
+                assert_ne!(description, "old description");
+                assert_ne!(display_name.as_deref(), Some("Old Name"));
+            }
+            other => panic!("expected platform extension, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn test_migrate_platform_extensions_preserves_existing_enabled_values() {
+        let mut config = Mapping::new();
+        let mut extensions = Mapping::new();
+
+        let analyze_entry = ExtensionEntry {
+            config: ExtensionConfig::Platform {
+                name: "analyze".to_string(),
+                description: "Analyze code structure".to_string(),
+                display_name: Some("Analyze".to_string()),
+                bundled: Some(true),
+                available_tools: Vec::new(),
+            },
+            enabled: true,
+        };
+        let developer_entry = ExtensionEntry {
+            config: ExtensionConfig::Platform {
+                name: "developer".to_string(),
+                description: "Write and edit files, and execute shell commands".to_string(),
+                display_name: Some("Developer".to_string()),
+                bundled: Some(true),
+                available_tools: Vec::new(),
+            },
+            enabled: false,
+        };
+        let custom_developer_entry = ExtensionEntry {
+            config: ExtensionConfig::Stdio {
+                name: "developer".to_string(),
+                description: "Custom user developer tools".to_string(),
+                cmd: "custom-developer".to_string(),
+                args: Vec::new(),
+                envs: Default::default(),
+                env_keys: Vec::new(),
+                timeout: Some(300),
+                bundled: None,
+                available_tools: Vec::new(),
+            },
+            enabled: true,
+        };
+
+        extensions.insert(
+            serde_yaml::Value::String("analyze".to_string()),
+            serde_yaml::to_value(&analyze_entry).unwrap(),
+        );
+        extensions.insert(
+            serde_yaml::Value::String("developer".to_string()),
+            serde_yaml::to_value(&developer_entry).unwrap(),
+        );
+        extensions.insert(
+            serde_yaml::Value::String("custom-developer".to_string()),
+            serde_yaml::to_value(&custom_developer_entry).unwrap(),
+        );
+        config.insert(
+            serde_yaml::Value::String(EXTENSIONS_CONFIG_KEY.to_string()),
+            serde_yaml::Value::Mapping(extensions),
+        );
+
+        assert!(run_migrations(&mut config));
+
+        let extensions_key = serde_yaml::Value::String(EXTENSIONS_CONFIG_KEY.to_string());
+        let extensions = config.get(&extensions_key).unwrap().as_mapping().unwrap();
+        let analyze: ExtensionEntry = serde_yaml::from_value(
+            extensions
+                .get(serde_yaml::Value::String("analyze".to_string()))
+                .unwrap()
+                .clone(),
+        )
+        .unwrap();
+        let developer: ExtensionEntry = serde_yaml::from_value(
+            extensions
+                .get(serde_yaml::Value::String("developer".to_string()))
+                .unwrap()
+                .clone(),
+        )
+        .unwrap();
+        let custom_developer: ExtensionEntry = serde_yaml::from_value(
+            extensions
+                .get(serde_yaml::Value::String("custom-developer".to_string()))
+                .unwrap()
+                .clone(),
+        )
+        .unwrap();
+
+        assert!(analyze.enabled);
+        assert!(!developer.enabled);
+        assert!(custom_developer.enabled);
     }
 
     #[test]