[app-server] Add a method to list experimental features. (#10721)

- [x] Add a method to list experimental features.

codex-rs/app-server-protocol/src/protocol/common.rs

@@ -265,6 +265,10 @@ client_request_definitions! {
         params: v2::ModelListParams,
         response: v2::ModelListResponse,
     },
+    ExperimentalFeatureList => "experimentalFeature/list" {
+        params: v2::ExperimentalFeatureListParams,
+        response: v2::ExperimentalFeatureListResponse,
+    },
     #[experimental("collaborationMode/list")]
     /// Lists collaboration mode presets.
     CollaborationModeList => "collaborationMode/list" {
@@ -1087,6 +1091,26 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn serialize_list_experimental_features() -> Result<()> {
+        let request = ClientRequest::ExperimentalFeatureList {
+            request_id: RequestId::Integer(8),
+            params: v2::ExperimentalFeatureListParams::default(),
+        };
+        assert_eq!(
+            json!({
+                "method": "experimentalFeature/list",
+                "id": 8,
+                "params": {
+                    "cursor": null,
+                    "limit": null
+                }
+            }),
+            serde_json::to_value(&request)?,
+        );
+        Ok(())
+    }
+
     #[test]
     fn mock_experimental_method_is_marked_experimental() {
         let request = ClientRequest::MockExperimentalMethod {

codex-rs/app-server-protocol/src/protocol/v2.rs

@@ -1043,6 +1043,46 @@ pub struct CollaborationModeListResponse {
     pub data: Vec<CollaborationModeMask>,
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ExperimentalFeatureListParams {
+    /// Opaque pagination cursor returned by a previous call.
+    #[ts(optional = nullable)]
+    pub cursor: Option<String>,
+    /// Optional page size; defaults to a reasonable server-side value.
+    #[ts(optional = nullable)]
+    pub limit: Option<u32>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ExperimentalFeature {
+    /// Stable key used in config.toml and CLI flag toggles.
+    pub flag_name: String,
+    /// User-facing display name shown in the experimental features UI.
+    pub display_name: String,
+    /// Short summary describing what the feature does.
+    pub description: String,
+    /// Announcement copy shown to users when the feature is introduced.
+    pub announcement: String,
+    /// Whether this feature is currently enabled in the loaded config.
+    pub enabled: bool,
+    /// Whether this feature is enabled by default.
+    pub default_enabled: bool,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ExperimentalFeatureListResponse {
+    pub data: Vec<ExperimentalFeature>,
+    /// Opaque cursor to pass to the next call to continue after the last item.
+    /// If None, there are no more items to return.
+    pub next_cursor: Option<String>,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(export_to = "v2/")]