agent: Don't offer feature-flag-gated tools in agent profiles

crates/agent/src/tests/mod.rs

@@ -3922,6 +3922,9 @@ async fn test_tool_updates_to_completion(cx: &mut TestAppContext) {
 #[gpui::test]
 async fn test_update_plan_tool_updates_thread_events(cx: &mut TestAppContext) {
     let ThreadTest { thread, model, .. } = setup(cx, TestModel::Fake).await;
+    cx.update(|cx| {
+        cx.update_flags(true, vec!["update-plan-tool".to_string()]);
+    });
     thread.update(cx, |thread, _cx| thread.add_tool(UpdatePlanTool));
     let fake_model = model.as_fake();
 

crates/agent/src/thread.rs

@@ -11,8 +11,8 @@ use acp_thread::{MentionUri, UserMessageId};
 use action_log::ActionLog;
 use agent_settings::UserAgentsMd;
 use feature_flags::{
-    CreateThreadToolFeatureFlag, FeatureFlagAppExt as _, HandoffFeatureFlag, LspToolFeatureFlag,
-    RenameToolFeatureFlag, UpdatePlanToolFeatureFlag, UpdateTitleToolFeatureFlag,
+    FeatureFlagAppExt as _, HandoffFeatureFlag, UpdatePlanToolFeatureFlag,
+    UpdateTitleToolFeatureFlag,
 };
 use zed_env_vars::{EnvVar, env_var};
 
@@ -3503,17 +3503,7 @@ impl Thread {
                     None
                 }
             })
-            .filter(|(tool_name, _)| match tool_name.as_ref() {
-                RenameTool::NAME => cx.has_flag::<RenameToolFeatureFlag>(),
-                FindReferencesTool::NAME
-                | GetCodeActionsTool::NAME
-                | ApplyCodeActionTool::NAME
-                | GoToDefinitionTool::NAME => cx.has_flag::<LspToolFeatureFlag>(),
-                CreateThreadTool::NAME | ListAgentsAndModelsTool::NAME => {
-                    cx.has_flag::<CreateThreadToolFeatureFlag>()
-                }
-                _ => true,
-            })
+            .filter(|(tool_name, _)| crate::tools::tool_feature_flag_enabled(tool_name, cx))
             .collect::<BTreeMap<_, _>>();
 
         let mut context_server_tools = Vec::new();

crates/agent/src/tools.rs

@@ -31,6 +31,11 @@ mod web_search_tool;
 mod write_file_tool;
 
 use crate::AgentTool;
+use feature_flags::{
+    CreateThreadToolFeatureFlag, FeatureFlagAppExt as _, LspToolFeatureFlag, RenameToolFeatureFlag,
+    UpdatePlanToolFeatureFlag, UpdateTitleToolFeatureFlag,
+};
+use gpui::App;
 use language_model::{LanguageModelRequestTool, LanguageModelToolSchemaFormat};
 use serde::{
     Deserialize, Deserializer,
@@ -158,7 +163,7 @@ macro_rules! tools {
 }
 
 // Adding a tool here (and constructing it in `Thread::add_default_tools`) is
-// not enough to make the model actually receive it. Two further gates will
+// not enough to make the model actually receive it. Three further gates will
 // silently drop the tool rather than fail to compile:
 //
 // 1. `assets/settings/default.json`: the `write` and `ask` agent profiles each
@@ -169,6 +174,9 @@ macro_rules! tools {
 //    `crates/settings_ui/src/pages/tool_permissions_setup.rs`: every tool must
 //    be in the permission-UI `TOOLS` list (if it calls
 //    `decide_permission_from_settings`) or in `EXCLUDED_TOOLS`.
+// 3. `tool_feature_flag_enabled`: some tools are gated behind a feature flag and
+//    are dropped unless it is active. The agent-profile UI uses the same gate so
+//    it never offers a tool the agent can't actually use.
 tools! {
     ApplyCodeActionTool,
     CopyPathTool,
@@ -196,3 +204,26 @@ tools! {
     WebSearchTool,
     WriteFileTool,
 }
+
+/// Some built-in tools are gated behind a feature flag and only become usable
+/// once that flag is active. Tools without a flag are always available.
+///
+/// This is the single source of truth for that gating: `Thread::enabled_tools`
+/// uses it to decide what the model receives, and the agent-profile
+/// configuration UI uses it to decide what to offer — so the UI can never list
+/// a tool the agent would silently drop (see #56778).
+pub fn tool_feature_flag_enabled(tool_name: &str, cx: &App) -> bool {
+    match tool_name {
+        RenameTool::NAME => cx.has_flag::<RenameToolFeatureFlag>(),
+        FindReferencesTool::NAME
+        | GetCodeActionsTool::NAME
+        | ApplyCodeActionTool::NAME
+        | GoToDefinitionTool::NAME => cx.has_flag::<LspToolFeatureFlag>(),
+        CreateThreadTool::NAME | ListAgentsAndModelsTool::NAME => {
+            cx.has_flag::<CreateThreadToolFeatureFlag>()
+        }
+        UpdatePlanTool::NAME => cx.has_flag::<UpdatePlanToolFeatureFlag>(),
+        UpdateTitleTool::NAME => cx.has_flag::<UpdateTitleToolFeatureFlag>(),
+        _ => true,
+    }
+}

crates/agent_ui/src/agent_configuration/manage_profiles_modal.rs

@@ -378,7 +378,10 @@ impl ManageProfilesModal {
                 let supported_by_provider = provider.as_ref().map_or(true, |provider| {
                     agent::tool_supports_provider(name, provider)
                 });
-                supported_by_provider
+                // Don't offer tools the agent can't actually use: tools gated
+                // behind an inactive feature flag are silently dropped before
+                // they reach the model (#56778).
+                supported_by_provider && agent::tool_feature_flag_enabled(name, cx)
             })
             .map(Arc::from)
             .collect();