feat(meta-tools): consolidate FeatureSet writes into manage_feature_set; bind upsert

Keeps the per-client meta-tool surface flat while giving the agent full
self-service CRUD (it could previously only create, never fix or remove).

- Replace `mcpmux_create_feature_set` with `mcpmux_manage_feature_set`
  (`action`: create | update | delete) — one tool covers all of CRUD on
  custom FeatureSets. Built-in/Starter sets are not mutable via MCP;
  cross-Space, unknown-tool-name, empty-name, and unknown-action inputs are
  rejected with actionable errors so the model can self-correct.
- Make `mcpmux_bind_current_workspace` idempotent (upsert): re-binding the
  same workspace REBINDS it instead of erroring, and `feature_set_id` is now
  optional (omit → bind the folder to no Space tools; built-ins still apply).
  No separate unbind — that's just a bind-config change, and deleting a
  binding row stays UI-only.
- Update the Tool Optimization built-in descriptor + dev docs to the new name.
- Tests: create / update (add+remove+rename) / delete, reject-builtin,
  unknown-action, rebind-on-second-call, bind-to-empty.

Signed-off-by: Mohammod Al Amin Ashik <maa.ashik00@gmail.com>

Author: its-mash

apps/desktop/src-tauri/src/commands/meta_tool_approval.rs

@@ -112,7 +112,7 @@ pub async fn revoke_meta_tool_grant(
 
 /// DEBUG/dev only: toggle auto-approval of all write meta tools.
 ///
-/// When on, every `mcpmux_*` write tool (create_feature_set,
+/// When on, every `mcpmux_*` write tool (manage_feature_set,
 /// bind_current_workspace, …) is approved without a dialog. This exists so a
 /// developer (or the in-app assistant) can self-create feature sets / bindings
 /// and exercise the routing end-to-end without clicking through approvals.

apps/desktop/src/lib/api/metaTools.ts

@@ -36,7 +36,7 @@ export async function revokeMetaToolGrant(clientId: string, toolName: string): P
 /**
  * DEBUG/dev only: toggle auto-approval of every write meta tool.
  *
- * When on, `mcpmux_create_feature_set` / `mcpmux_bind_current_workspace` and
+ * When on, `mcpmux_manage_feature_set` / `mcpmux_bind_current_workspace` and
  * friends are approved without a dialog — so a developer can self-create
  * feature sets and bindings and exercise routing end-to-end. Session-only:
  * resets on gateway restart (to the `MCPMUX_DEBUG_AUTO_APPROVE` env default).

crates/mcpmux-core/src/domain/builtin.rs

@@ -67,13 +67,14 @@ pub fn builtin_servers() -> Vec<BuiltinServerDescriptor> {
                 write: false,
             },
             BuiltinToolDescriptor {
-                name: "mcpmux_create_feature_set",
-                description: "Build a focused feature set from chosen tools.",
+                name: "mcpmux_manage_feature_set",
+                description: "Create, update, or delete a custom feature set of chosen tools.",
                 write: true,
             },
             BuiltinToolDescriptor {
                 name: "mcpmux_bind_current_workspace",
-                description: "Map the current folder to a feature set so it persists.",
+                description:
+                    "Map the current folder to a feature set so it persists (re-run to rebind).",
                 write: true,
             },
         ],

crates/mcpmux-gateway/src/services/meta_tools/approval.rs

@@ -119,7 +119,7 @@ pub struct ApprovalBroker {
     publisher: Mutex<Option<ApprovalPublisher>>,
     timeout: Duration,
     /// DEBUG/dev only: when set, every write meta-tool is auto-approved without
-    /// a dialog. Lets self-tests drive `mcpmux_create_feature_set` /
+    /// a dialog. Lets self-tests drive `mcpmux_manage_feature_set` /
     /// `mcpmux_bind_current_workspace` headlessly. Off by default; enabled via
     /// `MCPMUX_DEBUG_AUTO_APPROVE=1` at startup or the
     /// `set_meta_tools_auto_approve` command at runtime.

crates/mcpmux-gateway/src/services/meta_tools/mod.rs

@@ -83,7 +83,7 @@ pub fn build_default_registry(
     // user request — the read surface is just the two list_* tools above,
     // which an LLM can stitch into the same picture without an extra hop.
     // Writes — gated by ApprovalBroker.
-    registry.register(Box::new(tools::CreateFeatureSetTool));
+    registry.register(Box::new(tools::ManageFeatureSetTool));
     registry.register(Box::new(tools::BindCurrentWorkspaceTool));
     std::sync::Arc::new(registry)
 }