diff --git a/patterns/idp/__tests__/feature-toggles.test.ts b/patterns/idp/__tests__/feature-toggles.test.ts
index 54f46cf..208d677 100644
--- a/patterns/idp/__tests__/feature-toggles.test.ts
+++ b/patterns/idp/__tests__/feature-toggles.test.ts
@@ -54,15 +54,15 @@ describe('FileToggleStore', () => {
       expect(toggle.createdAt).toBeTruthy();
     });
 
-    it('creates a toggle with options', () => {
+    it('creates a toggle with options (new canonical namespaces)', () => {
       const store = new FileToggleStore(STORE_PATH);
-      const toggle = store.create('ENABLE_BETA', 'uiforge-webapp', {
+      const toggle = store.create('ENABLE_BETA', 'siza', {
         description: 'Beta features',
         enabled: true
       });
       expect(toggle.enabled).toBe(true);
       expect(toggle.description).toBe('Beta features');
-      expect(toggle.namespace).toBe('uiforge-webapp');
+      expect(toggle.namespace).toBe('siza');
     });
 
     it('throws when toggle already exists', () => {
@@ -171,6 +171,84 @@ describe('FileToggleStore', () => {
     });
   });
 
+  describe('canonical namespaces', () => {
+    it('accepts ui-mcp namespace', () => {
+      const store = new FileToggleStore(STORE_PATH);
+      const t = store.create('UI_FEATURE', 'ui-mcp');
+      expect(t.namespace).toBe('ui-mcp');
+    });
+
+    it('accepts siza namespace', () => {
+      const store = new FileToggleStore(STORE_PATH);
+      const t = store.create('SIZA_FEATURE', 'siza', { enabled: true });
+      expect(t.namespace).toBe('siza');
+      expect(t.enabled).toBe(true);
+    });
+
+    it('accepts legacy uiforge-mcp namespace for backwards compat', () => {
+      const store = new FileToggleStore(STORE_PATH);
+      const t = store.create('LEGACY_MCP', 'uiforge-mcp');
+      expect(t.namespace).toBe('uiforge-mcp');
+    });
+
+    it('filters by ui-mcp namespace', () => {
+      const store = new FileToggleStore(STORE_PATH);
+      store.create('A', 'ui-mcp', { enabled: true });
+      store.create('B', 'siza');
+      store.create('C', 'global');
+      const result = store.list({ namespace: 'ui-mcp' });
+      expect(result).toHaveLength(1);
+      expect(result[0]?.name).toBe('A');
+    });
+
+    it('filters by siza namespace', () => {
+      const store = new FileToggleStore(STORE_PATH);
+      store.create('A', 'ui-mcp');
+      store.create('B', 'siza', { enabled: true });
+      store.create('C', 'siza');
+      const result = store.list({ namespace: 'siza' });
+      expect(result).toHaveLength(2);
+    });
+  });
+
+  describe('create with custom strategies', () => {
+    it('persists custom strategy config', () => {
+      const store = new FileToggleStore(STORE_PATH);
+      const toggle = store.create('GRADUAL', 'global', {
+        strategies: [{ name: 'gradual-rollout', parameters: { rollout: 50 } }]
+      });
+      expect(toggle.strategies[0]?.name).toBe('gradual-rollout');
+      expect(toggle.strategies[0]?.parameters?.['rollout']).toBe(50);
+    });
+
+    it('persists user-ids strategy', () => {
+      const store = new FileToggleStore(STORE_PATH);
+      const toggle = store.create('BETA_USERS', 'global', {
+        strategies: [{ name: 'user-ids', parameters: { ids: ['u1', 'u2'] } }]
+      });
+      expect(toggle.strategies[0]?.name).toBe('user-ids');
+    });
+  });
+
+  describe('list filtering edge cases', () => {
+    it('filters by disabled (enabled: false)', () => {
+      const store = new FileToggleStore(STORE_PATH);
+      store.create('ON', 'global', { enabled: true });
+      store.create('OFF1', 'global');
+      store.create('OFF2', 'mcp-gateway');
+      const result = store.list({ enabled: false });
+      expect(result).toHaveLength(2);
+      expect(result.every(t => !t.enabled)).toBe(true);
+    });
+
+    it('returns empty array for namespace with no toggles', () => {
+      const store = new FileToggleStore(STORE_PATH);
+      store.create('A', 'global');
+      const result = store.list({ namespace: 'ui-mcp' });
+      expect(result).toHaveLength(0);
+    });
+  });
+
   describe('reload', () => {
     it('reloads store from file', () => {
       const store = new FileToggleStore(STORE_PATH);
diff --git a/patterns/idp/feature-toggles/cli.ts b/patterns/idp/feature-toggles/cli.ts
index 6af1d35..3e89e9d 100644
--- a/patterns/idp/feature-toggles/cli.ts
+++ b/patterns/idp/feature-toggles/cli.ts
@@ -7,8 +7,10 @@ import type { ToggleNamespace } from './schema.js';
 const VALID_NAMESPACES: ToggleNamespace[] = [
   'global',
   'mcp-gateway',
-  'uiforge-mcp',
-  'uiforge-webapp'
+  'ui-mcp',
+  'siza',
+  'uiforge-mcp', // legacy — prefer 'ui-mcp'
+  'uiforge-webapp' // legacy — prefer 'siza'
 ];
 
 function parseArgs(args: string[]) {
@@ -48,7 +50,7 @@ Usage:
 
 Options:
   --store <path>      Toggle store file (default: .forge/features.json)
-  --namespace <ns>    Filter by namespace: global, mcp-gateway, uiforge-mcp, uiforge-webapp
+  --namespace <ns>    Filter by namespace: global, mcp-gateway, ui-mcp, siza
   --description <d>   Toggle description
   --enabled           Filter or create as enabled
   --disabled          Filter by disabled
diff --git a/patterns/idp/feature-toggles/schema.ts b/patterns/idp/feature-toggles/schema.ts
index 24469e7..c80f007 100644
--- a/patterns/idp/feature-toggles/schema.ts
+++ b/patterns/idp/feature-toggles/schema.ts
@@ -1,4 +1,11 @@
-export type ToggleNamespace = 'global' | 'mcp-gateway' | 'uiforge-mcp' | 'uiforge-webapp';
+/** Canonical Forge Space namespaces. Legacy 'uiforge-mcp'/'uiforge-webapp' kept for backwards compat. */
+export type ToggleNamespace =
+  | 'global'
+  | 'mcp-gateway'
+  | 'ui-mcp'
+  | 'siza'
+  | 'uiforge-mcp' // @deprecated — use 'ui-mcp'
+  | 'uiforge-webapp'; // @deprecated — use 'siza'
 
 export type ToggleStrategy = 'default' | 'gradual-rollout' | 'user-ids';