fix(session-aware): trigger exclusivePairs pruning when user explicitly provides null/undefined; add tests for null/undefined activation

Author: cameroncooke

src/utils/__tests__/session-aware-tool-factory.test.ts

@@ -109,4 +109,48 @@ describe('createSessionAwareTool', () => {
     expect(result.content[0].text).toContain('Parameter validation failed');
     expect(result.content[0].text).toContain('Tip: set session defaults');
   });
+
+  it('exclusivePairs should prune conflicting session defaults when user provides null', async () => {
+    const handlerWithExclusive = createSessionAwareTool<Params>({
+      internalSchema,
+      logicFunction: logic,
+      getExecutor: () => createMockExecutor({ success: true }),
+      requirements: [
+        { allOf: ['scheme'], message: 'scheme is required' },
+        { oneOf: ['projectPath', 'workspacePath'], message: 'Provide a project or workspace' },
+      ],
+      exclusivePairs: [['projectPath', 'workspacePath']],
+    });
+
+    sessionStore.setDefaults({
+      scheme: 'App',
+      projectPath: '/path/proj.xcodeproj',
+    });
+
+    const res = await handlerWithExclusive({ workspacePath: null as unknown as string });
+    expect(res.isError).toBe(true);
+    expect(res.content[0].text).toContain('Provide a project or workspace');
+  });
+
+  it('exclusivePairs should prune when user provides undefined (key present)', async () => {
+    const handlerWithExclusive = createSessionAwareTool<Params>({
+      internalSchema,
+      logicFunction: logic,
+      getExecutor: () => createMockExecutor({ success: true }),
+      requirements: [
+        { allOf: ['scheme'], message: 'scheme is required' },
+        { oneOf: ['projectPath', 'workspacePath'], message: 'Provide a project or workspace' },
+      ],
+      exclusivePairs: [['projectPath', 'workspacePath']],
+    });
+
+    sessionStore.setDefaults({
+      scheme: 'App',
+      projectPath: '/path/proj.xcodeproj',
+    });
+
+    const res = await handlerWithExclusive({ workspacePath: undefined as unknown as string });
+    expect(res.isError).toBe(true);
+    expect(res.content[0].text).toContain('Provide a project or workspace');
+  });
 });

src/utils/typed-tool-factory.ts

@@ -92,11 +92,12 @@ export function createSessionAwareTool<TParams>(opts: {
       // Start with session defaults merged with explicit args (args override session)
       const merged: Record<string, unknown> = { ...sessionStore.getAll(), ...rawArgs };
 
-      // Apply exclusive pair pruning: if caller provided a key in a pair, remove other keys
-      // from that pair which came only from session defaults (not explicitly provided)
+      // Apply exclusive pair pruning: if caller provided/touched any key in a pair (even null/undefined),
+      // remove other keys from that pair which came only from session defaults (not explicitly provided).
+      // This ensures requirements and validation reflect the effective, post-prune payload.
       for (const pair of exclusivePairs) {
-        const provided = pair.filter((k) => rawArgs[k] != null);
-        if (provided.length > 0) {
+        const userTouched = pair.some((k) => Object.prototype.hasOwnProperty.call(rawArgs, k));
+        if (userTouched) {
           for (const k of pair) {
             if (rawArgs[k] == null && merged[k] != null) {
               delete merged[k];