fix(gemini): drop Agent dispatcher tool (#3349)

tests/runtime-converters.test.cjs

@@ -264,6 +264,28 @@ Use \${PHASE} in shell examples.
     assert.ok(result.includes('$PHASE'), 'escapes ${PHASE} shell variable for Gemini');
     assert.ok(!result.includes('${PHASE}'), 'removes Gemini template-string pattern');
   });
+
+  test('excludes Claude agent dispatcher tools from Gemini frontmatter', () => {
+    const input = `---
+name: gsd-debug-session-manager
+description: Manages debug sessions.
+tools: Read, Task, Agent, AskUserQuestion
+---
+
+<role>
+Coordinate debugger agents.
+</role>`;
+
+    const result = convertClaudeToGeminiAgent(input);
+    const frontmatter = result.split('---')[1] || '';
+
+    assert.ok(frontmatter.includes('  - read_file'), 'maps Read -> read_file');
+    assert.ok(frontmatter.includes('  - ask_user'), 'maps AskUserQuestion -> ask_user');
+    assert.ok(!frontmatter.includes('  - task'), 'does not emit invalid Gemini task tool');
+    assert.ok(!frontmatter.includes('  - agent'), 'does not emit invalid Gemini agent tool');
+    assert.ok(!frontmatter.includes('Task'), 'does not preserve Claude-only Task tool');
+    assert.ok(!frontmatter.includes('Agent'), 'does not preserve Claude-only Agent tool');
+  });
 });
 
 // ─── neutralizeAgentReferences (#766) ─────────────────────────────────────────