From 77aef861fef4b5443b026196a947ebb292045614 Mon Sep 17 00:00:00 2001
From: Christian Gunderman <gundermanc@gmail.com>
Date: Sat, 24 Jan 2026 01:30:18 +0000
Subject: [PATCH] fix(agents): default to all tools when tool list is omitted
 in subagents (#17422)

---
 .../core/src/agents/local-executor.test.ts    | 51 +++++++++++++++++++
 packages/core/src/agents/local-executor.ts    | 43 +++++++++-------
 2 files changed, 77 insertions(+), 17 deletions(-)

diff --git a/packages/core/src/agents/local-executor.test.ts b/packages/core/src/agents/local-executor.test.ts
index 2cd04a4a6e..b9e6488c1e 100644
--- a/packages/core/src/agents/local-executor.test.ts
+++ b/packages/core/src/agents/local-executor.test.ts
@@ -117,6 +117,23 @@ vi.mock('../telemetry/loggers.js', () => ({
   logRecoveryAttempt: vi.fn(),
 }));
 
+vi.mock('../utils/schemaValidator.js', () => ({
+  SchemaValidator: {
+    validate: vi.fn().mockReturnValue(null),
+    validateSchema: vi.fn().mockReturnValue(null),
+  },
+}));
+
+vi.mock('../utils/filesearch/crawler.js', () => ({
+  crawl: vi.fn().mockResolvedValue([]),
+}));
+
+vi.mock('../telemetry/clearcut-logger/clearcut-logger.js', () => ({
+  ClearcutLogger: class {
+    log() {}
+  },
+}));
+
 vi.mock('../utils/promptIdContext.js', async (importOriginal) => {
   const actual =
     await importOriginal<typeof import('../utils/promptIdContext.js')>();
@@ -441,6 +458,40 @@ describe('LocalAgentExecutor', () => {
       // Subagent should be filtered out
       expect(agentRegistry.getTool(subAgentName)).toBeUndefined();
     });
+
+    it('should default to ALL tools (except subagents) when toolConfig is undefined', async () => {
+      const subAgentName = 'recursive-agent';
+      // Register tools in parent registry
+      // LS_TOOL_NAME is already registered in beforeEach
+      const otherTool = new MockTool({ name: 'other-tool' });
+      parentToolRegistry.registerTool(otherTool);
+      parentToolRegistry.registerTool(new MockTool({ name: subAgentName }));
+
+      // Mock the agent registry to return the subagent name
+      vi.spyOn(
+        mockConfig.getAgentRegistry(),
+        'getAllAgentNames',
+      ).mockReturnValue([subAgentName]);
+
+      // Create definition and force toolConfig to be undefined
+      const definition = createTestDefinition();
+      definition.toolConfig = undefined;
+
+      const executor = await LocalAgentExecutor.create(
+        definition,
+        mockConfig,
+        onActivity,
+      );
+
+      const agentRegistry = executor['toolRegistry'];
+
+      // Should include standard tools
+      expect(agentRegistry.getTool(LS_TOOL_NAME)).toBeDefined();
+      expect(agentRegistry.getTool('other-tool')).toBeDefined();
+
+      // Should exclude subagent
+      expect(agentRegistry.getTool(subAgentName)).toBeUndefined();
+    });
   });
 
   describe('run (Execution Loop and Logic)', () => {
diff --git a/packages/core/src/agents/local-executor.ts b/packages/core/src/agents/local-executor.ts
index 506f333684..a75a92a4ec 100644
--- a/packages/core/src/agents/local-executor.ts
+++ b/packages/core/src/agents/local-executor.ts
@@ -114,24 +114,28 @@ export class LocalAgentExecutor<TOutput extends z.ZodTypeAny> {
       runtimeContext.getAgentRegistry().getAllAgentNames(),
     );
 
+    const registerToolByName = (toolName: string) => {
+      // Check if the tool is a subagent to prevent recursion.
+      // We do not allow agents to call other agents.
+      if (allAgentNames.has(toolName)) {
+        debugLogger.warn(
+          `[LocalAgentExecutor] Skipping subagent tool '${toolName}' for agent '${definition.name}' to prevent recursion.`,
+        );
+        return;
+      }
+
+      // If the tool is referenced by name, retrieve it from the parent
+      // registry and register it with the agent's isolated registry.
+      const tool = parentToolRegistry.getTool(toolName);
+      if (tool) {
+        agentToolRegistry.registerTool(tool);
+      }
+    };
+
     if (definition.toolConfig) {
       for (const toolRef of definition.toolConfig.tools) {
         if (typeof toolRef === 'string') {
-          // Check if the tool is a subagent to prevent recursion.
-          // We do not allow agents to call other agents.
-          if (allAgentNames.has(toolRef)) {
-            debugLogger.warn(
-              `[LocalAgentExecutor] Skipping subagent tool '${toolRef}' for agent '${definition.name}' to prevent recursion.`,
-            );
-            continue;
-          }
-
-          // If the tool is referenced by name, retrieve it from the parent
-          // registry and register it with the agent's isolated registry.
-          const toolFromParent = parentToolRegistry.getTool(toolRef);
-          if (toolFromParent) {
-            agentToolRegistry.registerTool(toolFromParent);
-          }
+          registerToolByName(toolRef);
         } else if (
           typeof toolRef === 'object' &&
           'name' in toolRef &&
@@ -142,10 +146,15 @@ export class LocalAgentExecutor<TOutput extends z.ZodTypeAny> {
         // Note: Raw `FunctionDeclaration` objects in the config don't need to be
         // registered; their schemas are passed directly to the model later.
       }
-
-      agentToolRegistry.sortTools();
+    } else {
+      // If no tools are explicitly configured, default to all available tools.
+      for (const toolName of parentToolRegistry.getAllToolNames()) {
+        registerToolByName(toolName);
+      }
     }
 
+    agentToolRegistry.sortTools();
+
     // Get the parent prompt ID from context
     const parentPromptId = promptIdContext.getStore();