diff --git a/packages/core/src/tools/tools.test.ts b/packages/core/src/tools/tools.test.ts
index edbc487160..9b200d6f38 100644
--- a/packages/core/src/tools/tools.test.ts
+++ b/packages/core/src/tools/tools.test.ts
@@ -6,6 +6,7 @@
 
 import { describe, it, expect, vi } from 'vitest';
 import {
+  BaseToolInvocation,
   DeclarativeTool,
   hasCycleInSchema,
   Kind,
@@ -272,3 +273,55 @@ describe('Tools Read-Only property', () => {
     expect(searcher.isReadOnly).toBe(true);
   });
 });
+
+describe('toJSON serialization', () => {
+  it('DeclarativeTool.toJSON should return essential metadata', () => {
+    const bus = createMockMessageBus();
+    class MyTool extends DeclarativeTool<object, ToolResult> {
+      build(_params: object): ToolInvocation<object, ToolResult> {
+        throw new Error('Not implemented');
+      }
+    }
+    const tool = new MyTool(
+      'name',
+      'display',
+      'desc',
+      Kind.Read,
+      { type: 'object' },
+      bus,
+    );
+    const json = tool.toJSON();
+
+    expect(json).toEqual({
+      name: 'name',
+      displayName: 'display',
+      description: 'desc',
+      kind: Kind.Read,
+      parameterSchema: { type: 'object' },
+    });
+    // Ensure messageBus is NOT included in serialization
+    expect(Object.keys(json)).not.toContain('messageBus');
+    expect(JSON.stringify(tool)).toContain('"name":"name"');
+    expect(JSON.stringify(tool)).not.toContain('messageBus');
+  });
+
+  it('BaseToolInvocation.toJSON should return only params', () => {
+    const bus = createMockMessageBus();
+    const params = { foo: 'bar' };
+    class MyInvocation extends BaseToolInvocation<object, ToolResult> {
+      getDescription() {
+        return 'desc';
+      }
+      async execute() {
+        return { llmContent: '', returnDisplay: '' };
+      }
+    }
+    const invocation = new MyInvocation(params, bus, 'tool');
+    const json = invocation.toJSON();
+
+    expect(json).toEqual({ params });
+    // Ensure messageBus is NOT included in serialization
+    expect(Object.keys(json)).not.toContain('messageBus');
+    expect(JSON.stringify(invocation)).toBe('{"params":{"foo":"bar"}}');
+  });
+});
diff --git a/packages/core/src/tools/tools.ts b/packages/core/src/tools/tools.ts
index 6b22f7a3e3..23e88b608b 100644
--- a/packages/core/src/tools/tools.ts
+++ b/packages/core/src/tools/tools.ts
@@ -379,6 +379,12 @@ export abstract class BaseToolInvocation<
     updateOutput?: (output: ToolLiveOutput) => void,
     options?: ExecuteOptions,
   ): Promise<TResult>;
+
+  toJSON() {
+    return {
+      params: this.params,
+    };
+  }
 }
 
 /**
@@ -498,6 +504,16 @@ export abstract class DeclarativeTool<
     return cloned;
   }
 
+  toJSON() {
+    return {
+      name: this.name,
+      displayName: this.displayName,
+      description: this.description,
+      kind: this.kind,
+      parameterSchema: this.parameterSchema,
+    };
+  }
+
   get isReadOnly(): boolean {
     return READ_ONLY_KINDS.includes(this.kind);
   }