diff --git a/.changeset/fix-anthropic-cua-triple-click.md b/.changeset/fix-anthropic-cua-triple-click.md
new file mode 100644
index 000000000..6f2d57fe6
--- /dev/null
+++ b/.changeset/fix-anthropic-cua-triple-click.md
@@ -0,0 +1,5 @@
+---
+"@browserbasehq/stagehand": patch
+---
+
+Fix Anthropic CUA `triple_click` action mapping.
diff --git a/packages/core/lib/v3/agent/AnthropicCUAClient.ts b/packages/core/lib/v3/agent/AnthropicCUAClient.ts
index 4bbe2d47b..752d208e2 100644
--- a/packages/core/lib/v3/agent/AnthropicCUAClient.ts
+++ b/packages/core/lib/v3/agent/AnthropicCUAClient.ts
@@ -901,6 +901,17 @@ export class AnthropicCUAClient extends AgentClient {
               (input.coordinate ? (input.coordinate as number[])[1] : 0),
             ...input,
           };
+        } else if (action === "triple_click" || action === "tripleClick") {
+          return {
+            type: "tripleClick",
+            x:
+              (input.x as number) ||
+              (input.coordinate ? (input.coordinate as number[])[0] : 0),
+            y:
+              (input.y as number) ||
+              (input.coordinate ? (input.coordinate as number[])[1] : 0),
+            ...input,
+          };
         } else if (action === "scroll") {
           // Convert Anthropic's coordinate, scroll_amount and scroll_direction into scroll_x and scroll_y
           const x =
diff --git a/packages/core/lib/v3/handlers/v3CuaAgentHandler.ts b/packages/core/lib/v3/handlers/v3CuaAgentHandler.ts
index 6cefa4b4d..af3a3dad8 100644
--- a/packages/core/lib/v3/handlers/v3CuaAgentHandler.ts
+++ b/packages/core/lib/v3/handlers/v3CuaAgentHandler.ts
@@ -324,6 +324,7 @@ export class V3CuaAgentHandler {
         }
         return { success: true };
       }
+      case "triple_click":
       case "tripleClick": {
         const { x, y } = action;
         if (recording) {
diff --git a/packages/core/tests/unit/anthropic-cua-triple-click.test.ts b/packages/core/tests/unit/anthropic-cua-triple-click.test.ts
new file mode 100644
index 000000000..727fe5173
--- /dev/null
+++ b/packages/core/tests/unit/anthropic-cua-triple-click.test.ts
@@ -0,0 +1,99 @@
+import { describe, expect, it, vi, beforeEach } from "vitest";
+import { AnthropicCUAClient } from "../../lib/v3/agent/AnthropicCUAClient.js";
+import Anthropic from "@anthropic-ai/sdk";
+
+vi.mock("@anthropic-ai/sdk", () => {
+  const mockCreate = vi.fn();
+
+  return {
+    default: class MockAnthropic {
+      beta = {
+        messages: {
+          create: mockCreate,
+        },
+      };
+    },
+  };
+});
+
+describe("AnthropicCUAClient triple_click handling", () => {
+  let mockCreate: ReturnType<typeof vi.fn>;
+  let client: AnthropicCUAClient;
+  let executedActions: Array<Record<string, unknown>>;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    const anthropic = new Anthropic({ apiKey: "test" });
+    mockCreate = anthropic.beta.messages.create as ReturnType<typeof vi.fn>;
+
+    client = new AnthropicCUAClient("anthropic", "claude-sonnet-4-5-20250929", undefined, {
+      apiKey: "test-key",
+    });
+    client.setViewport(1280, 720);
+    client.setScreenshotProvider(async () => "fake-base64-screenshot");
+
+    executedActions = [];
+    client.setActionHandler(async (action) => {
+      executedActions.push({ ...action });
+    });
+  });
+
+  it("should convert triple_click with coordinate array to tripleClick action", async () => {
+    mockCreate.mockResolvedValue({
+      id: "test-id",
+      content: [
+        {
+          type: "tool_use",
+          id: "tool-1",
+          name: "computer",
+          input: {
+            action: "triple_click",
+            coordinate: [640, 360],
+          },
+        },
+      ],
+      usage: { input_tokens: 10, output_tokens: 20 },
+    });
+
+    const logger = vi.fn();
+    await client.executeStep(
+      [{ role: "user", content: "triple click the paragraph" }],
+      logger,
+    );
+
+    expect(executedActions).toHaveLength(1);
+    expect(executedActions[0].type).toBe("tripleClick");
+    expect(executedActions[0].x).toBe(640);
+    expect(executedActions[0].y).toBe(360);
+  });
+
+  it("should convert triple_click with x/y fields to tripleClick action", async () => {
+    mockCreate.mockResolvedValue({
+      id: "test-id",
+      content: [
+        {
+          type: "tool_use",
+          id: "tool-2",
+          name: "computer",
+          input: {
+            action: "triple_click",
+            x: 100,
+            y: 200,
+          },
+        },
+      ],
+      usage: { input_tokens: 10, output_tokens: 20 },
+    });
+
+    const logger = vi.fn();
+    await client.executeStep(
+      [{ role: "user", content: "triple click the line" }],
+      logger,
+    );
+
+    expect(executedActions).toHaveLength(1);
+    expect(executedActions[0].type).toBe("tripleClick");
+    expect(executedActions[0].x).toBe(100);
+    expect(executedActions[0].y).toBe(200);
+  });
+});