fix: before_tool_call hook still double-fires when abort signal is present

The BEFORE_TOOL_CALL_WRAPPED Symbol is set with enumerable: false, but
wrapToolWithAbortSignal spreads the tool object ({ ...tool }) which only
copies enumerable properties — stripping the Symbol. This causes
toToolDefinitions to not recognize the tool as already wrapped, firing
the hook a second time.

Since every real agent session has an abort signal, this affects all
tool calls in practice.

Fix: change enumerable: false to enumerable: true so the Symbol
survives object spread in wrapToolWithAbortSignal.

Added e2e test that exercises the full wrap → abort → toToolDefinitions
chain and asserts the hook fires exactly once.

src/agents/pi-tools.before-tool-call.e2e.test.ts

@@ -2,6 +2,7 @@ import { beforeEach, describe, expect, it, vi } from "vitest";
 import { resetDiagnosticSessionStateForTest } from "../logging/diagnostic-session-state.js";
 import { getGlobalHookRunner } from "../plugins/hook-runner-global.js";
 import { toClientToolDefinitions, toToolDefinitions } from "./pi-tool-definition-adapter.js";
+import { wrapToolWithAbortSignal } from "./pi-tools.abort.js";
 import { wrapToolWithBeforeToolCallHook } from "./pi-tools.before-tool-call.js";
 
 vi.mock("../plugins/hook-runner-global.js");
@@ -162,6 +163,24 @@ describe("before_tool_call hook deduplication (#15502)", () => {
 
     expect(hookRunner.runBeforeToolCall).toHaveBeenCalledTimes(1);
   });
+
+  it("fires hook exactly once when tool goes through wrap + abort + toToolDefinitions", async () => {
+    const execute = vi.fn().mockResolvedValue({ content: [], details: { ok: true } });
+    // oxlint-disable-next-line typescript/no-explicit-any
+    const baseTool = { name: "Bash", execute, description: "bash", parameters: {} } as any;
+
+    const abortController = new AbortController();
+    const wrapped = wrapToolWithBeforeToolCallHook(baseTool, {
+      agentId: "main",
+      sessionKey: "main",
+    });
+    const withAbort = wrapToolWithAbortSignal(wrapped, abortController.signal);
+    const [def] = toToolDefinitions([withAbort]);
+
+    await def.execute("call-abort-dedup", { command: "ls" }, undefined, undefined, undefined);
+
+    expect(hookRunner.runBeforeToolCall).toHaveBeenCalledTimes(1);
+  });
 });
 
 describe("before_tool_call hook integration for client tools", () => {

src/agents/pi-tools.before-tool-call.ts

@@ -227,7 +227,7 @@ export function wrapToolWithBeforeToolCallHook(
   };
   Object.defineProperty(wrappedTool, BEFORE_TOOL_CALL_WRAPPED, {
     value: true,
-    enumerable: false,
+    enumerable: true,
   });
   return wrappedTool;
 }