diff --git a/src/agents/pi-tools.before-tool-call.e2e.test.ts b/src/agents/pi-tools.before-tool-call.e2e.test.ts
index 4734ddeb32a..b615245bc3d 100644
--- a/src/agents/pi-tools.before-tool-call.e2e.test.ts
+++ b/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", () => {
diff --git a/src/agents/pi-tools.before-tool-call.ts b/src/agents/pi-tools.before-tool-call.ts
index 1198c813fc8..a0a5ca4cb11 100644
--- a/src/agents/pi-tools.before-tool-call.ts
+++ b/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;
 }