diff --git a/src/hooks/comment-checker/hook.lazy-init.test.ts b/src/hooks/comment-checker/hook.lazy-init.test.ts
new file mode 100644
index 000000000..2598aa3c6
--- /dev/null
+++ b/src/hooks/comment-checker/hook.lazy-init.test.ts
@@ -0,0 +1,51 @@
+import { describe, expect, it, mock, afterAll } from "bun:test"
+
+const startPendingCallCleanup = mock(() => {})
+const initializeCommentCheckerCli = mock(() => {})
+
+mock.module("./cli-runner", () => ({
+  initializeCommentCheckerCli,
+  getCommentCheckerCliPathPromise: () => Promise.resolve("/tmp/fake-comment-checker"),
+  isCliPathUsable: () => true,
+  processWithCli: async () => {},
+  processApplyPatchEditsWithCli: async () => {},
+}))
+
+mock.module("./pending-calls", () => ({
+  registerPendingCall: () => {},
+  startPendingCallCleanup,
+  stopPendingCallCleanup: () => {},
+  takePendingCall: () => undefined,
+}))
+
+afterAll(() => {
+  mock.restore()
+})
+
+const { createCommentCheckerHooks } = await import("./hook")
+
+describe("comment-checker lazy initialization", () => {
+  it("initializes CLI and cleanup on first tool hook call only", async () => {
+    // given
+    const hooks = createCommentCheckerHooks()
+    const beforeHook = hooks["tool.execute.before"]
+    const input = { tool: "write", sessionID: "ses_test", callID: "call_test" }
+    const output = { args: { filePath: "src/a.ts" } }
+
+    // when
+    expect(startPendingCallCleanup).toHaveBeenCalledTimes(0)
+    expect(initializeCommentCheckerCli).toHaveBeenCalledTimes(0)
+
+    // then
+    await beforeHook(input, output)
+    expect(startPendingCallCleanup).toHaveBeenCalledTimes(1)
+    expect(initializeCommentCheckerCli).toHaveBeenCalledTimes(1)
+
+    // when
+    await beforeHook(input, output)
+
+    // then
+    expect(startPendingCallCleanup).toHaveBeenCalledTimes(1)
+    expect(initializeCommentCheckerCli).toHaveBeenCalledTimes(1)
+  })
+})
diff --git a/src/hooks/comment-checker/hook.ts b/src/hooks/comment-checker/hook.ts
index 56632b1f9..089aca2e9 100644
--- a/src/hooks/comment-checker/hook.ts
+++ b/src/hooks/comment-checker/hook.ts
@@ -28,6 +28,7 @@ import {
   stopPendingCallCleanup,
   takePendingCall,
 } from "./pending-calls"
+import { ensureCommentCheckerInitialization } from "./initialization-gate"
 
 import * as fs from "fs"
 import { tmpdir } from "os"
@@ -48,14 +49,16 @@ function debugLog(...args: unknown[]) {
 export function createCommentCheckerHooks(config?: CommentCheckerConfig) {
   debugLog("createCommentCheckerHooks called", { config })
 
-  startPendingCallCleanup()
-  initializeCommentCheckerCli(debugLog)
-
   return {
     "tool.execute.before": async (
       input: { tool: string; sessionID: string; callID: string },
       output: { args: Record<string, unknown> },
     ): Promise<void> => {
+      ensureCommentCheckerInitialization(() => {
+        startPendingCallCleanup()
+        initializeCommentCheckerCli(debugLog)
+      })
+
       debugLog("tool.execute.before:", {
         tool: input.tool,
         callID: input.callID,
diff --git a/src/hooks/comment-checker/initialization-gate.ts b/src/hooks/comment-checker/initialization-gate.ts
new file mode 100644
index 000000000..da9759a47
--- /dev/null
+++ b/src/hooks/comment-checker/initialization-gate.ts
@@ -0,0 +1,7 @@
+let initialized = false
+
+export function ensureCommentCheckerInitialization(initializer: () => void): void {
+  if (initialized) return
+  initialized = true
+  initializer()
+}