diff --git a/src/cache/lock.ts b/src/cache/lock.ts
index c42c69b..e734dee 100644
--- a/src/cache/lock.ts
+++ b/src/cache/lock.ts
@@ -1,5 +1,6 @@
 import { readFile, writeFile } from "node:fs/promises";
 import path from "node:path";
+import { isRecord } from "#core/is-record";
 
 export interface DocsCacheLockSource {
 	repo: string;
@@ -19,9 +20,6 @@ export interface DocsCacheLock {
 
 export const DEFAULT_LOCK_FILENAME = "docs-lock.json";
 
-const isRecord = (value: unknown): value is Record<string, unknown> =>
-	typeof value === "object" && value !== null && !Array.isArray(value);
-
 const assertString = (value: unknown, label: string): string => {
 	if (typeof value !== "string" || value.length === 0) {
 		throw new Error(`${label} must be a non-empty string.`);
diff --git a/src/commands/sync.ts b/src/commands/sync.ts
index 064d02d..27bf2a3 100644
--- a/src/commands/sync.ts
+++ b/src/commands/sync.ts
@@ -1,6 +1,7 @@
 import { createHash } from "node:crypto";
 import { access, mkdir, readFile } from "node:fs/promises";
 import path from "node:path";
+import { fileURLToPath } from "node:url";
 import pc from "picocolors";
 import type { DocsCacheLock, DocsCacheLockSource } from "#cache/lock";
 import { readLock, resolveLockPath, writeLock } from "#cache/lock";
@@ -18,6 +19,7 @@ import {
 	type DocsCacheResolvedSource,
 	loadConfig,
 } from "#config";
+import { isRecord } from "#core/is-record";
 import { resolveCacheDir, resolveTargetDir } from "#core/paths";
 import { fetchSource } from "#git/fetch-source";
 import { resolveRemoteCommit } from "#git/resolve-remote";
@@ -187,35 +189,56 @@ export const getSyncPlan = async (
 	};
 };
 
-const loadToolVersion = async () => {
-	const cwdPath = path.resolve(process.cwd(), "package.json");
+const TOOL_PACKAGE_NAME = "docs-cache";
+
+const readToolVersionFromPackageFile = async (packagePath: string) => {
 	try {
-		const raw = await readFile(cwdPath, "utf8");
-		const pkg = JSON.parse(raw.toString());
-		return typeof pkg.version === "string" ? pkg.version : "0.0.0";
+		const raw = await readFile(packagePath, "utf8");
+		const parsed: unknown = JSON.parse(raw);
+		if (!isRecord(parsed)) {
+			return null;
+		}
+		const pkgName = parsed.name;
+		const pkgVersion = parsed.version;
+		if (pkgName !== TOOL_PACKAGE_NAME) {
+			return null;
+		}
+		if (typeof pkgVersion !== "string" || pkgVersion.length === 0) {
+			return null;
+		}
+		return pkgVersion;
 	} catch {
-		// fallback to bundle-relative location
+		return null;
 	}
-	try {
-		const raw = await readFile(
-			new URL("../package.json", import.meta.url),
-			"utf8",
-		);
-		const pkg = JSON.parse(raw.toString());
-		return typeof pkg.version === "string" ? pkg.version : "0.0.0";
-	} catch {
-		// fallback to dist/chunks relative location
+};
+
+const findToolVersionFrom = async (startDir: string) => {
+	let currentDir = startDir;
+	while (true) {
+		const packagePath = path.join(currentDir, "package.json");
+		const version = await readToolVersionFromPackageFile(packagePath);
+		if (version) {
+			return version;
+		}
+		const parentDir = path.dirname(currentDir);
+		if (parentDir === currentDir) {
+			return null;
+		}
+		currentDir = parentDir;
 	}
-	try {
-		const raw = await readFile(
-			new URL("../../package.json", import.meta.url),
-			"utf8",
-		);
-		const pkg = JSON.parse(raw.toString());
-		return typeof pkg.version === "string" ? pkg.version : "0.0.0";
-	} catch {
-		return "0.0.0";
+};
+
+const loadToolVersion = async () => {
+	const moduleDir = path.dirname(fileURLToPath(import.meta.url));
+	const moduleVersion = await findToolVersionFrom(moduleDir);
+	if (moduleVersion) {
+		return moduleVersion;
+	}
+	const cwdVersion = await findToolVersionFrom(process.cwd());
+	if (cwdVersion) {
+		return cwdVersion;
 	}
+	return "0.0.0";
 };
 
 const buildLockSource = (
diff --git a/src/is-record.ts b/src/is-record.ts
new file mode 100644
index 0000000..c632f81
--- /dev/null
+++ b/src/is-record.ts
@@ -0,0 +1,2 @@
+export const isRecord = (value: unknown): value is Record<string, unknown> =>
+	typeof value === "object" && value !== null && !Array.isArray(value);
diff --git a/tests/sync-tool-version.test.js b/tests/sync-tool-version.test.js
index 3ab6ff0..e6d4856 100644
--- a/tests/sync-tool-version.test.js
+++ b/tests/sync-tool-version.test.js
@@ -33,15 +33,29 @@ test("sync writes lock toolVersion from package.json", async () => {
 		),
 		"utf8",
 	);
+	await writeFile(
+		path.join(tmpRoot, "package.json"),
+		JSON.stringify({
+			name: "not-docs-cache",
+			version: "9.9.9",
+		}),
+		"utf8",
+	);
 
-	await runSync({
-		configPath,
-		cacheDirOverride: cacheDir,
-		json: true,
-		lockOnly: true,
-		offline: true,
-		failOnMiss: false,
-	});
+	const originalCwd = process.cwd();
+	try {
+		process.chdir(tmpRoot);
+		await runSync({
+			configPath,
+			cacheDirOverride: cacheDir,
+			json: true,
+			lockOnly: true,
+			offline: true,
+			failOnMiss: false,
+		});
+	} finally {
+		process.chdir(originalCwd);
+	}
 
 	const lockRaw = await readFile(
 		path.join(tmpRoot, DEFAULT_LOCK_FILENAME),
@@ -49,7 +63,7 @@ test("sync writes lock toolVersion from package.json", async () => {
 	);
 	const lock = JSON.parse(lockRaw);
 	const pkgRaw = await readFile(
-		path.resolve(process.cwd(), "package.json"),
+		new URL("../package.json", import.meta.url),
 		"utf8",
 	);
 	const pkg = JSON.parse(pkgRaw);