diff --git a/src/lock.ts b/src/lock.ts
index 070446b..bfc09e5 100644
--- a/src/lock.ts
+++ b/src/lock.ts
@@ -8,6 +8,7 @@ export interface DocsCacheLockSource {
 	bytes: number;
 	fileCount: number;
 	manifestSha256: string;
+	rulesSha256?: string;
 	updatedAt: string;
 }
 
@@ -79,6 +80,10 @@ export const validateLock = (input: unknown): DocsCacheLock => {
 				value.manifestSha256,
 				`sources.${key}.manifestSha256`,
 			),
+			rulesSha256:
+				value.rulesSha256 === undefined
+					? undefined
+					: assertString(value.rulesSha256, `sources.${key}.rulesSha256`),
 			updatedAt: assertString(value.updatedAt, `sources.${key}.updatedAt`),
 		};
 	}
diff --git a/src/sync.ts b/src/sync.ts
index ee040df..5406d47 100644
--- a/src/sync.ts
+++ b/src/sync.ts
@@ -1,3 +1,4 @@
+import { createHash } from "node:crypto";
 import { access, mkdir, readFile } from "node:fs/promises";
 import path from "node:path";
 import pc from "picocolors";
@@ -42,10 +43,12 @@ type SyncResult = {
 	ref: string;
 	resolvedCommit: string;
 	lockCommit: string | null;
+	lockRulesSha256?: string;
 	status: "up-to-date" | "changed" | "missing";
 	bytes?: number;
 	fileCount?: number;
 	manifestSha256?: string;
+	rulesSha256?: string;
 };
 
 const formatBytes = (value: number) => {
@@ -79,6 +82,29 @@ const hasDocs = async (cacheDir: string, sourceId: string) => {
 	return await exists(path.join(sourceDir, MANIFEST_FILENAME));
 };
 
+const normalizePatterns = (patterns?: string[]) => {
+	if (!patterns || patterns.length === 0) {
+		return [];
+	}
+	const normalized = patterns
+		.map((pattern) => pattern.trim())
+		.filter((pattern) => pattern.length > 0);
+	return Array.from(new Set(normalized)).sort();
+};
+
+const computeRulesHash = (params: {
+	include: string[];
+	exclude?: string[];
+}) => {
+	const payload = {
+		include: normalizePatterns(params.include),
+		exclude: normalizePatterns(params.exclude),
+	};
+	const hash = createHash("sha256");
+	hash.update(JSON.stringify(payload));
+	return hash.digest("hex");
+};
+
 export const getSyncPlan = async (
 	options: SyncOptions,
 	deps: SyncDeps = {},
@@ -108,6 +134,9 @@ export const getSyncPlan = async (
 	const results: SyncResult[] = await Promise.all(
 		filteredSources.map(async (source) => {
 			const lockEntry = lockData?.sources?.[source.id];
+			const include = source.include ?? defaults.include;
+			const exclude = source.exclude;
+			const rulesSha256 = computeRulesHash({ include, exclude });
 			if (options.offline) {
 				const docsPresent = await hasDocs(resolvedCacheDir, source.id);
 				return {
@@ -116,10 +145,12 @@ export const getSyncPlan = async (
 					ref: lockEntry?.ref ?? source.ref ?? defaults.ref,
 					resolvedCommit: lockEntry?.resolvedCommit ?? "offline",
 					lockCommit: lockEntry?.resolvedCommit ?? null,
+					lockRulesSha256: lockEntry?.rulesSha256,
 					status: lockEntry && docsPresent ? "up-to-date" : "missing",
 					bytes: lockEntry?.bytes,
 					fileCount: lockEntry?.fileCount,
 					manifestSha256: lockEntry?.manifestSha256,
+					rulesSha256,
 				};
 			}
 			const resolved = await resolveCommit({
@@ -128,7 +159,9 @@ export const getSyncPlan = async (
 				allowHosts: defaults.allowHosts,
 				timeoutMs: options.timeoutMs,
 			});
-			const upToDate = lockEntry?.resolvedCommit === resolved.resolvedCommit;
+			const upToDate =
+				lockEntry?.resolvedCommit === resolved.resolvedCommit &&
+				lockEntry?.rulesSha256 === rulesSha256;
 			const status = lockEntry
 				? upToDate
 					? "up-to-date"
@@ -140,10 +173,12 @@ export const getSyncPlan = async (
 				ref: resolved.ref,
 				resolvedCommit: resolved.resolvedCommit,
 				lockCommit: lockEntry?.resolvedCommit ?? null,
+				lockRulesSha256: lockEntry?.rulesSha256,
 				status,
 				bytes: lockEntry?.bytes,
 				fileCount: lockEntry?.fileCount,
 				manifestSha256: lockEntry?.manifestSha256,
+				rulesSha256,
 			};
 		}),
 	);
@@ -199,6 +234,7 @@ const buildLock = async (
 			fileCount: result.fileCount ?? prior?.fileCount ?? 0,
 			manifestSha256:
 				result.manifestSha256 ?? prior?.manifestSha256 ?? result.resolvedCommit,
+			rulesSha256: result.rulesSha256 ?? prior?.rulesSha256,
 			updatedAt: now,
 		};
 	}
@@ -467,6 +503,10 @@ export const printSyncPlan = (
 	for (const result of plan.results) {
 		const shortResolved = ui.hash(result.resolvedCommit);
 		const shortLock = ui.hash(result.lockCommit);
+		const rulesChanged =
+			Boolean(result.lockRulesSha256) &&
+			Boolean(result.rulesSha256) &&
+			result.lockRulesSha256 !== result.rulesSha256;
 
 		if (result.status === "up-to-date") {
 			ui.item(
@@ -477,6 +517,14 @@ export const printSyncPlan = (
 			continue;
 		}
 		if (result.status === "changed") {
+			if (result.lockCommit === result.resolvedCommit && rulesChanged) {
+				ui.item(
+					symbols.warn,
+					result.id,
+					`${pc.dim("rules changed")} ${pc.gray(shortResolved)}`,
+				);
+				continue;
+			}
 			ui.item(
 				symbols.warn,
 				result.id,
diff --git a/tests/fixtures/docs.lock b/tests/fixtures/docs.lock
index 848e787..450f907 100644
--- a/tests/fixtures/docs.lock
+++ b/tests/fixtures/docs.lock
@@ -6,11 +6,12 @@
     "vitest": {
       "repo": "https://github.com/vitest-dev/vitest.git",
       "ref": "main",
-    "resolvedCommit": "0123456789abcdef0123456789abcdef01234567",
-    "bytes": 123456,
-    "fileCount": 512,
-    "manifestSha256": "abcd",
-    "updatedAt": "2026-01-30T12:00:00+01:00"
+      "resolvedCommit": "0123456789abcdef0123456789abcdef01234567",
+      "bytes": 123456,
+      "fileCount": 512,
+      "manifestSha256": "abcd",
+      "rulesSha256": "efgh",
+      "updatedAt": "2026-01-30T12:00:00+01:00"
     }
   }
 }
diff --git a/tests/lock.test.js b/tests/lock.test.js
index e72a127..b30dc50 100644
--- a/tests/lock.test.js
+++ b/tests/lock.test.js
@@ -27,6 +27,7 @@ test("lock fixture is valid", async (t) => {
 	const lock = module.validateLock(parsed);
 	assert.equal(lock.version, 1);
 	assert.ok(lock.sources.vitest);
+	assert.equal(lock.sources.vitest.rulesSha256, "efgh");
 });
 
 test("writeLock produces readable JSON", async (t) => {
diff --git a/tests/sync-include-exclude.test.js b/tests/sync-include-exclude.test.js
index bf3e073..c4fa4f9 100644
--- a/tests/sync-include-exclude.test.js
+++ b/tests/sync-include-exclude.test.js
@@ -131,3 +131,81 @@ test("exclude overrides include on overlap", async () => {
 	const docsRoot = path.join(cacheDir, "local");
 	assert.equal(await exists(path.join(docsRoot, "docs", "guide.md")), false);
 });
+
+test("sync re-materializes when include rules change", async () => {
+	const tmpRoot = path.join(
+		tmpdir(),
+		`docs-cache-rules-${Date.now().toString(36)}`,
+	);
+	const cacheDir = path.join(tmpRoot, ".docs");
+	const repoDir = path.join(tmpRoot, "repo");
+	const configPath = path.join(tmpRoot, "docs.config.json");
+
+	await mkdir(path.join(repoDir, "docs"), { recursive: true });
+	await writeFile(path.join(repoDir, "README.md"), "readme", "utf8");
+	await writeFile(path.join(repoDir, "docs", "guide.md"), "guide", "utf8");
+
+	const baseConfig = {
+		$schema:
+			"https://raw.githubusercontent.com/fbosch/docs-cache/main/docs.config.schema.json",
+		sources: [
+			{
+				id: "local",
+				repo: "https://example.com/repo.git",
+				include: ["docs/**"],
+			},
+		],
+	};
+	await writeFile(
+		configPath,
+		`${JSON.stringify(baseConfig, null, 2)}\n`,
+		"utf8",
+	);
+
+	const syncOptions = {
+		configPath,
+		cacheDirOverride: cacheDir,
+		json: false,
+		lockOnly: false,
+		offline: false,
+		failOnMiss: false,
+	};
+	const deps = {
+		resolveRemoteCommit: async () => ({
+			repo: "https://example.com/repo.git",
+			ref: "HEAD",
+			resolvedCommit: "abc123",
+		}),
+		fetchSource: async () => ({
+			repoDir,
+			cleanup: async () => undefined,
+		}),
+	};
+
+	await runSync(syncOptions, deps);
+
+	const docsRoot = path.join(cacheDir, "local");
+	assert.equal(await exists(path.join(docsRoot, "README.md")), false);
+	assert.equal(await exists(path.join(docsRoot, "docs", "guide.md")), true);
+
+	const updatedConfig = {
+		...baseConfig,
+		sources: [
+			{
+				id: "local",
+				repo: "https://example.com/repo.git",
+				include: ["README.md"],
+			},
+		],
+	};
+	await writeFile(
+		configPath,
+		`${JSON.stringify(updatedConfig, null, 2)}\n`,
+		"utf8",
+	);
+
+	await runSync(syncOptions, deps);
+
+	assert.equal(await exists(path.join(docsRoot, "README.md")), true);
+	assert.equal(await exists(path.join(docsRoot, "docs", "guide.md")), false);
+});
diff --git a/tests/sync-output.test.js b/tests/sync-output.test.js
index a5bba7d..b3886e3 100644
--- a/tests/sync-output.test.js
+++ b/tests/sync-output.test.js
@@ -28,6 +28,16 @@ test("printSyncPlan outputs summary and short hashes", () => {
 				lockCommit: "cccccccccccccccccccccccccccccccccccccccc",
 				status: "changed",
 			},
+			{
+				id: "gamma",
+				repo: "https://example.com/gamma.git",
+				ref: "main",
+				resolvedCommit: "dddddddddddddddddddddddddddddddddddddddd",
+				lockCommit: "dddddddddddddddddddddddddddddddddddddddd",
+				lockRulesSha256: "111111",
+				rulesSha256: "222222",
+				status: "changed",
+			},
 		],
 	};
 
@@ -44,9 +54,11 @@ test("printSyncPlan outputs summary and short hashes", () => {
 		process.stdout.write = originalWrite;
 	}
 
-	assert.ok(output.includes("2 sources"));
+	assert.ok(output.includes("3 sources"));
 	assert.ok(output.includes("alpha"));
 	assert.ok(output.includes("beta"));
+	assert.ok(output.includes("gamma"));
 	assert.ok(output.includes("aaaaaaa"));
 	assert.ok(output.includes("bbbbbbb"));
+	assert.ok(output.includes("rules changed"));
 });