diff --git a/.changeset/sync-get-latest-commit.md b/.changeset/sync-get-latest-commit.md
new file mode 100644
index 0000000..28b4b63
--- /dev/null
+++ b/.changeset/sync-get-latest-commit.md
@@ -0,0 +1,7 @@
+---
+"@getcirrus/pds": minor
+---
+
+Implement `com.atproto.sync.getLatestCommit`.
+
+This sync XRPC endpoint was previously unimplemented, so requests fell through to the XRPC proxy and returned `501 MethodNotImplemented`. Relays call `getLatestCommit` during their crawl bootstrap, so a freshly created repo could never be indexed by a fresh `requestCrawl`. The endpoint now returns the repo's head commit as `{ cid, rev }` (sourced from the same `rpcGetRepoStatus` data used by `getRepoStatus`/`listRepos`).
diff --git a/packages/pds/src/index.ts b/packages/pds/src/index.ts
index eb75f09..fe6a67f 100644
--- a/packages/pds/src/index.ts
+++ b/packages/pds/src/index.ts
@@ -212,6 +212,9 @@ app.get("/xrpc/com.atproto.sync.getRepo", (c) =>
 app.get("/xrpc/com.atproto.sync.getRepoStatus", (c) =>
 	sync.getRepoStatus(c, getAccountDO(c.env)),
 );
+app.get("/xrpc/com.atproto.sync.getLatestCommit", (c) =>
+	sync.getLatestCommit(c, getAccountDO(c.env)),
+);
 app.get("/xrpc/com.atproto.sync.getBlocks", (c) =>
 	sync.getBlocks(c, getAccountDO(c.env)),
 );
diff --git a/packages/pds/src/xrpc/sync.ts b/packages/pds/src/xrpc/sync.ts
index 40861da..709626a 100644
--- a/packages/pds/src/xrpc/sync.ts
+++ b/packages/pds/src/xrpc/sync.ts
@@ -117,6 +117,55 @@ export async function listRepos(
 	});
 }
 
+export async function getLatestCommit(
+	c: Context<AppEnv>,
+	accountDO: DurableObjectStub<AccountDurableObject>,
+): Promise<Response> {
+	const did = c.req.query("did");
+
+	if (!did) {
+		return c.json(
+			{
+				error: "InvalidRequest",
+				message: "Missing required parameter: did",
+			},
+			400,
+		);
+	}
+
+	// Validate DID format
+	if (!isDid(did)) {
+		return c.json(
+			{ error: "InvalidRequest", message: "Invalid DID format" },
+			400,
+		);
+	}
+
+	if (did !== c.env.DID) {
+		return c.json(
+			{
+				error: "RepoNotFound",
+				message: `Repository not found for DID: ${did}`,
+			},
+			404,
+		);
+	}
+
+	const [data, active] = await Promise.all([
+		accountDO.rpcGetRepoStatus(),
+		accountDO.rpcGetActive(),
+	]);
+
+	if (!active) {
+		return c.json(
+			{ error: "RepoDeactivated", message: "Repository has been deactivated" },
+			400,
+		);
+	}
+
+	return c.json({ cid: data.head, rev: data.rev });
+}
+
 export async function listBlobs(
 	c: Context<AppEnv>,
 	_accountDO: DurableObjectStub<AccountDurableObject>,
diff --git a/packages/pds/test/xrpc.test.ts b/packages/pds/test/xrpc.test.ts
index c01d311..6b5f1cc 100644
--- a/packages/pds/test/xrpc.test.ts
+++ b/packages/pds/test/xrpc.test.ts
@@ -1481,6 +1481,46 @@ describe("XRPC Endpoints", () => {
 			expect(data.status).toBeUndefined();
 		});
 
+		it("should get latest commit", async () => {
+			const response = await worker.fetch(
+				new Request(
+					`http://pds.test/xrpc/com.atproto.sync.getLatestCommit?did=${env.DID}`,
+				),
+				env,
+			);
+			expect(response.status).toBe(200);
+
+			const data = (await response.json()) as Record<string, unknown>;
+			expect(data).toMatchObject({
+				cid: expect.any(String),
+				rev: expect.any(String),
+			});
+		});
+
+		it("should reject getLatestCommit without a did", async () => {
+			const response = await worker.fetch(
+				new Request("http://pds.test/xrpc/com.atproto.sync.getLatestCommit"),
+				env,
+			);
+			expect(response.status).toBe(400);
+
+			const data = (await response.json()) as Record<string, unknown>;
+			expect(data.error).toBe("InvalidRequest");
+		});
+
+		it("should return RepoNotFound for an unknown did on getLatestCommit", async () => {
+			const response = await worker.fetch(
+				new Request(
+					"http://pds.test/xrpc/com.atproto.sync.getLatestCommit?did=did:web:unknown.example.com",
+				),
+				env,
+			);
+			expect(response.status).toBe(404);
+
+			const data = (await response.json()) as Record<string, unknown>;
+			expect(data.error).toBe("RepoNotFound");
+		});
+
 		it("should return deactivated status when account is inactive", async () => {
 			const deactivateResponse = await worker.fetch(
 				new Request(