diff --git a/src/client.ts b/src/client.ts
index 9ab28cf..fb12cb1 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -6,6 +6,7 @@ import {
   AxmeValidationError,
 } from "./errors.js";
 import { MeshClient } from "./mesh.js";
+import { SDK_VERSION } from "./version.js";
 
 export type AxmeClientConfig = {
   baseUrl?: string;
@@ -1921,6 +1922,7 @@ export class AxmeClient {
     const headers: Record<string, string> = {
       "x-api-key": this.apiKey,
       "Content-Type": "application/json",
+      "X-Axme-Client": `axme-sdk-typescript/${SDK_VERSION}`,
     };
     if (this.actorToken) {
       headers.Authorization = `Bearer ${this.actorToken}`;
diff --git a/src/index.ts b/src/index.ts
index 55856bc..ddb8b34 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,3 +1,4 @@
+export { SDK_VERSION } from "./version.js";
 export {
   AxmeClient,
   type AxmeClientConfig,
diff --git a/src/version.ts b/src/version.ts
new file mode 100644
index 0000000..f082305
--- /dev/null
+++ b/src/version.ts
@@ -0,0 +1,3 @@
+// Single source of truth for the SDK version sent in X-Axme-Client header.
+// Keep in sync with package.json version field on every release.
+export const SDK_VERSION = "0.2.0";
diff --git a/test/client.test.ts b/test/client.test.ts
index a4e1002..f0c4141 100644
--- a/test/client.test.ts
+++ b/test/client.test.ts
@@ -50,6 +50,19 @@ test("health returns parsed payload", async () => {
   assert.deepEqual(await client.health(), { ok: true });
 });
 
+test("health sends X-Axme-Client header", async () => {
+  const { SDK_VERSION } = await import("../src/version.js");
+  const client = new AxmeClient(
+    { baseUrl: "https://api.axme.test", apiKey: "token" },
+    async (_input, init) => {
+      const headers = init?.headers as Record<string, string>;
+      assert.equal(headers["X-Axme-Client"], `axme-sdk-typescript/${SDK_VERSION}`);
+      return new Response(JSON.stringify({ ok: true }), { status: 200 });
+    },
+  );
+  await client.health();
+});
+
 test("health includes actor token authorization when configured", async () => {
   const client = new AxmeClient(
     {