diff --git a/README.md b/README.md
index 6c3c2a6..9eb77a7 100644
--- a/README.md
+++ b/README.md
@@ -279,9 +279,12 @@ Textbee(
     api_key="your-api-key",
     base_url="https://api.textbee.dev/api/v1",  # the default
     timeout=30.0,  # seconds for each connect and each read
+    client_name="my-app/1.2.0",  # optional
 )
 ```
 
+Set `client_name` when you publish a tool or integration built on this SDK. It names your tool in the request headers, ahead of the SDK's own name. Use `name/version`.
+
 ### Self-hosted textbee
 
 Point `base_url` at your own instance. A bare origin gets `/api/v1` added, so all of these reach the same API:
diff --git a/src/textbee/_client.py b/src/textbee/_client.py
index b66a5e1..d30b3c7 100644
--- a/src/textbee/_client.py
+++ b/src/textbee/_client.py
@@ -26,6 +26,7 @@
 DEFAULT_BASE_URL = "https://api.textbee.dev/api/v1"
 DEFAULT_TIMEOUT = 30.0
 CLIENT_ID = f"textbee-python/{__version__}"
+_CLIENT_NAME_PART = re.compile(r"[A-Za-z0-9._-]{1,64}/[A-Za-z0-9._+-]{1,32}")
 
 DateInput = Union[str, datetime]
 QueryValue = Union[str, int, None]
@@ -46,6 +47,7 @@ def __init__(
         *,
         base_url: str | None = None,
         timeout: float = DEFAULT_TIMEOUT,
+        client_name: str | None = None,
     ) -> None:
         """Create a client.
 
@@ -63,6 +65,11 @@ def __init__(
 
         ``timeout`` is in seconds and applies to each connect and read, not to
         the request as a whole.
+
+        ``client_name`` names an app or tool built on this SDK, for example
+        ``my-app/1.2.0``. It is sent ahead of the SDK's own name in the client
+        headers. Each space-separated part must look like ``name/version``, or
+        ``ValueError`` is raised.
         """
         api_key = (api_key or "").strip()
         if not api_key:
@@ -74,6 +81,7 @@ def __init__(
         self._api_key = api_key
         self._base_url = _normalize_base_url(base_url)
         self._timeout = timeout
+        self._client_id = _client_id(client_name)
 
     def __repr__(self) -> str:
         return f"Textbee(base_url={self._base_url!r})"
@@ -292,8 +300,8 @@ def _request(
 
         headers = {
             "x-api-key": self._api_key,
-            "user-agent": CLIENT_ID,
-            "x-sdk-client": CLIENT_ID,
+            "user-agent": self._client_id,
+            "x-sdk-client": self._client_id,
             "accept": "application/json",
         }
         data = None
@@ -466,3 +474,12 @@ def _error_message(payload: Any, status: int) -> str:
                 return "; ".join(value)
 
     return f"HTTP {status}"
+
+
+def _client_id(client_name: str | None) -> str:
+    if client_name is None:
+        return CLIENT_ID
+    parts = client_name.split() if isinstance(client_name, str) else []
+    if not parts or len(parts) > 4 or not all(_CLIENT_NAME_PART.fullmatch(p) for p in parts):
+        raise ValueError("client_name must look like name/version, for example my-app/1.2.0")
+    return " ".join([*parts, CLIENT_ID])
diff --git a/tests/test_client.py b/tests/test_client.py
index 7c4b125..ba181e1 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -299,7 +299,7 @@ def test_never_puts_the_api_key_in_the_error_or_repr(self, http: FakeUrlopen) ->
         assert API_KEY not in repr(client())
 
 
-class TestTelemetryHeaders:
+class TestClientHeaders:
     def test_identifies_the_sdk_and_its_version_on_every_request(self, http: FakeUrlopen) -> None:
         client().get_devices()
 
@@ -308,6 +308,21 @@ def test_identifies_the_sdk_and_its_version_on_every_request(self, http: FakeUrl
         assert http.last.headers["x-sdk-client"] == expected
         assert http.last.headers["accept"] == "application/json"
 
+    def test_puts_a_client_name_ahead_of_the_sdk(self, http: FakeUrlopen) -> None:
+        Textbee(API_KEY, client_name=" my-tool/1.2.0  host/2.0.0-beta.1 ").get_devices()
+
+        expected = f"my-tool/1.2.0 host/2.0.0-beta.1 textbee-python/{__version__}"
+        assert http.last.headers["user-agent"] == expected
+        assert http.last.headers["x-sdk-client"] == expected
+
+    @pytest.mark.parametrize(
+        "client_name",
+        ["", "my tool", "my-tool", "a/1 b/2 c/3 d/4 e/5", "my-tool/1.0\nx: y"],
+    )
+    def test_rejects_a_malformed_client_name(self, client_name: str) -> None:
+        with pytest.raises(ValueError):
+            Textbee(API_KEY, client_name=client_name)
+
 
 class TestResponseEnvelopes:
     def test_returns_get_messages_as_data_and_meta_because_it_has_no_outer_wrapper(