diff --git a/python/packages/mistral/agent_framework_mistral/_chat_client.py b/python/packages/mistral/agent_framework_mistral/_chat_client.py
index b97fb8f072..bc95b9dadd 100644
--- a/python/packages/mistral/agent_framework_mistral/_chat_client.py
+++ b/python/packages/mistral/agent_framework_mistral/_chat_client.py
@@ -154,6 +154,8 @@ class MistralSettings(TypedDict, total=False):
         api_key: Mistral API key. Resolved from ``MISTRAL_API_KEY``.
         chat_model: Chat model name. Resolved from ``MISTRAL_CHAT_MODEL``.
         server_url: Optional server URL override. Resolved from ``MISTRAL_SERVER_URL``.
+            Ignored when a Mistral SDK client is injected; the injected client's own
+            endpoint is reported instead.
     """
 
     api_key: SecretString | None
@@ -389,20 +391,23 @@ def __init__(
             required_fields=[] if client is not None or http_client is not None else ["api_key"],
             api_key=api_key,
             chat_model=model,
-            server_url=server_url,
+            server_url=None if client is not None else server_url,
             env_file_path=env_file_path,
             env_file_encoding=env_file_encoding,
         )
 
         self.model = mistral_settings.get("chat_model")
-        self.server_url = mistral_settings.get("server_url")
         self._owns_client = not isinstance(client, Mistral)
         self._client_closed = False
+        # Settings are only consulted for a client this wrapper creates; an
+        # injected SDK client has its own endpoint and requires no key.
+        self.server_url = mistral_settings.get("server_url")
 
         if isinstance(client, Mistral):
+            # The injected SDK client owns the endpoint: requests go to it, so
+            # metadata must report its URL, not an ambient MISTRAL_SERVER_URL.
+            self.server_url = client.sdk_configuration.get_server_details()[0]
             self.client = client
-            if self.server_url is None:
-                self.server_url = client.sdk_configuration.get_server_details()[0]
         else:
             client_kwargs: dict[str, Any] = {"timeout_ms": _DEFAULT_TIMEOUT_MS}
             if resolved_api_key := mistral_settings.get("api_key"):
diff --git a/python/packages/mistral/agent_framework_mistral/_embedding_client.py b/python/packages/mistral/agent_framework_mistral/_embedding_client.py
index 29b0107c22..ee3990bc40 100644
--- a/python/packages/mistral/agent_framework_mistral/_embedding_client.py
+++ b/python/packages/mistral/agent_framework_mistral/_embedding_client.py
@@ -76,6 +76,8 @@ class MistralEmbeddingSettings(TypedDict, total=False):
         api_key: Mistral API key. Resolved from ``MISTRAL_API_KEY``.
         embedding_model: Embedding model name. Resolved from ``MISTRAL_EMBEDDING_MODEL``.
         server_url: Optional server URL override. Resolved from ``MISTRAL_SERVER_URL``.
+            Ignored when a Mistral SDK client is injected; the injected client's own
+            endpoint is reported instead.
     """
 
     api_key: SecretString | None
@@ -146,19 +148,22 @@ def __init__(
             required_fields=required_fields,
             api_key=api_key,
             embedding_model=model,
-            server_url=server_url,
+            server_url=None if client is not None else server_url,
             env_file_path=env_file_path,
             env_file_encoding=env_file_encoding,
         )
 
         self.model: str = mistral_settings["embedding_model"]  # type: ignore[assignment]
-        self.server_url = mistral_settings.get("server_url")
         self._owns_client = not isinstance(client, Mistral)
+        # Settings are only consulted for a client this wrapper creates; an
+        # injected SDK client has its own endpoint and requires no key.
+        self.server_url = mistral_settings.get("server_url")
 
         if isinstance(client, Mistral):
+            # The injected SDK client owns the endpoint: requests go to it, so
+            # metadata must report its URL, not an ambient MISTRAL_SERVER_URL.
+            self.server_url = client.sdk_configuration.get_server_details()[0]
             self.client = client
-            if self.server_url is None:
-                self.server_url = client.sdk_configuration.get_server_details()[0]
         else:
             client_kwargs: dict[str, Any] = {"timeout_ms": _DEFAULT_TIMEOUT_MS}
             if resolved_api_key := mistral_settings.get("api_key"):
diff --git a/python/packages/mistral/tests/mistral/test_mistral_injected_client_endpoint.py b/python/packages/mistral/tests/mistral/test_mistral_injected_client_endpoint.py
new file mode 100644
index 0000000000..14b135f9e1
--- /dev/null
+++ b/python/packages/mistral/tests/mistral/test_mistral_injected_client_endpoint.py
@@ -0,0 +1,74 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""An injected Mistral SDK client owns its endpoint (#9965).
+
+The wrapper used to resolve ``MISTRAL_SERVER_URL`` before inspecting the
+injected client, so ``service_url()`` reported the ambient URL (used for
+telemetry) while requests went to the injected client's endpoint.
+"""
+
+import os
+
+from mistralai.client import Mistral
+
+from agent_framework_mistral import MistralChatClient, MistralEmbeddingClient, RawMistralChatClient
+
+
+def _make_injected_sdk(server_url: str) -> Mistral:
+    return Mistral(api_key="dummy", server_url=server_url)
+
+
+def test_chat_service_url_uses_injected_client_endpoint(monkeypatch) -> None:
+    monkeypatch.setenv("MISTRAL_SERVER_URL", "https://env.example")
+    sdk = _make_injected_sdk("https://client.example")
+
+    client = RawMistralChatClient(client=sdk, model="mistral-test")
+
+    assert client.service_url() == "https://client.example"
+    assert client.server_url == "https://client.example"
+
+
+def test_embedding_service_url_uses_injected_client_endpoint(monkeypatch) -> None:
+    monkeypatch.setenv("MISTRAL_SERVER_URL", "https://env.example")
+    sdk = _make_injected_sdk("https://client.example")
+
+    client = MistralEmbeddingClient(client=sdk, model="mistral-embed")
+
+    assert client.service_url() == "https://client.example"
+    assert client.server_url == "https://client.example"
+
+
+def test_chat_service_url_uses_env_when_no_client(monkeypatch) -> None:
+    monkeypatch.setenv("MISTRAL_SERVER_URL", "https://env.example")
+    monkeypatch.setenv("MISTRAL_API_KEY", "env-key")
+
+    client = MistralChatClient()
+
+    assert client.service_url() == "https://env.example"
+
+
+def test_owned_client_keeps_explicit_server_url(monkeypatch) -> None:
+    monkeypatch.setenv("MISTRAL_API_KEY", "env-key")
+    monkeypatch.setenv("MISTRAL_SERVER_URL", "https://env.example")
+
+    raw = RawMistralChatClient(model="mistral-test", server_url="https://explicit.example")
+    assert raw.server_url == "https://explicit.example"
+
+    wrapped = MistralChatClient(server_url="https://explicit.example")
+    assert wrapped.service_url() == "https://explicit.example"
+
+
+def test_injected_client_consts_not_loaded(monkeypatch) -> None:
+    # No MISTRAL_API_KEY in the environment at all; injecting a client must not
+    # require one.
+    monkeypatch.delenv("MISTRAL_API_KEY", raising=False)
+    monkeypatch.delenv("MISTRAL_SERVER_URL", raising=False)
+    sdk = _make_injected_sdk("https://client.example")
+
+    chat = RawMistralChatClient(client=sdk, model="mistral-test")
+    embedding = MistralEmbeddingClient(client=sdk, model="mistral-embed")
+
+    assert chat._owns_client is False
+    assert embedding._owns_client is False
+    os.environ.pop("MISTRAL_API_KEY", None)
+    os.environ.pop("MISTRAL_SERVER_URL", None)