diff --git a/kotlin-sdk-client/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/client/Client.kt b/kotlin-sdk-client/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/client/Client.kt
index b88cb1b..59f2b7e 100644
--- a/kotlin-sdk-client/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/client/Client.kt
+++ b/kotlin-sdk-client/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/client/Client.kt
@@ -242,13 +242,18 @@ public open class Client(private val clientInfo: Implementation, options: Client
 
             Method.Defined.PromptsGet,
             Method.Defined.PromptsList,
-            Method.Defined.CompletionComplete,
             -> {
                 checkNotNull(serverCapabilities?.prompts) {
                     "Server does not support prompts (required for $method)"
                 }
             }
 
+            Method.Defined.CompletionComplete -> {
+                checkNotNull(serverCapabilities?.completions) {
+                    "Server does not support completions (required for $method)"
+                }
+            }
+
             Method.Defined.ResourcesList,
             Method.Defined.ResourcesTemplatesList,
             Method.Defined.ResourcesRead,
@@ -394,7 +399,7 @@ public open class Client(private val clientInfo: Implementation, options: Client
      * @param params The completion request parameters.
      * @param options Optional request options.
      * @return The completion result returned by the server, or `null` if none.
-     * @throws IllegalStateException If the server does not support prompts or completion.
+     * @throws IllegalStateException If the server does not support completions.
      */
     public suspend fun complete(params: CompleteRequest, options: RequestOptions? = null): CompleteResult =
         request(params, options)
diff --git a/kotlin-sdk-client/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/ClientAssertCapabilityTest.kt b/kotlin-sdk-client/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/ClientAssertCapabilityTest.kt
index 2f322ec..e9379a7 100644
--- a/kotlin-sdk-client/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/ClientAssertCapabilityTest.kt
+++ b/kotlin-sdk-client/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/ClientAssertCapabilityTest.kt
@@ -84,6 +84,25 @@ class ClientAssertCapabilityTest {
         ex.message.orEmpty() shouldContain "Client does not support tasks"
     }
 
+    @Test
+    fun `CompletionComplete does not throw when server declared completions`() = runTest {
+        val client = newTestClient(
+            serverCapabilities = ServerCapabilities(completions = ServerCapabilities.Completions),
+        )
+        client.exposedAssertCapabilityForMethod(Method.Defined.CompletionComplete)
+    }
+
+    @Test
+    fun `CompletionComplete throws when server has no completions capability`() = runTest {
+        val client = newTestClient(
+            serverCapabilities = ServerCapabilities(prompts = ServerCapabilities.Prompts()),
+        )
+        val ex = assertFailsWith<IllegalStateException> {
+            client.exposedAssertCapabilityForMethod(Method.Defined.CompletionComplete)
+        }
+        ex.message.orEmpty() shouldContain "Server does not support completions"
+    }
+
     private suspend fun newTestClient(
         serverCapabilities: ServerCapabilities = ServerCapabilities(),
         clientCapabilities: ClientCapabilities = ClientCapabilities(),