Modifies top level Server instructions to be a provider so it can be sourced dynamically for each session if desired

Author: jclyne

kotlin-sdk-server/api/kotlin-sdk-server.api

@@ -45,8 +45,8 @@ public final class io/modelcontextprotocol/kotlin/sdk/server/RegisteredTool {
 }
 
 public class io/modelcontextprotocol/kotlin/sdk/server/Server {
-	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Ljava/lang/String;)V
-	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Ljava/lang/String;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Lkotlin/jvm/functions/Function0;)V
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Lkotlin/jvm/functions/Function0;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun addPrompt (Lio/modelcontextprotocol/kotlin/sdk/Prompt;Lkotlin/jvm/functions/Function2;)V
 	public final fun addPrompt (Ljava/lang/String;Ljava/lang/String;Ljava/util/List;Lkotlin/jvm/functions/Function2;)V
 	public static synthetic fun addPrompt$default (Lio/modelcontextprotocol/kotlin/sdk/server/Server;Ljava/lang/String;Ljava/lang/String;Ljava/util/List;Lkotlin/jvm/functions/Function2;ILjava/lang/Object;)V
@@ -60,7 +60,7 @@ public class io/modelcontextprotocol/kotlin/sdk/server/Server {
 	public final fun addTools (Ljava/util/List;)V
 	public final fun close (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public final fun connect (Lio/modelcontextprotocol/kotlin/sdk/shared/Transport;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
-	protected final fun getInstructions ()Ljava/lang/String;
+	protected final fun getInstructionsProvider ()Lkotlin/jvm/functions/Function0;
 	protected final fun getOptions ()Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;
 	public final fun getPrompts ()Ljava/util/Map;
 	public final fun getResources ()Ljava/util/Map;

kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/Server.kt

@@ -53,13 +53,14 @@ public class ServerOptions(public val capabilities: ServerCapabilities, enforceS
  *
  * @param serverInfo Information about this server implementation (name, version).
  * @param options Configuration options for the server.
- * @param instructions Optional instructions from the server to the client about how to use this server.
+ * @param instructionsProvider Optional provider for instructions from the server to the client about how to use
+ * this server. The provider is called each time a new session is started to support dynamic instructions.
  */
 
 public open class Server(
     protected val serverInfo: Implementation,
     protected val options: ServerOptions,
-    protected val instructions: String? = null,
+    protected val instructionsProvider: (() -> String)? = null,
 ) {
     private val sessions = atomic(persistentListOf<ServerSession>())
 
@@ -96,7 +97,7 @@ public open class Server(
      * @return The initialized and connected server session.
      */
     public suspend fun connect(transport: Transport): ServerSession {
-        val session = ServerSession(serverInfo, options, instructions)
+        val session = ServerSession(serverInfo, options, instructionsProvider?.invoke())
 
         // Internal handlers for tools
         if (options.capabilities.tools != null) {

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/server/ServerTest.kt

@@ -479,7 +479,7 @@ class ServerTest {
         val serverOptions = ServerOptions(capabilities = ServerCapabilities())
         val instructions = "This is a test server. Use it for testing purposes only."
 
-        val server = Server(serverInfo, serverOptions, instructions)
+        val server = Server(serverInfo, serverOptions) { instructions }
 
         // The instructions should be stored internally and used in handleInitialize
         // We can't directly access the private field, but we can test it through initialization
@@ -492,7 +492,6 @@ class ServerTest {
         assertEquals(instructions, client.serverInstructions)
     }
 
-
     @Test
     fun `Server constructor should work without instructions parameter`() = runTest {
         val serverInfo = Implementation(name = "test server", version = "1.0")