Adds alternative constructor that takes a static instructions string

Author: jclyne

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

@@ -62,6 +62,19 @@ public open class Server(
     protected val options: ServerOptions,
     protected val instructionsProvider: (() -> String)? = null,
 ) {
+    /**
+     * Alternative constructor that provides the instructions directly as a string.
+     *
+     * @param serverInfo Information about this server implementation (name, version).
+     * @param options Configuration options for the server.
+     * @param instructions Instructions from the server to the client about how to use this server.
+     */
+    public constructor(
+        serverInfo: Implementation,
+        options: ServerOptions,
+        instructions: String,
+    ) : this(serverInfo, options, { instructions })
+
     private val sessions = atomic(persistentListOf<ServerSession>())
 
     @Suppress("ktlint:standard:backing-property-naming")

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

@@ -473,13 +473,32 @@ class ServerTest {
         assertEquals("Server does not support resources capability.", exception.message)
     }
 
+    @Test
+    fun `Server constructor should accept instructions provider parameter`() = runTest {
+        val serverInfo = Implementation(name = "test server", version = "1.0")
+        val serverOptions = ServerOptions(capabilities = ServerCapabilities())
+        val instructions = "This is a test server. Use it for testing purposes only."
+
+        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
+        val (clientTransport, serverTransport) = InMemoryTransport.createLinkedPair()
+        val client = Client(clientInfo = Implementation(name = "test client", version = "1.0"))
+
+        server.connect(serverTransport)
+        client.connect(clientTransport)
+
+        assertEquals(instructions, client.serverInstructions)
+    }
+
     @Test
     fun `Server constructor should accept instructions parameter`() = runTest {
         val serverInfo = Implementation(name = "test server", version = "1.0")
         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