MCP Core implementation - Initialization, Tools/List, Tools/Call (Missing Health monitor and tool cancellation)

include/zephyr/net/mcp/mcp_server.h

@@ -7,18 +7,107 @@
 #ifndef ZEPHYR_INCLUDE_NET_MCP_SERVER_H_
 #define ZEPHYR_INCLUDE_NET_MCP_SERVER_H_
 
+/**
+ * @file
+ * @brief Model Context Protocol (MCP) Server API
+ */
+
 #include <zephyr/kernel.h>
+#include <errno.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+typedef enum {
+#ifdef CONFIG_MCP_TOOLS_CAPABILITY
+	MCP_USR_TOOL_RESPONSE,
+	MCP_USR_TOOL_NOTIFICATION,
+#endif
+	MCP_USR_GENERIC_RESPONSE
+} mcp_app_msg_type_t;
+
+#ifdef CONFIG_MCP_TOOLS_CAPABILITY
+/**
+ * @brief Tool metadata structure
+ */
+typedef struct mcp_tool_metadata {
+	char name[CONFIG_MCP_TOOL_NAME_MAX_LEN];
+	char input_schema[CONFIG_MCP_TOOL_SCHEMA_MAX_LEN];
+#ifdef CONFIG_MCP_TOOL_DESC
+	char description[CONFIG_MCP_TOOL_DESC_MAX_LEN];
+#endif
+#ifdef CONFIG_MCP_TOOL_TITLE
+	char title[CONFIG_MCP_TOOL_NAME_MAX_LEN];
+#endif
+#ifdef CONFIG_MCP_TOOL_OUTPUT_SCHEMA
+	char output_schema[CONFIG_MCP_TOOL_SCHEMA_MAX_LEN];
+#endif
+} mcp_tool_metadata_t;
+
+/**
+ * @brief Tool callback function
+ *
+ * @param params JSON string with tool parameters
+ * @param execution_token Unique execution identifier
+ * @return 0 on success, negative errno on failure
+ */
+typedef int (*mcp_tool_callback_t)(const char *params, uint32_t execution_token);
+
+/**
+ * @brief Tool definition structure
+ */
+typedef struct mcp_tool_record {
+	mcp_tool_metadata_t metadata;
+	mcp_tool_callback_t callback;
+} mcp_tool_record_t;
+#endif
+
+typedef struct mcp_user_message {
+	mcp_app_msg_type_t type;
+	int length;
+	void *data;
+} mcp_app_message_t;
+
 /**
- * @brief Initialize the MCP Server.
+ * @brief Initialize the MCP Server
  *
+ * @return 0 on success, negative errno on failure
  */
 int mcp_server_init(void);
 
+/**
+ * @brief Start the MCP Server
+ *
+ * @return 0 on success, negative errno on failure
+ */
+int mcp_server_start(void);
+
+int mcp_server_submit_app_message(const mcp_app_message_t *user_msg, uint32_t execution_token);
+
+#ifdef CONFIG_MCP_TOOLS_CAPABILITY
+/**
+ * @brief Add a tool to the server
+ *
+ * @param tool_record Tool definition with metadata and callback
+ * @return 0 on success, negative errno on failure
+ * @retval -EINVAL Invalid tool_record
+ * @retval -EEXIST Tool name already exists
+ * @retval -ENOSPC Registry full
+ */
+int mcp_server_add_tool(const mcp_tool_record_t *tool_record);
+
+/**
+ * @brief Remove a tool from the server
+ *
+ * @param tool_name Name of tool to remove
+ * @return 0 on success, negative errno on failure
+ * @retval -EINVAL Invalid tool name
+ * @retval -ENOENT Tool not found
+ */
+int mcp_server_remove_tool(const char *tool_name);
+#endif
+
 #ifdef __cplusplus
 }
 #endif

samples/net/mcp/mcp_server_hello_world/prj.conf

@@ -17,10 +17,14 @@ CONFIG_MCP_SERVER=y
 CONFIG_LOG=y
 CONFIG_PRINTK=y
 
+# MCP library logging level
+CONFIG_MCP_LOG_LEVEL_INF=y
+
 # Network configuration
 CONFIG_NET_CONFIG_SETTINGS=y
 CONFIG_NET_CONFIG_NEED_IPV4=y
 CONFIG_NET_CONFIG_MY_IPV4_ADDR="192.0.2.1"
 
 # Sufficient stack size for HTTP + JSON processing
 CONFIG_MAIN_STACK_SIZE=4096
+CONFIG_HEAP_MEM_POOL_SIZE=16384

samples/net/mcp/mcp_server_hello_world/src/main.c

@@ -10,9 +10,99 @@
 
 LOG_MODULE_REGISTER(mcp_sample_hello, LOG_LEVEL_INF);
 
+#ifdef CONFIG_MCP_TOOLS_CAPABILITY
+/* Tool callback functions */
+static int hello_world_tool_callback(const char *params, uint32_t execution_token)
+{
+	printk("Hello World tool executed with params: %s, token: %u\n", params ? params : "none",
+	       execution_token);
+	return 0;
+}
+
+static int goodbye_world_tool_callback(const char *params, uint32_t execution_token)
+{
+	printk("Goodbye World tool executed with params: %s, token: %u\n", params ? params : "none",
+	       execution_token);
+	return 0;
+}
+
+/* Tool definitions */
+static const mcp_tool_record_t hello_world_tool = {
+	.metadata = {
+			.name = "hello_world",
+			.input_schema = "{\"type\":\"object\",\"properties\":{\"message\":{"
+					"\"type\":\"string\"}}}",
+#ifdef CONFIG_MCP_TOOL_DESC
+			.description = "A simple hello world greeting tool",
+#endif
+#ifdef CONFIG_MCP_TOOL_TITLE
+			.title = "Hello World Tool",
+#endif
+#ifdef CONFIG_MCP_TOOL_OUTPUT_SCHEMA
+			.output_schema = "{\"type\":\"object\",\"properties\":{\"response\":{"
+					 "\"type\":\"string\"}}}",
+#endif
+		},
+	.callback = hello_world_tool_callback};
+
+static const mcp_tool_record_t goodbye_world_tool = {
+	.metadata = {
+			.name = "goodbye_world",
+			.input_schema = "{\"type\":\"object\",\"properties\":{\"message\":{"
+					"\"type\":\"string\"}}}",
+#ifdef CONFIG_MCP_TOOL_DESC
+			.description = "A simple goodbye world farewell tool",
+#endif
+#ifdef CONFIG_MCP_TOOL_TITLE
+			.title = "Goodbye World Tool",
+#endif
+#ifdef CONFIG_MCP_TOOL_OUTPUT_SCHEMA
+			.output_schema = "{\"type\":\"object\",\"properties\":{\"response\":{"
+					 "\"type\":\"string\"}}}",
+#endif
+		},
+	.callback = goodbye_world_tool_callback};
+#endif /* CONFIG_MCP_TOOLS_CAPABILITY */
+
 int main(void)
 {
+	int ret;
+
 	printk("Hello World\n\r");
-	mcp_server_init();
+	printk("Initializing...\n\r");
+	ret = mcp_server_init();
+	if (ret != 0) {
+		printk("MCP Server initialization failed: %d\n\r", ret);
+		return ret;
+	}
+
+#ifdef CONFIG_MCP_TOOLS_CAPABILITY
+	printk("Registering Tool #1: Hello world!...\n\r");
+	ret = mcp_server_add_tool(&hello_world_tool);
+	if (ret != 0) {
+		printk("Tool #1 registration failed.\n\r");
+		return ret;
+	}
+	printk("Tool #1 registered.\n\r");
+
+	printk("Registering Tool #2: Goodbye world!...\n\r");
+	ret = mcp_server_add_tool(&goodbye_world_tool);
+	if (ret != 0) {
+		printk("Tool #2 registration failed.\n\r");
+		return ret;
+	}
+	printk("Tool #2 registered.\n\r");
+#else
+	printk("MCP Tools capability not enabled - skipping tool registration\n\r");
+#endif /* CONFIG_MCP_TOOLS_CAPABILITY */
+
+	printk("Starting...\n\r");
+	ret = mcp_server_start();
+	if (ret != 0) {
+		printk("MCP Server start failed: %d\n\r", ret);
+		return ret;
+	}
+
+	printk("MCP Server running...\n\r");
 	return 0;
 }

subsys/net/lib/mcp/CMakeLists.txt

@@ -3,6 +3,7 @@
 
 zephyr_library()
 
+zephyr_library_sources_ifdef(CONFIG_MCP_SERVER mcp_common.c)
 zephyr_library_sources_ifdef(CONFIG_MCP_SERVER mcp_server.c)
 zephyr_library_sources_ifdef(CONFIG_MCP_SERVER mcp_transport.c)
 zephyr_library_sources_ifdef(CONFIG_MCP_SERVER mcp_json.c)