mcp-c

mcp server frarmwork written in c, developing efficiently and effortlessly utilize annotate to generate code automatically, only need to focus on what to need to write mcp server function

how to use

1. write your own mcp tools under src/mcp_server
   • add attributes EXPORT and EXPORT_AS(name) to the functions and structs you want to use
2. build the project, cmake -B build -S . && cmake --build ., export.cpp will generate all the tedious code for you(like tools list, bridge json to struct, etc.)
3. run the project, ./mcpc

quick start

1. prerequisites

• vcpkg(only for windows)
• cmake
• clang
• cJSON

2. build the project windows

cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON ^
    -DCMAKE_TOOLCHAIN_FILE="path/to/vcpkg/scripts/buildsystems/vcpkg.cmake" ^
    -G "Ninja" ^
    -DVCPKG_APPLOCAL_DEPS=ON ^
    -DCMAKE_BUILD_TYPE=Release ^
    -B build -S . 

3. run the project

./mcpc

supported feature

1. export struct first you need to add the macro to the struct consider this file name struct.c

#include "export_macro.h" //first include the export macro
typedef enum EXPORT COLOR {
    RED,
    GREEN,
    BLUE
} COLOR;

typedef struct EXPORT_AS(cloth) cloth {
    enum COLOR color DES("color of the cloth");
    int size;
} cloth;

typedef struct EXPORT person {
    bool isMale DES("whether is male or not male is true");
    int age DES("age of the person");
    char* name;
    cloth wearing_cloths;
} person;

after you execute export.exe struct.c this will generate the serialize code under the src folder generated_bridge_code.c contained the code to parse a json to object generated_function_signatures.c contained the code of definition of the struct

the above code sample will generate a get_all_function_signatures_json function to generate definition json like the following

{
        "$defs":        {
                "COLOR":        {
                        "type": "integer",
                        "enum": ["RED", "GREEN", "BLUE"]
                },
                "cloth":        {
                        "type": "object",
                        "properties":   {
                                "color":        {
                                        "$ref": "#/$defs/COLOR",
                                        "description":  "color of the cloth"
                                },
                                "size": {
                                        "type": "integer"
                                }
                        },
                        "required":     ["color", "size"]
                },
                "person":       {
                        "type": "object",
                        "properties":   {
                                "isMale":       {
                                        "type": "boolean",
                                        "description":  "whether is male or not male is true"
                                },
                                "age":  {
                                        "type": "integer",
                                        "description":  "age of the person"
                                },
                                "name": {
                                        "type": "string"
                                },
                                "wearing_cloths":       {
                                        "$ref": "#/$defs/cloth"
                                }
                        },
                        "required":     ["isMale", "age", "name", "wearing_cloths"]
                }
        },
        "tools":[]
}

2. export function signature and struct via annotate

first you need to add the macro for functions and struct you need to export consider this file name func.c

#include "export_macro.h" //first include the export macro
... //struct definition here, with the code sample in section 1
EXPORT_AS(get_color) //if the function is a handler of tool "get_color", you need to add this macro
cJSON* get_color(COLOR c)
{

}

EXPORT_AS(get_person_info) //if the function is a handler of tool "get_person_info", you need to add this macro
cJSON* get_person_info(person* p, int id)
{

}

EXPORT_AS(tools, list) // if the function is a handler of tool "tools/list", you need to add this macro, use the comma to separate the tool name and the function name
cJSON* tools_list() {
    int i = 0;
    return get_all_function_signatures_json();
}

this will generate a get_all_function_signatures_json function which will return the following function signature json

{
   "#def": { ... } // param type defition here
   "tools":        [{
                        "name": "tools/list",
                        "description":  "",
                        "inputSchema":  {
                                "type": "object",
                                "properties":   {
                                },
                                "required":     [],
                                "additionalProperties": false,
                                "$schema":      "http://json-schema.org/draft-07/schema#"
                        }
                }, {
                        "name": "get_color",
                        "description":  "",
                        "inputSchema":  {
                                "type": "object",
                                "properties":   {
                                        "c":    {
                                                "$ref": "#/$defs/COLOR"
                                        }
                                },
                                "required":     ["c"],
                                "additionalProperties": false,
                                "$schema":      "http://json-schema.org/draft-07/schema#"
                        }
                }, {
                        "name": "get_person_info",
                        "description":  "",
                        "inputSchema":  {
                                "type": "object",
                                "properties":   {
                                        "p":    {
                                                "$ref": "#/$defs/person"
                                        },
                                        "id":   {
                                                "type": "integer"
                                        }
                                },
                                "required":     ["p", "id"],
                                "additionalProperties": false,
                                "$schema":      "http://json-schema.org/draft-07/schema#"
                        }
     }]
}

3. use EXPORT for short