Model Context Protocol in OCaml
anil.recoil.org
1(** MCP - Model Context Protocol implementation *)
2
3open Jsonrpc
4
5(** Common types *)
6
7(** Roles for conversation participants *)
8module Role : sig
9 type t = [ `User | `Assistant ]
10 include Json.Jsonable.S with type t := t
11end
12
13(** Progress tokens for long-running operations *)
14module ProgressToken : sig
15 type t = [ `String of string | `Int of int ]
16 include Json.Jsonable.S with type t := t
17end
18
19(** Request IDs *)
20module RequestId : sig
21 type t = [ `String of string | `Int of int ]
22 include Json.Jsonable.S with type t := t
23end
24
25(** Cursors for pagination *)
26module Cursor : sig
27 type t = string
28 include Json.Jsonable.S with type t := t
29end
30
31(** Annotations for objects *)
32module Annotated : sig
33 type t = {
34 annotations: annotation option;
35 }
36 and annotation = {
37 audience: Role.t list option;
38 priority: float option;
39 }
40 include Json.Jsonable.S with type t := t
41end
42
43(** Text content *)
44module TextContent : sig
45 type t = {
46 text: string;
47 annotations: Annotated.annotation option;
48 }
49 include Json.Jsonable.S with type t := t
50end
51
52(** Image content *)
53module ImageContent : sig
54 type t = {
55 data: string;
56 mime_type: string;
57 annotations: Annotated.annotation option;
58 }
59 include Json.Jsonable.S with type t := t
60end
61
62(** Audio content *)
63module AudioContent : sig
64 type t = {
65 data: string;
66 mime_type: string;
67 annotations: Annotated.annotation option;
68 }
69 include Json.Jsonable.S with type t := t
70end
71
72(** Base resource contents *)
73module ResourceContents : sig
74 type t = {
75 uri: string;
76 mime_type: string option;
77 }
78 include Json.Jsonable.S with type t := t
79end
80
81(** Text resource contents *)
82module TextResourceContents : sig
83 type t = {
84 uri: string;
85 text: string;
86 mime_type: string option;
87 }
88 include Json.Jsonable.S with type t := t
89end
90
91(** Binary resource contents *)
92module BlobResourceContents : sig
93 type t = {
94 uri: string;
95 blob: string;
96 mime_type: string option;
97 }
98 include Json.Jsonable.S with type t := t
99end
100
101(** Embedded resource *)
102module EmbeddedResource : sig
103 type t = {
104 resource: [ `Text of TextResourceContents.t | `Blob of BlobResourceContents.t ];
105 annotations: Annotated.annotation option;
106 }
107 include Json.Jsonable.S with type t := t
108end
109
110(** Content type used in messages *)
111type content =
112 | Text of TextContent.t
113 | Image of ImageContent.t
114 | Audio of AudioContent.t
115 | Resource of EmbeddedResource.t
116
117val yojson_of_content : content -> Json.t
118val content_of_yojson : Json.t -> content
119
120(** Message for prompts *)
121module PromptMessage : sig
122 type t = {
123 role: Role.t;
124 content: content;
125 }
126 include Json.Jsonable.S with type t := t
127end
128
129(** Message for sampling *)
130module SamplingMessage : sig
131 type t = {
132 role: Role.t;
133 content: [ `Text of TextContent.t | `Image of ImageContent.t | `Audio of AudioContent.t ];
134 }
135 include Json.Jsonable.S with type t := t
136end
137
138(** Implementation information *)
139module Implementation : sig
140 type t = {
141 name: string;
142 version: string;
143 }
144 include Json.Jsonable.S with type t := t
145end
146
147(** JSONRPC message types *)
148module JSONRPCMessage : sig
149 type notification = {
150 method_: string;
151 params: Json.t option;
152 }
153
154 type request = {
155 id: RequestId.t;
156 method_: string;
157 params: Json.t option;
158 progress_token: ProgressToken.t option;
159 }
160
161 type response = {
162 id: RequestId.t;
163 result: Json.t;
164 }
165
166 type error = {
167 id: RequestId.t;
168 code: int;
169 message: string;
170 data: Json.t option;
171 }
172
173 type t =
174 | Notification of notification
175 | Request of request
176 | Response of response
177 | Error of error
178
179 val yojson_of_notification : notification -> Json.t
180 val yojson_of_request : request -> Json.t
181 val yojson_of_response : response -> Json.t
182 val yojson_of_error : error -> Json.t
183 val yojson_of_t : t -> Json.t
184
185 val notification_of_yojson : Json.t -> notification
186 val request_of_yojson : Json.t -> request
187 val response_of_yojson : Json.t -> response
188 val error_of_yojson : Json.t -> error
189 val t_of_yojson : Json.t -> t
190
191 val create_notification : ?params:Json.t option -> method_:string -> unit -> t
192 val create_request : ?params:Json.t option -> ?progress_token:ProgressToken.t option -> id:RequestId.t -> method_:string -> unit -> t
193 val create_response : id:RequestId.t -> result:Json.t -> t
194 val create_error : id:RequestId.t -> code:int -> message:string -> ?data:Json.t option -> unit -> t
195end
196
197(** Initialize request/response *)
198module Initialize : sig
199 (** Initialize request *)
200 module Request : sig
201 type t = {
202 capabilities: Json.t; (** ClientCapabilities *)
203 client_info: Implementation.t;
204 protocol_version: string;
205 }
206 include Json.Jsonable.S with type t := t
207
208 val create : capabilities:Json.t -> client_info:Implementation.t -> protocol_version:string -> t
209 val to_jsonrpc : id:RequestId.t -> t -> JSONRPCMessage.t
210 end
211
212 (** Initialize result *)
213 module Result : sig
214 type t = {
215 capabilities: Json.t; (** ServerCapabilities *)
216 server_info: Implementation.t;
217 protocol_version: string;
218 instructions: string option;
219 meta: Json.t option;
220 }
221 include Json.Jsonable.S with type t := t
222
223 val create : capabilities:Json.t -> server_info:Implementation.t -> protocol_version:string -> ?instructions:string -> ?meta:Json.t -> unit -> t
224 val to_jsonrpc : id:RequestId.t -> t -> JSONRPCMessage.t
225 end
226end
227
228(** Initialized notification *)
229module Initialized : sig
230 module Notification : sig
231 type t = {
232 meta: Json.t option;
233 }
234 include Json.Jsonable.S with type t := t
235
236 val create : ?meta:Json.t -> unit -> t
237 val to_jsonrpc : t -> JSONRPCMessage.t
238 end
239end
240
241(** Parse a JSON message into an MCP message *)
242val parse_message : Json.t -> JSONRPCMessage.t
243
244(** Create JSONRPC message helpers *)
245val create_notification : ?params:Json.t option -> method_:string -> unit -> JSONRPCMessage.t
246val create_request : ?params:Json.t option -> ?progress_token:ProgressToken.t option -> id:RequestId.t -> method_:string -> unit -> JSONRPCMessage.t
247val create_response : id:RequestId.t -> result:Json.t -> JSONRPCMessage.t
248val create_error : id:RequestId.t -> code:int -> message:string -> ?data:Json.t option -> unit -> JSONRPCMessage.t