| 1 | /** |
| 2 | * Builds Model Context Protocol (MCP) servers with Effect. |
| 3 | * |
| 4 | * The `McpServer` service stores the tools, resources, resource templates, |
| 5 | * prompts, completions, and outgoing notifications exposed by a server. This |
| 6 | * module also includes the server runner, custom protocol, |
| 7 | * stdio, and HTTP layers, registration helpers, and APIs that let handlers ask |
| 8 | * the connected client for structured input or read its advertised |
| 9 | * capabilities. |
| 10 | * |
| 11 | * @stability unstable |
| 12 | * @since 4.0.0 |
| 13 | */ |
| 14 | import * as Arr from "../Array.ts" |
| 15 | import * as Cause from "../Cause.ts" |
| 16 | import * as Context from "../Context.ts" |
| 17 | import * as Data from "../Data.ts" |
| 18 | import * as Deferred from "../Deferred.ts" |
| 19 | import * as Effect from "../Effect.ts" |
| 20 | import * as ErrorReporter from "../ErrorReporter.ts" |
| 21 | import * as Exit from "../Exit.ts" |
| 22 | import * as Fiber from "../Fiber.ts" |
| 23 | import * as FindMyWay from "../http/FindMyWay.ts" |
| 24 | import * as Headers from "../http/Headers.ts" |
| 25 | import { appendPreResponseHandlerUnsafe } from "../http/HttpEffect.ts" |
| 26 | import * as HttpRouter from "../http/HttpRouter.ts" |
| 27 | import * as HttpServerRequest from "../http/HttpServerRequest.ts" |
| 28 | import * as HttpServerResponse from "../http/HttpServerResponse.ts" |
| 29 | import type * as JsonSchema from "../JsonSchema.ts" |
| 30 | import * as Layer from "../Layer.ts" |
| 31 | import * as Option from "../Option.ts" |
| 32 | import * as Predicate from "../Predicate.ts" |
| 33 | import * as PubSub from "../PubSub.ts" |
| 34 | import * as Queue from "../Queue.ts" |
| 35 | import * as RcMap from "../RcMap.ts" |
| 36 | import { CurrentLogLevel, Scheduler } from "../References.ts" |
| 37 | import * as Result from "../Result.ts" |
| 38 | import * as Rpc from "../rpc/Rpc.ts" |
| 39 | import * as RpcClient from "../rpc/RpcClient.ts" |
| 40 | import type * as RpcGroup from "../rpc/RpcGroup.ts" |
| 41 | import * as RpcMessage from "../rpc/RpcMessage.ts" |
| 42 | import * as RpcSerialization from "../rpc/RpcSerialization.ts" |
| 43 | import * as RpcServer from "../rpc/RpcServer.ts" |
| 44 | import * as Schema from "../Schema.ts" |
| 45 | import * as SchemaAST from "../SchemaAST.ts" |
| 46 | import * as Scope from "../Scope.ts" |
| 47 | import type { Stdio } from "../Stdio.ts" |
| 48 | import * as Stream from "../Stream.ts" |
| 49 | import * as AiError from "./AiError.ts" |
| 50 | import * as McpCore from "./internal/mcpCore.ts" |
| 51 | import * as McpProtocolInternal from "./internal/mcpProtocol.ts" |
| 52 | import * as McpRuntime from "./internal/mcpRuntime.ts" |
| 53 | import * as InternalStructuredOutput from "./internal/structured-output.ts" |
| 54 | import type * as McpProtocol from "./McpProtocol.ts" |
| 55 | import * as McpSchema from "./McpSchema.ts" |
| 56 | import { |
| 57 | CallToolResult, |
| 58 | ElicitationDeclined, |
| 59 | EnabledWhen, |
| 60 | GetPromptResult, |
| 61 | InternalError, |
| 62 | InvalidParams, |
| 63 | InvalidRequest, |
| 64 | isParam, |
| 65 | McpRequestContext, |
| 66 | McpServerClient, |
| 67 | McpServerClientMiddleware, |
| 68 | MethodNotFound, |
| 69 | Prompt, |
| 70 | Resource, |
| 71 | ResourceTemplate, |
| 72 | ServerNotificationRpcs, |
| 73 | TextContent, |
| 74 | Tool as McpTool, |
| 75 | ToolJson |
| 76 | } from "./McpSchema.ts" |
| 77 | import type { |
| 78 | CallTool, |
| 79 | ClientCapabilities, |
| 80 | Complete, |
| 81 | CompleteResult, |
| 82 | GetPrompt, |
| 83 | McpErrorBase, |
| 84 | Param, |
| 85 | PromptArgument, |
| 86 | PromptMessage, |
| 87 | ReadResourceResult, |
| 88 | ServerCapabilities |
| 89 | } from "./McpSchema.ts" |
| 90 | import * as Tool from "./Tool.ts" |
| 91 | import * as Toolkit from "./Toolkit.ts" |
| 92 | |
| 93 | type CompletionContext = typeof Complete.payloadSchema.Type["context"] |
| 94 | |
| 95 | interface QueuedServerNotification { |
| 96 | readonly notification: McpCore.ServerNotification |
| 97 | readonly targetClientId?: number | undefined |
| 98 | readonly delivered: Deferred.Deferred<void> |
| 99 | readonly requestContext?: McpRequestContext["Service"] | undefined |
| 100 | readonly requestHeaders?: Headers.Headers | undefined |
| 101 | } |
| 102 | |
| 103 | const internalState = new WeakMap<object, { |
| 104 | readonly core: McpCore.McpCore |
| 105 | readonly notifications: Queue.Dequeue<QueuedServerNotification> |
| 106 | readonly notificationDelivery: { consumers: number } |
| 107 | }>() |
| 108 | type ServerExtensions = NonNullable<ServerCapabilities["extensions"]> |
| 109 | type ServerNotificationRequest< |
| 110 | R extends Rpc.Any = RpcGroup.Rpcs<typeof BroadcastServerNotificationRpcs> |
| 111 | > = R extends Rpc.Any ? RpcMessage.Request<R> : never |
| 112 | |
| 113 | const BroadcastServerNotificationRpcs = ServerNotificationRpcs.omit("notifications/elicitation/complete") |
| 114 | const isLoggingLevel = Schema.is(McpSchema.LoggingLevel) |
| 115 | |
| 116 | const toInternalServerNotification = ( |
| 117 | message: ServerNotificationRequest |
| 118 | ): McpCore.ServerNotification | undefined => { |
| 119 | switch (message.tag) { |
| 120 | case "notifications/cancelled": |
| 121 | return McpCore.ServerNotification.Cancelled({ |
| 122 | requestId: message.payload.requestId, |
| 123 | reason: message.payload.reason, |
| 124 | metadata: message.payload._meta |
| 125 | }) |
| 126 | case "notifications/progress": |
| 127 | return McpCore.ServerNotification.Progress({ |
| 128 | progressToken: message.payload.progressToken, |
| 129 | progress: message.payload.progress, |
| 130 | total: message.payload.total, |
| 131 | message: message.payload.message, |
| 132 | metadata: message.payload._meta |
| 133 | }) |
| 134 | case "notifications/message": |
| 135 | return McpCore.ServerNotification.LoggingMessage({ |
| 136 | level: message.payload.level, |
| 137 | logger: message.payload.logger, |
| 138 | data: message.payload.data, |
| 139 | metadata: message.payload._meta |
| 140 | }) |
| 141 | case "notifications/resources/updated": |
| 142 | return McpCore.ServerNotification.ResourceUpdated({ |
| 143 | uri: message.payload.uri, |
| 144 | metadata: message.payload._meta |
| 145 | }) |
| 146 | case "notifications/resources/list_changed": |
| 147 | return McpCore.ServerNotification.ResourcesChanged({ metadata: message.payload?._meta }) |
| 148 | case "notifications/tools/list_changed": |
| 149 | return McpCore.ServerNotification.ToolsChanged({ metadata: message.payload?._meta }) |
| 150 | case "notifications/prompts/list_changed": |
| 151 | return McpCore.ServerNotification.PromptsChanged({ metadata: message.payload?._meta }) |
| 152 | default: |
| 153 | return undefined |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | // Request services must come from the invocation, including when a handler is registered during a request. |
| 158 | const omitRequestServices = Context.omit( |
| 159 | McpRequestContext, |
| 160 | McpServerClient, |
| 161 | HttpServerRequest.HttpServerRequest, |
| 162 | CurrentLogLevel |
| 163 | ) |
| 164 | |
| 165 | const provideInvocationContext = <A, E, R>( |
| 166 | effect: Effect.Effect<A, E, R>, |
| 167 | invocation: McpCore.McpInvocation |
| 168 | ): Effect.Effect<A, E, Exclude<R, McpRequestContext>> => { |
| 169 | let provided = Effect.provideService(effect, McpRequestContext, invocation.requestContext) |
| 170 | const requestMetadata = invocation.requestContext.requestMetadata |
| 171 | const logLevel = Predicate.hasProperty(requestMetadata, "io.modelcontextprotocol/logLevel") |
| 172 | ? requestMetadata["io.modelcontextprotocol/logLevel"] |
| 173 | : undefined |
| 174 | if (isLoggingLevel(logLevel)) { |
| 175 | provided = Effect.provideService( |
| 176 | provided, |
| 177 | CurrentLogLevel, |
| 178 | McpProtocolInternal.mcpLogLevels[logLevel].effect |
| 179 | ) |
| 180 | } |
| 181 | return (invocation.serverClient === undefined |
| 182 | ? provided |
| 183 | : Effect.provideService(provided, McpServerClient, invocation.serverClient)) as Effect.Effect< |
| 184 | A, |
| 185 | E, |
| 186 | Exclude<R, McpRequestContext> |
| 187 | > |
| 188 | } |
| 189 | |
| 190 | /** |
| 191 | * Service that stores and serves an MCP server's registered tools, resources, |
| 192 | * prompts, completions, and outgoing notifications. |
| 193 | * |
| 194 | * **Details** |
| 195 | * |
| 196 | * Handlers use this service to register capabilities and resolve incoming MCP |
| 197 | * requests. |
| 198 | * |
| 199 | * @stability unstable |
| 200 | * @category services |
| 201 | * @since 4.0.0 |
| 202 | */ |
| 203 | export class McpServer extends Context.Service<McpServer, { |
| 204 | readonly notifications: RpcClient.RpcClient<RpcGroup.Rpcs<typeof BroadcastServerNotificationRpcs>> |
| 205 | readonly notifyElicitationComplete: (options: { |
| 206 | readonly clientId: number |
| 207 | readonly elicitationId: string |
| 208 | }) => Effect.Effect<void> |
| 209 | readonly tools: ReadonlyArray<{ |
| 210 | readonly tool: McpTool |
| 211 | readonly annotations: Context.Context<never> |
| 212 | }> |
| 213 | readonly addTool: (options: { |
| 214 | readonly tool: McpTool |
| 215 | readonly annotations: Context.Context<never> |
| 216 | readonly handle: ( |
| 217 | payload: any |
| 218 | ) => Effect.Effect< |
| 219 | CallToolResult | McpSchema.InputRequired, |
| 220 | InternalError | InvalidParams, |
| 221 | McpRequestContext |
| 222 | > |
| 223 | }) => Effect.Effect<void> |
| 224 | readonly callTool: ( |
| 225 | requests: typeof CallTool.payloadSchema.Type |
| 226 | ) => Effect.Effect<CallToolResult, InternalError | InvalidParams, McpServerClient> |
| 227 | |
| 228 | readonly resources: ReadonlyArray<{ |
| 229 | readonly resource: Resource |
| 230 | readonly annotations: Context.Context<never> |
| 231 | }> |
| 232 | readonly addResource: (options: { |
| 233 | readonly resource: Resource |
| 234 | readonly annotations: Context.Context<never> |
| 235 | readonly handle: Effect.Effect< |
| 236 | ReadResourceResult, |
| 237 | InternalError, |
| 238 | McpRequestContext |
| 239 | > |
| 240 | }) => Effect.Effect<void> |
| 241 | |
| 242 | readonly resourceTemplates: ReadonlyArray<{ |
| 243 | readonly template: ResourceTemplate |
| 244 | readonly annotations: Context.Context<never> |
| 245 | }> |
| 246 | readonly addResourceTemplate: ( |
| 247 | options: { |
| 248 | readonly template: ResourceTemplate |
| 249 | readonly annotations: Context.Context<never> |
| 250 | readonly routerPath: string |
| 251 | readonly completions: Record< |
| 252 | string, |
| 253 | ( |
| 254 | input: string, |
| 255 | context: CompletionContext |
| 256 | ) => Effect.Effect<CompleteResult, InternalError> |
| 257 | > |
| 258 | readonly handle: ( |
| 259 | uri: string, |
| 260 | params: Array<string> |
| 261 | ) => Effect.Effect< |
| 262 | ReadResourceResult, |
| 263 | InvalidParams | InternalError, |
| 264 | McpRequestContext |
| 265 | > |
| 266 | } |
| 267 | ) => Effect.Effect<void> |
| 268 | |
| 269 | readonly findResource: ( |
| 270 | uri: string |
| 271 | ) => Effect.Effect<ReadResourceResult, McpErrorBase | InvalidParams | InternalError, McpServerClient> |
| 272 | |
| 273 | readonly prompts: ReadonlyArray<{ |
| 274 | readonly prompt: Prompt |
| 275 | readonly annotations: Context.Context<never> |
| 276 | }> |
| 277 | readonly addPrompt: (options: { |
| 278 | readonly prompt: Prompt |
| 279 | readonly annotations: Context.Context<never> |
| 280 | readonly completions: Record< |
| 281 | string, |
| 282 | ( |
| 283 | input: string, |
| 284 | context: CompletionContext |
| 285 | ) => Effect.Effect<CompleteResult, InternalError, McpRequestContext> |
| 286 | > |
| 287 | readonly handle: ( |
| 288 | params: Record<string, string> |
| 289 | ) => Effect.Effect<GetPromptResult | McpSchema.InputRequired, InternalError | InvalidParams, McpRequestContext> |
| 290 | }) => Effect.Effect<void> |
| 291 | readonly getPromptResult: ( |
| 292 | request: typeof GetPrompt.payloadSchema.Type |
| 293 | ) => Effect.Effect<GetPromptResult, InternalError | InvalidParams, McpServerClient> |
| 294 | |
| 295 | readonly completion: ( |
| 296 | complete: typeof Complete.payloadSchema.Type |
| 297 | ) => Effect.Effect<CompleteResult, InvalidParams | InternalError, McpServerClient> |
| 298 | }>()("effect/ai/McpServer") { |
| 299 | /** |
| 300 | * Builds an MCP server service from registered tools, prompts, resources, and completions. |
| 301 | * |
| 302 | * @stability unstable |
| 303 | * @since 4.0.0 |
| 304 | */ |
| 305 | static readonly make = Effect.gen(function*() { |
| 306 | const internalCore = yield* McpCore.make |
| 307 | const tools = Arr.empty<{ |
| 308 | readonly tool: McpTool |
| 309 | readonly annotations: Context.Context<never> |
| 310 | }>() |
| 311 | const resources: Array<{ |
| 312 | readonly resource: Resource |
| 313 | readonly annotations: Context.Context<never> |
| 314 | }> = [] |
| 315 | const resourceTemplates: Array<{ |
| 316 | readonly template: ResourceTemplate |
| 317 | readonly annotations: Context.Context<never> |
| 318 | }> = [] |
| 319 | const prompts: Array<{ |
| 320 | readonly prompt: Prompt |
| 321 | readonly annotations: Context.Context<never> |
| 322 | }> = [] |
| 323 | const notificationsQueue = yield* Queue.make<QueuedServerNotification>() |
| 324 | const notificationDelivery = { consumers: 0 } |
| 325 | const pendingListChanges = new Set<string>() |
| 326 | const dispatcher = (yield* Scheduler).makeDispatcher() |
| 327 | const notifications = yield* RpcClient.makeNoSerialization(BroadcastServerNotificationRpcs, { |
| 328 | spanPrefix: "McpServer/Notifications", |
| 329 | onFromClient: (options) => |
| 330 | Deferred.make<void>().pipe(Effect.flatMap((delivered) => |
| 331 | Effect.withFiber((fiber): Effect.Effect<void> => { |
| 332 | const message = options.message |
| 333 | if (message._tag !== "Request") { |
| 334 | return Effect.void |
| 335 | } |
| 336 | const notification = toInternalServerNotification(message) |
| 337 | if (notification === undefined) { |
| 338 | return Effect.void |
| 339 | } |
| 340 | const queued = { |
| 341 | notification, |
| 342 | delivered, |
| 343 | requestContext: Context.getOrUndefined(fiber.context, McpRequestContext), |
| 344 | requestHeaders: Context.getOrUndefined(fiber.context, HttpServerRequest.HttpServerRequest)?.headers |
| 345 | } |
| 346 | let enqueued = false |
| 347 | if (message.tag.includes("list_changed")) { |
| 348 | if (!pendingListChanges.has(message.tag)) { |
| 349 | enqueued = true |
| 350 | const tag = message.tag |
| 351 | dispatcher.scheduleTask(() => { |
| 352 | Queue.offerUnsafe(notificationsQueue, queued) |
| 353 | pendingListChanges.delete(message.tag) |
| 354 | }, 0) |
| 355 | pendingListChanges.add(tag) |
| 356 | } |
| 357 | } else { |
| 358 | enqueued = true |
| 359 | Queue.offerUnsafe(notificationsQueue, queued) |
| 360 | } |
| 361 | // write resumes the caller synchronously, so defer it until delivery completes. |
| 362 | const acknowledge = Effect.suspend(() => |
| 363 | notifications.write({ |
| 364 | clientId: 0, |
| 365 | requestId: message.id, |
| 366 | _tag: "Exit", |
| 367 | exit: Exit.void |
| 368 | }) |
| 369 | ) |
| 370 | return enqueued && queued.requestContext !== undefined && notificationDelivery.consumers > 0 |
| 371 | ? Effect.andThen(Deferred.await(delivered), acknowledge) |
| 372 | : acknowledge |
| 373 | }) |
| 374 | )) |
| 375 | }) |
| 376 | |
| 377 | const service = McpServer.of({ |
| 378 | notifications: notifications.client, |
| 379 | notifyElicitationComplete: ({ clientId, elicitationId }) => |
| 380 | Deferred.make<void>().pipe( |
| 381 | Effect.flatMap((delivered) => |
| 382 | Queue.offer(notificationsQueue, { |
| 383 | notification: McpCore.ServerNotification.ElicitationComplete({ elicitationId }), |
| 384 | targetClientId: clientId, |
| 385 | delivered |
| 386 | }).pipe( |
| 387 | Effect.andThen( |
| 388 | Effect.suspend(() => notificationDelivery.consumers > 0 ? Deferred.await(delivered) : Effect.void) |
| 389 | ) |
| 390 | ) |
| 391 | ) |
| 392 | ), |
| 393 | get tools() { |
| 394 | return tools |
| 395 | }, |
| 396 | addTool: (options) => |
| 397 | Effect.gen(function*() { |
| 398 | const existingIndex = tools.findIndex(({ tool }) => tool.name === options.tool.name) |
| 399 | if (existingIndex === -1) { |
| 400 | tools.push(options) |
| 401 | } else { |
| 402 | tools[existingIndex] = options |
| 403 | } |
| 404 | const enabledWhen = Context.getOrUndefined(options.annotations, EnabledWhen) |
| 405 | yield* internalCore.tools.register({ |
| 406 | descriptor: new McpTool({ |
| 407 | ...options.tool, |
| 408 | title: options.tool.title ?? options.tool.annotations?.title |
| 409 | }), |
| 410 | isVisible: (profile) => |
| 411 | enabledWhen === undefined || enabledWhen( |
| 412 | { |
| 413 | protocolVersion: profile.protocolVersion, |
| 414 | capabilities: profile.clientCapabilities, |
| 415 | clientInfo: profile.clientInfo |
| 416 | } |
| 417 | ), |
| 418 | handle: (call, invocation) => |
| 419 | provideInvocationContext(options.handle(call.arguments), invocation).pipe( |
| 420 | Effect.catchTags({ |
| 421 | InternalError: (error) => |
| 422 | Effect.fail( |
| 423 | new McpCore.ToolExecutionError({ |
| 424 | name: options.tool.name, |
| 425 | message: error.message |
| 426 | }) |
| 427 | ), |
| 428 | InvalidParams: (error) => |
| 429 | Effect.fail( |
| 430 | new (invocation.requestContext.requestState === undefined && |
| 431 | invocation.requestContext.inputResponses === undefined |
| 432 | ? McpCore.InvalidToolInput |
| 433 | : McpCore.InvalidToolContinuation)({ |
| 434 | name: options.tool.name, |
| 435 | message: error.message |
| 436 | }) |
| 437 | ) |
| 438 | }), |
| 439 | Effect.map((result) => |
| 440 | Predicate.isTagged(result, "InputRequired") |
| 441 | ? McpCore.OperationOutcome.InputRequired(result) |
| 442 | : McpCore.OperationOutcome.Complete(result) |
| 443 | ) |
| 444 | ) |
| 445 | }) |
| 446 | yield* notifications.client["notifications/tools/list_changed"]({}) |
| 447 | }), |
| 448 | callTool: (request) => |
| 449 | Effect.gen(function*() { |
| 450 | const client = yield* McpServerClient |
| 451 | const result = yield* internalCore.tools.call( |
| 452 | request, |
| 453 | McpProtocolInternal.invocationFromClient(client) |
| 454 | ).pipe( |
| 455 | Effect.mapError((error) => |
| 456 | new InvalidParams({ |
| 457 | message: error._tag === "ToolNotFound" |
| 458 | ? `Tool '${error.name}' not found` |
| 459 | : error.message |
| 460 | }) |
| 461 | ) |
| 462 | ) |
| 463 | if (result._tag === "InputRequired") { |
| 464 | return yield* new InvalidParams({ message: "Client input is not supported by this MCP protocol" }) |
| 465 | } |
| 466 | return result.value |
| 467 | }), |
| 468 | get resources() { |
| 469 | return resources |
| 470 | }, |
| 471 | get resourceTemplates() { |
| 472 | return resourceTemplates |
| 473 | }, |
| 474 | addResource: (options) => |
| 475 | Effect.gen(function*() { |
| 476 | const existingIndex = resources.findIndex(({ resource }) => resource.uri === options.resource.uri) |
| 477 | if (existingIndex === -1) { |
| 478 | resources.push(options) |
| 479 | } else { |
| 480 | resources[existingIndex] = options |
| 481 | } |
| 482 | yield* internalCore.resources.register({ |
| 483 | descriptor: options.resource, |
| 484 | isVisible: (profile) => { |
| 485 | const enabledWhen = Context.getOrUndefined(options.annotations, EnabledWhen) |
| 486 | return enabledWhen === undefined || enabledWhen({ |
| 487 | protocolVersion: profile.protocolVersion, |
| 488 | capabilities: profile.clientCapabilities, |
| 489 | clientInfo: profile.clientInfo |
| 490 | }) |
| 491 | }, |
| 492 | read: (invocation) => provideInvocationContext(options.handle, invocation) |
| 493 | }) |
| 494 | yield* notifications.client["notifications/resources/list_changed"]({}) |
| 495 | }), |
| 496 | addResourceTemplate: ({ annotations, completions, handle, routerPath, template }) => |
| 497 | Effect.gen(function*() { |
| 498 | const existingIndex = resourceTemplates.findIndex(({ template: current }) => |
| 499 | current.uriTemplate === template.uriTemplate |
| 500 | ) |
| 501 | if (existingIndex === -1) { |
| 502 | resourceTemplates.push({ template, annotations }) |
| 503 | } else { |
| 504 | resourceTemplates[existingIndex] = { template, annotations } |
| 505 | } |
| 506 | const templateMatcher = makeUriMatcher<true>() |
| 507 | templateMatcher.add(routerPath, true) |
| 508 | yield* internalCore.resources.registerTemplate({ |
| 509 | descriptor: template, |
| 510 | isVisible: (profile) => { |
| 511 | const enabledWhen = Context.getOrUndefined(annotations, EnabledWhen) |
| 512 | return enabledWhen === undefined || enabledWhen({ |
| 513 | protocolVersion: profile.protocolVersion, |
| 514 | capabilities: profile.clientCapabilities, |
| 515 | clientInfo: profile.clientInfo |
| 516 | }) |
| 517 | }, |
| 518 | match: (uri) => { |
| 519 | const match = templateMatcher.find(uri) |
| 520 | if (match === undefined) { |
| 521 | return undefined |
| 522 | } |
| 523 | const params: Array<string> = [] |
| 524 | for (const key of Object.keys(match.params)) { |
| 525 | params[Number(key)] = match.params[key]! |
| 526 | } |
| 527 | return params |
| 528 | }, |
| 529 | read: (uri, params, invocation) => provideInvocationContext(handle(uri, Array.from(params)), invocation) |
| 530 | }) |
| 531 | for (const [param, handle] of Object.entries(completions)) { |
| 532 | yield* internalCore.completions.register( |
| 533 | `resource/${template.uriTemplate}/${param}`, |
| 534 | (request, invocation) => |
| 535 | provideInvocationContext(handle(request.argument.value, request.context), invocation).pipe( |
| 536 | Effect.map((result) => ({ |
| 537 | values: result.completion.values, |
| 538 | total: result.completion.total, |
| 539 | hasMore: result.completion.hasMore, |
| 540 | metadata: result._meta |
| 541 | })) |
| 542 | ) |
| 543 | ) |
| 544 | } |
| 545 | yield* notifications.client["notifications/resources/list_changed"]({}) |
| 546 | }), |
| 547 | findResource: (uri) => |
| 548 | Effect.gen(function*() { |
| 549 | const client = yield* McpServerClient |
| 550 | return yield* internalCore.resources.read( |
| 551 | uri, |
| 552 | McpProtocolInternal.invocationFromClient(client) |
| 553 | ).pipe( |
| 554 | Effect.catchTag("ResourceNotFound", (error) => |
| 555 | Effect.fail(new InvalidParams({ message: `Resource '${error.uri}' not found` }))) |
| 556 | ) |
| 557 | }), |
| 558 | get prompts() { |
| 559 | return prompts |
| 560 | }, |
| 561 | addPrompt: (options) => |
| 562 | Effect.gen(function*() { |
| 563 | const existingIndex = prompts.findIndex(({ prompt }) => prompt.name === options.prompt.name) |
| 564 | if (existingIndex === -1) { |
| 565 | prompts.push(options) |
| 566 | } else { |
| 567 | prompts[existingIndex] = options |
| 568 | } |
| 569 | yield* internalCore.prompts.register({ |
| 570 | descriptor: options.prompt, |
| 571 | isVisible: (profile) => { |
| 572 | const enabledWhen = Context.getOrUndefined(options.annotations, EnabledWhen) |
| 573 | return enabledWhen === undefined || enabledWhen({ |
| 574 | protocolVersion: profile.protocolVersion, |
| 575 | capabilities: profile.clientCapabilities, |
| 576 | clientInfo: profile.clientInfo |
| 577 | }) |
| 578 | }, |
| 579 | get: (params, invocation) => |
| 580 | provideInvocationContext(options.handle(params), invocation).pipe( |
| 581 | Effect.map((result) => |
| 582 | Predicate.isTagged(result, "InputRequired") |
| 583 | ? McpCore.OperationOutcome.InputRequired(result) |
| 584 | : McpCore.OperationOutcome.Complete(result) |
| 585 | ) |
| 586 | ) |
| 587 | }) |
| 588 | for (const [param, handle] of Object.entries(options.completions)) { |
| 589 | yield* internalCore.completions.register( |
| 590 | `prompt/${options.prompt.name}/${param}`, |
| 591 | (request, invocation) => |
| 592 | provideInvocationContext(handle(request.argument.value, request.context), invocation).pipe( |
| 593 | Effect.map((result) => ({ |
| 594 | values: result.completion.values, |
| 595 | total: result.completion.total, |
| 596 | hasMore: result.completion.hasMore, |
| 597 | metadata: result._meta |
| 598 | })) |
| 599 | ) |
| 600 | ) |
| 601 | } |
| 602 | yield* notifications.client["notifications/prompts/list_changed"]({}) |
| 603 | }), |
| 604 | getPromptResult: Effect.fnUntraced(function*({ arguments: params, name }) { |
| 605 | const client = yield* McpServerClient |
| 606 | const outcome = yield* internalCore.prompts.get( |
| 607 | name, |
| 608 | params ?? {}, |
| 609 | McpProtocolInternal.invocationFromClient(client) |
| 610 | ).pipe( |
| 611 | Effect.catchTag("PromptNotFound", () => new InvalidParams({ message: `Prompt '${name}' not found` })) |
| 612 | ) |
| 613 | return outcome._tag === "Complete" |
| 614 | ? outcome.value |
| 615 | : yield* new InvalidParams({ message: "Client input is not supported by this MCP protocol" }) |
| 616 | }), |
| 617 | completion: Effect.fnUntraced(function*(complete) { |
| 618 | const client = yield* McpServerClient |
| 619 | const ref = complete.ref |
| 620 | const result = yield* internalCore.completions.complete({ |
| 621 | reference: ref.type === "ref/resource" |
| 622 | ? { type: "resourceTemplate", uriTemplate: ref.uri } |
| 623 | : { type: "prompt", name: ref.name }, |
| 624 | argument: complete.argument, |
| 625 | context: complete.context |
| 626 | }, McpProtocolInternal.invocationFromClient(client)) |
| 627 | return { |
| 628 | _meta: result.metadata, |
| 629 | completion: { |
| 630 | values: result.values, |
| 631 | total: result.total, |
| 632 | hasMore: result.hasMore |
| 633 | } |
| 634 | } |
| 635 | }) |
| 636 | }) |
| 637 | internalState.set(service, { core: internalCore, notifications: notificationsQueue, notificationDelivery }) |
| 638 | return service |
| 639 | }) |
| 640 | |
| 641 | /** |
| 642 | * Layer that provides the MCP server and client services. |
| 643 | * |
| 644 | * @stability unstable |
| 645 | * @since 4.0.0 |
| 646 | */ |
| 647 | static readonly layer: Layer.Layer<McpServer | McpServerClient> = Layer.effect(McpServer)(McpServer.make) as any |
| 648 | } |
| 649 | |
| 650 | const MCP_SESSION_ID_HEADER = "mcp-session-id" |
| 651 | const MCP_PROTOCOL_VERSION_HEADER = "mcp-protocol-version" |
| 652 | const MCP_INVALID_BATCH_METHOD = "invalid/json-rpc-batch" |
| 653 | const cancelledResponses = new WeakMap<object, string | number>() |
| 654 | const requestKey = (requestId: string | number): string => `${typeof requestId}:${requestId}` |
| 655 | |
| 656 | interface ActiveRequest { |
| 657 | readonly prepared: McpRuntime.PreparedRequest |
| 658 | readonly cancelled: boolean |
| 659 | } |
| 660 | |
| 661 | class McpClientKey extends Data.Class<{ |
| 662 | readonly clientId: number |
| 663 | readonly profile: McpCore.NegotiatedProtocolProfile<string> |
| 664 | }> {} |
| 665 | |
| 666 | /** |
| 667 | * Runs an MCP server over the current `RpcServer.Protocol`. |
| 668 | * |
| 669 | * **Details** |
| 670 | * |
| 671 | * The server serves registered tools, resources, and prompts. The selected MCP |
| 672 | * runtime handles protocol lifecycle state and determines which clients receive |
| 673 | * queued server notifications. |
| 674 | * |
| 675 | * @stability unstable |
| 676 | * @category running |
| 677 | * @since 4.0.0 |
| 678 | */ |
| 679 | export const run: (options: { |
| 680 | readonly name: string |
| 681 | readonly version: string |
| 682 | readonly instructions?: string | undefined |
| 683 | readonly description?: string | undefined |
| 684 | readonly websiteUrl?: string | undefined |
| 685 | readonly icons?: ReadonlyArray<McpSchema.Icon> | undefined |
| 686 | readonly protocols: Arr.NonEmptyReadonlyArray<McpProtocol.ProtocolAdapter> |
| 687 | readonly extensions?: ServerExtensions | undefined |
| 688 | }) => Effect.Effect< |
| 689 | never, |
| 690 | Cause.IllegalArgumentError, |
| 691 | McpServer | RpcServer.Protocol |
| 692 | > = Effect.fnUntraced(function*(options: { |
| 693 | readonly name: string |
| 694 | readonly version: string |
| 695 | readonly instructions?: string | undefined |
| 696 | readonly description?: string | undefined |
| 697 | readonly websiteUrl?: string | undefined |
| 698 | readonly icons?: ReadonlyArray<McpSchema.Icon> | undefined |
| 699 | readonly protocols: Arr.NonEmptyReadonlyArray<McpProtocol.ProtocolAdapter> |
| 700 | readonly extensions?: ServerExtensions | undefined |
| 701 | }) { |
| 702 | const runtimeOption = yield* Effect.serviceOption(McpRuntime.ServerRuntime) |
| 703 | const runtime = Option.isSome(runtimeOption) |
| 704 | ? runtimeOption.value |
| 705 | : yield* McpRuntime.make(options.protocols) |
| 706 | return yield* runWithRuntime(options, runtime, "custom") |
| 707 | }) |
| 708 | |
| 709 | const runWithRuntime = Effect.fnUntraced(function*( |
| 710 | options: { |
| 711 | readonly name: string |
| 712 | readonly version: string |
| 713 | readonly instructions?: string | undefined |
| 714 | readonly description?: string | undefined |
| 715 | readonly websiteUrl?: string | undefined |
| 716 | readonly icons?: ReadonlyArray<McpSchema.Icon> | undefined |
| 717 | readonly extensions?: ServerExtensions | undefined |
| 718 | }, |
| 719 | runtime: McpRuntime.ServerRuntimeShape, |
| 720 | transport: "custom" | "http" | "stdio" |
| 721 | ) { |
| 722 | const protocol = yield* RpcServer.Protocol |
| 723 | const server = yield* McpServer |
| 724 | const defaultLogLevel = yield* CurrentLogLevel |
| 725 | const isHttp = transport === "http" |
| 726 | const clientStates = new Map<number, { |
| 727 | protocol: McpProtocol.AnyProtocolAdapter |
| 728 | profile: McpCore.NegotiatedProtocolProfile<string> | undefined |
| 729 | sessionHeaders: Headers.Headers | undefined |
| 730 | }>() |
| 731 | const activeRequests = new Map<number, Map<string, ActiveRequest>>() |
| 732 | const reverseRequestClients = new Map<string, Array<McpClientKey>>() |
| 733 | const disconnectClient = (clientId: number) => { |
| 734 | activeRequests.delete(clientId) |
| 735 | clientStates.delete(clientId) |
| 736 | runtime.disconnect(clientId) |
| 737 | } |
| 738 | const sendRequestError = (clientId: number, requestId: string | number, error: unknown) => |
| 739 | protocol.send(clientId, { |
| 740 | _tag: "Exit", |
| 741 | requestId, |
| 742 | exit: { _tag: "Failure", cause: [{ _tag: "Fail", error }] } |
| 743 | }) |
| 744 | const removeReverseRequestClient = (requestId: string, key: McpClientKey) => { |
| 745 | const waiting = reverseRequestClients.get(requestId) |
| 746 | if (waiting === undefined) return |
| 747 | const remaining = waiting.filter((entry) => entry !== key) |
| 748 | if (remaining.length === 0) reverseRequestClients.delete(requestId) |
| 749 | else reverseRequestClients.set(requestId, remaining) |
| 750 | } |
| 751 | // A bounded PubSub would let one slow listener block the shared worker and |
| 752 | // legacy delivery. Each request scope releases its subscription on exit. |
| 753 | const serverNotifications = yield* PubSub.unbounded<McpProtocolInternal.CanonicalServerNotification>() |
| 754 | const sendNotification = ( |
| 755 | protocolVersion: string, |
| 756 | clientId: number, |
| 757 | notification: McpProtocol.ProjectedNotification |
| 758 | ) => |
| 759 | Effect.suspend(() => { |
| 760 | const selectedProtocol = runtime.selectProtocol(protocolVersion) |
| 761 | const rpc = selectedProtocol.serverNotificationRpcs.requests.get(notification.tag) |
| 762 | if (rpc === undefined) { |
| 763 | return Effect.die( |
| 764 | `MCP protocol ${protocolVersion} does not define server notification ${notification.tag}` |
| 765 | ) |
| 766 | } |
| 767 | return selectedProtocol.payloadCodecs(rpc).encode(notification.payload).pipe( |
| 768 | Effect.orDie, |
| 769 | Effect.flatMap((payload) => |
| 770 | protocol.send(clientId, { |
| 771 | _tag: "Request", |
| 772 | id: "", |
| 773 | tag: notification.tag, |
| 774 | payload, |
| 775 | headers: [], |
| 776 | isNotification: true |
| 777 | }) |
| 778 | ) |
| 779 | ) |
| 780 | }) |
| 781 | const cancelRequest = (clientId: number, requestId: RpcMessage.RequestId) => { |
| 782 | const requests = activeRequests.get(clientId) |
| 783 | const key = requestKey(requestId) |
| 784 | const request = requests?.get(key) |
| 785 | if (request === undefined) { |
| 786 | return false |
| 787 | } |
| 788 | requests!.set(key, { ...request, cancelled: true }) |
| 789 | return true |
| 790 | } |
| 791 | const terminateSubscription = ( |
| 792 | protocolVersion: string, |
| 793 | clientId: number, |
| 794 | requestId: RpcMessage.RequestId, |
| 795 | reason: string |
| 796 | ): Effect.Effect<void> => |
| 797 | Effect.suspend(() => { |
| 798 | if (!cancelRequest(clientId, requestId)) { |
| 799 | return Effect.void |
| 800 | } |
| 801 | return isHttp |
| 802 | ? protocol.end(clientId) |
| 803 | : sendNotification(protocolVersion, clientId, { |
| 804 | tag: "notifications/cancelled", |
| 805 | payload: { requestId, reason } |
| 806 | }) |
| 807 | }) |
| 808 | const handlers = yield* runtime.installHandlers({ |
| 809 | core: internalState.get(server)!.core, |
| 810 | subscribeServerNotifications: PubSub.subscribe(serverNotifications), |
| 811 | ...(!protocol.supportsNotifications ? {} : { |
| 812 | sendNotification, |
| 813 | markSubscriptionCancelled: (clientId: number, requestId: RpcMessage.RequestId) => |
| 814 | Effect.sync(() => { |
| 815 | cancelRequest(clientId, requestId) |
| 816 | }), |
| 817 | terminateSubscription |
| 818 | }), |
| 819 | defaultLogLevel, |
| 820 | serverInfo: options |
| 821 | }) |
| 822 | |
| 823 | const clients = yield* RcMap.make({ |
| 824 | lookup: Effect.fnUntraced(function*(key: McpClientKey) { |
| 825 | const selectedProtocol = runtime.selectProtocol(key.profile.protocolVersion) |
| 826 | let write!: (message: RpcMessage.FromServerEncoded) => Effect.Effect<void> |
| 827 | const reverseProtocol = yield* RpcClient.Protocol.make(Effect.fnUntraced(function*(writeResponse) { |
| 828 | let cid = 0 |
| 829 | write = (message) => writeResponse(cid, message) |
| 830 | return { |
| 831 | send(id, request, _transferables) { |
| 832 | cid = id |
| 833 | if (request._tag === "Request") { |
| 834 | const requestId = requestKey(request.id) |
| 835 | const waiting = reverseRequestClients.get(requestId) ?? [] |
| 836 | waiting.push(key) |
| 837 | reverseRequestClients.set(requestId, waiting) |
| 838 | return protocol.send(key.clientId, { |
| 839 | _tag: "Request", |
| 840 | id: request.id, |
| 841 | tag: request.tag, |
| 842 | payload: request.payload, |
| 843 | headers: [] |
| 844 | }).pipe(Effect.onError(() => Effect.sync(() => removeReverseRequestClient(requestId, key)))) |
| 845 | } |
| 846 | if (request._tag === "Interrupt") { |
| 847 | // A cancelled reverse request may never receive a reply. |
| 848 | removeReverseRequestClient(requestKey(request.requestId), key) |
| 849 | } |
| 850 | // Ack & co are not part of FromServerEncoded, but the JSON-RPC |
| 851 | // serializer encodes them symmetrically for reverse control flow |
| 852 | return protocol.send(key.clientId, request as any) |
| 853 | }, |
| 854 | supportsAck: true, |
| 855 | supportsTransferables: false, |
| 856 | supportsStructuredClone: false, |
| 857 | codecFor: protocol.codecFor |
| 858 | } |
| 859 | })) |
| 860 | const client = yield* selectedProtocol.makeReverseClient(key.profile).pipe( |
| 861 | Effect.provideService(RpcClient.Protocol, reverseProtocol) |
| 862 | ) |
| 863 | |
| 864 | return { client, write } as const |
| 865 | }), |
| 866 | idleTimeToLive: 10000 |
| 867 | }) |
| 868 | |
| 869 | const clientMiddleware = McpServerClientMiddleware.of((effect, { client, headers, payload, rpc }) => { |
| 870 | const session = runtime.resolveRequest(client.id, headers) |
| 871 | const isInitialize = rpc._tag.endsWith("/initialize") |
| 872 | if (!isInitialize && !session) { |
| 873 | const fiber = Fiber.getCurrent()! |
| 874 | const httpRequest = Context.getOrUndefined(fiber.context, HttpServerRequest.HttpServerRequest) |
| 875 | if (httpRequest) { |
| 876 | appendPreResponseHandlerUnsafe( |
| 877 | httpRequest, |
| 878 | () => |
| 879 | Effect.succeed( |
| 880 | HttpServerResponse.empty({ |
| 881 | status: headers[MCP_SESSION_ID_HEADER] === undefined ? 400 : 404 |
| 882 | }) |
| 883 | ) |
| 884 | ) |
| 885 | } |
| 886 | return Effect.die(new Error(`Mcp-Session-Id does not exist`)) |
| 887 | } |
| 888 | // RPC middleware erases the correlation between the initialize tag |
| 889 | // and its decoded payload. Restore it once after non-initialize requests |
| 890 | // without a session have been rejected above. |
| 891 | const initializePayload = session?.initializePayload ?? payload as typeof McpSchema.Initialize.payloadSchema.Type |
| 892 | const clientState = clientStates.get(client.id) |
| 893 | const selectedProtocol = session?.protocol ?? |
| 894 | clientState?.protocol ?? |
| 895 | runtime.protocolForInternalTag(rpc._tag) |
| 896 | if (!isProtocolVersion(selectedProtocol.protocolVersion) || selectedProtocol.protocolVersion === "2026-07-28") { |
| 897 | return Effect.die(`Unsupported selected MCP protocol version: ${selectedProtocol.protocolVersion}`) |
| 898 | } |
| 899 | const profile: McpCore.NegotiatedProtocolProfile = session?.negotiatedProfile ?? { |
| 900 | protocolVersion: selectedProtocol.protocolVersion, |
| 901 | clientCapabilities: initializePayload.capabilities, |
| 902 | clientInfo: initializePayload.clientInfo |
| 903 | } |
| 904 | if (clientState !== undefined) clientState.profile = profile |
| 905 | const requestContext = McpRequestContext.of({ |
| 906 | clientId: client.id, |
| 907 | protocolVersion: profile.protocolVersion, |
| 908 | clientCapabilities: profile.clientCapabilities, |
| 909 | clientInfo: profile.clientInfo, |
| 910 | requestMetadata: initializePayload._meta |
| 911 | }) |
| 912 | return Effect.provideService( |
| 913 | Effect.provideService( |
| 914 | Effect.provideService( |
| 915 | effect, |
| 916 | McpServerClient, |
| 917 | McpServerClient.of({ |
| 918 | clientId: client.id, |
| 919 | protocolVersion: profile.protocolVersion, |
| 920 | clientCapabilities: profile.clientCapabilities, |
| 921 | clientInfo: profile.clientInfo, |
| 922 | initializePayload, |
| 923 | requestMetadata: Predicate.isReadonlyObject(payload) && Predicate.isReadonlyObject(payload._meta) |
| 924 | ? payload._meta as Schema.JsonObject |
| 925 | : undefined, |
| 926 | getClient: RcMap.get( |
| 927 | clients, |
| 928 | new McpClientKey({ |
| 929 | clientId: client.id, |
| 930 | profile |
| 931 | }) |
| 932 | ).pipe( |
| 933 | Effect.map(({ client }) => client) |
| 934 | ) |
| 935 | }) |
| 936 | ), |
| 937 | McpRequestContext, |
| 938 | requestContext |
| 939 | ), |
| 940 | CurrentLogLevel, |
| 941 | runtime.effectLogLevel(client.id, headers, defaultLogLevel) |
| 942 | ) |
| 943 | }) |
| 944 | |
| 945 | const patchedProtocol = RpcServer.Protocol.of({ |
| 946 | ...protocol, |
| 947 | send: (clientId, response) => { |
| 948 | if (response._tag === "Exit") { |
| 949 | const requests = activeRequests.get(clientId) |
| 950 | const key = requestKey(response.requestId) |
| 951 | const cancelled = requests?.get(key)?.cancelled |
| 952 | if (requests !== undefined && requests.delete(key) && requests.size === 0) { |
| 953 | activeRequests.delete(clientId) |
| 954 | } |
| 955 | if (cancelled === true) { |
| 956 | if (transport === "custom") return Effect.void |
| 957 | cancelledResponses.set(response, response.requestId) |
| 958 | return protocol.send(clientId, response) |
| 959 | } |
| 960 | if ( |
| 961 | response.exit._tag === "Failure" && |
| 962 | !response.exit.cause.some((failure) => failure._tag === "Fail") |
| 963 | ) { |
| 964 | return protocol.send(clientId, { |
| 965 | _tag: "Exit", |
| 966 | requestId: response.requestId, |
| 967 | exit: { |
| 968 | _tag: "Failure", |
| 969 | cause: [{ |
| 970 | _tag: "Fail", |
| 971 | error: new InternalError({ message: "Internal error" }) |
| 972 | }] |
| 973 | } |
| 974 | }) |
| 975 | } |
| 976 | } |
| 977 | return protocol.send(clientId, response) |
| 978 | }, |
| 979 | run: (f) => |
| 980 | protocol.run((clientId, request_) => { |
| 981 | const fiber = Fiber.getCurrent()! |
| 982 | const request = request_ as unknown as |
| 983 | | RpcMessage.FromServerEncoded |
| 984 | | RpcMessage.FromClientEncoded |
| 985 | const httpRequest = isHttp |
| 986 | ? Context.getOrUndefined(fiber.context, HttpServerRequest.HttpServerRequest) |
| 987 | : undefined |
| 988 | if (httpRequest !== undefined && request._tag !== "Eof") { |
| 989 | appendPreResponseHandlerUnsafe(httpRequest, (_, response) => |
| 990 | Effect.succeed( |
| 991 | response.status === 200 && |
| 992 | response.body._tag === "Uint8Array" && |
| 993 | response.body.contentLength === 0 |
| 994 | ? HttpServerResponse.empty({ |
| 995 | headers: Headers.remove(response.headers, "content-type"), |
| 996 | status: 202 |
| 997 | }) |
| 998 | : response |
| 999 | )) |
| 1000 | } |
| 1001 | switch (request._tag) { |
| 1002 | case "Request": { |
| 1003 | const headers = isHttp |
| 1004 | ? Context.getUnsafe( |
| 1005 | Fiber.getCurrent()!.context, |
| 1006 | HttpServerRequest.HttpServerRequest |
| 1007 | ).headers |
| 1008 | : Headers.fromInput(request.headers) |
| 1009 | const cancellationRequest = request.tag === "notifications/cancelled" && |
| 1010 | typeof request.payload === "object" && request.payload !== null && "requestId" in request.payload && |
| 1011 | (typeof request.payload.requestId === "string" || typeof request.payload.requestId === "number") |
| 1012 | ? activeRequests.get(clientId)?.get(requestKey(request.payload.requestId)) |
| 1013 | : undefined |
| 1014 | const prepare = cancellationRequest === undefined |
| 1015 | ? runtime.prepareRequest(clientId, headers, request) |
| 1016 | : Effect.succeed(cancellationRequest.prepared) |
| 1017 | return Effect.gen(function*() { |
| 1018 | const prepared = yield* prepare |
| 1019 | const clientState = clientStates.get(clientId) |
| 1020 | if (isHttp && clientState === undefined) { |
| 1021 | // HTTP EOF only ends the request body; handlers and streamed replies may still be running. |
| 1022 | yield* Scope.addFinalizer( |
| 1023 | Context.getUnsafe(fiber.context, Scope.Scope), |
| 1024 | Effect.sync(() => disconnectClient(clientId)) |
| 1025 | ) |
| 1026 | } |
| 1027 | const session = prepared.binding |
| 1028 | const selectedProtocol = prepared.protocol |
| 1029 | // Select before dated payload decoding: legacy requests use |
| 1030 | // their session's adapter; modern requests carry their own version. |
| 1031 | clientStates.set(clientId, { |
| 1032 | protocol: selectedProtocol, |
| 1033 | profile: prepared.profile ?? clientState?.profile, |
| 1034 | sessionHeaders: isHttp && headers[MCP_SESSION_ID_HEADER] !== undefined |
| 1035 | ? Headers.fromInput({ [MCP_SESSION_ID_HEADER]: headers[MCP_SESSION_ID_HEADER] }) |
| 1036 | : clientState?.sessionHeaders |
| 1037 | }) |
| 1038 | if (request.tag === MCP_INVALID_BATCH_METHOD) { |
| 1039 | return yield* sendRequestError( |
| 1040 | clientId, |
| 1041 | request.id, |
| 1042 | new InvalidRequest({ message: "JSON-RPC batches are not supported" }) |
| 1043 | ) |
| 1044 | } |
| 1045 | if (httpRequest !== undefined && session !== undefined) { |
| 1046 | appendPreResponseHandlerUnsafe(httpRequest, (_, res) => |
| 1047 | Effect.succeed( |
| 1048 | HttpServerResponse.setHeader( |
| 1049 | res, |
| 1050 | MCP_PROTOCOL_VERSION_HEADER, |
| 1051 | session.protocol.protocolVersion |
| 1052 | ) |
| 1053 | )) |
| 1054 | } |
| 1055 | const routedRequest = runtime.routeClientRequest(selectedProtocol, request) |
| 1056 | const rpc = runtime.clientRpcs.requests.get(routedRequest.tag) |
| 1057 | const isClientNotification = selectedProtocol.clientNotificationRpcs.requests.has(request.tag) |
| 1058 | if (rpc && isClientNotification && request.isNotification) { |
| 1059 | if (!session && selectedProtocol.runtime._tag === "Stateful") { |
| 1060 | if (httpRequest) { |
| 1061 | appendPreResponseHandlerUnsafe( |
| 1062 | httpRequest, |
| 1063 | () => |
| 1064 | Effect.succeed( |
| 1065 | HttpServerResponse.empty({ |
| 1066 | status: headers[MCP_SESSION_ID_HEADER] === undefined ? 400 : 404 |
| 1067 | }) |
| 1068 | ) |
| 1069 | ) |
| 1070 | } |
| 1071 | return |
| 1072 | } |
| 1073 | const decode = selectedProtocol.payloadCodecs(rpc).decode(request.payload) |
| 1074 | return yield* Effect.gen(function*() { |
| 1075 | const payload = yield* decode |
| 1076 | if (request.tag === "notifications/cancelled") { |
| 1077 | const cancellation = yield* selectedProtocol.normalizeCancellation(payload) |
| 1078 | const key = requestKey(cancellation.requestId) |
| 1079 | let ownerClientId = clientId |
| 1080 | if (isHttp) { |
| 1081 | if (session === undefined) { |
| 1082 | return |
| 1083 | } |
| 1084 | // Each HTTP POST has its own transport ID, but cancellation belongs to the session. |
| 1085 | const owner = Array.from(activeRequests).find(([, requests]) => |
| 1086 | requests.get(key)?.prepared.binding === session |
| 1087 | ) |
| 1088 | if (owner === undefined) { |
| 1089 | return |
| 1090 | } |
| 1091 | ownerClientId = owner[0] |
| 1092 | } |
| 1093 | if (!cancelRequest(ownerClientId, cancellation.requestId)) { |
| 1094 | return |
| 1095 | } |
| 1096 | return yield* f(ownerClientId, { |
| 1097 | _tag: "Interrupt", |
| 1098 | requestId: cancellation.requestId |
| 1099 | }) |
| 1100 | } |
| 1101 | const handler = handlers.mapUnsafe.get(rpc.key) as Rpc.Handler<string> | undefined |
| 1102 | const handled = handler |
| 1103 | ? handler.handler(payload, { |
| 1104 | rpc, |
| 1105 | requestId: RpcMessage.RequestId(request.id), |
| 1106 | client: new Rpc.ServerClient(clientId), |
| 1107 | headers |
| 1108 | }) as any as Effect.Effect<void> |
| 1109 | : Effect.void |
| 1110 | return yield* prepared.requestContext === undefined |
| 1111 | ? handled |
| 1112 | : Effect.provideService(handled, McpRequestContext, prepared.requestContext) |
| 1113 | }).pipe(Effect.ignoreCause) |
| 1114 | } |
| 1115 | if (!rpc || isClientNotification) { |
| 1116 | if (request.isNotification) { |
| 1117 | return |
| 1118 | } |
| 1119 | return yield* sendRequestError( |
| 1120 | clientId, |
| 1121 | request.id, |
| 1122 | new MethodNotFound({ message: `Method not found: ${request.tag}` }) |
| 1123 | ) |
| 1124 | } |
| 1125 | const decoded = yield* Effect.result(selectedProtocol.payloadCodecs(rpc).decode(request.payload)) |
| 1126 | if (Result.isFailure(decoded)) { |
| 1127 | return yield* request.isNotification |
| 1128 | ? Effect.void |
| 1129 | : sendRequestError(clientId, request.id, new InvalidParams({ message: "Invalid method parameters" })) |
| 1130 | } |
| 1131 | if (request.isNotification !== true) { |
| 1132 | const requests = activeRequests.get(clientId) ?? new Map<string, ActiveRequest>() |
| 1133 | requests.set(requestKey(request.id), { prepared, cancelled: false }) |
| 1134 | activeRequests.set(clientId, requests) |
| 1135 | } |
| 1136 | const handled = f(clientId, routedRequest) |
| 1137 | return yield* prepared.requestContext === undefined |
| 1138 | ? handled |
| 1139 | : Effect.provideService(handled, McpRequestContext, prepared.requestContext) |
| 1140 | }).pipe( |
| 1141 | Effect.catch((error) => |
| 1142 | request.isNotification |
| 1143 | ? Effect.void |
| 1144 | : sendRequestError( |
| 1145 | clientId, |
| 1146 | request.id, |
| 1147 | Predicate.isTagged(error, "ProtocolError") |
| 1148 | ? McpProtocolInternal.ProtocolError.fromFeature(error) |
| 1149 | : new InvalidParams({ message: "Invalid request metadata" }) |
| 1150 | ) |
| 1151 | ) |
| 1152 | ) |
| 1153 | } |
| 1154 | case "Ping": |
| 1155 | case "Ack": |
| 1156 | case "Interrupt": |
| 1157 | return f(clientId, request) |
| 1158 | case "Eof": |
| 1159 | if (!isHttp) { |
| 1160 | disconnectClient(clientId) |
| 1161 | } |
| 1162 | return f(clientId, request) |
| 1163 | case "Pong": |
| 1164 | case "Exit": |
| 1165 | case "Chunk": |
| 1166 | case "ClientProtocolError": |
| 1167 | case "Defect": { |
| 1168 | const requestId = request._tag === "Exit" |
| 1169 | ? requestKey(request.requestId) |
| 1170 | : undefined |
| 1171 | const session = isHttp |
| 1172 | ? runtime.resolveRequest( |
| 1173 | clientId, |
| 1174 | Context.getUnsafe(Fiber.getCurrent()!.context, HttpServerRequest.HttpServerRequest).headers |
| 1175 | ) |
| 1176 | : undefined |
| 1177 | const waiting = requestId === undefined ? undefined : reverseRequestClients.get(requestId) |
| 1178 | const reverseKey = waiting?.find((key) => |
| 1179 | isHttp ? key.profile === session?.negotiatedProfile : key.clientId === clientId |
| 1180 | ) |
| 1181 | if (request._tag === "Exit" && reverseKey === undefined) { |
| 1182 | return Effect.void |
| 1183 | } |
| 1184 | if (reverseKey !== undefined && requestId !== undefined) { |
| 1185 | removeReverseRequestClient(requestId, reverseKey) |
| 1186 | } |
| 1187 | const targetClientId = reverseKey?.clientId ?? clientId |
| 1188 | const clientState = clientStates.get(targetClientId) |
| 1189 | const selectedProtocol = clientState?.protocol ?? runtime.protocols[0] |
| 1190 | const profile = reverseKey?.profile ?? clientState?.profile ?? { |
| 1191 | protocolVersion: selectedProtocol.protocolVersion, |
| 1192 | clientCapabilities: {}, |
| 1193 | clientInfo: { name: "unknown", version: "unknown" } |
| 1194 | } |
| 1195 | return RcMap.get( |
| 1196 | clients, |
| 1197 | new McpClientKey({ |
| 1198 | clientId: targetClientId, |
| 1199 | profile |
| 1200 | }) |
| 1201 | ).pipe( |
| 1202 | Effect.flatMap(({ write }) => write(request)), |
| 1203 | Effect.scoped |
| 1204 | ) |
| 1205 | } |
| 1206 | } |
| 1207 | }) |
| 1208 | }) |
| 1209 | |
| 1210 | const { notificationDelivery, notifications } = internalState.get(server)! |
| 1211 | yield* Effect.acquireRelease( |
| 1212 | Effect.sync(() => { |
| 1213 | notificationDelivery.consumers++ |
| 1214 | }), |
| 1215 | () => |
| 1216 | Effect.sync(() => { |
| 1217 | notificationDelivery.consumers-- |
| 1218 | }) |
| 1219 | ) |
| 1220 | const notificationTails = new Map<number, Deferred.Deferred<void>>() |
| 1221 | yield* Queue.take(notifications).pipe( |
| 1222 | Effect.flatMap(Effect.fnUntraced(function*(queued) { |
| 1223 | const { delivered, notification, targetClientId, requestContext, requestHeaders } = queued |
| 1224 | if (McpProtocolInternal.isSubscriptionServerNotification(notification)) { |
| 1225 | yield* PubSub.publish(serverNotifications, { notification, targetClientId }) |
| 1226 | } |
| 1227 | const clientIds = yield* patchedProtocol.clientIds |
| 1228 | for (const clientId of clientStates.keys()) { |
| 1229 | if (!clientIds.has(clientId)) { |
| 1230 | clientStates.delete(clientId) |
| 1231 | // HTTP UUID sessions are stored separately and outlive request-scoped client IDs. |
| 1232 | runtime.disconnect(clientId) |
| 1233 | } |
| 1234 | } |
| 1235 | const requestNotification = notification._tag === "LoggingMessage" || notification._tag === "Progress" |
| 1236 | const deliveryClientIds = requestNotification && requestContext !== undefined |
| 1237 | ? [requestContext.clientId] |
| 1238 | : targetClientId === undefined |
| 1239 | ? isHttp ? clientStates.keys() : runtime.deliveryClientIds() |
| 1240 | : [targetClientId] |
| 1241 | const deliveries: Array<Effect.Effect<void>> = [] |
| 1242 | let hasOriginDelivery = false |
| 1243 | for (const clientId of deliveryClientIds) { |
| 1244 | if (targetClientId !== undefined && clientId !== targetClientId) { |
| 1245 | continue |
| 1246 | } |
| 1247 | if (!clientIds.has(clientId)) { |
| 1248 | runtime.disconnect(clientId) |
| 1249 | continue |
| 1250 | } |
| 1251 | // This must stay below stale-client cleanup so transports without |
| 1252 | // notification support still prune initializedClients. |
| 1253 | if (!patchedProtocol.supportsNotifications) { |
| 1254 | continue |
| 1255 | } |
| 1256 | const selectedProtocol = requestNotification && requestContext !== undefined |
| 1257 | ? runtime.selectProtocol(requestContext.protocolVersion) |
| 1258 | : clientStates.get(clientId)?.protocol |
| 1259 | if (!selectedProtocol) { |
| 1260 | continue |
| 1261 | } |
| 1262 | // Reserve delivery order before forking so one blocked client cannot hold up another. |
| 1263 | const previous = notificationTails.get(clientId) |
| 1264 | const isOrigin = clientId === (targetClientId ?? requestContext?.clientId) |
| 1265 | hasOriginDelivery ||= isOrigin |
| 1266 | // Await delivery to the explicit target or originating request, not unrelated broadcast recipients. |
| 1267 | const completed = isOrigin ? delivered : Deferred.makeUnsafe<void>() |
| 1268 | notificationTails.set(clientId, completed) |
| 1269 | const delivery = Effect.gen(function*() { |
| 1270 | if (previous !== undefined) yield* Deferred.await(previous) |
| 1271 | const projected = yield* selectedProtocol.projectNotification(notification) |
| 1272 | if (projected === undefined) { |
| 1273 | return |
| 1274 | } |
| 1275 | if ( |
| 1276 | notification._tag === "Progress" && selectedProtocol.runtime._tag === "Stateless" && |
| 1277 | requestContext?.requestMetadata?.progressToken !== notification.progressToken |
| 1278 | ) { |
| 1279 | return |
| 1280 | } |
| 1281 | if (notification._tag === "LoggingMessage" && selectedProtocol.runtime._tag === "Stateless") { |
| 1282 | const metadata = requestContext?.requestMetadata |
| 1283 | const level = Predicate.hasProperty(metadata, "io.modelcontextprotocol/logLevel") |
| 1284 | ? metadata["io.modelcontextprotocol/logLevel"] |
| 1285 | : undefined |
| 1286 | |
| 1287 | if ( |
| 1288 | requestContext?.clientId !== clientId || |
| 1289 | !isLoggingLevel(level) || |
| 1290 | McpSchema.LoggingLevel.literals.indexOf(notification.level) < |
| 1291 | McpSchema.LoggingLevel.literals.indexOf(level) |
| 1292 | ) { |
| 1293 | return |
| 1294 | } |
| 1295 | } else if ( |
| 1296 | !runtime.canDeliver( |
| 1297 | clientId, |
| 1298 | (requestContext?.clientId === clientId ? requestHeaders : undefined) ?? |
| 1299 | clientStates.get(clientId)?.sessionHeaders ?? Headers.empty, |
| 1300 | notification, |
| 1301 | defaultLogLevel |
| 1302 | ) |
| 1303 | ) { |
| 1304 | return |
| 1305 | } |
| 1306 | const rpc = selectedProtocol.serverNotificationRpcs.requests.get(projected.tag) |
| 1307 | if (!rpc) { |
| 1308 | return |
| 1309 | } |
| 1310 | const encoded = yield* selectedProtocol.payloadCodecs(rpc).encode(projected.payload) |
| 1311 | yield* patchedProtocol.send(clientId, { |
| 1312 | _tag: "Request", |
| 1313 | id: "", |
| 1314 | tag: projected.tag, |
| 1315 | payload: encoded, |
| 1316 | headers: [], |
| 1317 | isNotification: true |
| 1318 | }) |
| 1319 | }).pipe( |
| 1320 | Effect.ignoreCause, |
| 1321 | Effect.ensuring(Effect.sync(() => { |
| 1322 | Deferred.doneUnsafe(completed, Exit.void) |
| 1323 | if (notificationTails.get(clientId) === completed) notificationTails.delete(clientId) |
| 1324 | })) |
| 1325 | ) |
| 1326 | deliveries.push(delivery) |
| 1327 | } |
| 1328 | if (!hasOriginDelivery) yield* Deferred.succeed(delivered, undefined) |
| 1329 | yield* Effect.all(deliveries, { concurrency: "unbounded", discard: true }).pipe( |
| 1330 | Effect.forkScoped({ startImmediately: true }) |
| 1331 | ) |
| 1332 | })), |
| 1333 | Effect.ignoreCause, |
| 1334 | Effect.forever, |
| 1335 | Effect.forkScoped |
| 1336 | ) |
| 1337 | |
| 1338 | return yield* RpcServer.make(runtime.clientRpcs, { |
| 1339 | spanPrefix: "McpServer", |
| 1340 | disableFatalDefects: true |
| 1341 | }).pipe( |
| 1342 | Effect.provideService(RpcServer.Protocol, patchedProtocol), |
| 1343 | Effect.provideService(McpServerClientMiddleware, clientMiddleware), |
| 1344 | Effect.provide(handlers) |
| 1345 | ) |
| 1346 | }, Effect.scoped) |
| 1347 | |
| 1348 | /** |
| 1349 | * Creates a layer that starts an MCP server over an existing |
| 1350 | * `RpcServer.Protocol` and provides `McpServer`. Request handlers receive |
| 1351 | * `McpRequestContext`; initialized legacy requests additionally receive |
| 1352 | * `McpServerClient`. |
| 1353 | * |
| 1354 | * **When to use** |
| 1355 | * |
| 1356 | * Use when you already have a custom or externally provided |
| 1357 | * `RpcServer.Protocol` and want to start an MCP server as part of a layer |
| 1358 | * graph. |
| 1359 | * |
| 1360 | * **Details** |
| 1361 | * |
| 1362 | * The returned layer forks `run(options)` in the layer scope and merges |
| 1363 | * `McpServer.layer`, so registration layers can use the `McpServer` service |
| 1364 | * while the server is running. |
| 1365 | * |
| 1366 | * **Gotchas** |
| 1367 | * |
| 1368 | * Unlike `layerStdio` and `layerHttp`, this layer does not install a concrete |
| 1369 | * transport. The surrounding layer graph must provide `RpcServer.Protocol`. |
| 1370 | * |
| 1371 | * @see {@link run} for the effect form used by this layer |
| 1372 | * @see {@link layerStdio} for a stdio-backed layer that installs the MCP protocol and NDJSON-RPC serialization |
| 1373 | * @see {@link layerHttp} for an HTTP-backed layer that registers with `HttpRouter` and installs JSON-RPC serialization |
| 1374 | * |
| 1375 | * @stability unstable |
| 1376 | * @category layers |
| 1377 | * @since 4.0.0 |
| 1378 | */ |
| 1379 | export const layer = (options: { |
| 1380 | readonly name: string |
| 1381 | readonly version: string |
| 1382 | readonly instructions?: string | undefined |
| 1383 | readonly description?: string | undefined |
| 1384 | readonly websiteUrl?: string | undefined |
| 1385 | readonly icons?: ReadonlyArray<McpSchema.Icon> | undefined |
| 1386 | readonly protocols: Arr.NonEmptyReadonlyArray<McpProtocol.ProtocolAdapter> |
| 1387 | readonly extensions?: ServerExtensions | undefined |
| 1388 | }): Layer.Layer<McpServer | McpServerClient, Cause.IllegalArgumentError, RpcServer.Protocol> => |
| 1389 | layerWithRuntime(options, "custom").pipe( |
| 1390 | Layer.provide(McpRuntime.layer(options.protocols)) |
| 1391 | ) |
| 1392 | |
| 1393 | const layerWithRuntime = (options: { |
| 1394 | readonly name: string |
| 1395 | readonly version: string |
| 1396 | readonly instructions?: string | undefined |
| 1397 | readonly description?: string | undefined |
| 1398 | readonly websiteUrl?: string | undefined |
| 1399 | readonly icons?: ReadonlyArray<McpSchema.Icon> | undefined |
| 1400 | readonly extensions?: ServerExtensions | undefined |
| 1401 | }, transport: "custom" | "http" | "stdio"): Layer.Layer< |
| 1402 | McpServer | McpServerClient, |
| 1403 | never, |
| 1404 | RpcServer.Protocol | McpRuntime.ServerRuntime |
| 1405 | > => |
| 1406 | Layer.effectDiscard( |
| 1407 | Effect.gen(function*() { |
| 1408 | const runtime = yield* McpRuntime.ServerRuntime |
| 1409 | yield* Effect.forkScoped(runWithRuntime(options, runtime, transport)) |
| 1410 | }) |
| 1411 | ).pipe( |
| 1412 | Layer.provideMerge(McpServer.layer) |
| 1413 | ) |
| 1414 | |
| 1415 | /** |
| 1416 | * Creates a layer that runs an MCP server over standard input and output. |
| 1417 | * |
| 1418 | * **When to use** |
| 1419 | * |
| 1420 | * Use when an MCP client launches the server as a subprocess and communicates |
| 1421 | * through newline-delimited JSON-RPC messages. |
| 1422 | * |
| 1423 | * **Details** |
| 1424 | * |
| 1425 | * The selected protocol adapter controls the dated RPC schemas and JSON-RPC |
| 1426 | * batch policy. The layer provides `McpServer`, supplies request-scoped |
| 1427 | * `McpRequestContext` and legacy `McpServerClient` services to handlers, and |
| 1428 | * requires `Stdio`. |
| 1429 | * |
| 1430 | * @see {@link layer} for running over an existing `RpcServer.Protocol` |
| 1431 | * @see {@link layerHttp} for the single-endpoint HTTP transport |
| 1432 | * |
| 1433 | * @stability unstable |
| 1434 | * @category layers |
| 1435 | * @since 4.0.0 |
| 1436 | */ |
| 1437 | export const layerStdio = (options: { |
| 1438 | readonly name: string |
| 1439 | readonly version: string |
| 1440 | readonly instructions?: string | undefined |
| 1441 | readonly description?: string | undefined |
| 1442 | readonly websiteUrl?: string | undefined |
| 1443 | readonly icons?: ReadonlyArray<McpSchema.Icon> | undefined |
| 1444 | readonly protocols: Arr.NonEmptyReadonlyArray<McpProtocol.ProtocolAdapter> |
| 1445 | readonly extensions?: ServerExtensions | undefined |
| 1446 | }): Layer.Layer<McpServer | McpServerClient, Cause.IllegalArgumentError, Stdio> => |
| 1447 | layerWithRuntime(options, "stdio").pipe( |
| 1448 | Layer.provide(McpRuntime.layer(options.protocols)), |
| 1449 | Layer.provide(RpcServer.layerProtocolStdio), |
| 1450 | Layer.provide(Layer.succeed( |
| 1451 | RpcSerialization.RpcSerialization, |
| 1452 | mcpStdioSerialization(options.protocols) |
| 1453 | )) |
| 1454 | ) |
| 1455 | |
| 1456 | const mcpStdioSerialization = ( |
| 1457 | protocols: Arr.NonEmptyReadonlyArray<McpProtocol.ProtocolAdapter> |
| 1458 | ): RpcSerialization.RpcSerialization["Service"] => { |
| 1459 | const serialization = mcpJsonRpcSerialization({ |
| 1460 | contentType: "application/json-rpc" |
| 1461 | }) |
| 1462 | return RpcSerialization.RpcSerialization.of({ |
| 1463 | contentType: serialization.contentType, |
| 1464 | includesFraming: true, |
| 1465 | codecFor: serialization.codecFor, |
| 1466 | makeUnsafe: () => { |
| 1467 | const frames = RpcSerialization.ndjson.makeUnsafe() |
| 1468 | const parser = serialization.makeUnsafe() |
| 1469 | let selectedProtocol: McpProtocol.ProtocolAdapter | undefined |
| 1470 | return { |
| 1471 | decode: (data) => { |
| 1472 | const decoded: Array<unknown> = [] |
| 1473 | for (const frame of frames.decode(data)) { |
| 1474 | if (Array.isArray(frame)) { |
| 1475 | const acceptsBatch = selectedProtocol?.runtime.transport.jsonRpc.acceptsBatches === true |
| 1476 | if ( |
| 1477 | !acceptsBatch || |
| 1478 | frame.length === 0 || |
| 1479 | frame.some(McpRuntime.hasRequestProtocolVersion) || |
| 1480 | frame.some(isInitializeJsonRpcMessage) |
| 1481 | ) { |
| 1482 | decoded.push({ |
| 1483 | _tag: "Request", |
| 1484 | id: null, |
| 1485 | tag: MCP_INVALID_BATCH_METHOD, |
| 1486 | payload: null, |
| 1487 | headers: [] |
| 1488 | }) |
| 1489 | continue |
| 1490 | } |
| 1491 | } else if (isInitializeJsonRpcMessage(frame)) { |
| 1492 | const offered = getJsonRpcProtocolVersion(frame) |
| 1493 | selectedProtocol = McpRuntime.selectStatefulProtocol(protocols, offered) |
| 1494 | } |
| 1495 | decoded.push(...parser.decode(JSON.stringify(frame))) |
| 1496 | } |
| 1497 | return decoded |
| 1498 | }, |
| 1499 | encode: (response) => { |
| 1500 | const invalidBatchExit = decodeInvalidBatchExit(response) |
| 1501 | if (Result.isSuccess(invalidBatchExit)) { |
| 1502 | return JSON.stringify({ |
| 1503 | jsonrpc: "2.0", |
| 1504 | id: null, |
| 1505 | error: { |
| 1506 | code: McpSchema.INVALID_REQUEST_ERROR_CODE, |
| 1507 | message: "JSON-RPC batches are not supported" |
| 1508 | } |
| 1509 | }) + "\n" |
| 1510 | } |
| 1511 | const encoded = parser.encode(response) |
| 1512 | return encoded === undefined ? undefined : `${encoded}\n` |
| 1513 | } |
| 1514 | } |
| 1515 | } |
| 1516 | }) |
| 1517 | } |
| 1518 | |
| 1519 | /** |
| 1520 | * Registers a Streamable HTTP MCP endpoint at `options.path`. |
| 1521 | * |
| 1522 | * **When to use** |
| 1523 | * |
| 1524 | * Use to expose an MCP server through an existing `HttpRouter`. |
| 1525 | * |
| 1526 | * **Details** |
| 1527 | * |
| 1528 | * POST serves JSON-RPC and accepted notification-only requests return `202`. |
| 1529 | * Modern routing-header mismatches and unsupported protocol versions return |
| 1530 | * JSON-RPC errors with status `400`; unknown modern RPC methods return a |
| 1531 | * JSON-RPC method-not-found error with status `404`. Unsupported HTTP methods |
| 1532 | * return `405`. Requests carrying an `Origin` header are rejected unless the |
| 1533 | * exact origin appears in `allowedOrigins`; Origin-less non-browser clients |
| 1534 | * remain valid. The surrounding HTTP server remains responsible for binding |
| 1535 | * to an appropriate interface and installing authentication. |
| 1536 | * |
| 1537 | * `layerHttp` always implements the single-endpoint Streamable HTTP topology. |
| 1538 | * Using `v2024_11_05` here is a custom compatibility transport for that |
| 1539 | * revision's schema. It does not implement the historical two-endpoint |
| 1540 | * HTTP+SSE transport, GET SSE, event resumption, session expiry, or client |
| 1541 | * session termination. |
| 1542 | * |
| 1543 | * @see {@link layerStdio} for exposing the server over stdio |
| 1544 | * @see {@link layer} for the base MCP server layer without a transport protocol |
| 1545 | * |
| 1546 | * @stability unstable |
| 1547 | * @category layers |
| 1548 | * @since 4.0.0 |
| 1549 | */ |
| 1550 | export const layerHttp = (options: { |
| 1551 | readonly name: string |
| 1552 | readonly version: string |
| 1553 | readonly instructions?: string | undefined |
| 1554 | readonly description?: string | undefined |
| 1555 | readonly websiteUrl?: string | undefined |
| 1556 | readonly icons?: ReadonlyArray<McpSchema.Icon> | undefined |
| 1557 | readonly path: HttpRouter.PathInput |
| 1558 | readonly protocols: Arr.NonEmptyReadonlyArray<McpProtocol.ProtocolAdapter> |
| 1559 | readonly extensions?: ServerExtensions | undefined |
| 1560 | readonly allowedOrigins?: ReadonlyArray<string> | undefined |
| 1561 | }): Layer.Layer<McpServer | McpServerClient, Cause.IllegalArgumentError, HttpRouter.HttpRouter> => { |
| 1562 | const runtime = McpRuntime.layer(options.protocols) |
| 1563 | const methodNotAllowedResponse = HttpServerResponse.empty({ |
| 1564 | status: 405, |
| 1565 | headers: { allow: "POST" } |
| 1566 | }) |
| 1567 | const methodNotAllowed = (request: HttpServerRequest.HttpServerRequest) => |
| 1568 | isAllowedMcpOrigin(request, options.allowedOrigins) |
| 1569 | ? Effect.succeed(methodNotAllowedResponse) |
| 1570 | : Effect.succeed(HttpServerResponse.empty({ status: 403 })) |
| 1571 | const routes = Layer.mergeAll( |
| 1572 | HttpRouter.add("GET", options.path, methodNotAllowed), |
| 1573 | HttpRouter.add("PUT", options.path, methodNotAllowed), |
| 1574 | HttpRouter.add("PATCH", options.path, methodNotAllowed), |
| 1575 | HttpRouter.add("DELETE", options.path, methodNotAllowed), |
| 1576 | HttpRouter.add("OPTIONS", options.path, methodNotAllowed) |
| 1577 | ) |
| 1578 | return Layer.merge(layerWithRuntime(options, "http"), routes).pipe( |
| 1579 | Layer.provide(layerMcpProtocolHttp(options)), |
| 1580 | Layer.provide(runtime), |
| 1581 | Layer.provide(RpcSerialization.layerJsonRpc()) |
| 1582 | ) |
| 1583 | } |
| 1584 | |
| 1585 | const layerMcpProtocolHttp = (options: { |
| 1586 | readonly path: HttpRouter.PathInput |
| 1587 | readonly allowedOrigins?: ReadonlyArray<string> | undefined |
| 1588 | }): Layer.Layer< |
| 1589 | RpcServer.Protocol, |
| 1590 | never, |
| 1591 | McpRuntime.ServerRuntime | HttpRouter.HttpRouter |
| 1592 | > => |
| 1593 | Layer.effect(RpcServer.Protocol)(Effect.gen(function*() { |
| 1594 | const runtime = yield* McpRuntime.ServerRuntime |
| 1595 | const { httpEffect, protocol } = yield* RpcServer.makeProtocolWithHttpEffect().pipe( |
| 1596 | Effect.provideService(RpcSerialization.RpcSerialization, mcpHttpSerialization) |
| 1597 | ) |
| 1598 | const router = yield* HttpRouter.HttpRouter |
| 1599 | yield* router.add("POST", options.path, (request) => { |
| 1600 | if (!isAllowedMcpOrigin(request, options.allowedOrigins)) { |
| 1601 | return Effect.succeed(HttpServerResponse.empty({ status: 403 })) |
| 1602 | } |
| 1603 | if (mcpMediaTypes(request.headers["content-type"])[0] !== "application/json") { |
| 1604 | return Effect.succeed(HttpServerResponse.empty({ status: 415 })) |
| 1605 | } |
| 1606 | const accepted = mcpMediaTypes(request.headers["accept"]) |
| 1607 | if (!accepted.includes("application/json") || !accepted.includes("text/event-stream")) { |
| 1608 | return Effect.succeed(HttpServerResponse.empty({ status: 406 })) |
| 1609 | } |
| 1610 | return Effect.gen(function*() { |
| 1611 | const parsed = yield* Effect.result( |
| 1612 | Effect.flatMap(request.text, Schema.decodeEffect(Schema.UnknownFromJsonString)) |
| 1613 | ) |
| 1614 | const admission = runtime.admitHttp(request.headers, parsed) |
| 1615 | if (admission._tag === "Rejected") { |
| 1616 | return admission.response |
| 1617 | } |
| 1618 | const response = Effect.map(httpEffect, (response) => { |
| 1619 | // Completed responses may already contain notifications followed by the result. |
| 1620 | const hasMultipleMessages = response.body._tag === "Uint8Array" && |
| 1621 | response.body.body.subarray(0, -1).includes(10) |
| 1622 | return admission.isSubscription || response.body._tag === "Stream" || hasMultipleMessages |
| 1623 | ? toServerSentEvents(response, admission.isSubscription) |
| 1624 | : response |
| 1625 | }) |
| 1626 | return yield* admission.acknowledge |
| 1627 | ? Effect.catchCause(response, () => Effect.succeed(HttpServerResponse.empty({ status: 202 }))) |
| 1628 | : response |
| 1629 | }) |
| 1630 | }) |
| 1631 | return protocol |
| 1632 | })) |
| 1633 | |
| 1634 | const mcpHttpSerialization: RpcSerialization.RpcSerialization["Service"] = (() => { |
| 1635 | const serialization = mcpJsonRpcSerialization() |
| 1636 | return RpcSerialization.RpcSerialization.of({ |
| 1637 | contentType: serialization.contentType, |
| 1638 | includesFraming: true, |
| 1639 | codecFor: serialization.codecFor, |
| 1640 | makeUnsafe: () => { |
| 1641 | const parser = serialization.makeUnsafe() |
| 1642 | return { |
| 1643 | decode: parser.decode, |
| 1644 | encode: (response) => { |
| 1645 | const encoded = parser.encode(response) |
| 1646 | // Preserve message boundaries when the HTTP transport joins buffered chunks. |
| 1647 | return typeof encoded === "string" ? `${encoded}\n` : encoded |
| 1648 | } |
| 1649 | } |
| 1650 | } |
| 1651 | }) |
| 1652 | })() |
| 1653 | |
| 1654 | const isEncodedMcpFailureCause = Schema.is(Schema.TaggedStruct("Cause", { |
| 1655 | data: Schema.Tuple([Schema.TaggedStruct("Fail", { |
| 1656 | error: Schema.toEncoded(McpSchema.McpError) |
| 1657 | })]) |
| 1658 | })) |
| 1659 | |
| 1660 | const normalizeMcpJsonRpcResponse = (response: unknown): unknown => { |
| 1661 | if (Array.isArray(response)) { |
| 1662 | return response.map(normalizeMcpJsonRpcResponse) |
| 1663 | } |
| 1664 | if (!Predicate.isReadonlyObject(response) || !Predicate.hasProperty(response, "error")) { |
| 1665 | return response |
| 1666 | } |
| 1667 | return isEncodedMcpFailureCause(response.error) |
| 1668 | ? { ...response, error: response.error.data[0].error } |
| 1669 | : response |
| 1670 | } |
| 1671 | |
| 1672 | function mcpJsonRpcSerialization(options?: { |
| 1673 | readonly contentType?: string | undefined |
| 1674 | }): RpcSerialization.RpcSerialization["Service"] { |
| 1675 | const serialization = RpcSerialization.jsonRpc(options) |
| 1676 | return RpcSerialization.RpcSerialization.of({ |
| 1677 | ...serialization, |
| 1678 | makeUnsafe: () => { |
| 1679 | const parser = serialization.makeUnsafe() |
| 1680 | const cancelledIds = new Set<string | number>() |
| 1681 | return { |
| 1682 | decode: parser.decode, |
| 1683 | encode: (response) => { |
| 1684 | if (Predicate.isReadonlyObject(response)) { |
| 1685 | const cancelledId = cancelledResponses.get(response) |
| 1686 | if (cancelledId !== undefined) { |
| 1687 | cancelledResponses.delete(response) |
| 1688 | cancelledIds.add(cancelledId) |
| 1689 | } |
| 1690 | } |
| 1691 | const encoded = parser.encode(response) |
| 1692 | if (typeof encoded !== "string") return encoded |
| 1693 | if (cancelledIds.size === 0 && !encoded.includes("\"_tag\":\"Cause\"")) return encoded |
| 1694 | let message: unknown = JSON.parse(encoded) |
| 1695 | if (cancelledIds.size > 0) { |
| 1696 | // Count cancelled completions toward the batch, but never write their responses. |
| 1697 | // https://modelcontextprotocol.io/specification/2025-03-26/basic/utilities/cancellation |
| 1698 | const keep = (message: unknown) => |
| 1699 | !(Predicate.isReadonlyObject(message) && !Predicate.hasProperty(message, "method") && |
| 1700 | (typeof message.id === "string" || typeof message.id === "number") && cancelledIds.delete(message.id)) |
| 1701 | if (Array.isArray(message)) { |
| 1702 | const remaining = message.filter(keep) |
| 1703 | if (remaining.length === 0) return undefined |
| 1704 | message = remaining |
| 1705 | } else if (!keep(message)) { |
| 1706 | return undefined |
| 1707 | } |
| 1708 | } |
| 1709 | return JSON.stringify(normalizeMcpJsonRpcResponse(message)) |
| 1710 | } |
| 1711 | } |
| 1712 | } |
| 1713 | }) |
| 1714 | } |
| 1715 | |
| 1716 | const toServerSentEvents = (response: HttpServerResponse.HttpServerResponse, keepAlive: boolean) => { |
| 1717 | const encoder = new TextEncoder() |
| 1718 | const decoder = new TextDecoder() |
| 1719 | const frame = (data: Uint8Array) => |
| 1720 | encoder.encode(decoder.decode(data).trimEnd().split("\n").map((message) => `data: ${message}\n\n`).join("")) |
| 1721 | const options = { |
| 1722 | status: response.status, |
| 1723 | statusText: response.statusText, |
| 1724 | headers: Headers.remove(response.headers, "content-type"), |
| 1725 | cookies: response.cookies, |
| 1726 | contentType: "text/event-stream" |
| 1727 | } |
| 1728 | if (response.body._tag === "Stream") { |
| 1729 | const events = response.body.stream.pipe(Stream.map(frame)) |
| 1730 | if (!keepAlive) { |
| 1731 | return HttpServerResponse.stream(events, options) |
| 1732 | } |
| 1733 | // Keep a native timer pending so workerd does not treat idle subscriptions as hung requests. |
| 1734 | const keepAliveComments = Stream.tick("15 seconds").pipe( |
| 1735 | Stream.drop(1), |
| 1736 | Stream.map(() => encoder.encode(": keepalive\n\n")) |
| 1737 | ) |
| 1738 | return HttpServerResponse.stream(Stream.merge(events, keepAliveComments, { haltStrategy: "left" }), options) |
| 1739 | } |
| 1740 | if (response.body._tag === "Uint8Array") { |
| 1741 | return HttpServerResponse.uint8Array(frame(response.body.body), options) |
| 1742 | } |
| 1743 | return HttpServerResponse.setHeader(response, "content-type", "text/event-stream") |
| 1744 | } |
| 1745 | |
| 1746 | const isAllowedMcpOrigin = ( |
| 1747 | request: HttpServerRequest.HttpServerRequest, |
| 1748 | allowedOrigins: ReadonlyArray<string> | undefined |
| 1749 | ): boolean => { |
| 1750 | const origin = request.headers["origin"] |
| 1751 | return origin === undefined || (allowedOrigins ?? []).includes(origin) |
| 1752 | } |
| 1753 | |
| 1754 | const mcpMediaTypes = (header: string | undefined): ReadonlyArray<string> => |
| 1755 | header === undefined |
| 1756 | ? [] |
| 1757 | : header.split(",").flatMap((part) => { |
| 1758 | const [mediaType, ...parameters] = part.split(";") |
| 1759 | const quality = parameters |
| 1760 | .map((parameter) => parameter.trim().toLowerCase()) |
| 1761 | .find((parameter) => parameter.startsWith("q=")) |
| 1762 | if (quality !== undefined) { |
| 1763 | const value = Number(quality.slice(2)) |
| 1764 | if (!Number.isFinite(value) || value <= 0 || value > 1) { |
| 1765 | return [] |
| 1766 | } |
| 1767 | } |
| 1768 | return [mediaType.trim().toLowerCase()] |
| 1769 | }) |
| 1770 | |
| 1771 | const InitializeJsonRpcMessage = Schema.Struct({ |
| 1772 | method: Schema.Literal("initialize") |
| 1773 | }) |
| 1774 | |
| 1775 | const isInitializeJsonRpcMessage = (message: unknown): boolean => |
| 1776 | Result.isSuccess(Schema.decodeUnknownResult(InitializeJsonRpcMessage)(message)) |
| 1777 | |
| 1778 | const JsonRpcProtocolVersion = Schema.Struct({ |
| 1779 | params: Schema.Struct({ |
| 1780 | protocolVersion: Schema.String |
| 1781 | }) |
| 1782 | }) |
| 1783 | |
| 1784 | const getJsonRpcProtocolVersion = (message: unknown): string | undefined => { |
| 1785 | const decoded = Schema.decodeUnknownResult(JsonRpcProtocolVersion)(message) |
| 1786 | return Result.isSuccess(decoded) ? decoded.success.params.protocolVersion : undefined |
| 1787 | } |
| 1788 | |
| 1789 | const INTERNAL_TOOL_ERROR_MESSAGE = "Tool execution failed due to an internal server error." |
| 1790 | |
| 1791 | const toolErrorResult = (message: string): CallToolResult => |
| 1792 | new CallToolResult({ |
| 1793 | isError: true, |
| 1794 | content: [{ type: "text", text: message }] |
| 1795 | }) |
| 1796 | |
| 1797 | const toolResultContent = (encoded: unknown): CallToolResult["content"] => |
| 1798 | encoded === undefined ? [] : [{ type: "text", text: JSON.stringify(encoded) }] |
| 1799 | |
| 1800 | /** |
| 1801 | * Registers a `Toolkit` with the `McpServer`. |
| 1802 | * |
| 1803 | * @stability unstable |
| 1804 | * @category handlers |
| 1805 | * @since 4.0.0 |
| 1806 | */ |
| 1807 | export const registerToolkit: <Tools extends Record<string, Tool.Any>>( |
| 1808 | toolkit: Toolkit.Toolkit<Tools> |
| 1809 | ) => Effect.Effect< |
| 1810 | void, |
| 1811 | never, |
| 1812 | McpServer | Tool.HandlersFor<Tools> | Exclude<Tool.HandlerServices<Tools>, McpRequestContext> |
| 1813 | > = Effect.fnUntraced(function*<Tools extends Record<string, Tool.Any>>( |
| 1814 | toolkit: Toolkit.Toolkit<Tools> |
| 1815 | ) { |
| 1816 | const registry = yield* McpServer |
| 1817 | const built = yield* (toolkit as any as Effect.Effect< |
| 1818 | Toolkit.WithHandler<Tools>, |
| 1819 | never, |
| 1820 | Exclude<Tool.HandlersFor<Tools>, McpRequestContext> |
| 1821 | >).pipe(Effect.updateContext((context: Context.Context<Exclude<Tool.HandlersFor<Tools>, McpRequestContext>>) => { |
| 1822 | // Toolkit handlers also retain the context in which their layer was built. |
| 1823 | const services = new Map(context.mapUnsafe) |
| 1824 | for (const tool of Object.values(toolkit.tools)) { |
| 1825 | const handler = services.get(tool.id) as Tool.Handler<string> | undefined |
| 1826 | if (handler !== undefined) { |
| 1827 | services.set(tool.id, { ...handler, context: omitRequestServices(handler.context) }) |
| 1828 | } |
| 1829 | } |
| 1830 | return Context.makeUnsafe(services) |
| 1831 | })) |
| 1832 | const services = omitRequestServices(yield* Effect.context<never>()) |
| 1833 | const reportCause = (cause: Cause.Cause<unknown>) => Effect.provideContext(ErrorReporter.report(cause), services) |
| 1834 | // Interruption propagates; anything else is logged, reported and scrubbed. |
| 1835 | const internalToolError = (cause: Cause.Cause<unknown>) => { |
| 1836 | const failure = Cause.findFail(cause) |
| 1837 | return Result.isFailure(failure) && !Cause.hasDies(cause) |
| 1838 | ? Effect.failCause(failure.failure) |
| 1839 | : Effect.logError(cause).pipe( |
| 1840 | Effect.andThen(reportCause(cause)), |
| 1841 | Effect.as(toolErrorResult(INTERNAL_TOOL_ERROR_MESSAGE)) |
| 1842 | ) |
| 1843 | } |
| 1844 | const registrations: Array<Parameters<typeof registry.addTool>[0]> = [] |
| 1845 | for (const tool of Object.values(built.tools)) { |
| 1846 | const strict = Tool.getStrictMode(tool) === true |
| 1847 | const rawJsonSchema = Tool.isDynamic(tool) ? tool.jsonSchema : undefined |
| 1848 | if (strict && rawJsonSchema !== undefined) { |
| 1849 | return yield* Effect.die( |
| 1850 | `McpServer cannot strictly validate the raw JSON Schema for tool '${tool.name}'; use an Effect Schema instead` |
| 1851 | ) |
| 1852 | } |
| 1853 | const decodeOptions: SchemaAST.ParseOptions = { |
| 1854 | onExcessProperty: strict ? "error" : "ignore", |
| 1855 | errors: "all" |
| 1856 | } |
| 1857 | const annotations = tool.annotations |
| 1858 | const toolMeta = Context.getOrUndefined(annotations, Tool.Meta) |
| 1859 | const isDeclaredFailure = Schema.is(tool.failureSchema) |
| 1860 | const encodeFailure = Schema.encodeUnknownEffect(tool.failureSchema) as ( |
| 1861 | error: unknown |
| 1862 | ) => Effect.Effect<unknown, Schema.SchemaError, Tool.HandlerServices<Tools[keyof Tools]>> |
| 1863 | const declaredFailureResult = (error: unknown) => |
| 1864 | error instanceof Error && error.message !== "" |
| 1865 | ? Effect.succeed(toolErrorResult(error.message)) |
| 1866 | : Effect.map(encodeFailure(error), (encoded) => |
| 1867 | new CallToolResult({ isError: true, content: toolResultContent(encoded) })) |
| 1868 | const handleCause = (cause: Cause.Cause<unknown>) => { |
| 1869 | const failure = Cause.findFail(cause) |
| 1870 | if (Result.isSuccess(failure)) { |
| 1871 | const error = failure.success.error |
| 1872 | const origin = Context.get(Cause.reasonAnnotations(failure.success), Toolkit.FailureOrigin) |
| 1873 | if (origin === "parameters" && isParameterValidationError(error)) { |
| 1874 | return Effect.fail(new InvalidParams({ message: error.reason.message })) |
| 1875 | } |
| 1876 | if (origin === "handler" && isDeclaredFailure(error)) { |
| 1877 | return Effect.catchCause(declaredFailureResult(error), internalToolError) |
| 1878 | } |
| 1879 | } |
| 1880 | return internalToolError(cause) |
| 1881 | } |
| 1882 | const outputSchema = yield* Schema.decodeUnknownEffect(McpSchema.ToolOutputJson)( |
| 1883 | toolJsonSchema(tool.successSchema, false) |
| 1884 | ).pipe(Effect.orDie) |
| 1885 | const inputSchema = yield* Schema.decodeUnknownEffect(ToolJson)( |
| 1886 | rawJsonSchema ?? toolJsonSchema(tool.parametersSchema, strict) |
| 1887 | ).pipe( |
| 1888 | Effect.catchTag("SchemaError", (error) => |
| 1889 | Effect.die( |
| 1890 | rawJsonSchema !== undefined |
| 1891 | ? `McpServer cannot register tool '${tool.name}': its raw JSON Schema must have an object root ` + |
| 1892 | `(type: "object").\n\n${error.message}` |
| 1893 | : `McpServer cannot register tool '${tool.name}': its parameters must encode to a JSON Schema with an ` + |
| 1894 | `object root (type: "object"), such as a Schema.Struct. Use Tool.EmptyParams for a tool without ` + |
| 1895 | `parameters.\n\n${error.message}` |
| 1896 | )) |
| 1897 | ) |
| 1898 | const mcpTool = new McpTool({ |
| 1899 | name: tool.name, |
| 1900 | description: Tool.getDescription(tool), |
| 1901 | inputSchema, |
| 1902 | outputSchema, |
| 1903 | annotations: { |
| 1904 | ...(Context.getOption(tool.annotations, Tool.Title).pipe( |
| 1905 | Option.map((title) => ({ title })), |
| 1906 | Option.getOrUndefined |
| 1907 | )), |
| 1908 | readOnlyHint: Context.get(tool.annotations, Tool.Readonly), |
| 1909 | destructiveHint: Context.get(tool.annotations, Tool.Destructive), |
| 1910 | idempotentHint: Context.get(tool.annotations, Tool.Idempotent), |
| 1911 | openWorldHint: Context.get(tool.annotations, Tool.OpenWorld) |
| 1912 | }, |
| 1913 | _meta: toolMeta |
| 1914 | }) |
| 1915 | registrations.push({ |
| 1916 | tool: mcpTool, |
| 1917 | annotations, |
| 1918 | handle(payload) { |
| 1919 | return built.handle(tool.name as keyof Tools, payload ?? {}, undefined, decodeOptions).pipe( |
| 1920 | Stream.unwrap, |
| 1921 | Stream.runLast, |
| 1922 | Effect.flatMap(Effect.fromOption), |
| 1923 | Effect.flatMap((result) => |
| 1924 | // Declared failures return their encoded payload; anything else is classified by origin. |
| 1925 | result.isFailure && result.failureOrigin !== "handler" |
| 1926 | ? Effect.failCause(Cause.annotate( |
| 1927 | Cause.fail(result.result), |
| 1928 | Context.make(Toolkit.FailureOrigin, result.failureOrigin ?? "result") |
| 1929 | )) |
| 1930 | : Effect.succeed( |
| 1931 | new CallToolResult({ |
| 1932 | isError: result.isFailure, |
| 1933 | structuredContent: result.isFailure ? undefined : result.encodedResult, |
| 1934 | content: toolResultContent(result.encodedResult) |
| 1935 | }) |
| 1936 | ) |
| 1937 | ), |
| 1938 | Effect.catchCause(handleCause), |
| 1939 | Effect.provideContext(services as Context.Context<Tool.HandlerServices<Tools[keyof Tools]>>) |
| 1940 | ) |
| 1941 | } |
| 1942 | }) |
| 1943 | } |
| 1944 | for (const registration of registrations) { |
| 1945 | yield* registry.addTool(registration) |
| 1946 | } |
| 1947 | }) |
| 1948 | |
| 1949 | const isParameterValidationError = ( |
| 1950 | error: unknown |
| 1951 | ): error is AiError.AiError & { readonly reason: AiError.ToolParameterValidationError } => |
| 1952 | AiError.isAiError(error) && error.reason._tag === "ToolParameterValidationError" |
| 1953 | |
| 1954 | // MCP requires an object root, so a top-level `$ref` is inlined. |
| 1955 | const toolJsonSchema = (schema: Schema.Constraint, strict: boolean): JsonSchema.JsonSchema => { |
| 1956 | const document = InternalStructuredOutput.resolveTopLevelReference( |
| 1957 | Schema.toJsonSchemaDocument(schema, { onExcessProperty: strict ? "error" : "ignore" }) |
| 1958 | ) |
| 1959 | return Object.keys(document.definitions).length === 0 |
| 1960 | ? document.schema |
| 1961 | : { ...document.schema, $defs: document.definitions } |
| 1962 | } |
| 1963 | |
| 1964 | /** |
| 1965 | * Registers an `AiToolkit` with the `McpServer`. |
| 1966 | * |
| 1967 | * @stability unstable |
| 1968 | * @category layers |
| 1969 | * @since 4.0.0 |
| 1970 | */ |
| 1971 | export const toolkit = <Tools extends Record<string, Tool.Any>>( |
| 1972 | toolkit: Toolkit.Toolkit<Tools> |
| 1973 | ): Layer.Layer< |
| 1974 | never, |
| 1975 | never, |
| 1976 | Tool.HandlersFor<Tools> | Exclude<Tool.HandlerServices<Tools>, McpRequestContext> |
| 1977 | > => |
| 1978 | Layer.effectDiscard(registerToolkit(toolkit)).pipe( |
| 1979 | Layer.provide(McpServer.layer) |
| 1980 | ) |
| 1981 | |
| 1982 | /** |
| 1983 | * Utility type that validates a completion-handler record against the allowed |
| 1984 | * parameter keys. |
| 1985 | * |
| 1986 | * @stability unstable |
| 1987 | * @category utility types |
| 1988 | * @since 4.0.0 |
| 1989 | */ |
| 1990 | export type ValidateCompletions<Completions, Keys extends string> = |
| 1991 | & Completions |
| 1992 | & { |
| 1993 | readonly [K in keyof Completions]: K extends Keys ? ( |
| 1994 | input: string, |
| 1995 | context: CompletionContext |
| 1996 | ) => any |
| 1997 | : never |
| 1998 | } |
| 1999 | |
| 2000 | /** |
| 2001 | * Completion-handler map for a resource URI template. |
| 2002 | * |
| 2003 | * **Details** |
| 2004 | * |
| 2005 | * Each schema interpolation contributes a parameter key, using an explicit |
| 2006 | * `Param` name when present or `paramN` otherwise, and each handler returns |
| 2007 | * candidate values for that parameter. |
| 2008 | * |
| 2009 | * @stability unstable |
| 2010 | * @category models |
| 2011 | * @since 4.0.0 |
| 2012 | */ |
| 2013 | export type ResourceCompletions<Schemas extends ReadonlyArray<Schema.Constraint>> = { |
| 2014 | readonly [ |
| 2015 | K in Extract<keyof Schemas, `${number}`> as Schemas[K] extends Param<infer Id, infer _S> ? Id |
| 2016 | : `param${K}` |
| 2017 | ]: ( |
| 2018 | input: string, |
| 2019 | context: CompletionContext |
| 2020 | ) => Effect.Effect<Array<Schemas[K]["Type"]>, any, any> |
| 2021 | } |
| 2022 | |
| 2023 | /** |
| 2024 | * Registers an MCP resource or resource template from an Effect program. |
| 2025 | * |
| 2026 | * **When to use** |
| 2027 | * |
| 2028 | * Use when you are already inside an Effect program with an `McpServer` |
| 2029 | * service and need to add a concrete resource or URI-template resource |
| 2030 | * directly. |
| 2031 | * |
| 2032 | * @see {@link resource} for the layer-based resource registration wrapper |
| 2033 | * |
| 2034 | * @stability unstable |
| 2035 | * @category handlers |
| 2036 | * @since 4.0.0 |
| 2037 | */ |
| 2038 | export const registerResource: { |
| 2039 | <E, R>(options: { |
| 2040 | readonly uri: string |
| 2041 | readonly name: string |
| 2042 | readonly description?: string | undefined |
| 2043 | readonly mimeType?: string | undefined |
| 2044 | readonly audience?: ReadonlyArray<"user" | "assistant"> | undefined |
| 2045 | readonly priority?: number | undefined |
| 2046 | readonly content: Effect.Effect< |
| 2047 | ReadResourceResult | string | Uint8Array, |
| 2048 | E, |
| 2049 | R |
| 2050 | > |
| 2051 | readonly annotations?: Context.Context<never> | undefined |
| 2052 | }): Effect.Effect<void, never, Exclude<R, McpRequestContext> | McpServer> |
| 2053 | <const Schemas extends ReadonlyArray<Schema.Constraint>>(segments: TemplateStringsArray, ...schemas: Schemas): < |
| 2054 | E, |
| 2055 | R, |
| 2056 | const Completions extends Partial<ResourceCompletions<Schemas>> = {} |
| 2057 | >(options: { |
| 2058 | readonly name: string |
| 2059 | readonly description?: string | undefined |
| 2060 | readonly mimeType?: string | undefined |
| 2061 | readonly audience?: ReadonlyArray<"user" | "assistant"> | undefined |
| 2062 | readonly priority?: number | undefined |
| 2063 | readonly completion?: ValidateCompletions<Completions, keyof ResourceCompletions<Schemas>> | undefined |
| 2064 | readonly content: (uri: string, ...params: { readonly [K in keyof Schemas]: Schemas[K]["Type"] }) => Effect.Effect< |
| 2065 | ReadResourceResult | string | Uint8Array, |
| 2066 | E, |
| 2067 | R |
| 2068 | > |
| 2069 | readonly annotations?: Context.Context<never> | undefined |
| 2070 | }) => Effect.Effect< |
| 2071 | void, |
| 2072 | never, |
| 2073 | | Exclude< |
| 2074 | | Schemas[number]["DecodingServices"] |
| 2075 | | Schemas[number]["EncodingServices"] |
| 2076 | | R |
| 2077 | | (Completions[keyof Completions] extends (input: string) => infer Ret ? |
| 2078 | Ret extends Effect.Effect<infer _A, infer _E, infer _R> ? _R : never |
| 2079 | : never), |
| 2080 | McpRequestContext |
| 2081 | > |
| 2082 | | McpServer |
| 2083 | > |
| 2084 | } = function() { |
| 2085 | if (arguments.length === 1) { |
| 2086 | const options = arguments[0] as { |
| 2087 | readonly uri: string |
| 2088 | readonly name: string |
| 2089 | readonly description?: string | undefined |
| 2090 | readonly mimeType?: string | undefined |
| 2091 | readonly audience?: ReadonlyArray<"user" | "assistant"> | undefined |
| 2092 | readonly priority?: number | undefined |
| 2093 | readonly content: Effect.Effect<ReadResourceResult | string | Uint8Array, any, any> |
| 2094 | readonly annotations?: Context.Context<never> | undefined |
| 2095 | } |
| 2096 | return Effect.gen(function*() { |
| 2097 | const services = omitRequestServices(yield* Effect.context<any>()) |
| 2098 | const registry = yield* McpServer |
| 2099 | yield* registry.addResource({ |
| 2100 | resource: new Resource({ |
| 2101 | ...options, |
| 2102 | annotations: options |
| 2103 | }), |
| 2104 | handle: options.content.pipe( |
| 2105 | Effect.provideContext(services), |
| 2106 | Effect.map((content) => resolveResourceContent(options.uri, content)), |
| 2107 | Effect.catchCause((cause) => { |
| 2108 | const prettyError = Cause.prettyErrors(cause)[0] |
| 2109 | return Effect.fail(new InternalError({ message: prettyError.message })) |
| 2110 | }) |
| 2111 | ), |
| 2112 | annotations: options.annotations ?? Context.empty() |
| 2113 | }) |
| 2114 | }) |
| 2115 | } |
| 2116 | const { |
| 2117 | params, |
| 2118 | routerPath, |
| 2119 | schema, |
| 2120 | uriPath |
| 2121 | } = compileUriTemplate(...(arguments as any as [any, any])) |
| 2122 | return Effect.fnUntraced(function*<E, R>(options: { |
| 2123 | readonly name: string |
| 2124 | readonly description?: string | undefined |
| 2125 | readonly mimeType?: string | undefined |
| 2126 | readonly audience?: ReadonlyArray<"user" | "assistant"> | undefined |
| 2127 | readonly priority?: number | undefined |
| 2128 | readonly completion?: |
| 2129 | | Record< |
| 2130 | string, |
| 2131 | ( |
| 2132 | input: string, |
| 2133 | context: CompletionContext |
| 2134 | ) => Effect.Effect<any> |
| 2135 | > |
| 2136 | | undefined |
| 2137 | readonly content: (uri: string, ...params: Array<any>) => Effect.Effect< |
| 2138 | ReadResourceResult | string | Uint8Array, |
| 2139 | E, |
| 2140 | R |
| 2141 | > |
| 2142 | readonly annotations?: Context.Context<never> | undefined |
| 2143 | }) { |
| 2144 | const services = omitRequestServices(yield* Effect.context<any>()) |
| 2145 | const registry = yield* McpServer |
| 2146 | const decode = Schema.decodeUnknownEffect(schema) |
| 2147 | const template = new ResourceTemplate({ |
| 2148 | ...options, |
| 2149 | uriTemplate: uriPath, |
| 2150 | annotations: options! |
| 2151 | }) |
| 2152 | const completions: Record< |
| 2153 | string, |
| 2154 | ( |
| 2155 | input: string, |
| 2156 | context: CompletionContext |
| 2157 | ) => Effect.Effect<CompleteResult, InternalError> |
| 2158 | > = Object.create(null) |
| 2159 | for (const [param, handle] of Object.entries(options.completion ?? {})) { |
| 2160 | const encodeArray = Schema.encodeUnknownEffect(Schema.Array(params[param])) |
| 2161 | const handler = ( |
| 2162 | input: string, |
| 2163 | context: CompletionContext |
| 2164 | ) => |
| 2165 | handle(input, context).pipe( |
| 2166 | Effect.flatMap(encodeArray), |
| 2167 | Effect.map((values) => ({ |
| 2168 | completion: { |
| 2169 | values: values as Array<string>, |
| 2170 | total: values.length, |
| 2171 | hasMore: false |
| 2172 | } |
| 2173 | })), |
| 2174 | Effect.catchCause((cause) => { |
| 2175 | const prettyError = Cause.prettyErrors(cause)[0] |
| 2176 | return Effect.fail(new InternalError({ message: prettyError.message })) |
| 2177 | }), |
| 2178 | Effect.provideContext(services) |
| 2179 | ) |
| 2180 | completions[param] = handler |
| 2181 | } |
| 2182 | yield* registry.addResourceTemplate({ |
| 2183 | template, |
| 2184 | routerPath, |
| 2185 | completions, |
| 2186 | annotations: options.annotations ?? Context.empty(), |
| 2187 | handle: (uri, params) => |
| 2188 | decode(params).pipe( |
| 2189 | Effect.mapError((error) => new InvalidParams({ message: error.message })), |
| 2190 | Effect.flatMap((params: any) => |
| 2191 | options.content(uri, ...params).pipe( |
| 2192 | Effect.map((content) => resolveResourceContent(uri, content)), |
| 2193 | Effect.catchCause((cause) => { |
| 2194 | const prettyError = Cause.prettyErrors(cause)[0] |
| 2195 | return Effect.fail(new InternalError({ message: prettyError.message })) |
| 2196 | }) |
| 2197 | ) |
| 2198 | ), |
| 2199 | Effect.provideContext(services) |
| 2200 | ) |
| 2201 | }) |
| 2202 | }) |
| 2203 | } as any |
| 2204 | |
| 2205 | /** |
| 2206 | * Creates a layer that registers an MCP resource or resource template. |
| 2207 | * |
| 2208 | * **When to use** |
| 2209 | * |
| 2210 | * Use to compose resource registration into an MCP server layer. |
| 2211 | * |
| 2212 | * @see {@link registerResource} for the Effect-level resource registration API |
| 2213 | * |
| 2214 | * @stability unstable |
| 2215 | * @category layers |
| 2216 | * @since 4.0.0 |
| 2217 | */ |
| 2218 | export const resource: { |
| 2219 | <E, R>(options: { |
| 2220 | readonly uri: string |
| 2221 | readonly name: string |
| 2222 | readonly description?: string | undefined |
| 2223 | readonly mimeType?: string | undefined |
| 2224 | readonly audience?: ReadonlyArray<"user" | "assistant"> | undefined |
| 2225 | readonly priority?: number | undefined |
| 2226 | readonly content: Effect.Effect< |
| 2227 | ReadResourceResult | string | Uint8Array, |
| 2228 | E, |
| 2229 | R |
| 2230 | > |
| 2231 | }): Layer.Layer<never, never, Exclude<R, McpRequestContext>> |
| 2232 | <const Schemas extends ReadonlyArray<Schema.Constraint>>(segments: TemplateStringsArray, ...schemas: Schemas): < |
| 2233 | E, |
| 2234 | R, |
| 2235 | const Completions extends Partial<ResourceCompletions<Schemas>> = {} |
| 2236 | >(options: { |
| 2237 | readonly name: string |
| 2238 | readonly description?: string | undefined |
| 2239 | readonly mimeType?: string | undefined |
| 2240 | readonly audience?: ReadonlyArray<"user" | "assistant"> | undefined |
| 2241 | readonly priority?: number | undefined |
| 2242 | readonly completion?: ValidateCompletions<Completions, keyof ResourceCompletions<Schemas>> | undefined |
| 2243 | readonly content: (uri: string, ...params: { readonly [K in keyof Schemas]: Schemas[K]["Type"] }) => Effect.Effect< |
| 2244 | ReadResourceResult | string | Uint8Array, |
| 2245 | E, |
| 2246 | R |
| 2247 | > |
| 2248 | }) => Layer.Layer< |
| 2249 | never, |
| 2250 | never, |
| 2251 | Exclude< |
| 2252 | | R |
| 2253 | | (Completions[keyof Completions] extends (input: string) => infer Ret ? |
| 2254 | Ret extends Effect.Effect<infer _A, infer _E, infer _R> ? _R : never |
| 2255 | : never), |
| 2256 | McpRequestContext |
| 2257 | > |
| 2258 | > |
| 2259 | } = function() { |
| 2260 | if (arguments.length === 1) { |
| 2261 | return Layer.effectDiscard(registerResource(arguments[0])).pipe( |
| 2262 | Layer.provide(McpServer.layer) |
| 2263 | ) |
| 2264 | } |
| 2265 | const register = registerResource(...(arguments as any as [any, any])) |
| 2266 | return (options: any) => |
| 2267 | Layer.effectDiscard(register(options)).pipe( |
| 2268 | Layer.provide(McpServer.layer) |
| 2269 | ) |
| 2270 | } as any |
| 2271 | |
| 2272 | /** |
| 2273 | * Registers an MCP prompt from an Effect program. |
| 2274 | * |
| 2275 | * **When to use** |
| 2276 | * |
| 2277 | * Use when you are already inside an Effect program with an `McpServer` |
| 2278 | * service and need to add a prompt handler directly. |
| 2279 | * |
| 2280 | * **Details** |
| 2281 | * |
| 2282 | * Parameters are decoded with the supplied schema, completion handlers encode |
| 2283 | * per-parameter suggestions, and string prompt content is converted into a user |
| 2284 | * text message. |
| 2285 | * |
| 2286 | * @see {@link prompt} for the layer-based prompt registration wrapper |
| 2287 | * |
| 2288 | * @stability unstable |
| 2289 | * @category handlers |
| 2290 | * @since 4.0.0 |
| 2291 | */ |
| 2292 | export const registerPrompt = < |
| 2293 | E, |
| 2294 | R, |
| 2295 | Params extends Schema.Struct.Fields = {}, |
| 2296 | const Completions extends { |
| 2297 | readonly [K in keyof Params]?: ( |
| 2298 | input: string, |
| 2299 | context: CompletionContext |
| 2300 | ) => Effect.Effect<Array<Params[K]["Type"]>, any, any> |
| 2301 | } = {} |
| 2302 | >( |
| 2303 | options: { |
| 2304 | readonly name: string |
| 2305 | readonly title?: string | undefined |
| 2306 | readonly description?: string | undefined |
| 2307 | readonly parameters?: Params | undefined |
| 2308 | readonly completion?: ValidateCompletions<Completions, Extract<keyof Params, string>> | undefined |
| 2309 | readonly content: ( |
| 2310 | params: Schema.Struct.Type<Params> |
| 2311 | ) => Effect.Effect<Array<PromptMessage> | string, E, R> |
| 2312 | readonly annotations?: Context.Context<never> | undefined |
| 2313 | } |
| 2314 | ): Effect.Effect< |
| 2315 | void, |
| 2316 | never, |
| 2317 | Exclude<Schema.Struct.DecodingServices<Params> | R, McpRequestContext> | McpServer |
| 2318 | > => { |
| 2319 | const args = Arr.empty<PromptArgument>() |
| 2320 | const props: Record<string, Schema.Constraint> = options.parameters ?? {} |
| 2321 | for (const [name, prop] of Object.entries(props)) { |
| 2322 | args.push({ |
| 2323 | name, |
| 2324 | description: SchemaAST.resolveDescription(prop.ast), |
| 2325 | required: !SchemaAST.isOptional(prop.ast) |
| 2326 | }) |
| 2327 | } |
| 2328 | const prompt = new Prompt({ |
| 2329 | name: options.name, |
| 2330 | title: options.title, |
| 2331 | description: options.description, |
| 2332 | arguments: args |
| 2333 | }) |
| 2334 | const decode = options.parameters |
| 2335 | ? Schema.decodeEffect(Schema.Struct(props)) |
| 2336 | : () => Effect.succeed({} as Params) |
| 2337 | const completion: Record< |
| 2338 | string, |
| 2339 | ( |
| 2340 | input: string, |
| 2341 | context: CompletionContext |
| 2342 | ) => Effect.Effect<any> |
| 2343 | > = options.completion ?? {} |
| 2344 | return Effect.gen(function*() { |
| 2345 | const registry = yield* McpServer |
| 2346 | const services = omitRequestServices( |
| 2347 | yield* Effect.context< |
| 2348 | Exclude<R | Schema.Struct.DecodingServices<Params>, McpRequestContext> |
| 2349 | >() |
| 2350 | ) |
| 2351 | const completions: Record< |
| 2352 | string, |
| 2353 | ( |
| 2354 | input: string, |
| 2355 | context: CompletionContext |
| 2356 | ) => Effect.Effect<CompleteResult, InternalError, McpRequestContext> |
| 2357 | > = Object.create(null) |
| 2358 | for (const [param, handle] of Object.entries(completion)) { |
| 2359 | const encodeArray = Schema.encodeEffect(Schema.Array(props[param])) |
| 2360 | const handler = ( |
| 2361 | input: string, |
| 2362 | context: CompletionContext |
| 2363 | ) => |
| 2364 | handle(input, context).pipe( |
| 2365 | Effect.flatMap(encodeArray), |
| 2366 | Effect.map((values) => ({ |
| 2367 | completion: { |
| 2368 | values: values as Array<string>, |
| 2369 | total: values.length, |
| 2370 | hasMore: false |
| 2371 | } |
| 2372 | })), |
| 2373 | Effect.catchCause((cause) => { |
| 2374 | const prettyError = Cause.prettyErrors(cause)[0] |
| 2375 | return Effect.fail(new InternalError({ message: prettyError.message })) |
| 2376 | }), |
| 2377 | Effect.provide(services) |
| 2378 | ) |
| 2379 | completions[param] = handler as any |
| 2380 | } |
| 2381 | yield* registry.addPrompt({ |
| 2382 | prompt, |
| 2383 | completions, |
| 2384 | annotations: options.annotations ?? Context.empty(), |
| 2385 | handle: (params) => |
| 2386 | decode(params).pipe( |
| 2387 | Effect.mapError((error) => new InvalidParams({ message: error.message })), |
| 2388 | Effect.flatMap((params) => |
| 2389 | options.content(params as any).pipe( |
| 2390 | Effect.catchCause((cause) => { |
| 2391 | const prettyError = Cause.prettyErrors(cause)[0] |
| 2392 | return Effect.fail(new InternalError({ message: prettyError.message })) |
| 2393 | }) |
| 2394 | ) |
| 2395 | ), |
| 2396 | Effect.map((messages) => { |
| 2397 | messages = typeof messages === "string" ? |
| 2398 | [{ |
| 2399 | role: "user", |
| 2400 | content: TextContent.make({ text: messages }) |
| 2401 | }] : |
| 2402 | messages |
| 2403 | return new GetPromptResult({ messages, description: prompt.description }) |
| 2404 | }), |
| 2405 | Effect.provideContext(services as Context.Context<unknown>) |
| 2406 | ) |
| 2407 | }) |
| 2408 | }) |
| 2409 | } |
| 2410 | |
| 2411 | /** |
| 2412 | * Creates a layer that registers an MCP prompt. |
| 2413 | * |
| 2414 | * **When to use** |
| 2415 | * |
| 2416 | * Use to compose prompt registration into an MCP server layer. |
| 2417 | * |
| 2418 | * **Details** |
| 2419 | * |
| 2420 | * Parameters are decoded with the supplied schema, completion handlers encode |
| 2421 | * per-parameter suggestions, and string prompt content is converted into a user |
| 2422 | * text message. |
| 2423 | * |
| 2424 | * @see {@link registerPrompt} for the Effect-level prompt registration API |
| 2425 | * |
| 2426 | * @stability unstable |
| 2427 | * @category layers |
| 2428 | * @since 4.0.0 |
| 2429 | */ |
| 2430 | export const prompt = < |
| 2431 | E, |
| 2432 | R, |
| 2433 | Params extends Schema.Struct.Fields = {}, |
| 2434 | const Completions extends { |
| 2435 | readonly [K in keyof Params]?: ( |
| 2436 | input: string, |
| 2437 | context: CompletionContext |
| 2438 | ) => Effect.Effect<Array<Params[K]["Type"]>, any, any> |
| 2439 | } = {} |
| 2440 | >( |
| 2441 | options: { |
| 2442 | readonly name: string |
| 2443 | readonly title?: string | undefined |
| 2444 | readonly description?: string | undefined |
| 2445 | readonly parameters?: Params | undefined |
| 2446 | readonly completion?: ValidateCompletions<Completions, Extract<keyof Params, string>> | undefined |
| 2447 | readonly content: ( |
| 2448 | params: Schema.Struct.Type<Params> |
| 2449 | ) => Effect.Effect<Array<PromptMessage> | string, E, R> |
| 2450 | readonly annotations?: Context.Context<never> | undefined |
| 2451 | } |
| 2452 | ): Layer.Layer< |
| 2453 | never, |
| 2454 | never, |
| 2455 | Exclude<Schema.Struct.DecodingServices<Params> | R, McpRequestContext> |
| 2456 | > => |
| 2457 | Layer.effectDiscard(registerPrompt(options)).pipe( |
| 2458 | Layer.provide(McpServer.layer) |
| 2459 | ) |
| 2460 | |
| 2461 | /** |
| 2462 | * Collects structured input from the current MCP client and decodes the |
| 2463 | * accepted response with `schema`. |
| 2464 | * |
| 2465 | * **Details** |
| 2466 | * |
| 2467 | * Accepted content is decoded with the supplied schema, declined requests fail |
| 2468 | * with `ElicitationDeclined`, and canceled requests interrupt the effect. |
| 2469 | * |
| 2470 | * @stability unstable |
| 2471 | * @category accessors |
| 2472 | * @since 4.0.0 |
| 2473 | */ |
| 2474 | export const elicit: <S extends Schema.ConstraintEncoder<Record<string, unknown>, unknown>>(options: { |
| 2475 | readonly message: string |
| 2476 | readonly schema: S |
| 2477 | }) => Effect.Effect< |
| 2478 | S["Type"], |
| 2479 | ElicitationDeclined, |
| 2480 | McpServerClient | S["DecodingServices"] |
| 2481 | > = Effect.fnUntraced(function*<S extends Schema.ConstraintEncoder<Record<string, unknown>, unknown>>(options: { |
| 2482 | readonly message: string |
| 2483 | readonly schema: S |
| 2484 | }) { |
| 2485 | const { getClient } = yield* McpServerClient |
| 2486 | const client = yield* getClient |
| 2487 | const schema = options.schema |
| 2488 | const request = yield* Schema.decodeUnknownEffect(McpSchema.ElicitRequestFormParams)({ |
| 2489 | mode: "form", |
| 2490 | message: options.message, |
| 2491 | requestedSchema: toolJsonSchema(schema, false) |
| 2492 | }).pipe(Effect.orDie) |
| 2493 | const res = yield* client.elicit(request).pipe( |
| 2494 | Effect.catchCause((cause) => Effect.fail(new ElicitationDeclined({ cause: Cause.squash(cause), request }))) |
| 2495 | ) |
| 2496 | switch (res.action) { |
| 2497 | case "accept": |
| 2498 | return yield* Effect.orDie(Schema.decodeUnknownEffect(schema)(res.content)) |
| 2499 | case "cancel": |
| 2500 | return yield* Effect.interrupt |
| 2501 | case "decline": |
| 2502 | return yield* new ElicitationDeclined({ request }) |
| 2503 | } |
| 2504 | }, Effect.scoped) |
| 2505 | |
| 2506 | /** |
| 2507 | * Accesses the current client's capabilities. |
| 2508 | * |
| 2509 | * @stability unstable |
| 2510 | * @category accessors |
| 2511 | * @since 4.0.0 |
| 2512 | */ |
| 2513 | export const clientCapabilities: Effect.Effect< |
| 2514 | ClientCapabilities, |
| 2515 | never, |
| 2516 | McpRequestContext |
| 2517 | > = McpRequestContext.useSync((_) => _.clientCapabilities) |
| 2518 | |
| 2519 | // ----------------------------------------------------------------------------- |
| 2520 | // Internal |
| 2521 | // ----------------------------------------------------------------------------- |
| 2522 | |
| 2523 | const makeUriMatcher = <A>() => { |
| 2524 | const router = FindMyWay.make<A>({ |
| 2525 | ignoreTrailingSlash: true, |
| 2526 | ignoreDuplicateSlashes: true, |
| 2527 | caseSensitive: true |
| 2528 | }) |
| 2529 | const add = (uri: string, value: A) => { |
| 2530 | router.on("GET", `/${uri}`, value) |
| 2531 | } |
| 2532 | const find = (uri: string) => router.find("GET", `/${uri}`) |
| 2533 | |
| 2534 | return { add, find } as const |
| 2535 | } |
| 2536 | |
| 2537 | const compileUriTemplate = (segments: TemplateStringsArray, ...schemas: ReadonlyArray<Schema.Constraint>) => { |
| 2538 | let routerPath = segments[0].replace(":", "::") |
| 2539 | let uriPath = segments[0] |
| 2540 | const params: Record<string, Schema.Top> = Object.create(null) |
| 2541 | let pathSchema = Schema.Tuple([]) as Schema.Top |
| 2542 | if (schemas.length > 0) { |
| 2543 | const arr: Array<Schema.Top> = [] |
| 2544 | for (let i = 0; i < schemas.length; i++) { |
| 2545 | const toCodecStringTree = Schema.toCodecStringTree(schemas[i]) |
| 2546 | const segment = segments[i + 1] |
| 2547 | const key = String(i) |
| 2548 | arr.push(toCodecStringTree) |
| 2549 | routerPath += `:${key}${segment.replace(":", "::")}` |
| 2550 | const schema = schemas[i] |
| 2551 | const paramName = isParam(schema) ? (schema as Param<string, Schema.Top>).name : `param${key}` |
| 2552 | params[paramName] = toCodecStringTree |
| 2553 | uriPath += `{${paramName}}${segment}` |
| 2554 | } |
| 2555 | pathSchema = Schema.Tuple(arr) |
| 2556 | } |
| 2557 | return { |
| 2558 | routerPath, |
| 2559 | uriPath, |
| 2560 | schema: pathSchema, |
| 2561 | params |
| 2562 | } as const |
| 2563 | } |
| 2564 | |
| 2565 | const resolveResourceContent = ( |
| 2566 | uri: string, |
| 2567 | content: ReadResourceResult | string | Uint8Array |
| 2568 | ): ReadResourceResult => { |
| 2569 | if (typeof content === "string") { |
| 2570 | return { |
| 2571 | contents: [{ |
| 2572 | uri, |
| 2573 | text: content |
| 2574 | }] |
| 2575 | } |
| 2576 | } else if (content instanceof Uint8Array) { |
| 2577 | return { |
| 2578 | contents: [{ |
| 2579 | uri, |
| 2580 | blob: content |
| 2581 | }] |
| 2582 | } |
| 2583 | } |
| 2584 | return content |
| 2585 | } |
| 2586 | |
| 2587 | const InvalidBatchExit = Schema.TaggedStruct("Exit", { |
| 2588 | requestId: Schema.Null, |
| 2589 | exit: Schema.TaggedStruct("Failure", { |
| 2590 | cause: Schema.Unknown |
| 2591 | }) |
| 2592 | }) |
| 2593 | |
| 2594 | const decodeInvalidBatchExit = Schema.decodeUnknownResult(InvalidBatchExit) |
| 2595 | |
| 2596 | const isProtocolVersion = (version: string): version is McpProtocol.ProtocolVersion => |
| 2597 | version === "2024-11-05" || |
| 2598 | version === "2025-03-26" || |
| 2599 | version === "2025-06-18" || |
| 2600 | version === "2025-11-25" || |
| 2601 | version === "2026-07-28" |