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McpServer unstable

Builds Model Context Protocol (MCP) servers with Effect.

The McpServer service stores the tools, resources, resource templates, prompts, completions, and outgoing notifications exposed by a server. This module also includes the server runner, custom protocol, stdio, and HTTP layers, registration helpers, and APIs that let handlers ask the connected client for structured input or read its advertised capabilities.

17 exports Since v4.0.0 Source

Accessors

clientCapabilities

unstable
Since v4.0.0

Accesses the current client's capabilities.

Signature

declare const clientCapabilities: Effect.Effect<ClientCapabilities, never, McpRequestContext>

elicit

unstable
Since v4.0.0

Collects structured input from the current MCP client and decodes the accepted response with schema.

Details

Accepted content is decoded with the supplied schema, declined requests fail with ElicitationDeclined, and canceled requests interrupt the effect.

Signature

declare const elicit: <S extends Schema.ConstraintEncoder<Record<string, unknown>, unknown>>(options: {
  readonly message: string;
  readonly schema: S;
}) => Effect.Effect<S["Type"], ElicitationDeclined, McpServerClient | S["DecodingServices"]>

Handlers

registerPrompt

unstable
Since v4.0.0

Registers an MCP prompt from an Effect program.

Details

Decodes parameters and encodes completion suggestions using their schemas. String content becomes a user text message.

See

  • prompt for the layer-based prompt registration wrapper

Signature

declare function registerPrompt<E, R, Params extends Fields = {}, Completions extends { [K in string | number | symbol]: (input: string, context: {
  readonly arguments?: {
    [key: string]: string;
  };
} | undefined) => Effect<Array<Params[K]["Type"]>, any, any> } = {}>(options: {
  readonly annotations?: Context<never>;
  readonly completion?: ValidateCompletions<Completions, Extract<keyof Params, string>>;
  readonly content: (params: View<Params>) => Effect<string | Array<PromptMessage>, E, R>;
  readonly description?: string;
  readonly name: string;
  readonly parameters?: Params;
  readonly title?: string;
}): Effect<void, never, McpServer | Exclude<R, McpRequestContext> | Exclude<DecodingServices<Params>, McpRequestContext> | Exclude<Params[Extract<keyof Completions, keyof Params>]["EncodingServices"], McpRequestContext> | Exclude<CompletionServices<Completions>, McpRequestContext>>

registerResource

unstable
Since v4.0.0

Registers an MCP resource or resource template from an Effect program.

See

  • resource for the layer-based resource registration wrapper

Signature

declare const registerResource: {
  <E, R>(options: {
    readonly annotations?: Context.Context<never>;
    readonly audience?: ReadonlyArray<"user" | "assistant">;
    readonly content: Effect.Effect<ReadResourceResult | string | Uint8Array, E, R>;
    readonly description?: string;
    readonly mimeType?: string;
    readonly name: string;
    readonly priority?: number;
    readonly uri: string;
  }): Effect<void, never, McpServer | Exclude<R, McpRequestContext>>;
  <Schemas extends readonly Array<Constraint>>(segments: TemplateStringsArray, ...schemas: Schemas): <E, R, Completions extends Partial<ResourceCompletions<Schemas>> = {}>(options: {
    readonly annotations?: Context.Context<never>;
    readonly audience?: ReadonlyArray<"user" | "assistant">;
    readonly completion?: ValidateCompletions<Completions, keyof ResourceCompletions<Schemas>>;
    readonly content: (uri: string, ...params: { [K in keyof Schemas]: Schemas[K]["Type"] }) => Effect.Effect<ReadResourceResult | string | Uint8Array, E, R>;
    readonly description?: string;
    readonly mimeType?: string;
    readonly name: string;
    readonly priority?: number;
  }) => Effect<void, never, McpServer | Exclude<R, McpRequestContext> | Exclude<Schemas[number]["DecodingServices"], McpRequestContext> | Exclude<Schemas[number]["EncodingServices"], McpRequestContext> | Exclude<CompletionServices<Completions>, McpRequestContext>>;
}

registerToolkit

unstable
Since v4.0.0

Registers a Toolkit with the McpServer.

Signature

declare const registerToolkit: <Tools extends Record<string, Tool.Any>>(toolkit: Toolkit.Toolkit<Tools>) => Effect.Effect<void, never, McpServer | Tool.HandlersFor<Tools> | Exclude<Tool.HandlerServices<Tools[keyof Tools]>, McpRequestContext>>

Layers

layer

unstable
Since v4.0.0

Creates a layer that starts an MCP server over an existing RpcServer.Protocol and provides McpServer. Request handlers receive McpRequestContext; initialized legacy requests additionally receive McpServerClient.

When to use

Use when you already have a custom or externally provided RpcServer.Protocol and want to start an MCP server as part of a layer graph.

Details

The returned layer forks run(options) in the layer scope and merges McpServer.layer, so registration layers can use the McpServer service while the server is running.

Gotchas

Unlike layerStdio and layerHttp, this layer does not install a concrete transport. The surrounding layer graph must provide RpcServer.Protocol.

See

  • run for the effect form used by this layer
  • layerStdio for a stdio-backed layer that installs the MCP protocol and NDJSON-RPC serialization
  • layerHttp for an HTTP-backed layer that registers with HttpRouter and installs JSON-RPC serialization

Signature

declare function layer(options: {
  readonly description?: string;
  readonly extensions?: {
    [key: `${string}/${string}`]: Json;
  };
  readonly icons?: readonly Array<Icon>;
  readonly instructions?: string;
  readonly name: string;
  readonly protocols: readonly [ProtocolAdapter<ProtocolVersion, RuntimeDescriptor>, ProtocolAdapter<ProtocolVersion, RuntimeDescriptor>];
  readonly version: string;
  readonly websiteUrl?: string;
}): Layer<McpServerClient | McpServer, IllegalArgumentError, Protocol>

layerHttp

unstable
Since v4.0.0

Registers a Streamable HTTP MCP endpoint at options.path.

When to use

Use to expose an MCP server through an existing HttpRouter.

Details

POST serves JSON-RPC and accepted notification-only requests return 202. Header mismatches, unsupported protocol versions, and invalid session-header usage return JSON-RPC errors with status 400. Unknown modern RPC methods return a JSON-RPC method-not-found error with status 404. Session requests without MCP-Protocol-Version use the version negotiated at initialization. Unsupported HTTP methods return 405. Requests with an Origin header are rejected unless the exact origin appears in allowedOrigins; Origin-less non-browser clients remain valid. The surrounding HTTP server remains responsible for binding to an appropriate interface and installing authentication.

With allowSessionTermination, a DELETE carrying Mcp-Session-Id ends that session with 204 and interrupts its in-flight requests; later requests with that id get 404. DELETE validates the session and MCP-Protocol-Version headers like POST. Without the option, or when only sessionless revisions such as v2026_07_28 are configured, DELETE returns 405. Any caller holding a session id can end that session, so authenticate requests in the surrounding router.

Set allowSubscriptions: false to disable v2026_07_28 subscriptions. Discovery advertises listChanged: false, and subscriptions/listen returns Method not found. Request-scoped progress and logs, legacy protocols, and default subscription behavior are unchanged.

The layer runs one long-lived MCP server that every POST shares. For serverless hosts where execution must belong to each request, use layerHttpRequestScoped instead.

layerHttp always implements the single-endpoint Streamable HTTP topology. Using v2024_11_05 here is a custom compatibility transport for that revision's schema. It does not implement the historical two-endpoint HTTP+SSE transport, GET SSE, event resumption, or session expiry.

Gotchas

This layer starts a scoped server fiber. For sharing it across Cloudflare Workers requests, see HttpRouter.toWebHandler for setup and limitations.

See

  • layerStdio for exposing the server over stdio
  • layer for the base MCP server layer without a transport protocol

Signature

declare function layerHttp(options: {
  readonly allowedOrigins?: readonly Array<string>;
  readonly allowSessionTermination?: boolean;
  readonly allowSubscriptions?: boolean;
  readonly description?: string;
  readonly extensions?: {
    [key: `${string}/${string}`]: Json;
  };
  readonly icons?: readonly Array<Icon>;
  readonly instructions?: string;
  readonly name: string;
  readonly path: PathInput;
  readonly protocols: readonly [ProtocolAdapter<ProtocolVersion, RuntimeDescriptor>, ProtocolAdapter<ProtocolVersion, RuntimeDescriptor>];
  readonly version: string;
  readonly websiteUrl?: string;
}): Layer<McpServerClient | McpServer, IllegalArgumentError, HttpRouter>

layerHttpRequestScoped

unstable
Since v4.0.0

Registers a request-scoped Streamable HTTP MCP endpoint at options.path.

When to use

Use when serving on serverless hosts such as Cloudflare Workers, where execution must belong to the HTTP request rather than a shared long-lived server.

Details

Each POST runs its own server in the request scope, with no background fiber, timer, or queue consumer left after the response body completes. Only sessionless protocols such as v2026_07_28 are accepted. Tools, resources, prompts, completions, multi round-trip input requests, and the request's own progress and log notifications are supported. Legacy reverse requests through McpServer.elicit are not available.

Discovery advertises listChanged: false, subscriptions/listen returns Method not found, and DELETE returns 405. Request-scoped clients receive no broadcast notifications such as list changes. Those still reach clients of a layerHttp endpoint sharing the same McpServer, and are dropped when no such endpoint exists. Use layerHttp on a long-lived host for sessions, subscriptions, or legacy reverse requests.

HTTP admission, origin checks, and JSON-RPC errors follow layerHttp. Configuring a sessionful protocol through an untyped caller fails layer construction with IllegalArgumentError.

See

  • layerHttp for the long-lived HTTP transport and HTTP admission policy

Signature

declare function layerHttpRequestScoped(options: {
  readonly allowedOrigins?: readonly Array<string>;
  readonly description?: string;
  readonly extensions?: {
    [key: `${string}/${string}`]: Json;
  };
  readonly icons?: readonly Array<Icon>;
  readonly instructions?: string;
  readonly name: string;
  readonly path: PathInput;
  readonly protocols: readonly [ProtocolAdapter<ProtocolVersion, StatelessRuntimeDescriptor>, ProtocolAdapter<ProtocolVersion, StatelessRuntimeDescriptor>];
  readonly version: string;
  readonly websiteUrl?: string;
}): Layer<McpServerClient | McpServer, IllegalArgumentError, HttpRouter>

layerStdio

unstable
Since v4.0.0

Creates a layer that runs an MCP server over standard input and output.

When to use

Use when an MCP client launches the server as a subprocess and communicates through newline-delimited JSON-RPC messages.

Details

The selected protocol adapter controls the dated RPC schemas and JSON-RPC batch policy. The layer provides McpServer, supplies request-scoped McpRequestContext and legacy McpServerClient services to handlers, and requires Stdio.

See

  • layer for running over an existing RpcServer.Protocol
  • layerHttp for the single-endpoint HTTP transport

Signature

declare function layerStdio(options: {
  readonly description?: string;
  readonly extensions?: {
    [key: `${string}/${string}`]: Json;
  };
  readonly icons?: readonly Array<Icon>;
  readonly instructions?: string;
  readonly name: string;
  readonly protocols: readonly [ProtocolAdapter<ProtocolVersion, RuntimeDescriptor>, ProtocolAdapter<ProtocolVersion, RuntimeDescriptor>];
  readonly version: string;
  readonly websiteUrl?: string;
}): Layer<McpServerClient | McpServer, IllegalArgumentError, Stdio>

prompt

unstable
Since v4.0.0

Creates a layer that registers an MCP prompt.

See

Signature

declare function prompt<E, R, Params extends Fields = {}, Completions extends { [K in string | number | symbol]: (input: string, context: {
  readonly arguments?: {
    [key: string]: string;
  };
} | undefined) => Effect<Array<Params[K]["Type"]>, any, any> } = {}>(options: {
  readonly annotations?: Context<never>;
  readonly completion?: ValidateCompletions<Completions, Extract<keyof Params, string>>;
  readonly content: (params: View<Params>) => Effect<string | Array<PromptMessage>, E, R>;
  readonly description?: string;
  readonly name: string;
  readonly parameters?: Params;
  readonly title?: string;
}): Layer<never, never, Exclude<R, McpRequestContext> | Exclude<DecodingServices<Params>, McpRequestContext> | Exclude<Params[Extract<keyof Completions, keyof Params>]["EncodingServices"], McpRequestContext> | Exclude<CompletionServices<Completions>, McpRequestContext>>

resource

unstable
Since v4.0.0

Creates a layer that registers an MCP resource or resource template.

See

Signature

declare const resource: {
  <E, R>(options: {
    readonly audience?: ReadonlyArray<"user" | "assistant">;
    readonly content: Effect.Effect<ReadResourceResult | string | Uint8Array, E, R>;
    readonly description?: string;
    readonly mimeType?: string;
    readonly name: string;
    readonly priority?: number;
    readonly uri: string;
  }): Layer<never, never, Exclude<R, McpRequestContext>>;
  <Schemas extends readonly Array<Constraint>>(segments: TemplateStringsArray, ...schemas: Schemas): <E, R, Completions extends Partial<ResourceCompletions<Schemas>> = {}>(options: {
    readonly audience?: ReadonlyArray<"user" | "assistant">;
    readonly completion?: ValidateCompletions<Completions, keyof ResourceCompletions<Schemas>>;
    readonly content: (uri: string, ...params: { [K in keyof Schemas]: Schemas[K]["Type"] }) => Effect.Effect<ReadResourceResult | string | Uint8Array, E, R>;
    readonly description?: string;
    readonly mimeType?: string;
    readonly name: string;
    readonly priority?: number;
  }) => Layer<never, never, Exclude<R, McpRequestContext> | Exclude<Schemas[number]["DecodingServices"], McpRequestContext> | Exclude<Schemas[number]["EncodingServices"], McpRequestContext> | Exclude<CompletionServices<Completions>, McpRequestContext>>;
}

toolkit

unstable
Since v4.0.0

Registers an AiToolkit with the McpServer.

Signature

declare function toolkit<Tools extends Record<string, Any>>(toolkit: Toolkit<Tools>): Layer<never, never, HandlersFor<Tools> | Exclude<HandlerServices<Tools[keyof Tools]>, McpRequestContext>>

Models

ResourceCompletions

type unstable
Since v4.0.0

Completion-handler map for a resource URI template.

Details

Each schema interpolation contributes a parameter key, using an explicit Param name when present or paramN otherwise, and each handler returns candidate values for that parameter.

Signature

type ResourceCompletions<Schemas extends ReadonlyArray<Schema.Constraint>> = { [K in Extract<keyof Schemas, `${number}`>]: (input: string, context: CompletionContext) => Effect.Effect<Array<Schemas[K]["Type"]>, any, any> }

Running

run

unstable
Since v4.0.0

Runs an MCP server over the current RpcServer.Protocol.

Details

The server serves registered tools, resources, and prompts. The selected MCP runtime handles protocol lifecycle state and determines which clients receive queued server notifications.

Signature

declare const run: (options: {
  readonly description?: string;
  readonly extensions?: ServerExtensions;
  readonly icons?: ReadonlyArray<McpSchema.Icon>;
  readonly instructions?: string;
  readonly name: string;
  readonly protocols: Arr.NonEmptyReadonlyArray<McpProtocol.ProtocolAdapter>;
  readonly version: string;
  readonly websiteUrl?: string;
}) => Effect.Effect<never, Cause.IllegalArgumentError, McpServer | RpcServer.Protocol>

Services

McpServer

unstable
Since v4.0.0

Service that stores and serves an MCP server's registered tools, resources, prompts, completions, and outgoing notifications.

Details

Handlers use this service to register capabilities and resolve incoming MCP requests.

Signature

declare class McpServer extends Shape<"effect/ai/McpServer", {
  readonly addPrompt: (options: {
    readonly annotations: Context<never>;
    readonly completions: Record<string, (input: string, context: CompletionContext) => Effect.Effect<CompleteResult, InternalError, McpRequestContext>>;
    readonly handle: (params: Record<string, string>) => Effect<GetPromptResult | InputRequired, InvalidParams | InternalError, McpRequestContext>;
    readonly prompt: Prompt;
  }) => Effect<void>;
  readonly addResource: (options: {
    readonly annotations: Context<never>;
    readonly handle: Effect<ReadResourceResult, InternalError, McpRequestContext>;
    readonly resource: Resource;
  }) => Effect<void>;
  readonly addResourceTemplate: (options: {
    readonly annotations: Context<never>;
    readonly completions: Record<string, (input: string, context: CompletionContext) => Effect.Effect<CompleteResult, InternalError>>;
    readonly handle: (uri: string, params: Array<string>) => Effect<ReadResourceResult, InvalidParams | InternalError, McpRequestContext>;
    readonly routerPath: string;
    readonly template: ResourceTemplate;
  }) => Effect<void>;
  readonly addTool: (options: {
    readonly annotations: Context<never>;
    readonly handle: (payload: any) => Effect<CallToolResult | InputRequired, InvalidParams | InternalError, McpRequestContext>;
    readonly tool: Tool;
  }) => Effect<void>;
  readonly callTool: (requests: {
    readonly _meta?: {
      [key: string]: Json;
      readonly progressToken?: string | number;
    };
    readonly arguments?: {
      [key: string]: any;
    };
    readonly name: string;
  }) => Effect<CallToolResult, InvalidParams | InternalError, McpServerClient>;
  readonly completion: (complete: {
    readonly argument: {
      readonly name: string;
      readonly value: string;
    };
    readonly context?: {
      readonly arguments?: {
        [key: string]: string;
      };
    };
    readonly ref: ResourceReference | PromptReference;
  }) => Effect<CompleteResult, InvalidParams | InternalError, McpServerClient>;
  readonly findResource: (uri: string) => Effect<ReadResourceResult, McpErrorBase | InvalidParams | InternalError, McpServerClient>;
  readonly getPromptResult: (request: {
    readonly _meta?: {
      [key: string]: Json;
      readonly progressToken?: string | number;
    };
    readonly arguments?: {
      [key: string]: string;
    };
    readonly name: string;
    readonly title?: string;
  }) => Effect<GetPromptResult, InvalidParams | InternalError, McpServerClient>;
  readonly notifications: {
    "notifications/cancelled": <AsQueue extends boolean = false, Discard = false>(input: {
      readonly _meta?: {
        [key: string]: unknown;
      };
      readonly reason?: string;
      readonly requestId: string | number;
    }, options?: {
      readonly context?: Context<never>;
      readonly discard?: Discard;
      readonly headers?: Input;
    }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
    "notifications/message": <AsQueue extends boolean = false, Discard = false>(input: {
      readonly _meta?: {
        [key: string]: unknown;
      };
      readonly data: any;
      readonly level: "error" | "debug" | "info" | "notice" | "warning" | "critical" | "alert" | "emergency";
      readonly logger?: string;
    }, options?: {
      readonly context?: Context<never>;
      readonly discard?: Discard;
      readonly headers?: Input;
    }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
    "notifications/progress": <AsQueue extends boolean = false, Discard = false>(input: {
      readonly _meta?: {
        [key: string]: unknown;
      };
      readonly message?: string;
      readonly progress: number;
      readonly progressToken: string | number;
      readonly total?: number;
    }, options?: {
      readonly context?: Context<never>;
      readonly discard?: Discard;
      readonly headers?: Input;
    }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
    "notifications/prompts/list_changed": <AsQueue extends boolean = false, Discard = false>(input: {
      readonly _meta?: {
        [key: string]: unknown;
      };
    } | undefined, options?: {
      readonly context?: Context<never>;
      readonly discard?: Discard;
      readonly headers?: Input;
    }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
    "notifications/resources/list_changed": <AsQueue extends boolean = false, Discard = false>(input: {
      readonly _meta?: {
        [key: string]: unknown;
      };
    } | undefined, options?: {
      readonly context?: Context<never>;
      readonly discard?: Discard;
      readonly headers?: Input;
    }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
    "notifications/resources/updated": <AsQueue extends boolean = false, Discard = false>(input: {
      readonly _meta?: {
        [key: string]: unknown;
      };
      readonly uri: string;
    }, options?: {
      readonly context?: Context<never>;
      readonly discard?: Discard;
      readonly headers?: Input;
    }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
    "notifications/tools/list_changed": <AsQueue extends boolean = false, Discard = false>(input: {
      readonly _meta?: {
        [key: string]: unknown;
      };
    } | undefined, options?: {
      readonly context?: Context<never>;
      readonly discard?: Discard;
      readonly headers?: Input;
    }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
  };
  readonly notifyElicitationComplete: (options: {
    readonly clientId: number;
    readonly elicitationId: string;
  }) => Effect<void>;
  readonly prompts: readonly Array<{
    readonly annotations: Context<never>;
    readonly prompt: Prompt;
  }>;
  readonly resources: readonly Array<{
    readonly annotations: Context<never>;
    readonly resource: Resource;
  }>;
  readonly resourceTemplates: readonly Array<{
    readonly annotations: Context<never>;
    readonly template: ResourceTemplate;
  }>;
  readonly tools: readonly Array<{
    readonly annotations: Context<never>;
    readonly tool: Tool;
  }>;
}, this> {
  constructor(_: never);
  static readonly layer: Layer<McpServerClient | McpServer>;
  static readonly make: Effect<{
    readonly addPrompt: (options: {
      readonly annotations: Context<never>;
      readonly completions: Record<string, (input: string, context: CompletionContext) => Effect.Effect<CompleteResult, InternalError, McpRequestContext>>;
      readonly handle: (params: Record<string, string>) => Effect<GetPromptResult | InputRequired, InvalidParams | InternalError, McpRequestContext>;
      readonly prompt: Prompt;
    }) => Effect<void>;
    readonly addResource: (options: {
      readonly annotations: Context<never>;
      readonly handle: Effect<ReadResourceResult, InternalError, McpRequestContext>;
      readonly resource: Resource;
    }) => Effect<void>;
    readonly addResourceTemplate: (options: {
      readonly annotations: Context<never>;
      readonly completions: Record<string, (input: string, context: CompletionContext) => Effect.Effect<CompleteResult, InternalError>>;
      readonly handle: (uri: string, params: Array<string>) => Effect<ReadResourceResult, InvalidParams | InternalError, McpRequestContext>;
      readonly routerPath: string;
      readonly template: ResourceTemplate;
    }) => Effect<void>;
    readonly addTool: (options: {
      readonly annotations: Context<never>;
      readonly handle: (payload: any) => Effect<CallToolResult | InputRequired, InvalidParams | InternalError, McpRequestContext>;
      readonly tool: Tool;
    }) => Effect<void>;
    readonly callTool: (requests: {
      readonly _meta?: {
        [key: string]: Json;
        readonly progressToken?: string | number;
      };
      readonly arguments?: {
        [key: string]: any;
      };
      readonly name: string;
    }) => Effect<CallToolResult, InvalidParams | InternalError, McpServerClient>;
    readonly completion: (complete: {
      readonly argument: {
        readonly name: string;
        readonly value: string;
      };
      readonly context?: {
        readonly arguments?: {
          [key: string]: string;
        };
      };
      readonly ref: ResourceReference | PromptReference;
    }) => Effect<CompleteResult, InvalidParams | InternalError, McpServerClient>;
    readonly findResource: (uri: string) => Effect<ReadResourceResult, McpErrorBase | InvalidParams | InternalError, McpServerClient>;
    readonly getPromptResult: (request: {
      readonly _meta?: {
        [key: string]: Json;
        readonly progressToken?: string | number;
      };
      readonly arguments?: {
        [key: string]: string;
      };
      readonly name: string;
      readonly title?: string;
    }) => Effect<GetPromptResult, InvalidParams | InternalError, McpServerClient>;
    readonly notifications: {
      "notifications/cancelled": <AsQueue extends boolean = false, Discard = false>(input: {
        readonly _meta?: {
          [key: string]: unknown;
        };
        readonly reason?: string;
        readonly requestId: string | number;
      }, options?: {
        readonly context?: Context<never>;
        readonly discard?: Discard;
        readonly headers?: Input;
      }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
      "notifications/message": <AsQueue extends boolean = false, Discard = false>(input: {
        readonly _meta?: {
          [key: string]: unknown;
        };
        readonly data: any;
        readonly level: "error" | "debug" | "info" | "notice" | "warning" | "critical" | "alert" | "emergency";
        readonly logger?: string;
      }, options?: {
        readonly context?: Context<never>;
        readonly discard?: Discard;
        readonly headers?: Input;
      }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
      "notifications/progress": <AsQueue extends boolean = false, Discard = false>(input: {
        readonly _meta?: {
          [key: string]: unknown;
        };
        readonly message?: string;
        readonly progress: number;
        readonly progressToken: string | number;
        readonly total?: number;
      }, options?: {
        readonly context?: Context<never>;
        readonly discard?: Discard;
        readonly headers?: Input;
      }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
      "notifications/prompts/list_changed": <AsQueue extends boolean = false, Discard = false>(input: {
        readonly _meta?: {
          [key: string]: unknown;
        };
      } | undefined, options?: {
        readonly context?: Context<never>;
        readonly discard?: Discard;
        readonly headers?: Input;
      }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
      "notifications/resources/list_changed": <AsQueue extends boolean = false, Discard = false>(input: {
        readonly _meta?: {
          [key: string]: unknown;
        };
      } | undefined, options?: {
        readonly context?: Context<never>;
        readonly discard?: Discard;
        readonly headers?: Input;
      }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
      "notifications/resources/updated": <AsQueue extends boolean = false, Discard = false>(input: {
        readonly _meta?: {
          [key: string]: unknown;
        };
        readonly uri: string;
      }, options?: {
        readonly context?: Context<never>;
        readonly discard?: Discard;
        readonly headers?: Input;
      }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
      "notifications/tools/list_changed": <AsQueue extends boolean = false, Discard = false>(input: {
        readonly _meta?: {
          [key: string]: unknown;
        };
      } | undefined, options?: {
        readonly context?: Context<never>;
        readonly discard?: Discard;
        readonly headers?: Input;
      }) => Effect<Discard extends true ? void : void, Discard extends true ? never : never, never>;
    };
    readonly notifyElicitationComplete: (options: {
      readonly clientId: number;
      readonly elicitationId: string;
    }) => Effect<void>;
    readonly prompts: readonly Array<{
      readonly annotations: Context<never>;
      readonly prompt: Prompt;
    }>;
    readonly resources: readonly Array<{
      readonly annotations: Context<never>;
      readonly resource: Resource;
    }>;
    readonly resourceTemplates: readonly Array<{
      readonly annotations: Context<never>;
      readonly template: ResourceTemplate;
    }>;
    readonly tools: readonly Array<{
      readonly annotations: Context<never>;
      readonly tool: Tool;
    }>;
  }, never, Scope>;
}

Utility Types

CompletionServices

type unstable
Since v4.0.0

Utility type that collects the services required by the handlers of a completion-handler record, including handlers declared as optional.

Signature

type CompletionServices<Completions> = { [K in keyof Completions]: NonNullable<Completions[K]> extends (...args: any) => infer Ret ? Effect.Services<Ret> : never }[keyof Completions]

ValidateCompletions

type unstable
Since v4.0.0

Utility type that validates a completion-handler record against the allowed parameter keys.

Signature

type ValidateCompletions<Completions, Keys extends string> = Completions & { [K in keyof Completions]: K extends Keys ? (input: string, context: CompletionContext) => any : never }