246 lines
9.9 KiB
JavaScript
246 lines
9.9 KiB
JavaScript
/**
|
|
* Experimental server task features for MCP SDK.
|
|
* WARNING: These APIs are experimental and may change without notice.
|
|
*
|
|
* @experimental
|
|
*/
|
|
import { CreateMessageResultSchema, ElicitResultSchema } from '../../types.js';
|
|
/**
|
|
* Experimental task features for low-level MCP servers.
|
|
*
|
|
* Access via `server.experimental.tasks`:
|
|
* ```typescript
|
|
* const stream = server.experimental.tasks.requestStream(request, schema, options);
|
|
* ```
|
|
*
|
|
* For high-level server usage with task-based tools, use `McpServer.experimental.tasks` instead.
|
|
*
|
|
* @experimental
|
|
*/
|
|
export class ExperimentalServerTasks {
|
|
constructor(_server) {
|
|
this._server = _server;
|
|
}
|
|
/**
|
|
* Sends a request and returns an AsyncGenerator that yields response messages.
|
|
* The generator is guaranteed to end with either a 'result' or 'error' message.
|
|
*
|
|
* This method provides streaming access to request processing, allowing you to
|
|
* observe intermediate task status updates for task-augmented requests.
|
|
*
|
|
* @param request - The request to send
|
|
* @param resultSchema - Zod schema for validating the result
|
|
* @param options - Optional request options (timeout, signal, task creation params, etc.)
|
|
* @returns AsyncGenerator that yields ResponseMessage objects
|
|
*
|
|
* @experimental
|
|
*/
|
|
requestStream(request, resultSchema, options) {
|
|
return this._server.requestStream(request, resultSchema, options);
|
|
}
|
|
/**
|
|
* Sends a sampling request and returns an AsyncGenerator that yields response messages.
|
|
* The generator is guaranteed to end with either a 'result' or 'error' message.
|
|
*
|
|
* For task-augmented requests, yields 'taskCreated' and 'taskStatus' messages
|
|
* before the final result.
|
|
*
|
|
* @example
|
|
* ```typescript
|
|
* const stream = server.experimental.tasks.createMessageStream({
|
|
* messages: [{ role: 'user', content: { type: 'text', text: 'Hello' } }],
|
|
* maxTokens: 100
|
|
* }, {
|
|
* onprogress: (progress) => {
|
|
* // Handle streaming tokens via progress notifications
|
|
* console.log('Progress:', progress.message);
|
|
* }
|
|
* });
|
|
*
|
|
* for await (const message of stream) {
|
|
* switch (message.type) {
|
|
* case 'taskCreated':
|
|
* console.log('Task created:', message.task.taskId);
|
|
* break;
|
|
* case 'taskStatus':
|
|
* console.log('Task status:', message.task.status);
|
|
* break;
|
|
* case 'result':
|
|
* console.log('Final result:', message.result);
|
|
* break;
|
|
* case 'error':
|
|
* console.error('Error:', message.error);
|
|
* break;
|
|
* }
|
|
* }
|
|
* ```
|
|
*
|
|
* @param params - The sampling request parameters
|
|
* @param options - Optional request options (timeout, signal, task creation params, onprogress, etc.)
|
|
* @returns AsyncGenerator that yields ResponseMessage objects
|
|
*
|
|
* @experimental
|
|
*/
|
|
createMessageStream(params, options) {
|
|
// Access client capabilities via the server
|
|
const clientCapabilities = this._server.getClientCapabilities();
|
|
// Capability check - only required when tools/toolChoice are provided
|
|
if ((params.tools || params.toolChoice) && !clientCapabilities?.sampling?.tools) {
|
|
throw new Error('Client does not support sampling tools capability.');
|
|
}
|
|
// Message structure validation - always validate tool_use/tool_result pairs.
|
|
// These may appear even without tools/toolChoice in the current request when
|
|
// a previous sampling request returned tool_use and this is a follow-up with results.
|
|
if (params.messages.length > 0) {
|
|
const lastMessage = params.messages[params.messages.length - 1];
|
|
const lastContent = Array.isArray(lastMessage.content) ? lastMessage.content : [lastMessage.content];
|
|
const hasToolResults = lastContent.some(c => c.type === 'tool_result');
|
|
const previousMessage = params.messages.length > 1 ? params.messages[params.messages.length - 2] : undefined;
|
|
const previousContent = previousMessage
|
|
? Array.isArray(previousMessage.content)
|
|
? previousMessage.content
|
|
: [previousMessage.content]
|
|
: [];
|
|
const hasPreviousToolUse = previousContent.some(c => c.type === 'tool_use');
|
|
if (hasToolResults) {
|
|
if (lastContent.some(c => c.type !== 'tool_result')) {
|
|
throw new Error('The last message must contain only tool_result content if any is present');
|
|
}
|
|
if (!hasPreviousToolUse) {
|
|
throw new Error('tool_result blocks are not matching any tool_use from the previous message');
|
|
}
|
|
}
|
|
if (hasPreviousToolUse) {
|
|
// Extract tool_use IDs from previous message and tool_result IDs from current message
|
|
const toolUseIds = new Set(previousContent.filter(c => c.type === 'tool_use').map(c => c.id));
|
|
const toolResultIds = new Set(lastContent.filter(c => c.type === 'tool_result').map(c => c.toolUseId));
|
|
if (toolUseIds.size !== toolResultIds.size || ![...toolUseIds].every(id => toolResultIds.has(id))) {
|
|
throw new Error('ids of tool_result blocks and tool_use blocks from previous message do not match');
|
|
}
|
|
}
|
|
}
|
|
return this.requestStream({
|
|
method: 'sampling/createMessage',
|
|
params
|
|
}, CreateMessageResultSchema, options);
|
|
}
|
|
/**
|
|
* Sends an elicitation request and returns an AsyncGenerator that yields response messages.
|
|
* The generator is guaranteed to end with either a 'result' or 'error' message.
|
|
*
|
|
* For task-augmented requests (especially URL-based elicitation), yields 'taskCreated'
|
|
* and 'taskStatus' messages before the final result.
|
|
*
|
|
* @example
|
|
* ```typescript
|
|
* const stream = server.experimental.tasks.elicitInputStream({
|
|
* mode: 'url',
|
|
* message: 'Please authenticate',
|
|
* elicitationId: 'auth-123',
|
|
* url: 'https://example.com/auth'
|
|
* }, {
|
|
* task: { ttl: 300000 } // Task-augmented for long-running auth flow
|
|
* });
|
|
*
|
|
* for await (const message of stream) {
|
|
* switch (message.type) {
|
|
* case 'taskCreated':
|
|
* console.log('Task created:', message.task.taskId);
|
|
* break;
|
|
* case 'taskStatus':
|
|
* console.log('Task status:', message.task.status);
|
|
* break;
|
|
* case 'result':
|
|
* console.log('User action:', message.result.action);
|
|
* break;
|
|
* case 'error':
|
|
* console.error('Error:', message.error);
|
|
* break;
|
|
* }
|
|
* }
|
|
* ```
|
|
*
|
|
* @param params - The elicitation request parameters
|
|
* @param options - Optional request options (timeout, signal, task creation params, etc.)
|
|
* @returns AsyncGenerator that yields ResponseMessage objects
|
|
*
|
|
* @experimental
|
|
*/
|
|
elicitInputStream(params, options) {
|
|
// Access client capabilities via the server
|
|
const clientCapabilities = this._server.getClientCapabilities();
|
|
const mode = params.mode ?? 'form';
|
|
// Capability check based on mode
|
|
switch (mode) {
|
|
case 'url': {
|
|
if (!clientCapabilities?.elicitation?.url) {
|
|
throw new Error('Client does not support url elicitation.');
|
|
}
|
|
break;
|
|
}
|
|
case 'form': {
|
|
if (!clientCapabilities?.elicitation?.form) {
|
|
throw new Error('Client does not support form elicitation.');
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
// Normalize params to ensure mode is set for form mode (defaults to 'form' per spec)
|
|
const normalizedParams = mode === 'form' && params.mode === undefined ? { ...params, mode: 'form' } : params;
|
|
// Cast to ServerRequest needed because TypeScript can't narrow the union type
|
|
// based on the discriminated 'method' field when constructing the object literal
|
|
return this.requestStream({
|
|
method: 'elicitation/create',
|
|
params: normalizedParams
|
|
}, ElicitResultSchema, options);
|
|
}
|
|
/**
|
|
* Gets the current status of a task.
|
|
*
|
|
* @param taskId - The task identifier
|
|
* @param options - Optional request options
|
|
* @returns The task status
|
|
*
|
|
* @experimental
|
|
*/
|
|
async getTask(taskId, options) {
|
|
return this._server.getTask({ taskId }, options);
|
|
}
|
|
/**
|
|
* Retrieves the result of a completed task.
|
|
*
|
|
* @param taskId - The task identifier
|
|
* @param resultSchema - Zod schema for validating the result
|
|
* @param options - Optional request options
|
|
* @returns The task result
|
|
*
|
|
* @experimental
|
|
*/
|
|
async getTaskResult(taskId, resultSchema, options) {
|
|
return this._server.getTaskResult({ taskId }, resultSchema, options);
|
|
}
|
|
/**
|
|
* Lists tasks with optional pagination.
|
|
*
|
|
* @param cursor - Optional pagination cursor
|
|
* @param options - Optional request options
|
|
* @returns List of tasks with optional next cursor
|
|
*
|
|
* @experimental
|
|
*/
|
|
async listTasks(cursor, options) {
|
|
return this._server.listTasks(cursor ? { cursor } : undefined, options);
|
|
}
|
|
/**
|
|
* Cancels a running task.
|
|
*
|
|
* @param taskId - The task identifier
|
|
* @param options - Optional request options
|
|
*
|
|
* @experimental
|
|
*/
|
|
async cancelTask(taskId, options) {
|
|
return this._server.cancelTask({ taskId }, options);
|
|
}
|
|
}
|
|
//# sourceMappingURL=server.js.map
|