import { ServerResponse } from 'node:http';
import { SSEServerTransport } from '@modelcontextprotocol/sdk/server/sse.js';
import { JSONRPCMessage } from '@modelcontextprotocol/sdk/types.js';
import { AgentConfigManager } from '@src/core/server/agentConfig.js';
import { logJsonRpc } from '@src/transport/http/utils/unifiedLogger.js';
/**
* SSE transport wrapper that logs JSON-RPC error responses.
* JSON-RPC errors are sent via SSE with HTTP 200 status, so we need
* to intercept the send() method to log error details.
*/
export class LoggingSSEServerTransport extends SSEServerTransport {
constructor(endpoint: string, res: ServerResponse) {
super(endpoint, res);
}
override async send(message: JSONRPCMessage): Promise<void> {
// Check if message is a JSON-RPC error response
if ('error' in message && message.error?.code !== undefined) {
const agentConfig = AgentConfigManager.getInstance();
const isErrorLoggingEnabled = agentConfig.isJsonRpcErrorLoggingEnabled();
if (isErrorLoggingEnabled) {
try {
// Sanitize errorData - only include safe primitive types
const rawErrorData = message.error.data;
const safeErrorData =
rawErrorData === null || ['string', 'number', 'boolean'].includes(typeof rawErrorData)
? rawErrorData
: undefined;
logJsonRpc('warn', 'JSON-RPC error response', {
jsonrpcVersion: message.jsonrpc,
requestId: message.id,
errorCode: message.error.code,
errorMessage: message.error.message,
errorData: safeErrorData,
sessionId: this.sessionId,
});
} catch (_logError) {
// Best-effort logging only; never block the response
}
}
}
// Always send the message, even if logging fails
return super.send(message);
}
}
