import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import type {
LoggingLevel,
LoggingMessageNotificationParams,
} from '@modelcontextprotocol/sdk/types.js';
import { formatUnknownErrorMessage } from '../lib/errors.js';
import { isRecord } from '../lib/type-guards.js';
const MCP_LOGGER_NAME = 'filesystem-mcp';
const LOG_LEVEL_ORDER: Record<LoggingLevel, number> = {
debug: 0,
info: 1,
notice: 2,
warning: 3,
error: 4,
critical: 5,
alert: 6,
emergency: 7,
};
export interface LoggingState {
minimumLevel: LoggingLevel;
}
export function createLoggingState(
minimumLevel: LoggingLevel = 'debug'
): LoggingState {
return { minimumLevel };
}
function canSendMcpLogs(server: McpServer): boolean {
const capabilities = server.server.getClientCapabilities();
if (!isRecord(capabilities)) return false;
if (!('logging' in capabilities)) return false;
return !!capabilities['logging'];
}
export function logToMcp(
server: McpServer | undefined,
level: LoggingLevel,
data: string,
minLevel: LoggingLevel = 'debug'
): void {
if (LOG_LEVEL_ORDER[level] < LOG_LEVEL_ORDER[minLevel]) {
return;
}
if (!server || !canSendMcpLogs(server)) {
console.error(data);
return;
}
const params: LoggingMessageNotificationParams = {
level,
logger: MCP_LOGGER_NAME,
data,
};
void server.sendLoggingMessage(params).catch((error: unknown) => {
console.error(
`Failed to send MCP log: ${level} | ${data}`,
formatUnknownErrorMessage(error)
);
});
}
