ruvnet/ruflo · error

[mcp] failed to connect client

Error message

[mcp] failed to connect client

What it means

Log warning in executeToolCalls: connecting an MCP Client to a server needed by the batch's tool calls failed; that server (and its tools) is skipped while other servers in the batch still execute.

Source

Thrown at ruflo/src/ruvocal/src/lib/server/textGeneration/mcp/toolInvocation.ts:142

				eta: 10,
			},
		};
	}

	// Preload clients per distinct server used in this batch
	const distinctServerNames = Array.from(
		new Set(prepared.map((p) => mapping[p.call.name]?.server).filter(Boolean) as string[])
	);
	const clientMap = new Map<string, Client>();
	await Promise.all(
		distinctServerNames.map(async (name) => {
			const cfg = serverLookup.get(name);
			if (!cfg) return;
			try {
				const client = await getClient(cfg, abortSignal);
				clientMap.set(name, client);
			} catch (e) {
				logger.warn({ server: name, err: String(e) }, "[mcp] failed to connect client");
			}
		})
	);

	// Async queue to stream results in finish order
	function createQueue<T>() {
		const items: T[] = [];
		const waiters: Array<(v: IteratorResult<T>) => void> = [];
		let closed = false;
		return {
			push(item: T) {
				const waiter = waiters.shift();
				if (waiter) waiter({ value: item, done: false });
				else items.push(item);
			},
			close() {
				closed = true;
				let waiter: ((v: IteratorResult<T>) => void) | undefined;

View on GitHub (pinned to fa13ee4ad6)

Solutions

1. Verify the MCP server URL/command, credentials, and network reachability; ensure the server process is running and the client transport (SSE/HTTP/stdio) matches the server.

When it happens

Trigger: Thrown at ruflo/src/ruvocal/src/lib/server/textGeneration/mcp/toolInvocation.ts:142 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of ruvnet/ruflo@fa13ee4ad6 (2026-08-18). Data as JSON: /api/errors/326d03265be6dd55. Report an issue: GitHub.