ruvnet/ruflo · error

[router] candidate failed

Error message

[router] candidate failed

What it means

Log warning in makeRouterEndpoint's candidate loop: the current candidate model threw during endpoint creation or generation; the error is recorded as lastErr and the loop proceeds to the next candidate in the resolved route list.

Source

Thrown at ruflo/src/ruvocal/src/lib/server/router/endpoint.ts:298

		}

		const fallbackModel = config.LLM_ROUTER_FALLBACK_MODEL || routerModel.id;
		const { candidates } = resolveRouteModels(routeSelection.routeName, routes, fallbackModel);

		let lastErr: unknown = undefined;
		for (const candidate of candidates) {
			try {
				logger.info(
					{ route: routeSelection.routeName, model: candidate },
					"[router] trying candidate"
				);
				const ep = await createCandidateEndpoint(candidate);
				const gen = await ep({ ...params });
				return metadataThenStream(gen, candidate, routeSelection.routeName);
			} catch (e) {
				lastErr = e;
				const { message: errMsg, statusCode: errStatus } = extractUpstreamError(e);
				logger.warn(
					{
						route: routeSelection.routeName,
						model: candidate,
						err: errMsg,
						...(errStatus && { status: errStatus }),
					},
					"[router] candidate failed"
				);
				continue;
			}
		}

		// Exhausted all candidates — throw to signal upstream failure
		// Forward the upstream error to the client
		const { message, statusCode } = extractUpstreamError(lastErr);
		throw statusCode ? new HTTPError(message, statusCode) : new Error(message);
	};
}

View on GitHub (pinned to fa13ee4ad6)

Solutions

1. Inspect the candidate endpoint's error details in the log context; fix the failing candidate (auth, model name, or availability) or remove it from the candidate list.

When it happens

Trigger: Thrown at ruflo/src/ruvocal/src/lib/server/router/endpoint.ts:298 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/cb03a3323b0e4fc7. Report an issue: GitHub.