cline/cline · error

Unknown MCP server: ${serverName}

Error message

Unknown MCP server: ${serverName}

What it means

Error "Unknown MCP server: ${serverName}" thrown in cline/cline.

Source

Thrown at sdk/packages/core/src/extensions/mcp/config-loader.ts:864

	options: LoadMcpSettingsOptions = {},
): McpServerOAuthState | undefined {
	const config = loadMcpSettingsFile(options);
	if (!Object.hasOwn(config.mcpServers, serverName)) {
		return undefined;
	}
	return normalizeMcpServerOAuthState(config.mcpServers[serverName]?.oauth);
}

function buildOAuthStateMutator(
	serverName: string,
	updater: (current: McpServerOAuthState) => McpServerOAuthState,
	options: UpdateMcpServerOAuthStateOptions,
): McpSettingsMutator<McpServerOAuthState> {
	return (settings) => {
		const servers = settings.mcpServers as Record<string, unknown>;
		const server = getOwnServerRecord(servers, serverName);
		if (!server) {
			throw new Error(`Unknown MCP server: ${serverName}`);
		}
		if (options.expectedOAuthClient !== undefined) {
			const parsedClient = oauthClientSchema.safeParse(server.oauthClient);
			const currentClient = parsedClient.success
				? parsedClient.data
				: undefined;
			const expectedClient = options.expectedOAuthClient ?? undefined;
			if (
				currentClient?.clientId !== expectedClient?.clientId ||
				currentClient?.clientSecret !== expectedClient?.clientSecret
			) {
				throw new McpOAuthClientChangedError(serverName);
			}
		}

		const current = validateOauthState(server.oauth) ?? {};
		const updated = normalizeMcpServerOAuthState(updater(current));
		if (updated) {

View on GitHub (pinned to 491b30b806)

When it happens

Trigger: Thrown at sdk/packages/core/src/extensions/mcp/config-loader.ts:864 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of cline/cline@491b30b806 (2026-08-25). Data as JSON: /api/errors/f0675d77f2964ab3. Report an issue: GitHub.