sipeed/picoclaw · error

unsupported transport %q

Error message

unsupported transport %q

What it means

buildServerConfig normalizes opts.Transport with config.NormalizeMCPTransportType, defaults empty to 'stdio', then accepts only stdio, http, and sse. Any other normalized value is rejected, quoting the ORIGINAL --transport string you typed, so the message reflects your input even after case-normalization.

Source

Thrown at cmd/picoclaw/internal/mcp/add.go:183

		)
	}

	targetArgs := make([]string, 0, len(positional)-2+len(serverArgs))
	targetArgs = append(targetArgs, positional[2:]...)
	targetArgs = append(targetArgs, serverArgs...)

	return opts, positional[0], positional[1], targetArgs, false, nil
}

func buildServerConfig(target string, args []string, opts addOptions) (config.MCPServerConfig, error) {
	transport := config.NormalizeMCPTransportType(opts.Transport)
	if transport == "" {
		transport = "stdio"
	}
	switch transport {
	case "stdio", "http", "sse":
	default:
		return config.MCPServerConfig{}, fmt.Errorf("unsupported transport %q", opts.Transport)
	}

	env, err := parseEnvAssignments(opts.Env)
	if err != nil {
		return config.MCPServerConfig{}, err
	}
	headers, err := parseHeaderAssignments(opts.Headers)
	if err != nil {
		return config.MCPServerConfig{}, err
	}

	server := config.MCPServerConfig{
		Enabled:  true,
		Type:     transport,
		Deferred: opts.Deferred,
	}

	switch transport {

View on GitHub (pinned to 49183d7e8d)

Solutions

1. Use one of: stdio, http, sse
2. Check `picoclaw mcp add --help` on your build for the supported list
3. Upgrade picoclaw if newer docs mention a transport your binary lacks

Example fix

# before
picoclaw mcp add ws-server wss://example.com/mcp --transport ws
# after
picoclaw mcp add ws-server https://example.com/mcp --transport http

case "${TRANSPORT:-stdio}" in stdio|http|sse) ;; *) echo "unsupported transport: $TRANSPORT"; exit 2;; esac

func isSupportedMCPTransport(t string) bool {
    switch config.NormalizeMCPTransportType(t) {
    case "stdio", "http", "sse":
        return true
    }
    return false
}

When it happens

Trigger: `--transport websocket`, `--transport ws`, `--transport grpc`, or typos like 'htpp' - anything that normalizes to a value outside {stdio, http, sse}.

Common situations: Assuming streamable 'ws' exists; following docs newer than the installed picoclaw; CLI autocompletion suggesting a removed value.

Related errors

• --env can only be used with stdio transport
• --env-file can only be used with stdio transport
• %s transport does not accept command arguments
• --header can only be used with http or sse transport
• target %q looks like a remote MCP URL, but transport is %q.

AI-assisted analysis of sipeed/picoclaw@49183d7e8d (2026-08-15). Data as JSON: /api/errors/557ae8d2919fb250. Report an issue: GitHub.