sipeed/picoclaw · error

missing value for %s

Error message

missing value for %s

What it means

`picoclaw mcp add` parses its arguments manually (not via cobra) so that everything after the server command can be forwarded to it. When --transport/-t appears as the final token with nothing following, the parser has no value to consume and returns this error before any config work starts.

Source

Thrown at cmd/picoclaw/internal/mcp/add.go:112

		switch {
		case arg == "--help" || arg == "-h":
			return addOptions{}, "", "", nil, true, nil
		case arg == "--":
			if i+1 < len(args) {
				explicitCommand = append(explicitCommand, args[i+1:]...)
			}
			i = len(args)
		case arg == "--force" || arg == "-f":
			opts.Force = true
		case arg == "--deferred":
			t := true
			opts.Deferred = &t
		case arg == "--no-deferred":
			f := false
			opts.Deferred = &f
		case arg == "--transport" || arg == "-t":
			if i+1 >= len(args) {
				return addOptions{}, "", "", nil, false, fmt.Errorf("missing value for %s", arg)
			}
			i++
			opts.Transport = args[i]
		case strings.HasPrefix(arg, "--transport="):
			opts.Transport = strings.TrimPrefix(arg, "--transport=")
		case arg == "--env" || arg == "-e":
			if i+1 >= len(args) {
				return addOptions{}, "", "", nil, false, fmt.Errorf("missing value for %s", arg)
			}
			i++
			opts.Env = append(opts.Env, args[i])
		case arg == "--env-file":
			if i+1 >= len(args) {
				return addOptions{}, "", "", nil, false, fmt.Errorf("missing value for %s", arg)
			}
			i++
			opts.EnvFile = args[i]
		case strings.HasPrefix(arg, "--env="):

View on GitHub (pinned to 49183d7e8d)

Solutions

1. Supply the value: `--transport http` or use the explicit form `--transport=http`
2. Quote script expansions so the token survives: `--transport "$TRANSPORT"`
3. Guard scripts: skip the flag when the variable is empty

Example fix

# before
picoclaw mcp add myapi https://example.com/mcp --transport
# after
picoclaw mcp add myapi https://example.com/mcp --transport=http

# prefer = forms so a missing value is a shell syntax error, not a runtime one
picoclaw mcp add name url --transport=http

func hasFlagValue(args []string, names ...string) bool {
    for i, a := range args {
        for _, n := range names {
            if a == n {
                return i+1 < len(args)
            }
        }
    }
    return true
}

When it happens

Trigger: `picoclaw mcp add name url --transport` or `... -t` as the last argument; also when a script passes an empty unquoted variable so the value token disappears.

Common situations: Truncated shell line; quoting mistake; conditional flag assembly in scripts with an unset variable.

Related errors

• the --no-truncate option can only be used in conjunction wit
• usage: picoclaw mcp add [flags] <name> <command-or-url> [arg
• %s transport does not accept command arguments
• --header can only be used with http or sse transport
• either --every or --cron must be specified

AI-assisted analysis of sipeed/picoclaw@49183d7e8d (2026-08-15). Data as JSON: /api/errors/3f64734f25b3151e. Report an issue: GitHub.