multica-ai/multica · error

%s must be a JSON object, not null

Error message

%s must be a JSON object, not null

What it means

Error "%s must be a JSON object, not null" thrown in multica-ai/multica.

Source

Thrown at server/cmd/multica/cmd_agent.go:1343

	if trimmed == "" {
		if allowNull {
			return nil, fmt.Errorf("%s: empty input; pass 'null' to clear or a JSON object to set", flag)
		}
		return nil, fmt.Errorf("%s: empty input; pass a JSON object", flag)
	}
	var probe any
	if err := json.Unmarshal([]byte(trimmed), &probe); err != nil {
		if allowNull {
			return nil, fmt.Errorf("%s must be a valid JSON object, or 'null' to clear", flag)
		}
		return nil, fmt.Errorf("%s must be a valid JSON object", flag)
	}
	if probe == nil {
		if allowNull {
			// null → clear (NULL column server-side; on create it is a no-op).
			return json.RawMessage("null"), nil
		}
		return nil, fmt.Errorf("%s must be a JSON object, not null", flag)
	}
	if _, ok := probe.(map[string]any); !ok {
		if allowNull {
			return nil, fmt.Errorf("%s must be a JSON object, or 'null' to clear", flag)
		}
		return nil, fmt.Errorf("%s must be a JSON object", flag)
	}
	return json.RawMessage(trimmed), nil
}

// resolveMcpConfig collects the --mcp-config, --mcp-config-stdin, and
// --mcp-config-file flags and returns the raw JSON value to send, a bool
// indicating whether the caller supplied any of them, and any error. Mirrors
// resolveCustomEnv; the only behavioural difference is the clear sentinel
// (`null` here vs `{}` for custom_env), because mcp_config distinguishes an
// explicit empty object from an absent config server-side.
func resolveMcpConfig(cmd *cobra.Command) (json.RawMessage, bool, error) {
	return resolveMcpJSONObject(cmd, "mcp-config", true)

View on GitHub (pinned to 2c0912b6ec)

Solutions

1. Pass a JSON object; null is not allowed here.

When it happens

Trigger: Thrown at server/cmd/multica/cmd_agent.go:1343 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of multica-ai/multica@2c0912b6ec (2026-08-15). Data as JSON: /api/errors/e1dafe3a8e6ff380. Report an issue: GitHub.