alibaba/open-code-review · error

unknown MCP server field %q: supported fields are type, comm

Error message

unknown MCP server field %q: supported fields are type, command, args, env, url, headers, tools, setup

What it means

setMCPServerValue only recognizes the fields type, command, args, env, url, headers, tools and setup; any other field name passed on the MCP server config key falls into the default case and is rejected with this message listing the supported fields.

Source

Thrown at cmd/opencodereview/config_cmd.go:927

			return fmt.Errorf("invalid JSON array for %s: %w", key, err)
		}
		seen := make(map[string]struct{}, len(tools))
		filtered := make([]string, 0, len(tools))
		for _, t := range tools {
			if t == "" {
				return fmt.Errorf("tool names in %s must not be empty", key)
			}
			if _, dup := seen[t]; dup {
				continue
			}
			seen[t] = struct{}{}
			filtered = append(filtered, t)
		}
		entry.Tools = filtered
	case "setup":
		entry.Setup = value
	default:
		return fmt.Errorf("unknown MCP server field %q: supported fields are type, command, args, env, url, headers, tools, setup", field)
	}

	cfg.MCPServers[name] = entry
	return nil
}

// parseMCPHeaders parses a JSON object of header key-value pairs.
// Example: {"Authorization": "Bearer $TOKEN", "X-Custom": "value"}
func parseMCPHeaders(value string) (map[string]string, error) {
	var m map[string]string
	if err := json.Unmarshal([]byte(value), &m); err != nil {
		return nil, fmt.Errorf("expected JSON object: %w", err)
	}
	for k, v := range m {
		if k == "" {
			return nil, fmt.Errorf("header name must not be empty")
		}
		if v == "" {

View on GitHub (pinned to 5cf97d0d15)

Solutions

1. Use only: type, command, args, env, url, headers, tools, setup
2. Fix the typo in the field name indicated in the %q
3. Run `ocr config get mcp-servers.<name>` to see the existing entry shape

Example fix

// before
ocr config set mcp-servers.myserver.endpoint https://mcp.example.com
// after
ocr config set mcp-servers.myserver.url https://mcp.example.com

var mcpServerFields = map[string]bool{
    "type": true, "command": true, "args": true, "env": true,
    "url": true, "headers": true, "tools": true, "setup": true,
}
if !mcpServerFields[field] { return fmt.Errorf("unsupported field %q", field) }

func isKnownMCPField(f string) bool { return mcpServerFields[f] }

if err := setMCPServerValue(cfg, name, field, value); err != nil {
    if strings.Contains(err.Error(), "unknown MCP server field") { /* correct the field name from the message */ }
    return err
}

When it happens

Trigger: `ocr config set mcp-servers.myserver.timeout 30` or any typo/unknown key such as `url` misspelled as `endpoint`, or nested fields not supported by this setter.

Common situations: Typos in field names; assuming fields from other MCP config formats (e.g. server-level settings like timeout or disabled) are supported; copying field names from a different tool's schema.

Related errors

• MCP server %q not found
• invalid headers for %s: %w
• tool names in %s must not be empty
• load config: %w
• unset supports provider, max_tokens, effort, custom_provider

AI-assisted analysis of alibaba/open-code-review@5cf97d0d15 (2026-09-02). Data as JSON: /api/errors/a1fe16cd9af7a8e6. Report an issue: GitHub.