MCP Arc exposes 7 tools across two example servers. (3) No parameter descriptions anywhere, LLMs cannot infer what email, national_id, card_number, cvv, amount, api_key, or api_key mean in context. (4) No output schemas documented. (5) No error handling guidance. (6) Sensitive parameters (cvv, api_key, card_number) exposed as tool inputs, violating secret-injection pattern. Tools 1-4 have better structure but still lack parameter descriptions and output documentation.

• Remove duplicate tools 5-7 or consolidate into single definitions. Duplicates with degraded schemas confuse LLMs and waste reasoning cycles.
• Add 50-200 character descriptions to all tools explaining WHAT they do and WHEN to use them. E.g., 'Look up a customer record by email address or national ID. Returns customer name, contact info, and account status.'
• Add descriptions to every parameter. E.g., 'email: Customer email address (required for lookup). Format: valid email string.' 'amount: Charge amount in USD cents (1-999999). Must be positive integer.'
• Move api_key, cvv, and card_number out of tool parameters. Inject these server-side from environment variables or a secrets vault. Document which secrets each tool requires in its description.
• Document output schemas for all tools. E.g., 'Returns: {found: boolean, email: string, national_id: string, name: string}'. Include field types and what each field represents.