Single tool 'add' has a basic description but lacks depth and context. Description (79 chars) is below the 194-char baseline for production tools. Input schema is present with proper types (float) and parameter descriptions, but the tool description does not explain WHEN to use it, what prerequisites exist (OAuth + Stripe subscription), or what the return format is. No output schema documented. The tool is gated behind subscription logic via decorator, but this critical context is absent from the description text itself, LLMs cannot infer it from the decorator alone.

• Expand tool description to 150 - 250 characters. Include: 'Add two numbers. Requires active Stripe subscription and valid OAuth token. Returns result as text in content array. Call this only if you have confirmed the user has an active subscription.'
• Document the output schema explicitly: 'Returns {"content": [{"type": "text", "text": "<result>"}]}'
• Add error handling guidance: 'If subscription is invalid, returns 403 Forbidden. If OAuth token is expired, returns 401 Unauthorized, ask user to re-authenticate.'
• Consider renaming to 'add_numbers_premium' or 'add_with_subscription' to signal the gating context to LLMs upfront.
• Add parameter constraints in descriptions: 'a: First number (float, any value). b: Second number (float, any value).'

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry