Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description fully covers behavior: it returns field names and delivered_at timestamps (null for old records), never exposes values, is free, and requires proof of ownership. It does not discuss error handling or limits, but the core behavior is well explained.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise at four sentences, front-loads the core purpose, and uses clear structure. Every sentence adds value, with no redundant or extraneous content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simple parameter set and presence of an output schema, the description provides all necessary context: purpose, return value structure, authentication requirement, and cost. No gaps remain.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with detailed parameter descriptions. The description adds context about dpop_token being proof of ownership, but does not fundamentally extend meaning beyond the schema. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb ('List') and the resource ('stored patron credential field names'), and distinguishes it from siblings like weather_delete_patron_credential or weather_update_patron_credential by noting it returns only names and timestamps, not values.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description tells when to use ('verify which fields are configured and how old each one is') and notes prerequisites (proof of npub ownership). It does not explicitly list when not to use or compare to alternatives, but the purpose is sufficiently clear to avoid misuse.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.