mercury_list_cards

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

No annotations present, but description adds behavioral context: returns card list structure, and importantly states that card creation, freezing, and PIN ops are not supported by the Mercury API. This goes beyond a simple listing description.

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?

Five sentences well-organized into purpose, usage guidelines, and return format. Every sentence adds value; no redundancy.

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?

For a simple list tool with one parameter and no output schema, the description covers use cases, limitations, and return structure completely. It provides enough context for an agent to correctly select and invoke the tool.

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 a single parameter (accountId) fully described in schema. Description does not add new semantic info beyond schema, so baseline 3 applies.

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?

Clearly states 'List physical and virtual cards attached to a Mercury account.' Verb 'List' and resource 'cards' are specific. Distinguishes from sibling 'mercury_list_credit_transactions' by explicitly stating what not to use.

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?

Explicitly provides USE WHEN (enumerating cards for audits, freezing review, cardholder lookups) and DO NOT USE (for IO Credit transactions, pointing to alternative tool). Also notes unsupported operations.

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