Rotating 5% windows

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

With no annotations, the description carries the burden of behavioral disclosure. It usefully states the data is live/upcoming, permanent, and from the same verified data as the app, implying a read-only lookup. However, it does not mention output format, authentication needs, or limitations.

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 one tight sentence that front-loads the main content, gives illustrative examples, and adds a credibility note about verified data. No filler or 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 tool with one optional parameter and no output schema, the description provides enough scope for an agent to call it correctly. Minor gaps remain around expected return structure and date formatting, but the tool's low complexity keeps these from being critical.

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?

The input schema provides zero description for card_id, so the description must compensate. It does so by explicitly stating the parameter is an optional filter, which is the core semantic needed. It does not define what a card id looks like or where to obtain one, but the single optional parameter makes this adequate.

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 identifies the resource: live/upcoming rotating-category windows and permanent merchant benefits, with concrete card examples. It lacks an explicit verb like 'list' or 'retrieve,' but the intent is unambiguous from the content.

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?

No guidance is given on when to use this tool versus siblings like lookup_merchant or search_cards. The phrase 'Optionally filter by card id' addresses parameter usage, not tool selection, so the agent gets no routing help.

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