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

Annotations already cover the safety profile (readOnly, idempotent, closed-world, non-destructive), so the description is not required to restate them. It adds genuinely useful context beyond the schema: output is percentages and medians only, the data is CC BY 4.0 licensed, and the caller must cite the report URL. It does not describe latency or pagination, but for a static zero-arg report that is minor.

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?

Two dense sentences with the subject (MaxWorth report) front-loaded, followed by the enumerated figures and licensing terms. No filler sentences, though the content list is compressed into a single comma-heavy clause.

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?

No output schema exists, so the description carries the job of describing returns — and it does, naming the specific metrics returned and their statistical form (percentages and medians). With zero params and rich annotations, nothing an agent needs to invoke this correctly is missing.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. Schema coverage is reported at 100% on an empty object.

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?

States a specific verb (reports) and resource (MaxWorth's headline figures on US cardholder credit/deadline tracking), and enumerates the exact content returned: cards and fees per user, recurring credits, deadlines per year, most-skipped credits, logged-use index. It does not explicitly name which sibling it differs from (e.g. list_credits), but the aggregate-report framing makes it distinguishable.

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 statement of when to prefer this over list_credits, get_card, or search_cards, and no prerequisites or exclusions. An agent must infer from the word 'report' that this is the aggregate-statistics entry point rather than card-level detail.

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