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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds value beyond them by disclosing the return payload (name, issuer, annual fee, canonical page URL to cite), which matters because there is no output schema. It stops short of 5 by omitting anything about result limits or pagination behavior.

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 tightly written sentences with zero filler: the search scope comes first and the return payload second. Every clause carries information an agent can act on.

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 three-parameter read tool with no output schema, the description covers purpose, market scope, and return fields well. The remaining gap is the undocumented limit parameter and any note on result-count behavior, which keeps it out of the top band.

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 description coverage is 67%, with query and country documented in the schema and the description restating the market scope (US, Canada, Australia). The description adds no syntax or format detail beyond the schema, and the limit parameter (default 10, max 25) is undocumented in both places, so a 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?

States a specific verb and resource ("Find credit cards in the MaxWorth catalogue") plus the searchable dimensions (name or issuer) and the covered markets. It does not explicitly differentiate itself from close siblings like get_card, compare_cards, or search_card_offers, so it stops short of a 5.

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?

Usage is implied by "find ... by name or issuer," giving an agent a reasonable sense of when to reach for this over a detail lookup. However, no alternative is named and no when-not-to-use condition is given, leaving routing among the ten siblings to inference.

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