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

With no annotations, the description carries the behavioral burden. It discloses that results are short rows, only includes card facts, and limits results to cards open to new applicants. It does not explain how filters interact or matching behavior, but the core behavioral boundaries are clear.

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 sentences with no filler. The first sentence states the tool's purpose and main filter axes; the second sentence points to the sibling tool and sets data-boundary expectations.

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 10-parameter search tool with no annotations and no output schema, the description explains what is returned, what is excluded, and where to get fuller data. It leaves some ambiguity about exact return fields and filter combination, but not enough to prevent correct selection and invocation.

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 100%, so the schema already documents all 10 parameters. The description broadly repeats the filter categories but adds no new meaning beyond what the schema provides, keeping this at the baseline.

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 uses a specific verb and resource: 'Find credit cards open to new applicants,' and lists concrete filter dimensions such as issuer, annual fee, network, and benefits. It also distinguishes itself from get_card_facts by noting it returns a short row rather than a full record.

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?

It explicitly tells the agent to 'call get_card_facts for one card's full record,' which names the alternative and the condition for using it. It also states what this tool will not provide — earning rates, welcome-offer amounts, transfer ratios, and bonus sizes — helping route the agent elsewhere.

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