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

With no annotations, the description must disclose behavioral traits. It states that the tool returns summary statistics, but it does not clarify important behaviors such as whether state and county_fips are mutually exclusive, how invalid inputs are handled, or what data source is used. The lack of detail beyond the immediate return format leaves the agent uncertain about edge cases and constraints.

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 efficiently structured: a one-line summary, a sentence on return values, and a compact args list. Every sentence provides necessary information without redundancy or fluff. The front-loaded summary immediately orients the agent.

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?

The description explains the purpose, return values, and parameter formats, which is decent for a retrieval tool. However, it lacks guidance on how state and county_fips interact (e.g., are they alternatives, or can both be provided?), and it does not mention any usage limitations. Since an output schema exists, return structure is covered, but the missing parameter relationship is a notable gap.

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 0%, leaving the description to carry the full burden. The description provides meaningful parameter details: state is 'Two-letter US state abbreviation (e.g. 'CA', 'TX')', county_fips is 'Five-digit county FIPS code (e.g. '06037' for LA County)', and year has a default. This adds clear format and example information, though it does not explain parameter dependencies or whether at least one is required.

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 states the tool's function: 'Get aggregate mortgage lending statistics for a geographic area.' It specifies the resource (aggregate stats) and the verb (get), and mentions returns such as applications, originations, denials, and loan amounts. It does not explicitly differentiate from sibling tools like get_denial_reasons or get_lending_by_race, but the 'aggregate' scope provides implicit distinction.

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?

The description gives a clear use case: 'Useful for understanding overall lending activity in a state or county.' This indicates when to use the tool but does not provide exclusions or references to alternatives like the sibling tools. No explicit when-not-to-use guidance is given, so it falls short of a 5.

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