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

Annotations already establish readOnlyHint=true and openWorldHint=true, and the description adds substantial behavioral context beyond that: it discloses the paid x402 model, exact price per successful call, payment chains, and that failed calls are not charged. It also clarifies the data boundary by stating only assessor-published building characteristics are returned and no owner data is included.

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 three compact sentences with the scope, exclusions, and pricing front-loaded. Every sentence carries useful information: what data is returned, what is excluded, and how billing works.

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?

Given an output schema, annotations, and 100% schema coverage, the description is nearly complete for calling the tool correctly. The main remaining gap is explicit routing versus the closely related Cook County property-records sibling, which would help avoid tool-selection ambiguity.

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 both the PIN and limit parameters are already well documented in the schema. The description reinforces that PIN is 14-digit and that results are per assessment year, but it does not add meaningful semantics for the limit parameter beyond what the schema provides; 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?

Clearly identifies the resource (Cook County Assessor building characteristics), lookup key (14-digit PIN), and returned fields (year built, square footage, bedrooms, land details). It also scopes the data to assessor-published building data with no owner data. It does not explicitly distinguish itself from the nearby sibling realestate_cook_county_property_records, so it falls 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?

The description implies usage by requiring a 14-digit PIN and noting that owner data is excluded, which helps an agent understand the appropriate lookup context. However, it does not state when to use this tool instead of related Cook County or other property-record siblings, nor does it give explicit exclusions or alternatives.

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