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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful context beyond annotations: free daily allowance, reset time, post-allowance payment method, and the exact shape of returned data.

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 somewhat long but every section earns its place: pricing, return fields, and sibling differentiation. The most attention-grabbing detail (free tier) is front-loaded.

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 single-parameter, read-only lookup with no output schema, the description is complete: it covers input format, return fields, cost behavior, and when to choose an alternative tool. No critical operational detail 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?

Schema coverage is 100% and the schema already explains the PIN pattern, dashes, example, and address fallback. The description mostly restates the 10/14-digit PIN requirement without adding new parameter meaning beyond the schema.

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 names a specific resource ('Cook County, IL parcel record') and a precise input ('10- or 14-digit PIN'), then lists exact return fields. It also distinguishes itself from the dossier sibling by calling itself 'the cheap single-property lookup.'

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?

Explicitly says to use get_cook_county_property_dossier when sales, permits, or assessments are needed, and to call search_chicago_property_by_address first when only a street address is available. This gives clear routing guidance versus siblings.

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