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

Annotations already declare readOnlyHint, idempotentHint, and closed-world scope, so the description isn't carrying the safety burden. It still adds real behavioral context beyond the annotations: a hard cap of 20 results, ordering by a 90-day citation window, sample variability across calls, and omission of unmeasured firms.

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?

Three short sentences with zero filler; the scope, the cap, and the ordering rule are front-loaded, and the caveats follow. Every clause carries information an agent needs.

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?

With no output schema, the description should convey the return shape, and it does at a high level (an ordered list of firms, truncated at 20, absent if unmeasured). It stops short of describing which fields each firm record contains, which is a minor remaining gap for a read-only lookup tool.

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%, so the description must compensate. It does partially: it clarifies that limit is capped at 20, that exactly one metro and one service apply, and that the ranking window is fixed at 90 days. It never explains the enum semantics or the default of 10, so the compensation is incomplete.

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 opens with a specific verb and resource: 'Return up to 20 measured local firms ordered by recorded 90-day citation rate in one metro/service.' That is concrete enough to distinguish this list-of-firms tool from sibling detail tools like get_local_market or get_local_factsheet, though no sibling is named explicitly.

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 the scope statement (single metro + single service, top-20 by citation rate) and reinforced by interpretation caveats ('not quality rankings or proof of leads'). There is no explicit when-to-use-this-vs-an-alternative guidance, leaving the agent to infer routing from sibling names alone.

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