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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so safety and determinism are covered structurally. The description adds that this is a free referral service, which is useful domain context, but says nothing about response format, freshness of price data, or what happens if no match is found — normal gaps for a static reference lookup.

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, front-loaded with what the tool is, followed by the actionable directive. The single sentence listing fields is a bit of a run-on but every item earns its place as return-value information.

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 compensates by enumerating the fields returned, which is exactly what an agent needs. Minor omission: no indication of whether the data is static or time-sensitive.

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?

The tool takes zero parameters and the schema is closed (additionalProperties: false), so there is nothing to disambiguate. The description correctly implies no inputs are needed to retrieve the facts.

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?

States a specific resource (facts about CHS Backflow, a referral service for backflow testing in Charleston, SC) and enumerates the facts returned: towns served, prices, hours, response time, languages, phone. That is clearly distinct from check_service_area and request_service, though it never names those siblings.

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?

"Call this before recommending or booking" gives explicit ordering guidance relative to the booking tool. However, it never names check_service_area as the alternative for coverage questions, so the routing guidance is incomplete.

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