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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world). The description adds genuinely useful behavioral context beyond that: the coverage boundary is strictly São Paulo, and the tool 'não pede nem guarda dados pessoais', which reassures on privacy handling for a lookup that takes a place name.

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, front-loaded with what the tool determines and the scope boundary, then input guidance, then the privacy note. Every sentence carries information an agent can act on; no filler.

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 simple boolean coverage check with an output schema and full annotation coverage, the description supplies purpose, business-rule scope, input guidance, and privacy behavior. The only omission is the relationship to the sibling tool, which is a minor gap given the low complexity.

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 the schema already documents both parameters, including why uf is optional and helpful for disambiguation. The description's 'se souber, a UF' merely restates that optionality, adding no syntax or format detail beyond the schema. Baseline 3 applies.

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 verb and resource ('Diz se um município está na área atendida pela CSolar Energia') and even defines the scope of that area (state of São Paulo, 645 municipalities). It does not explicitly name or contrast with the sibling estimate_solar_system, but the function is unambiguously different from an estimation tool.

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 when to use it (to check coverage for solar installation) and instructs on inputs ('Informe o município e, se souber, a UF'), but it never states when NOT to use it or routes the agent to estimate_solar_system as the follow-up. Usage is implied rather than spelled out.

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