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

Annotations already cover readOnlyHint and openWorldHint, so the safety profile is handled. The description adds real behavioral context: 'Cheap, cacheable' and an enumeration of the response contents (supported countries, field availability percentages, freshness class, limitations, fallback behavior). It stops short of stating caching duration or staleness bounds, so not a 5.

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?

Four sentences, front-loaded with purpose before usage and exclusion. Every clause earns its place — no repetition of the title or schema.

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?

There is no output schema, but the description compensates by summarizing the return payload (countries, availability percentages, freshness class, limitations, fallback). Combined with the explicit exclusion and optional-param scope, an agent has everything needed to call it correctly.

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% and the single optional 'country' parameter is fully documented in the schema (ISO alpha-2, omit for all). The description adds no syntax beyond that; the field names it lists are returned values, not inputs. 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+resource ('Check FirmaDB country and field coverage') and immediately scopes it to pre-workflow planning. The closing sentence explicitly names what the tool is not for and which siblings handle company data, allowing clear differentiation from search/get/verify/enrich.

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?

Gives an explicit when-to-use trigger ('an agent needs to know whether fields such as employee_count ... are populated for a country') and an explicit when-not ('Do NOT use this to retrieve company records'), pointing to the alternative tools by name.

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