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

Annotations (readOnlyHint, destructiveHint, idempotentHint, openWorldHint) already cover safety and idempotency. The description adds no behavioral traits beyond the schema, such as noting that the year must be within 1900-2100 (already in schema) or explaining the output format. It is adequate but not enriched.

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 very short (one sentence plus a source attribution). It is front-loaded with the key action. The 'BrasilAPI MIT' part is extraneous but not harmful. Could be slightly more efficient without the attribution.

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?

Given the presence of an output schema and thorough annotations, the description is minimally complete for a straightforward data retrieval tool. It states the core function but omits details like year range (though in schema) or holiday types. No major gaps remain.

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% (year parameter described). The description adds no new semantic value beyond restating the schema's purpose. Baseline score 3 is appropriate as the schema carries the parameter meaning.

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 clearly states the tool's purpose: returning all Brazilian national holidays for a given year. It uses a specific verb (returns) and resource (Brazilian national holidays), and the name 'gov.brasilapi.holidays' distinguishes it from general holiday tools like 'calendar.holidays.by_country'.

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 provides no guidance on when to use this tool versus alternatives (e.g., calendar.holidays for other countries). It does not mention any prerequisites or edge cases, leaving the agent without context for selection.

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