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

Annotations already cover readOnly, idempotent, non-destructive, and closed-world, so the safety profile is handled. The description adds non-annotation context: results are 'resumido' (summarized shape, important since there is no output schema) and limited to 'cursos ativos' (active-only scope). It does not mention pagination or result counts, but otherwise adds real value.

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 core action and scope are front-loaded in the first clause, the enum glosses are compact, and the closing routing sentence removes ambiguity. No filler sentences.

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 declaring the response is a summarized list and pointing to get_course for full detail. Annotations cover the safety/behavioral profile, so nothing an agent needs to call this correctly is missing.

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 baseline is 3, but the description goes beyond the enum labels by defining each modality's meaning ('profissionalizante' = formação completa com DRT, 'livre' = Express/short specialization, 'ead' = online assíncrono). That domain gloss helps the agent pick the right filter value.

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 with scope: lists ALL active courses, summarized, with an optional modality filter. It also distinguishes itself from the get_course sibling by specifying this returns the summarized view while get_course + slug returns detail.

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?

Explicitly routes the agent to the alternative tool ('Use get_course com o slug pra detalhe completo') and notes the filter is optional, which tells the agent when this listing is sufficient. It does not state any explicit when-not conditions, but the context is clear.

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