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

Annotations already declare readOnly and idempotent behavior, and the description adds a 1-hour cache, the upstream endpoint, and a detailed correction note about the M/S to Material/Servico translation that explains why the API works despite the upstream enum. This is meaningful behavioral context beyond what annotations provide.

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 front-loaded with the core purpose, followed by endpoint, use cases, the bug-fix note, and caching. It is slightly longer than strictly necessary, but every section contributes useful context and the structure is clear.

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 an output schema present and annotations covering the safety profile, the description covers purpose, endpoint, typical usage, a parameter edge case, and caching. No major invocation-relevant information appears to be missing, apart from explicit sibling differentiation.

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 all parameters. The description reinforces the CATMAT/CATSER mapping and explains the tipo M/S translation quirk, but it does not add new formats, defaults, or syntax beyond what the schema provides.

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 opens with a specific verb and resource: 'Lista todos os PGCs que incluem determinado item de catálogo (CATMAT/CATSER)', clearly identifying this as a filtered list lookup by catalog item. It also names the exact upstream endpoint, reinforcing the scope. It does not explicitly name a sibling, but the resource and filter are enough to distinguish it from other PGC tools.

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 states concrete use cases: answering which agencies planned to buy a given item this year and in what quantity, plus input to ETP and quantitative benchmarking. This is clear and actionable, though it does not explicitly say when not to use it or name alternatives like compras_pgc_listar/pras_pgc_agregacao.

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