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

Annotations already declare read-only, idempotent, non-destructive, so safety is covered. The description adds substantial operational behavior: edge cache of up to 6 hours, per-request recomputation of prazos/preços, `Cache-Control: no-cache` forcing an origin read, and the `x-origem-cache` header reporting hit/miss/bypass. That is real value beyond the annotations, though no auth or rate-limit notes are given.

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?

Front-loaded with the resource and its two returned dates, then legal justification, cost, and cache semantics. Every sentence carries information, though the lei/artigo citation and the cache-header detail make it longer than strictly necessary for selection.

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 does the work of naming the returned values and flagging that the impugnação date is an estimate (3 business days before the session, national holidays). It omits the output shape and any error behavior for an invalid id, but covers the essentials for a one-parameter read tool.

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?

One parameter with 100% schema description coverage; the schema already explains that `id` is the compra id from the search. The description adds nothing about the parameter, so the baseline of 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 the resource precisely ('Prazos da compra') and enumerates the two values returned: proposal-publication end and the last day for impugnação, with the legal basis (Lei 14.133 art. 164). It lacks an explicit verb and does not distinguish itself from siblings like 'compra', so an agent must infer the boundary, but the data it yields is unambiguous.

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?

Usage is implied: pass a compra id (from 'busca') and receive that purchase's deadlines. There is no explicit when-to-use/when-not, nor any naming of the sibling ('compra') that would return the broader record instead. Adequate but leaves routing to inference.

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