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

Annotations already declare read-only/idempotent/non-destructive, but the description adds substantial operational context: parallel index queries, partial-failure behavior where one index's error is surfaced while the other result stands, the TST recurring-number quirk, and the absence diagnostic. This is behavior an agent cannot infer from annotations.

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?

Dense but well front-loaded: what it does first, then mechanics, then failure/special cases, then the sibling reroute. Length is justified by the non-obvious return shape, though the prose could be trimmed slightly.

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 fully documents the return contract (instancias[], instancia_mais_recente, consultas[], ausencia) and edge cases. An agent has everything needed to call and interpret this 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?

Only one parameter (numero_processo) at 0% schema coverage. The description implies it is a CNJ number and that the originating tribunal is derived from it, but never documents the format or validation, so it only partially compensates for the missing schema description.

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 (localizar) and resource (processo/instância) and scopes it to lookup by CNJ number only. It clearly distinguishes itself from datajud_get_processo and datajud_movimentos by naming them for adjacent tasks.

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?

Explains the core use case (find current instance from CNJ number) and routes the agent to datajud_movimentos for a full per-instance timeline. It does not explicitly contrast when to prefer this over datajud_get_processo, so it falls just short of full when/when-not guidance.

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