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

Annotations already declare readOnlyHint: true, idempotentHint: true, and destructiveHint: false, so the agent knows it's a safe, read-only operation. The description adds useful context: the tool is hosted by the platform, requires no platform credentials, and has a pay-per-query cost with pre-paid credits. It also discloses data privacy aspects (LGPD). This adds behavioral context beyond annotations, but could go further (e.g., rate limits or latency). No contradiction.

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 a single paragraph, concise, and front-loaded with the tool's purpose. It includes legal and cost information that is potentially useful but not excessive. It could be slightly better structured with line breaks, but it's not verbose.

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?

The tool is moderately complex (requires two parameters, likely a data lookup). The description covers the source, pricing, and data responsibility, and there is no output schema. However, it lacks parameter format guidance and any response format information. Given the annotations convey safety, the description is adequate but leaves out important operational details.

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?

The input schema has only 'placa' and 'renavam' with no descriptions, and the description provides zero parameter-level information. The schema coverage is 0%, so the description must compensate but does not mention any parameter details (e.g., formats, length, or that 'placa' is the license plate). This is a significant gap.

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 that the tool performs an IPVA query at SEFAZ GO, an official source. It uses a specific verb ('consultar') and resource ('SEFAZ GO: IPVA'), distinguishing it from siblings that are mostly utility tools (authenticate, connect, marketplace). However, it doesn't explicitly name alternatives for similar queries (e.g., other state SEFAZ tools), so it loses a point.

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 implicit usage context by stating it is for consulting official Brazilian sources and is not for confidential data. It also mentions payment per query with pre-paid credits, which hints at usage prerequisites. However, there is no explicit comparison to alternatives or when not to use it. This is adequate but not explicit.

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