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

Annotations already provide readOnlyHint=true and idempotentHint=true. The description adds that it simulates without issuing a note, confirming non-destructive behavior. It lists the specific taxes simulated. No contradictions. The output schema (mentioned in context) likely covers return values, so description does not need to detail them.

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, clear sentence that efficiently conveys purpose and key limitations. However, it could be slightly more structured to also introduce parameters without losing conciseness.

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?

Given simple complexity, good annotations, and an output schema, the description covers purpose and usage context. The major gap is the complete lack of parameter semantics, which hinders the agent from using the tool correctly. Additional details about the parameters are needed for completeness.

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 has two integer parameters (Count, Capacity) with 0% description coverage. The tool description does not mention or explain these parameters. 'Lista de produtos' suggests some relation but not mapped to Count/Capacity. Without explanation, an AI agent cannot understand or correctly use these parameters.

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?

Description clearly states it simulates tax calculation (ICMS, PIS, COFINS, IPI, ST) on a list of products without issuing a note. The verb 'simular' and resource 'cálculo de impostos' are specific. This distinguishes it from siblings like nfe_emitir (issue invoice) and nfe_previsualizar (preview invoice).

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 explicitly states the tool simulates without issuing a note ('sem emitir nota') and positions it for pricing ('Útil para precificação'). This gives clear context. Though it does not explicitly name alternatives or when not to use, the sibling list and the 'without emitting' clause help differentiation.

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