Decode NF-e access key

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

No annotations are provided, so the description carries full burden. It mentions a cost ($0.005) and what fields are extracted, which adds some behavioral context. However, it does not disclose any error conditions, rate limits, or side effects. For a read-only decoding tool, this is adequate but not comprehensive.

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 consists of two concise sentences. The first sentence states the action and key outputs; the second adds cost context. It is front-loaded with the most important information and contains no redundant or irrelevant content.

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 the tool has only one parameter, no output schema, and no annotations, the description covers the essential aspects: input format, extracted fields, and cost. It lacks explicit return format details, but listing the fields provides reasonable completeness for a simple decoding 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?

Schema description coverage is 100% (the sole parameter access_key is described as '44-digit NF-e access key'). The description does not add extra meaning for the parameter beyond what the schema already provides. Baseline score of 3 applies per rules.

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 explicitly states it decodes a 44-digit Brazilian NF-e/NFC-e access key and lists specific extracted fields (issuer CNPJ, state, emission date, invoice number, model). This clearly distinguishes it from sibling tools like decode_boleto or decode_tender_id, which serve different document types.

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 implies usage for NF-e keys but does not explicitly state when to use this tool instead of alternatives. No when-not or exclusion criteria are provided. Given sibling tools cover different document types, the context is clear but lacks explicit guidance.

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