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

Annotations already establish this as a safe, idempotent read, but the description goes well beyond them by disclosing per-call cost ($0.01 USDC), the payment protocol (x402 v2 on Base), the required PAYMENT-SIGNATURE header, and the concrete endpoint. That is exactly the operational context an agent needs to actually invoke a paid tool.

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 core purpose and the sibling routing come first, followed by returns, inputs and payment mechanics — a good front-loaded order with no filler. The payment/endpoint sentence is a little implementation-heavy, but it is necessary for invocation, so only a minor deduction.

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 compensates by enumerating the returned fields (active flag, licence number, name, NEQ, city, restriction flag, categories). Inputs, cost and transport are all covered, so nothing required to call this tool correctly is missing.

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%, so the schema already documents neq, name and licence with formats and patterns. The description only restates the accepted inputs ('name, NEQ or RBQ licence number') without adding matching or format semantics, so the baseline 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 a precise verb and resource ('does this Québec contractor hold an ACTIVE RBQ licence right now?') plus the exact return payload. It explicitly distinguishes itself from the sibling qc-contractor-check, so an agent can route between the two without opening either schema.

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?

Names the condition that selects this tool ('vet many contractors fast') and the alternative for the other case ('use qc-contractor-check for RENA and penalties'). Accepted input identifiers are also stated, leaving nothing to inference.

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