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

Annotations already cover read-only/idempotent/open-world safety; the description adds that exactly one evidence-bearing result is returned, that the source is public supplier/procurement data, and that the response contains a continuation instruction to the paid x402 service. It also explicitly clarifies no payment is taken, which is beyond what the annotations state.

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?

Two short sentences front-load the free/single-result nature and then state the paid continuation; every phrase earns its place. 'No payment is required' reinforces 'FREE' without being wasteful given payment concerns.

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?

For a low-complexity, one-parameter, read-only tool, the description covers what the agent needs: what is returned (one evidence-bearing result), how it connects to the paid service (continuation), and cost (none). It is slightly vague about the format of the 'exact continuation' and does not describe output structure, but the annotations and schema cover the rest.

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 single parameter q is fully documented in the schema ('Commercial need, product, service, supplier category, or procurement topic'), so the description adds little beyond that. The description's mention of 'supplier/procurement discovery' loosely reinforces q's purpose but introduces no new semantics.

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 states a concrete action ('return one evidence-bearing public supplier/procurement discovery result'), specifies the exact scope (single result, public, supplier/procurement), and contrasts with the paid x402 service. An agent can distinguish this free preview tool from the paid offer siblings.

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 makes the free/paid relationship clear ('FREE,' 'No payment required,' 'exact continuation to the 0.05 USDC... service'), implying it is the entry point before the paid service. However, it never explicitly states when to prefer this over siblings such as mars_x402_commercial_intelligence_offer or find_counterparty, nor gives exclusions.

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