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

No annotations are provided, so the description carries the full burden and does meaningful work: it discloses the paid x402 mechanism ($0.02 USDC per call, on Base) and the result ordering (cheapest region first), both beyond what the schema conveys. It does not describe error behavior or the exact response shape, which keeps it from a 5.

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 tightly packed sentences with no waste; the core purpose and output scope lead, and the payment caveat follows. Every clause earns its place.

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 simple two-parameter lookup with no output schema, the description covers scope, coverage, ordering, and cost. It could say more about the returned structure (e.g., currency, region fields), but an agent has enough to call it correctly.

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 both `type` and `priceType` are already documented in structured data; the description adds no syntax, format, or enum guidance beyond them. 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 specific verb+resource: hourly price of one cloud instance type across every region where it's sold, on-demand and spot, sorted cheapest first. That is concrete and distinguishable from the aggregate cloudprice_compute/cloudprice_gpu siblings by implication, though it never explicitly contrasts with them.

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 described output (per-region pricing, on-demand plus spot) implies the use case of comparing a single instance type across regions, but there is no explicit when-to-use, when-not, or pointer to a sibling tool for other pricing needs. The only stated constraint is the per-call cost.

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