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

With no annotations, the description carries the full burden and does add real behavioral detail: a per-call price of $0.005 USDC paid via x402 on Base, and results ordered cheapest region first. It omits what happens on payment failure, rate limits, or error modes, so it is not fully complete for a paid endpoint.

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 tight sentences with zero waste: the core result and ordering come first, followed by the payment model. 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 read tool with no output schema, the description adequately conveys the return shape (all regions, cheapest first) and the billing model. Payment-failure and error behavior are the only meaningful omissions.

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 coverage is 100%, so both parameters are already documented in the schema, and the description adds only mild context ('on-demand and spot' hints at the priceType values, 'in every region' clarifies the type's scope). Baseline 3 is appropriate since the schema does the heavy lifting.

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 and resource: hourly price of one cloud instance type across every region, covering AWS EC2 and Azure VM SKUs, on-demand and spot, sorted cheapest-first. An agent can immediately tell this is a per-instance-type price lookup, though it never names how it differs from siblings like cloudprice_compute or cloudprice_gpu.

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?

Usage is only implied via the phrase 'one cloud instance type' and the on-demand/spot scope; there is no explicit statement of when to choose this over cloudprice_compute, cloudprice_gpu, or list_services. No prerequisites or exclusions are given, leaving sibling selection to inference.

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