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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses ordering (newest first), a hard row cap (up to 100), that each row carries its source, and a concrete cost model (50 free calls/day, then $0.01 USDC on Base via x402). The payment/rate-limit disclosure is material operational context an agent would otherwise not have.

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?

Three sentences, front-loaded with the trigger, then the mechanics, then the cost. Every clause carries distinct information and nothing is repeated from the name or title.

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 read-only, non-nested, five-parameter query tool with full schema coverage and no output schema, the description covers trigger, scope, ordering, cap, returned provenance, and pricing. Nothing an agent needs in order to call it 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 coverage is 100%, so the schema already documents all five parameters, including the enum and the anyOf requirement. The description's 'one chip or provider' is slightly narrower than the schema, which explicitly permits giving both, and it adds no format or edge-case detail beyond the schema.

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 gives a specific verb and resource ('Lists list-price changes'), plus scope details (since a date, one chip or provider, newest first). It implicitly separates itself from snapshot siblings like compute_list_prices and get-gpu-price by focusing on *changes* over time, but never names those siblings, so an agent must still infer the boundary.

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?

'Use when you need to know whether GPU rental prices moved' is an explicit use-case trigger. It gives no when-not condition and no named alternative for the adjacent case (current price vs. price movement), leaving some routing to inference.

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