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

Annotations already establish read-only, idempotent, non-destructive behavior; the description adds the paid call cost (0.10 USDC) and the 'current snapshot' nature. It does not mention output format, pagination, or data freshness, but with low risk annotations this is acceptable.

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 with the cost warning front-loaded and no filler. Every clause adds information about cost or data content.

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-only tool the description covers the returned data, but the 'AWS or Azure' phrasing conflicts with the schema's gcp option and leaves the actual provider scope ambiguous. It also uses ri_type without defining it, which matters more because there is no output schema.

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%, with region and provider fully documented including an enum and default. The description adds little beyond confirming the result is per-region and mentions ri_type, which is output vocabulary rather than parameter guidance.

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 names the exact data returned: current reserved effective hourly price for every instance type and ri_type in a region, which distinguishes it from spot/on-demand snapshots. It loses a point because it has no explicit verb like 'get/list' and its parenthetical says 'AWS or Azure' even though the schema provider enum includes gcp.

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?

No statement about when to prefer this tool over sibling tools such as reserved, ondemand_snapshot, or spot_snapshot. The only guidance is implied by the word 'reserved', which requires the agent to infer the intended use case.

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