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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds meaningful behavioral context beyond annotations: it is a paid call costing 0.10 USDC and provides current pricing. This is valuable for an agent deciding whether to invoke the tool.

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?

The description is two short sentences with no filler. The paid cost is front-loaded and the core purpose is stated immediately. Every word contributes to understanding the tool's function and cost.

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?

The tool is simple with only two well-documented parameters, and the description states what it returns (current on-demand list prices for every instance type in a region) and its cost. There is no output schema, so a bit more detail on the return shape could help, but for a snapshot/pricing tool this is reasonably complete.

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 both 'provider' and 'region' fully documented including examples and enum values. The description adds little beyond the schema, only clarifying that the result covers every instance type in a region. Baseline 3 is appropriate because the schema carries the parameter documentation burden.

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 clearly identifies the resource: current on-demand list prices for every instance type in a region. It lacks an explicit verb like 'get' or 'list', but 'Current on-demand list price' conveys the retrieval intent. It is distinct enough from siblings like reserved_snapshot and spot_snapshot by specifying 'on-demand' and 'region'.

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 gives context that this is a region-scoped, paid on-demand pricing lookup, but it does not state when to prefer it over alternatives such as 'ondemand' or 'spot_snapshot'. No exclusions or comparison to sibling tools are provided, so an agent must infer usage from the name and brief description.

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