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

Annotations already mark the tool as readOnly and non-destructive. The description adds the critical behavioral fact that this estimate does not charge the user, which is not directly derivable from the annotations. This is meaningful context beyond the structured fields and is consistent with them.

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 very short and front-loads the key value proposition. The 'FREE QUALIFICATION.' prefix is somewhat redundant with 'without charging' but does not add much waste. It is appropriately sized for a simple one-parameter tool.

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?

With no output schema and only one parameter, the description should clarify the meaning of 'id' and the conditions under which a cost is 'exact known'. It leaves the core input unexplained and does not specify the return format beyond saying it returns a price or cost. The description is not complete enough for an agent to invoke the tool correctly without additional inference.

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?

The input schema has one parameter, 'id', with 0% schema description coverage, and the tool description does not explain what 'id' represents or how it is used. An agent has no way to know what ID to supply, making this a significant and unaddressed gap.

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 states a clear verb and resource: it returns an advertised USD price or request-credit cost. The phrase 'without charging' distinguishes it from purchase/checkout tools like get_stripe_checkout_link. However, it does not explicitly name sibling tools or explain what entity 'id' refers to, so it falls just short of full differentiation.

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 implies use when you need a cost estimate before committing, especially with 'FREE QUALIFICATION' and 'without charging'. It does not provide explicit when-to-use/when-not-to-use guidance or name alternative tools such as get_offer or get_stripe_checkout_link, leaving the routing largely to inference.

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