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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), and the description adds genuinely new context: pricing ($0.05 per successful call, paid via x402 in USDC on Base) and what is returned (parsed structure, comparison result, failure reason). It does not mention rate limits or error/edge handling, but the cost and auth model is disclosed.

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?

Front-loaded with the tool's identity and capabilities, then the return values, then pricing—a sensible order with no filler. It is a single dense multi-clause sentence, which is slightly harder to scan but every clause carries information.

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 six-parameter, multi-op tool with no output schema and no required params, the description covers what each op does, what comes back, and the payment requirement, which is enough to invoke correctly. The only real omission is the sort operation present in the enum.

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%, so every parameter is already documented in the schema; baseline is 3. The description reinforces op-to-parameter mapping (two versions for compare, range+version for satisfies) but adds no syntax or format detail beyond the schema, and it never explains the versions/sort parameter.

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 specific operations (parse, compare, satisfies) and the resource (semantic version), so an agent can immediately tell it apart from siblings like string_similarity or base_convert. It omits one enum mode, sort, which is inconsistent with the schema's op list, keeping it short of a 5.

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?

It maps each operation to its intent and its inputs ('compare two versions by precedence including prerelease ordering', 'test whether a version satisfies a range expression'), giving clear context for choosing an op. There are no explicit when-not conditions or sibling alternatives, but the sibling set is functionally unrelated so the routing risk is low.

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