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

Annotations already declare readOnly, idempotent, non-open-world behavior, so safety is covered. The description adds genuinely new operational context the annotations cannot carry: the x402 payment requirement and per-call price ($0.05 USDC on Base), plus what a failed range test returns (the reason). It omits any note about the cost applying only to successful calls vs attempts beyond the stated "per successful call".

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 operation set before the return/pricing details. The first sentence is a long semicolon-separated list, but every clause maps to a distinct mode; no filler.

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?

No output schema exists, and the description compensates by stating what comes back (parsed structure, comparison result, mismatch reason). The main gap is that the `sort` operation present in the enum and `versions` parameter is never mentioned in the description, leaving one mode unexplained.

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 baseline is 3, but the description goes beyond the schema by naming the supported range grammars (caret, tilde, hyphen, x-ranges, comparator sets) and giving an example (^1.2.0), which meaningfully clarifies the `range` 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 a specific resource (semantic version) and enumerates the concrete operations: parse into major/minor/patch/prerelease/build, compare by precedence, and test range satisfaction. It is immediately distinguishable from every sibling (code_hash, code_jwt, code_url), none of which touch versioning.

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 clearly maps the three main use cases to intent ("compare two versions by precedence including prerelease ordering", "test whether a version satisfies a range expression"), which effectively tells the agent when to pick each mode. It stops short of explicit when-not guidance or naming alternatives, but with unrelated siblings there is little competition to disambiguate.

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