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

Beyond the readOnlyHint annotation, the description discloses payment behavior (USDC/USDT on Base via x402), a free tier (3 free calls per wallet), and the deterministic vs random nature of v4/v5. This adds useful behavioral context not captured by annotations, though it could be more explicit about potential side effects of payment, which are already implied.

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 concise sentences, with the core purpose front-loaded and supplementary payment/free-tier info following. Every word earns its place, and the structure makes it easy to parse quickly.

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?

Given the output schema exists and annotations declare read-only, the description covers purpose, versions, and payment constraints sufficiently. It omits explicit mention of count limits or error conditions, but those are in the schema, so the description remains largely complete for correct invocation.

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?

With 100% schema coverage, the baseline is 3, but the description adds semantic depth by explaining that v5 is deterministic and uses namespace and name, and that payment occurs via x402, which directly clarifies the role of name, namespace, and x_payment. This goes beyond the schema's individual parameter descriptions, providing valuable inter-parameter context.

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 states the tool generates RFC 4122 UUIDs, specifying both v4 (random) and v5 (deterministic) variants, with a clear verb and resource. It distinguishes itself from sibling tools like hash by focusing on UUID generation, making it unambiguous.

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 mentions 'Key-less, local generation' and payment details, implying when it can be used, but does not explicitly contrast with alternatives like hash or other generation tools. It lacks explicit 'when not to use' guidance or mention of specific use cases, leaving some inference to the agent.

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