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

No annotations are provided, so the description carries the full behavioral burden. It is a pure, non-destructive string transformation, so the safety profile is evident, but the description never states the output shape (e.g. '1st', '2nd', '11th') or behavior on non-numeric input, which is the one thing an agent would want disclosed here.

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?

A single front-loaded sentence with no filler. Nothing could be removed without losing meaning.

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 trivial one-parameter pure function with no output schema, the description is nearly complete. The remaining gap is that it does not show a sample output or note the 11/12/13 exception cases, which is the only real risk of misuse.

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% and there is a single parameter, but the schema's own description ('Value to process') is generic and does not say the input is a number, while the parameter is typed as string. The tool description partially compensates by saying 'a number', which is genuinely useful, but no accepted formats or ranges are given.

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 specific verb and resource ('Add an ordinal suffix to a number'), which is unambiguous. However, it does not distinguish this tool from the sibling x402-to-ordinal, which appears to perform the same or an adjacent transformation, so the agent has no basis to choose between them.

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?

No when-to-use guidance, no exclusions, and no mention of the overlapping sibling x402-to-ordinal. The agent must infer usage context entirely from the name.

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