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, yet it discloses nothing about the operation. It does not say whether a value is parsed as an integer, how invalid or negative inputs are handled, or what the boolean-shaped result looks like.

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 text is short only because it is a duplicated restatement of the name, which wastes one of its two fragments entirely. This is under-specification rather than economy of language.

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 simple predicate tool with no annotations and no output schema, the description should at minimum define 'semi prime' and indicate the result type. It does neither, so an agent cannot confidently invoke it vis-à-vis the many sibling number predicates.

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?

Only one parameter exists and schema description coverage is 100% (the schema already documents 'value' as 'Value to process'), so the baseline of 3 applies. The description adds no meaning beyond the schema, but the schema does the documenting.

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 text 'Is Semi Prime: Is Semi Prime' merely restates the tool name twice, giving no verb-plus-resource expansion beyond the literal name. It also fails to distinguish this predicate from the many sibling predicates like x402-is-prime, x402-is-semiperfect, or x402-is-smith, so an agent learns nothing about what 'semi prime' specifically tests.

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?

There is no statement of when to use this tool, when not to, or which alternative predicate to prefer. With dozens of near-identical 'is-X-number' siblings, the absence of any routing guidance leaves the agent to guess.

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