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

No annotations provided, so the description carries the full burden. It defines the term 'Smith number' but says nothing about return format (boolean vs text), error handling for non-numeric input, or whether the input is parsed as an integer. The trailing 'Provide value.' is a vague parameter nudge rather than behavioral context.

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?

Two sentences, front-loaded with the purpose and a concise definition. The trailing 'Provide value.' is slightly redundant given the schema but not egregious.

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 single-parameter predicate tool with no annotations and no output schema, the description is insufficient: it omits return type (boolean vs string), input constraints (integer only?), and edge-case behavior. A consumer cannot reliably interpret the result from the description alone.

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% (the single 'value' parameter is documented as 'Value to process'), so the schema baseline is 3. The description mentions 'Provide value' but adds no format details (e.g., integer string, range limits) beyond what the schema already says.

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?

States a specific verb (check) and resource (whether a number is a Smith number), and defines the concept. Clear and distinguishable from siblings like x402-is-prime. The name 'x402-is-smith' is abbreviated but the description disambiguates.

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 reference to sibling tools. The agent is left to infer that this is a single-number checker for a specific number-theory property.

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