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

With no annotations, the description carries the full burden, but it only states the formula. It does not disclose expected input format, units (Hz vs radians/s?), edge cases (frequency=0), output shape, or whether it accepts natural language. This is a minimal formula restatement rather than behavioral disclosure.

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 very short: one clause explaining the formula plus one imperative instruction. Every sentence earns its place, and the core definition is front-loaded. Minor waste: 'Period:' prefix and the redundant restatement of the reciprocal definition, but overall it is tight.

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 calculation tool with no parameters and no output schema, the description is minimally functional but missing key operational details: units, how frequency is provided (free text?), expected precision, and error handling for invalid/zero frequencies. Among a huge sibling list of similar physics calculators, it does not give an agent enough to call it reliably.

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?

The schema has zero parameters, so the description's instruction 'Provide frequency value' is the only semantic guidance. Context signals mark schema_description_coverage as 100% because there are no schema properties, giving it a baseline 3. The description adds a small hint that the frequency is user-supplied, but no format or unit details.

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 ('Calculate') and resource ('the period of a wave') and defines period as the reciprocal of frequency. It is reasonably clear what the tool computes, though the name itself already signals the concept, and the description adds only a formula restatement without distinguishing it from related physics tools.

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 guidance on when to use this vs sibling tools like x402-frequency, x402-wavelength, x402-wave-speed, or x402-frequency-unit. The instruction 'Provide frequency value' implies the usage context but does not state prerequisites, units, or alternatives. The agent must infer when to invoke this tool among hundreds of physics calculators.

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