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

With no annotations provided, the description carries the full burden of transparency. It discloses the core behavioral traits: it calculates pace in both km and mile units, predicts race finish times, and provides splits. While it does not mention edge cases or input handling, the tool is a straightforward calculator, so this level of disclosure is sufficient and adds value beyond the schema.

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 sentences, front-loaded with the tool's name and key function, followed by a compact list of outputs. Every clause adds value with no redundancy or fluff.

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 tool's simplicity (4 numeric inputs, no output schema, no nested objects), the description covers the essential inputs and outputs. It explains what the user provides and what they receive. A minor gap is the lack of explicit mention of return format or units for splits, but overall it is sufficiently complete for a calculator of this type.

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 0%, so the description must compensate. It mentions 'any distance and time' and clarifies the meaning of the inputs by explaining outputs (pace per km/mile, finish times). However, it does not explicitly map each parameter (distanceKm, hours, minutes, seconds) to their roles or units, relying on names and schema constraints. This is adequate but not complete.

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's function with an action verb ('Calculate') and specific resource ('running pace'), and elaborates on outputs ('per-km and per-mile pace', 'predicted finish times for 5K, 10K, half marathon, and marathon, plus splits'). This distinguishes it from the many sibling calculators by focusing on a unique, well-defined domain.

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 provides clear context for when to use the tool—whenever a user needs running pace, race predictions, or splits from distance and time. It does not explicitly name alternatives or exclusions, but the specificity of 'running pace' naturally isolates it from other calculator siblings, offering implicit guidance.

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