percentiles

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

With no annotations, the description carries the full burden. It discloses the warning about p99 being the maximum for n<100, which is a key behavioral caveat, and states the calculation methods. However, it does not disclose return format, edge cases (e.g., empty array), or whether both methods are returned separately, leaving some ambiguity.

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 core purpose, and includes a valuable caveat. Every sentence earns its place with no filler or redundancy. It is appropriately concise for a simple tool.

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 (one parameter, no output schema), the description provides the key facts: which percentiles, calculation methods, and a warning. However, it lacks clarity on the output structure (e.g., does it return an object with both nearest-rank and interpolation results?) and does not address potential edge cases, making it incomplete for a fully informed agent.

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 for the 'nums' parameter. It provides no explanation of what the array should contain, constraints, or how it is used beyond the tool name. The parameter semantics are essentially left to the schema type alone, which is insufficient.

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 computes p50/p90/p95/p99 percentile values using two methods (nearest-rank and linear interpolation). It names the specific percentiles and the resource (numeric array), making it distinct from sibling tools like calc_stats which likely provide broader statistics.

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 implies usage when percentile values are needed, but does not provide explicit guidance on when to use this tool over alternatives like calc_stats or compare_threshold. No exclusions or alternative tool mentions are present, so it falls into 'implied usage'.

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