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

The annotations already declare this a pure, non-destructive, closed-world read (readOnlyHint true, destructiveHint false, openWorldHint false), so safety behavior is covered. The description adds the SI unit convention (m/s, s → m), which constrains inputs meaningfully, but nothing about edge cases such as negative values or unit-mismatched inputs. With annotations carrying the safety profile and an output schema present, a 3 is appropriate.

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?

A single short sentence that front-loads the formula and ends with the unit conversion. Every element – verb, formula, units – earns its place with no filler.

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 deterministic two-parameter arithmetic tool with full schema coverage, an output schema, and annotations covering safety, the description supplies everything needed to invoke it correctly. The only omission is any note on rejecting or interpreting non-physical inputs such as negative speed or time, a minor gap for this complexity level.

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%, and the schema already documents both parameters with units ('Speed in m/s', 'Time in seconds') plus examples. The description's '(SI: m/s, s → m)' merely restates that unit mapping and adds no syntax or range information beyond it, so the baseline 3 applies.

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 gives a precise verb ('Calculate'), resource ('distance'), and the exact formula d = speed × time with SI units, so an agent knows exactly what computation happens. It does not, however, name a sibling such as calculator_physics_speed (which solves for the other variable) or calculator_speed, leaving the agent to infer sibling boundaries from the surrounding tool list.

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?

Usage is implied by the formula: call this when distance is the unknown and speed and time are known. There is no explicit statement of when to prefer it over calculator_physics_speed or calculator_speed, and no exclusions or prerequisites are given.

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