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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so the safety profile is fully covered. The description adds the units (kg, m/s, joules) and formula, but no auth, edge-case, or domain-constraint behavior beyond that; a 3 is appropriate when annotations carry the load.

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?

Compact, front-loaded with the formula and purpose in the first clause, then inputs, outputs, and a routing pointer. Every clause carries information, though the trailing list_bundles pointer is the least essential element.

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?

With an output schema present, the description need not explain the return structure, and it correctly gives the formula, input units, and output units. Nothing critical is missing for a two-parameter pure-computation tool.

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 both parameters already carry unit descriptions ('Mass in kg', 'Velocity in m/s'). The description repeats those units without adding format, range, or validation detail, so it does not exceed the schema-driven baseline.

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 ('Compute') plus the exact formula KE=½·m·v², which unambiguously distinguishes it from siblings like calculate_energy_physics or calculate_earthquake_energy. An agent can identify the required inputs and outputs from the description alone.

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?

Gives concrete application contexts ('physics, vehicle safety analysis') and points to list_bundles for related 'science' calculators, which helps routing. It stops short of naming a specific competing sibling or stating when NOT to use this tool, so it falls short of the 5 benchmark.

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