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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description adds real context beyond them: the exact formula applied, the unit convention of each input, and the unit of the returned value.

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?

Front-loaded with the formula and computation, then units, then output. Four short sentences with little waste, though the trailing list_bundles pointer is marginally useful discovery filler rather than core definition content.

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 needn't explain return structure, and it still names the return unit. One gap: the schema exposes force_n as an input (and required parameters are zero), yet the description frames force as an output only, leaving the agent unclear on whether force_n should ever be supplied.

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%, so the schema already documents all three parameters and the baseline is 3. The description restates mass in kg and acceleration in m/s², which is mildly clarifying but adds no syntax, ranges, or handling of the unusual force_n input present in the schema.

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, resource, and the governing formula (F=m·a), which unambiguously separates it from lookalike physics siblings such as calculate_kinetic_energy or calculate_energy_physics. An agent can identify the exact computation without opening the schema.

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?

"Use for physics problems" gives an implied domain but names no alternative calculator and no exclusions (e.g., when to prefer calculate_kinetic_energy or calculate_spring_constant instead). The only cross-reference points at list_bundles, a discovery tool rather than a competing calculation.

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