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

Annotations already declare a pure, idempotent, read-only computation, so the safety profile is covered. The description adds only that it returns range, peak, and flight time, which the output schema already carries, so it contributes little behavioral context beyond structured fields.

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?

Three short, front-loaded sentences with no redundancy; inputs and outputs are clearly separated. The trailing cross-reference to list_bundles is mildly useful but 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 a full output schema and safety annotations, the description needn't explain return values or reversibility, and it doesn't. It is complete enough to call correctly, missing only domain disambiguation from adjacent physics calculators.

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 coverage is 100%, so velocity, angle_deg, and height are fully documented with units in the schema. The description merely restates those input names and adds no format, default, or constraint detail beyond the schema 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) and resource (projectile trajectory) and enumerates the outputs (range, max height, time of flight). With no competing projectile sibling in the list, an agent can select it unambiguously.

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 or ballistics" gives implied context but names no alternatives and no when-not conditions. It suggests a domain rather than routing the agent against the many other calculate_* physics tools like calculate_kinetic_energy or calculate_energy_physics.

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