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

Annotations already establish readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the agent knows this is a safe, self-contained computation. The description adds nothing beyond that profile (no note on return shape, though an output schema exists, and no error behavior for non-3D input). Adequate but thin against the already-declared safety profile.

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 eight-word sentence that front-loads the operation and the operand type. Every word earns its place with no redundancy.

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 annotations covering safety, a full input schema, and an output schema documenting the return value, the description covers enough for correct invocation. It could add a note about the resulting vector's orientation or error handling for malformed input, but nothing critical is missing.

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 baseline is 3, but the description adds a constraint the schema does not express: the vectors must be 3-dimensional, whereas the schema only says 'array of numbers' with no minItems/maxItems. That extra constraint is genuinely useful for correct invocation.

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 states a specific operation (cross product) on a specific resource (two 3-dimensional vectors), which is unambiguous against sibling math tools like calculator_dot or calculator_vector. It does not explicitly name those siblings to differentiate, keeping it just below a 5.

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?

There is no guidance on when to use this versus calculator_dot, calculator_vector, calculator_normal, or calculator_unit_vector, all of which live in the same sibling set. The dimensionality note implies applicability but never states preconditions or exclusions.

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