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

No annotations are provided, so the description carries the full behavioral burden, yet it discloses nothing: not that the operation is a pure, side-effect-free computation, not the formula implied (Pythagorean), and not what the result looks like. Only the (implied) arithmetic nature of the operation is inferable, which is minimal.

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?

Extremely short, but the brevity reflects under-specification rather than efficiency. It is two hyphenated fragments that repeat the tool name instead of front-loading anything an agent could act on.

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 no annotations and no output schema, the description is the only source of behavioral context, and it is inadequate: it does not state the returned value, units, or formula for a two-parameter calculator whose inputs are documented only as opaque strings.

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%, with both width and length documented in the schema ('Width to process', 'Length to process'), so the baseline of 3 applies. The description adds no meaning beyond the schema — no units, no note that both inputs are numeric strings despite being typed as strings, and no explanation of what 'process' means.

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 is essentially a restatement of the tool name: 'Rectangular Diagonal: Diagonal of rectangular.' It conveys a noun phrase rather than a verb+resource action, and the phrasing 'of rectangular' is grammatically vague (rectangle? rectangular prism?). With many sibling geometry tools (cuboid-diagonal, cube-diagonal, cube-space-diagonal, rect-prism-volume), it does not differentiate itself from any of them.

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 when-to-use guidance, no prerequisites, and no mention of alternatives such as cuboid-diagonal or cube-diagonal. The agent gets no signal about when this rectangle-diagonal tool is the right choice versus those siblings.

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