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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds only the mathematical method and an example, with no extra behavioral context such as input-combination requirements or result constraints.

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?

The description is very short and front-loaded, with no wasted text. It is perhaps under-specified rather than overlong, but in terms of size and structure it is efficient.

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?

Output schema and annotations are present, so return values and safety do not need explanation. However, with five optional parameters and zero required inputs, the description omits the critical invocation rule: how many and which inputs must be supplied (e.g., any two of a, b, c, angle_a, angle_b). That gap is significant for correct use.

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 each parameter is already documented in the schema. The description adds a small illustrative mapping (a=3, b=4 → c=5), but does not explain the expected number or combination of optional inputs beyond that 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?

The description identifies a specific resource (right triangle) and method (Pythagoras and trig), which distinguishes it from the general calculator_triangle sibling. It is clear what the tool computes, though it does not explicitly contrast itself with calculator_trigonometry or calculator_triangle.

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?

It gives a worked example but no guidance on when to use this tool versus related alternatives like calculator_triangle or calculator_trigonometry. There are no prerequisites, no exclusions, and no explanation of valid input combinations.

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