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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only mentions that the expression is discarded; it does not state whether the operation is read-only, what side effects occur, what errors can be raised, or what output is returned.

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 concise at only two sentences, but it is under-specified rather than appropriately concise. It lacks any mapping to the nine parameters and offers no usable structure to help an agent invoke the tool correctly.

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 nine heterogeneous parameters, no output schema, and no annotations, the description is radically incomplete. The mismatch between the arithmetic purpose and the schema makes it nearly impossible for an agent to confidently select or correctly invoke this tool.

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; the schema already documents each parameter. The description adds no parameter-level meaning and does not indicate which parameter, if any, holds the arithmetic expression, leaving a significant gap between the stated purpose and the actual parameters.

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 ('Evaluate a+b style arithmetic'), but the input schema contains no expression parameter; instead it lists unrelated parameters like ref, url, city, and query. This mismatch prevents an agent from mapping the stated purpose to any callable argument and does not distinguish the tool from its many sibling check/shape tools.

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 about when to use this tool versus alternatives. The phrase 'Expression discarded' hints at a non-persistent operation, but it does not explain when calc-eval should be selected over similar validation or shape-check tools.

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