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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does add one useful trait—the expression is 'discarded'—but it does not state whether the call has side effects, requires authentication, returns a result, or fails on invalid expressions.

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 short and front-loads the core action with no filler. However, the second sentence is ambiguous and the brevity is not backed by enough operational detail to make the structure genuinely helpful.

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?

There is no output schema or annotation coverage, and the description omits the input mechanism, allowed arithmetic syntax, return format, and error behavior. Relative to the richer sibling tools, calc-eval is under-specified to the point of being unusable.

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?

The description never maps its core concept, the arithmetic expression, to any of the seven schema properties (ref, url, city, feed, host, json, path), and the schema lacks an expression parameter entirely. Because the description adds no parameter-level meaning and does not compensate for this missing input, an agent cannot construct a valid call.

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 names a concrete action, 'Evaluate a+b style arithmetic', which distinguishes it from the sibling tools, none of which are arithmetic evaluators. However, its clarity is undermined by the ambiguous phrase 'Expression discarded' and by the fact that no schema parameter obviously carries an arithmetic expression.

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 calc-eval instead of a sibling tool, no conditions for use, and no mention of alternatives. The only usage signal is the one-sentence action, which implies arithmetic evaluation but does not state what input is expected or what kinds of expressions are valid.

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