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

With no annotations, the description carries the full burden of behavioral disclosure, but it only says 'Expression discarded,' which is ambiguous and incomplete. It does not state whether the result is returned, whether all inputs are discarded, what side effects occur, or what the tool actually does with any of the nine schema parameters.

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 text is short and 'Evaluate a+b style arithmetic' is front-loaded, but the second phrase 'Expression discarded' is confusing rather than informative. This is under-specification rather than effective conciseness; the brevity does not help the agent understand invocation.

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?

For a tool with nine parameters, no annotations, no output schema, and no usage guidance, this description is grossly incomplete. It omits the expression parameter, the return behavior, the relationship to the schema fields, and any operational context, leaving an agent unable to invoke it correctly.

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?

Although schema coverage is 100%, the description does not connect 'expression' to any of the nine parameters. An agent cannot determine which field, if any, holds the arithmetic expression, and the param descriptions are about URLs, files, JSON, and search queries—none of which match the tool's advertised purpose.

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 specific verb ('Evaluate') and a resource ('a+b style arithmetic'), so it is not a tautology. However, it is vague because no schema parameter corresponds to an arithmetic expression, and it does not distinguish this tool from the many shape-checking siblings like domain-shape or validate-json.

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 calc-eval versus any alternative tool. The sibling list includes several validation and shape-checking tools, but the description gives no conditions, exclusions, or routing hints to help an agent choose correctly.

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