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

With no annotations provided, the description bears the full burden of behavioral disclosure. It only hints at statelessness with 'Expression discarded,' but does not disclose the return format, error behavior, side effects, or whether any actual computation result 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 very short and front-loaded, which is good. However, the second sentence adds ambiguity rather than clarity, and the overall terseness omits necessary context, so it is not an effective concise description.

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?

The definition is not complete enough for an agent to call correctly: there is no output schema, no mention of a return value, no required parameter, and a mismatch between the described expression input and the actual schema. The agent would be left guessing what to pass and what to expect.

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 schema properties all have their own descriptions, but the tool description never connects its stated 'expression' input to any of the seven properties. An agent cannot tell which parameter carries the arithmetic expression, and none of ref, url, city, feed, host, json, or path semantically represents an expression.

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 action: evaluate a+b style arithmetic. However, the phrase 'Expression discarded' creates ambiguity about whether the tool computes a result or only checks/discards the input, and the input schema contains no obvious 'expression' parameter to match the stated purpose.

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?

No guidance is given about when to use this tool rather than related siblings such as validate-json, domain-shape, or other shape-check tools. There are no conditions, exclusions, or alternative tool references to help an agent select it appropriately.

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