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

With no annotations provided, the description carries the full burden. It states 'Expression discarded' but does not explain what is discarded or what the tool actually does with the parameters. There is no mention of side effects, permissions, or return values. The behavior is entirely opaque.

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 extremely short, which is concise, but it lacks essential context. The two sentences are not informative enough to guide an agent, and the second sentence is cryptic. It is under-specified rather than appropriately concise.

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 tool has nine parameters, no output schema, and no annotations. The description does not explain the return value, the semantics of the check, or any usage context. It is grossly incomplete for an agent to call 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?

The input schema has 100% description coverage for its parameters, so the schema itself explains each field. However, the tool description adds no meaning about how these parameters relate to the stated arithmetic evaluation, and the description's purpose does not align with the parameters, leaving the agent unsure of how to fill them.

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 'Evaluate a+b style arithmetic' which gives a vague purpose, but the input schema contains nine unrelated parameters (ref, url, city, feed, etc.) with no arithmetic expression field. The description does not clarify how these parameters are used, making the tool's purpose ambiguous and potentially misleading.

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?

The description provides no guidance on when to use this tool versus the many sibling tools (e.g., domain-shape, validate-json). It does not mention any alternative or exclusions.

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