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

No annotations are provided, so the description must fully disclose behavior. It says 'Expression discarded' but does not explain what happens to the provided parameters, whether the tool validates them, returns a result, or has side effects. The reference to arithmetic is inconsistent with the actual parameters, and no return format or side effects are described.

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, but it is under-specified rather than concise. Two sentences, the first of which is inaccurate and the second ambiguous, fail to convey any useful information. Efficiency is irrelevant when the content is misleading.

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 9 parameters and no output schema, the description provides almost no context. It does not explain the purpose of the parameters, the expected behavior, or the return value. An agent cannot correctly invoke this tool based on the description alone, especially given the mismatch between the description and schema.

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 descriptions already cover 100% of parameters (e.g., 'Git ref name; discarded after the shape check'), so the baseline is 3. However, the tool description adds no meaning beyond the schema and actively introduces a misleading concept of arithmetic that is not reflected in any parameter, potentially confusing the agent.

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' but the input schema contains parameters like ref, url, city, feed, host, json, path, zone, and query – none of which represent an arithmetic expression. The stated purpose is misleading and does not match the actual tool function, which appears to be some kind of shape check or validation based on the parameter names.

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 its siblings such as domain-shape, file-path-ok, or normalize-url. There is no mention of conditions, exclusions, or alternatives, leaving the agent without any basis to select it.

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