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. It only says 'Expression discarded,' which is cryptic and does not explain what the tool actually does, what it returns, or side effects. The schema suggests it might validate shapes of various inputs, but the description does not confirm that.

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, which is concise, but it is under-specified and not front-loaded with useful information. It is concise but ineffective because it does not convey the tool's purpose or usage.

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, no output schema, and no annotations, the description is completely inadequate. An agent cannot determine what to pass, what the tool does, or what to expect in return. The schema alone is insufficient to infer usage.

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 tool description does not mention any parameters. The schema provides descriptions for each of the 9 parameters, but those descriptions are about parameter content (e.g., 'Git ref name; discarded after the shape check') and do not clarify how they relate to the stated arithmetic purpose. The description adds zero value beyond the schema.

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 is a clear verb+resource, but it is immediately contradicted by the input schema, which contains no arithmetic expression parameter and instead lists unrelated fields like url, city, json, etc. This makes the purpose ambiguous and does not distinguish it from siblings that also handle URLs, JSON, or timezones.

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 any of the 27 siblings. No context, no exclusions, no mention of alternatives or conditions.

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