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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'Expression discarded', which is meaningless given there is no expression parameter. It does not mention side effects, permissions, or what happens with the listed inputs, leaving the agent completely in the dark.

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, but this is under-specification rather than effective conciseness. It does not front-load any useful information, and every word is either irrelevant or 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 is wholly inadequate. It doesn't explain the tool's functionality, how to invoke it, or what to expect. The 'Expression discarded' comment is nonsensical, and an agent would have no idea how to call this tool 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 the schema documents each parameter, the description adds no value and directly contradicts the schema by suggesting an arithmetic operation that none of the parameters support. It fails to explain that these parameters are likely inputs to separate checks, and instead confuses the agent further.

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 claims to evaluate 'a+b style arithmetic', but the input schema contains no expression parameter. Instead it lists ref, url, city, feed, host, json, path, zone, and query, all unrelated to arithmetic. This is actively misleading and does not clarify the tool's real purpose, which appears to be a multi-purpose utility from the sibling set.

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 on when to use this tool versus alternatives. There is no mention of context, exclusions, or any criteria that would help an agent choose this tool over its many siblings.

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