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 mentions 'Expression discarded' but there is no expression parameter, and it does not describe any side effects, return behavior, restrictions, or requirements. The description is actively uninformative and potentially misleading.

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 (one sentence), but conciseness without substance is under-specification. It omits essential information about the 9 parameters and the tool's operation, so it does not earn its brevity.

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?

Given the tool's complexity (9 parameters, no output schema, no annotations), the description is profoundly inadequate. It could not enable an agent to call the tool correctly or understand its behavior, and it fails to cover any of the parameter semantics or intended use.

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 schema description coverage is 100%, the tool description adds no value for the parameters. It does not relate 'a+b style arithmetic' to any of the documented parameters, nor does it explain how they are used or discarded. The description is disconnected from the schema and fails to enhance parameter understanding.

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 '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 are arithmetic expressions. This is misleading and fails to state what the tool actually does with these parameters or how it distinguishes from siblings.

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 or when to prefer a sibling. It offers no context about use cases, exclusions, or alternatives, leaving the agent without any selection criteria.

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