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 states 'Expression discarded' but there is no expression parameter. It does not mention any side effects, permissions, or operational characteristics. The mismatch between description and schema is a severe transparency failure.

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 a single sentence, but it is under-specified rather than concise. It omits critical information about the parameters and operation. The brevity is not an asset because it fails to convey any usable guidance.

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?

For a tool with 9 parameters, no output schema, and no annotations, this description is completely inadequate. It provides no explanation of how parameters are used, what the tool does with them, or what results look like. An agent cannot correctly invoke this tool based on the description alone.

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 description does not reference any of the 9 parameters. Even though schema descriptions exist (100% coverage), the description's arithmetic claim conflicts with the schema's parameter set, actively confusing rather than clarifying. It adds no value and actively misleads.

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 none of the 9 parameters (ref, url, city, feed, host, json, path, zone, query) relate to arithmetic expressions. The name 'calc-eval' suggests calculation, but the schema covers URLs, cities, JSON validation, etc. This is misleading and fails to convey the actual purpose.

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 provided on when to use this tool versus its 29 siblings. There is no mention of context, prerequisites, or exclusion criteria. An agent would have no idea when to select this tool.

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