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 does reveal that the expression is discarded, indicating no persistence, but it does not disclose what is returned, whether evaluation produces a numeric result, error behavior, or side effects. This is insufficient for a tool with no output schema.

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 brief and front-loads the core action. There is no fluff or redundant restatement. The second clause is terse but contributes a behavioral note; the main weakness is not verbosity but missing semantic connection.

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?

The tool has 9 parameters, no output schema, no annotations, and a description that omits both the return contract and the parameter to use for the expression. The agent cannot reliably select or invoke this tool, so the description is far from contextually complete.

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%, all nine parameters describe unrelated concerns such as URLs, hosts, JSON text, paths, and search text. None of them is an arithmetic expression, and the description never maps 'a+b' to any parameter. An agent cannot determine how to pass the expression, making the tool practically unusable.

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 names a specific operation ('Evaluate') and a specific resource ('a+b style arithmetic'), which distinguishes it from the sibling shape/status/search tools. However, the second sentence 'Expression discarded' leaves the result of evaluation unspecified, so the purpose is clear but not fully actionable.

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?

There is no guidance about when to use this tool versus any sibling, nor any conditions, exclusions, or alternatives. The description only implies that arithmetic evaluation is the use case; it does not say when this tool is preferable or what disqualifies a request.

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