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

With no annotations, the description carries the full burden. 'Expression discarded' discloses that input is not retained, but it does not say whether a result is returned, what the output is, or whether there are side effects. This is too little behavioral context for a tool with no annotations.

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 only two short, direct sentences with no filler, and the core verb is front-loaded. It is concise, though its brevity creates the under-specification penalized elsewhere.

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 optional parameters, no output schema, no annotations, and many sibling alternatives, the description is not complete enough. It omits the return behavior and the parameter-to-expression mapping that an agent needs to call the 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?

Schema coverage is 100%, so the baseline is 3 even without parameter information in the description. However, the description adds nothing to link the nine schema parameters to the arithmetic expression, leaving real uncertainty about how to invoke the tool correctly.

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 a+b style arithmetic'), which gives some idea of the tool's purpose. But it does not identify which schema parameter carries the expression, what the result is, or how this differs from the many sibling shape-check tools, so the purpose remains vague.

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 on when to use calc-eval versus visible alternatives like validate-json or the various shape-check tools. No when, when-not, or alternative routing is provided.

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