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

The description provides minimal behavioral context: it says the expression is discarded, implying no persistence. However, there is no mention of what the tool returns, whether evaluation is synchronous, what expression syntax is supported, or any side-effect profile. With no annotations, the description carries the full burden and falls short.

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 compact and front-loaded: the core purpose appears in the first sentence. The second sentence adds a behavioral note without fluff. It is concise, though too terse to compensate for the missing parameter mapping.

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, no annotations, and no output schema, a one-sentence description is not nearly enough. An agent cannot determine which field holds the expression, what the expected output format is, or how this tool compares to the many sibling utilities. The definition is incomplete for correct invocation.

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 schema covers all 9 parameters descriptively, but none of them is clearly the arithmetic expression. The description says 'Evaluate a+b style arithmetic' yet does not indicate which parameter receives the expression, creating a significant mapping gap. The description adds no useful parameter-level meaning beyond the schema.

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 clearly states that the tool evaluates simple 'a+b style arithmetic', which is a specific verb and resource. It does not explicitly differentiate from sibling tools, but the arithmetic-evaluation purpose is reasonably distinct among the listed shape-check and fetch tools.

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 the many sibling tools, no mention of alternatives, and no criteria for when arithmetic evaluation is appropriate. The description leaves the agent to infer usage entirely.

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