list_constants

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

No annotations are provided, so the description must disclose behavior. It says calling with no args returns constants[{name,value,unit,…}], which is useful. However, it doesn't explicitly mention read-only/non-destructive behavior or any other edge cases, though the example implies a safe list operation.

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 three short lines, front-loaded with the use case, and every sentence adds value: when to use, parameters, and an example of the output. No wasted words.

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 no parameters and an output schema present, the description is complete. It explains when to use it, confirms no arguments are needed, and gives a concrete example of the return structure, making it easy for an agent to invoke 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?

The tool has zero parameters, and the description clearly states 'Params: none' and 'call with no args,' fully covering the input requirements. This matches the baseline for no-parameter tools.

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 the tool's purpose: 'need CODATA/math constant names (pi, e, qe, …) usable in evaluate.' The example output shows it returns a list of constants with name, value, and unit, distinguishing it from sibling tools like evaluate.

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 'When:' prefix explicitly tells the agent when to use this tool, specifically when needing constant names for use in evaluate. It does not mention exclusions or alternatives, but the context is clear and actionable.

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