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

The description accurately characterizes the conversion behavior without contradicting any annotations (none provided). It implies a stateless transformation, which is transparent for this kind of utility. No behavioral surprises beyond the stated purpose.

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, well-structured sentence that immediately conveys the core functionality. Every word contributes meaning, and the key information (input types, output) is front-loaded.

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 simple conversion tool with one parameter and no output schema, the description is largely complete. It could benefit from clarifying the output format (e.g., an object containing both representations), but the basic idea is clear.

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 provides only the parameter name 'value' with type string (0% description coverage). The description fills the gap by specifying valid inputs: 'unix seconds or ISO-8601'. This adds essential 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 the tool converts between Unix seconds and ISO-8601, specifying both input types and the output as both formats. This distinguishes it from siblings like datetime_parse which parse arbitrary date strings, and timezone_convert which adjusts timezones.

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 description explains what the tool does but provides no guidance on when to use it versus alternatives such as datetime_parse or time_convert-like tools. With many sibling tools, explicit context for selection would be beneficial.

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