time_add

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

With no annotations, the description carries the full burden, but it does disclose one non-obvious behavior: negative values perform subtraction. It says nothing about DST handling, timezone conversion behavior, the default of datetime='now', or whether out-of-range units are normalized.

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?

One short sentence, front-loaded with the core action, with the negative-value caveat folded in parenthetically. Nothing is wasted or buried.

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 an 8-parameter, unannotated utility tool with no schema descriptions, the definition is too thin. The output schema relieves it of explaining return values, but format, timezone, and datetime-default semantics are essential to calling this correctly and are absent.

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 description coverage is 0% across 8 parameters, so the description must compensate and does not. It never explains format, timezone semantics, or the datetime default ('now'), leaving the agent to infer the meaning of the format and timezone strings from parameter titles alone.

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 states a specific verb (add/subtract) and resources (duration, date/time), making the operation unmistakable. It does not name any sibling such as time_difference or time_now for contrast, but the purpose is clear on its own.

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?

Use is implied: this is the tool for shifting a datetime by a duration, and the negative-value note hints at reversal. There is no explicit when-to-use or when-not-to-use guidance, and no routing advice against siblings like time_difference or time_convert.

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