datetime_diff

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

No annotations are provided, so the description bears full responsibility for behavioral disclosure. It only states the tool computes a difference but does not mention the output format, whether it supports time zones, error handling, or side effects. This is insufficient for a calculation tool.

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 sentence, which is concise and to the point. The '[datetime]' prefix may be redundant but does not harm clarity. It could be slightly more efficient without the prefix, but overall it is well-structured.

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 low parameter documentation and no behavioral details, the description is incomplete. An output schema exists, so return values are covered, but the input semantics are insufficiently explained. For a simple tool, the description should at least mention the unit parameter's possible values.

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%, meaning no parameter descriptions exist in the schema. The description implies two datetime strings but does not explain the 'unit' parameter (optional, default null). This leaves the agent guessing about how to specify the unit for the difference. The description adds minimal value beyond the raw 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 computes the absolute difference between two datetime strings. The verb 'Compute' and resource 'difference between two datetime strings' are specific and distinguish it from sibling tools like datetime_add_duration, datetime_convert_timezone, and datetime_parse.

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?

No guidance is provided on when to use this tool versus alternatives. There is no mention of prerequisites, context, or when not to use it. The description simply states the function without any usage context.

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