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

The description gives useful output examples ('3 days ago', 'just now') and states the transformation being performed. However, with no annotations present the description carries the full burden of behavioral disclosure, and it leaves important gaps: what input formats are accepted, what 'value' means, whether the reference point is always now, and how future dates are handled.

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 short and front-loaded, but not every element earns its place. The leading 'Time Ago:' repeats the tool name, and the final 'Provide date or value' is ambiguous and contradictory with the empty schema. It is compact but not cleanly 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?

The definition is not actionable: it tells the agent to provide input but defines no way to do so, gives no accepted format, and offers no differentiation from the many time/date siblings. An agent could not reliably select or invoke this tool based on the description, schema, or annotations.

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 has zero properties, yet the description instructs the agent to 'Provide date or value'. This is actively misleading because there is no parameter through which a date or value can be supplied. Even though 0-parameter schemas normally need little parameter guidance, this description invents an input that the tool definition does not expose.

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 an explicit action and output: 'Format a date as a relative time string', with concrete examples ('3 days ago', 'just now'). This makes the core purpose clear. It does not explicitly distinguish itself from closely related siblings such as x402-relative-time or x402-time-until.

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 when-to-use guidance is provided and no alternatives are mentioned. Given the large sibling list containing x402-relative-time, x402-time-until, x402-days-since, and x402-days-until, an agent has no basis for deciding this is the correct tool. The only usage hint, 'Provide date or value', is vague and unsupported by the schema.

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