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

With no annotations, the description carries the full behavioral burden and discloses almost nothing. It does not say whether the operation is pure computation or a mutation, whether the input date format matters, or how timezone/DST is handled; 'add hours to a time' implies a rollover across day boundaries but never confirms it.

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?

It is short and front-loaded, but half of it is redundant with the tool name and title ('Add Hours: Add hours to a time'). There is no waste in length, yet the brevity comes at the cost of any useful content.

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?

Given three under-specified parameters, no annotations, and no output schema, the description should at minimum explain the input date format, the meaning of 'n', and the return shape. None of that is present, so an agent cannot reliably invoke it.

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?

Nominal schema coverage is 100%, but the schema texts are non-informative placeholders ('N to process', 'Date to process', 'Hours to process') that give no real semantics. The description adds nothing to clarify the critical ambiguity — what 'n' means and what units/format 'hours' and 'date' accept.

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 verb and resource ('Add hours to a time'), but it largely restates the tool name and title ('Add Hours') rather than elaborating. It gives no hint of how this differs from the many adjacent siblings such as x402-add-days, x402-add-months, x402-add-years, or x402-date-math.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives. In a catalog containing dozens of date-arithmetic siblings, the absence of any routing signal leaves the agent to guess purely from the name.

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