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

With no annotations, the description carries the full behavioral burden, and it does disclose the two things that matter most for a pure computation: that the date defaults to 'now' and that the return is an ISO timestamp (valuable since there is no output schema). However, it says nothing about timezone handling, month-end/overflow behavior, or the signed-wallet/payment model beyond the trailing trial-call note.

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 tight sentence front-loads the operation and its return value with no filler. The appended '🆓 5 free trial calls per signed wallet' is promotional rather than selection-relevant, slightly diluting an otherwise efficient definition.

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 three-parameter tool with zero schema descriptions, no annotations, and no output schema, the description leaves key gaps: the meaning of 'n', the ambiguity between 'n' and 'months', and timezone/month-overflow semantics. It correctly documents the return type and the default date, but not enough for confident invocation.

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 coverage is 0% across three parameters, and the description only loosely maps to two of them ('a number of months' and 'a date (or now)'). The parameter named 'n' is never explained and directly conflicts with the more plausibly named 'months', leaving a real risk of populating the wrong field.

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?

States a specific verb+resource pair ('Add Months: Adds a number of months to a date') and names the output ('resulting ISO timestamp'), which cleanly separates it from siblings like x402-add-days and x402-add-years by the unit operated on. It stops short of explicitly naming those siblings as the alternatives, so an agent must infer the contrast rather than read it.

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 statement of when to reach for this tool versus x402-add-days, x402-add-years, x402-next-month, or x402-prev-month. The parenthetical '(or now)' hints that the date argument is optional, but that is a parameter default, not usage guidance, and no exclusions or prerequisites are given.

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