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

No annotations are provided, so the description carries the full burden of behavioral disclosure, and it discloses nothing: no mention of output shape, whether year/month default when omitted, or how invalid inputs 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?

It is short, but the brevity comes from under-specification rather than efficiency — the single fragment repeats the name and communicates no information an agent can act on.

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 no annotations, no output schema, ambiguous semantics, and zero required parameters, the definition is wholly inadequate for an agent to call the tool correctly. Nothing indicates what a valid month value looks like or what the return contains.

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 100% with only two simple string parameters ("Year to process", "Month to process"), so the schema itself documents the inputs. The description adds nothing beyond that, but per the high-coverage baseline a 3 is appropriate.

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?

"Month Days: Month Days" restates the tool name/title verbatim and adds no verb, resource, or scope information. An agent cannot determine from the description whether this returns a count of days in a month, a list of day names, or something else.

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 indication of when to use this tool versus the numerous date siblings such as x402-days-in-month, x402-days-in-month-year, x402-month-name, or x402-day-name-full. No context, prerequisites, or exclusions are given.

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