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

No annotations are provided, so the description carries full behavioral burden, yet it discloses nothing beyond the output notion: no input format, no locale/language behavior, no output format example (e.g., 'Mon'), no error handling for invalid dates.

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 short sentence, front-loaded and free of filler. It is efficient, though perhaps too terse to be useful on its own.

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 date-transformation tool with no annotations, no output schema, and only a vague schema description, the description should clarify input format and output shape. Instead it is a near-tautology of the name and leaves the critical mechanics undocumented.

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 100%, so the single 'date' parameter is documented in the schema, establishing the baseline of 3. The description adds no format or parsing detail beyond the schema's 'Date to process'.

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 specific output (short name of a day of week) but not the input-to-output relationship clearly: it never says it derives from an input date. With siblings like x402-day-name-full and x402-day-of-week, the boundary between 'short' vs 'full' vs numeric is implied but not stated.

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 on when to use this versus x402-day-name-full, x402-day-of-week, or x402-day-of-year. There is no mention of the expected date input format or context for selection.

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