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 genuinely useful facts: auth mode is paid and each call costs $0.005 via x402/MPP, plus the HTTP endpoint. It does not describe error behavior, input validation, or the response shape, so the disclosure is partial.

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 bloated with origin URL, hostname, brand, provider aliases, family key and repeated keyword lines, and the actual functional summary is buried in the middle. The useful content could fit in two sentences; most of the payload does not earn its place.

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?

It specifies the returned fields, pricing and auth, which is adequate context for a pure date-computation tool with no output schema. The gaps are the undocumented required parameters and any failure/validation behavior.

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 0% and the description never explains year/month/day — no ranges, no whether month is 1-12, no format expectations, even though all three are required. For a low-coverage schema the description should compensate, and here it does not.

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 Summary line states a specific verb+resource and enumerates the outputs (weekday, ISO week, day of year, quarter, leap year, weekend), which lets an agent distinguish it from siblings like business_days, iran_holiday_check, and gregorian_to_jalali. It is clear but never explicitly contrasts itself with those neighbours, so it falls short of the top score.

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?

The 'Use case' lines (find ISO week, check weekend/leap year, get quarter and day of year) give concrete scenarios, so usage is implied rather than absent. However there is no guidance on when to prefer this over business_days or iran_holiday_check, and no stated exclusions or prerequisites.

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