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

Annotations already declare readOnlyHint and destructiveHint=false, so the 'changes nothing' line is partly redundant, but the description adds real behavioral context the annotations don't: the required sites:read scope, Tokyo-date day boundaries, and the pv-null-on-no-data return behavior. It doesn't cover rate limits or caching, so not a 5.

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?

Two tight sentences, front-loaded with the safety signal and then the returned data. Slightly dense with parenthetical date/scope clauses, but every clause carries information an agent needs.

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 output schema, the description usefully names the return values (daily pv series plus this month's total) and the null case. Combined with a fully documented 2-param schema and explicit annotations, it's sufficient, though it doesn't explain the pv units or how the monthly total relates to the series.

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 3 is the baseline, but the description adds meaning beyond the schema: the 1-90 range for days, the 30 default, and that dates are Tokyo-based. It still leaves the exact format/interpretation of month-total untouched, so a 4 rather than a 5.

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?

Names a specific resource and scope: the site's daily page views as shown in the admin graph, plus this month's total. An agent knows exactly what it returns. It does not differentiate itself from the sibling get_usage, which plausibly overlaps, so it falls short of a 5.

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?

Usage is only implied by 'Read-only; changes nothing' and the sites:read key scope, which tells the agent this is a safe read for a given site. There is no explicit statement of when to prefer this over get_usage or other usage/analytics siblings, and no exclusions.

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