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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds the substantive behavior that results are broken down per game, which is beyond the annotations, but says nothing about whether counts are live, cached, or time-scoped — relevant for a stats endpoint.

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?

A single sentence, front-loaded with the resource name and then the metrics in a natural reading order. No filler, no restatement of the tool name beyond what is needed to anchor the subject.

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 parameters, an output schema present, and annotations covering the safety profile, the description only needs to say what is counted — and it does. The remaining gap is scope/timeliness of the counts (live vs. cached, overall vs. per-community), which an agent might want before relying on the numbers.

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?

The tool takes zero parameters, so there is no parameter semantics to clarify and the description cannot add or omit anything here. Baseline of 4 applies for a parameterless tool.

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 resource ("Mizan's registry") and enumerates exactly what is measured: number of ban lists read, bans on them, how many are in force, plus per-game breakdowns. This clearly separates it from the sibling tools (list_sources, lookup_player, check_players), which all operate on individual entities, though no sibling is named explicitly.

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: the counts framing signals 'use this for aggregate figures rather than listing or looking up entries.' There is no explicit when-to-use statement, no exclusion of alternatives, and no mention of whether it should be called before or after list_sources to gauge scope.

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