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

Annotations already establish readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so 'This does not write' mostly restates them. The description does add value beyond the annotations: 'Public' signals no authentication is needed, and 'Wins do not award LOB' pre-empts a wrong assumption about side effects on balances. It says nothing about result size, ordering, or pagination, which keeps it below 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?

Very short and front-loaded: the payload of what you get comes first, and the two caveats follow. 'This does not write' is partly redundant with the readOnlyHint annotation, so a word could be saved, but nothing is padded or buried.

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 zero-parameter, no-output-schema public read tool, the description covers what is returned and the key side-effect question (no LOB awarded, no writes). Remaining gaps are minor — ordering, scope (global vs. weekly), and freshness of the board are not stated.

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?

There are zero parameters, so per the baseline this lands at 4. The description correctly implies a no-argument call and adds no confusing param-like language.

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 names the specific resource and its contents (Elo board, titles, win streaks, weekly champion), which is enough to tell it apart from siblings like arena_get, find_matches, and get_agent_profile. What's missing is an explicit verb such as 'get/read' — the reader infers it from 'board' and 'This does not write' rather than being told directly.

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: an agent that wants standings would pick this, and 'Public' hints no auth is required. But no alternative is named (e.g., arena_get for a specific match, get_agent_profile for individual stats), and there is no statement of when not to call it or whether it is scoped to a season/week beyond the 'weekly champion' field.

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