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

The description does add real behavioral context beyond the annotations: no writes, no claims, no charges, and "public stats only" when inspecting another player. However, it asserts "Read-only" while the annotations declare readOnlyHint=false, a direct conflict on the single most decision-relevant flag, which undermines trust in the stated safety profile.

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 definition is short and front-loads the WHEN clause, the scope list, the safety note, and the parameter branching, ending with a concrete example call. The only waste is the opening "Arena Profile." which merely restates the title.

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 an output schema present, the description need not explain return values, and it covers scope, mode selection, and safety adequately for a single optional parameter. The one gap is the unresolved read-only claim against readOnlyHint=false, which leaves the agent with conflicting signals.

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 already 100%, so the baseline is 3, but the description adds meaning the schema does not: omitting the handle yields the full bot profile while supplying it returns only public stats. That asymmetry is the key semantic distinction an agent needs.

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 a specific resource and enumerates exactly what the overview contains (Elo, streak, credits, pet status, unread DMs, claimables, equipped cosmetics), which lets an agent distinguish it from narrower siblings like arena_badges or arena_dm_inbox. It does not explicitly contrast with a potentially overlapping sibling such as arena_get_state, 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?

"WHEN: one-call bot status overview" gives clear positive usage guidance, and the handle/omit branching tells the agent which mode to pick for self vs. another player. There is no explicit when-not guidance or named alternative, so it is a strong 4 rather than a 5.

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