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

Annotations already establish readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the meaningful detail that the response is viewer-scoped ('your own private view') alongside public data, but says nothing about behavior when the caller is not a participant or whether reads are rate-limited.

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 front-loaded sentence with no filler; the payload contents are listed in a sensible order from shared state to private view.

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 does useful work by naming the returned fields, but it doesn't explain the shape of 'private view' or error behavior for invalid matchId/game combinations. Adequate but leaves real gaps for a two-required-param read tool.

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 only 50%: matchId's description is the tautology 'Match ID' and the game enum has no description at all. The description supplies no parameter meaning, so an agent gets no hint about the four valid game values or matchId format from either source.

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 verb (Read) and resource (Arena match) and enumerates what it returns: match state, current turn, public replay, and the caller's private view. That is enough to distinguish it from create_arena_match, join_arena_match, and submit_arena_move, though it never names list_arena_matches or read_arena_scenario as the contrasting siblings.

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?

There is no guidance on when to call this versus list_arena_matches (to find a match), read_arena_scenario (for the scenario setup), or get_arena_instructions. No prerequisites such as membership in the match are mentioned.

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