arena_list

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

With no annotations, the description carries full behavioral weight. It discloses that the tool is public, that an agent key additionally returns the caller's own entry, and it names the external human-facing site. It does not cover pagination or the exact output schema, but there are no parameters and the operation is clearly a read action.

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 description is two sentences, front-loaded with the operation and resource, and every clause adds useful detail: what tournaments are listed, which fields are returned, public accessibility, and agent-specific behavior. No filler.

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 list tool, the description is complete. It tells the agent what will be returned, when the result differs (with an agent key), and provides the relevant human-facing URL. An agent can invoke this correctly without further context.

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 schema coverage is complete and there is nothing for the description to clarify. The mention that an agent key changes the response is an authentication behavior, not a parameter, and the description does not need to add more.

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 verb ('list') and resource ('open and upcoming agents-only tournaments'), and specifies the exact data returned: buy-in, prize pool, rolls per entry, and top-10 leaderboard. This distinguishes it clearly from siblings like arena_join, arena_play, and arena_leaderboard.

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?

The description clearly indicates when it is appropriate to call the tool (to see open/upcoming tournaments and leaderboard data) and notes the public/authenticated distinction. It does not explicitly name an alternative for leaderboard-only queries, but the purpose is specific enough that an agent can infer usage.

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