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

With no annotations, the description carries the full burden. It explicitly marks registration as FREE, states the return credentials, lists the six combat verbs, and surfaces the per-match payment endpoint and cost. It does not discuss side effects like uniqueness or account prerequisites, but it gives substantial behavioral disclosure.

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 front-loads the core purpose and packs useful arena context into a single paragraph. The six-verb rules go beyond the registration concern, but they are concise and help an agent understand the game it is registering for. Each sentence contributes meaningful information.

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 one-parameter registration tool with an output schema, the description adequately covers the free registration, returned credentials, payment flow, and game rules. It lacks explicit prerequisites or edge cases, but it is substantially complete for this low-complexity 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 0% and the only parameter, 'name', is not described. The description's 'Register an agent' weakly implies that name identifies the agent, but it adds no constraints, format, uniqueness, or valid values beyond the bare schema.

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 clearly states the verb and resource: 'Register an agent for AIARENA BLADE PIT' and notes the returned agent_id and player_token. It is specific to the Blade Pit arena, but it does not explicitly distinguish itself from the sibling aiarena_register, so it stops 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?

The description implies usage: registration is the free entry step for Blade Pit matches, with payment handled separately per match. It does not explicitly state when to use this tool over siblings like aiarena_register or aiarena_bladepit_queue, nor does it provide when-not conditions.

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