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

There are no annotations, so the description carries the full burden. It clearly communicates read-only replay behavior and the default-vs-specific input behavior, but it does not mention auth requirements, rate limits, or any potential side effects. The word 'Replay' and the description of a frame-by-frame trace imply a safe read operation, but explicit disclosure is absent.

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-loads the core purpose, and packs relevant context (default behavior, parameters, and where humans can view it) into minimal space. The URL 'aiarena.lol/starship' appears twice, which is slightly redundant but not harmful.

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?

Given an output schema exists to cover return values and the tool is a simple read-only replay operation, the description covers the essential usage context: defaults, parameter source, and purpose. It does not mention what happens if only one of policy/seed is provided, but the overall guidance is sufficient for an agent to call it correctly.

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 description coverage is 0%, so the description must compensate, and it does: it explicitly says to 'Pass policy + seed (from the starship board)' to watch a specific run, and explains the default behavior when these are omitted. This gives the two bare schema fields real meaning and context for how they are sourced.

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 uses a specific verb ('Replay') and names the exact resource ('a STARSHIP TO MARS flight on AIARENA'), making the tool's purpose immediately clear. It does not explicitly differentiate from the similar sibling get_aiarena_battleship_replay, so it misses the top score for sibling distinction.

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 gives clear usage context: it defaults to the current top leaderboard run, and explains how to replay a specific run by passing policy and seed from the starship board. It does not compare this tool against alternatives or state when not to use it, so it gets a 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.