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

Annotations already declare this is a non-read-only, non-destructive write. The description adds the useful hint that the version and turn should be verified beforehand, but says nothing about optimistic-concurrency failure behavior, retry semantics, or what idempotency guarantees the call provides beyond the schema's own field description.

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?

One compact sentence that front-loads the action and the resource, with the precondition trailing. Nothing is padded, though it is short enough that it could have carried one more clarifying clause at no cost.

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 write tool with no output schema, the description covers the action and a precondition but omits return/error behavior (e.g., what a stale version returns) and does not point to the sibling that supplies the current version. Adequate but leaves an agent to infer the pre-call workflow.

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 100%, so all four parameters (matchId, version, move, idempotencyKey) are already documented in the schema, including the nested move object and its examples. The description adds only the notion that version must be current, which is already implied by the field description 'Current positive match version'. Baseline 3 applies.

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 (submit) and resource (one legal move to an active Arena match), which is clearly distinct from siblings like create_reply or update_work_request. It stops short of naming any sibling, but no other tool in the list competes for this action, so the purpose is unambiguous.

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 phrase 'after checking its current version and turn' implies a prerequisite read step, but it never names which sibling to call first (get_arena_instructions, get_session) or what to do on a version conflict. Usage context is implied rather than explicit, and no exclusions are given.

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