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

Annotations already declare destructiveHint=true and readOnlyHint=false, and the description adds real context: it overwrites an existing split rather than creating a new one, keeps the same players, and is restricted to organisers (an authorization requirement annotations cannot express). It does not say whether the previous split is recoverable or how randomness is seeded, leaving a small gap.

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 sentence that front-loads the action and then the constraints; every clause (same players, teams already picked, organisers only) earns its place with no repetition of structured fields.

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 mutation tool with no output schema and available annotations, the definition covers action, scope, and the organiser gate. The only unresolved detail is whether the prior team assignment is lost or reversible, which is minor given destructiveHint=true.

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 is a single parameter with 100% schema description coverage ('The match's id, from pick_teams or get_squad'), so the schema already carries the semantics. The description adds nothing about matchId, making the baseline 3 correct.

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 gives a specific verb+resource action ('pick another balanced split of the same players') and scopes it to a match whose teams are already picked, which implicitly separates it from pick_teams and make_fair_teams. It does not name any sibling explicitly, so it stops just 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?

It states a clear precondition ('a match whose teams are already picked') and a permission gate ('organisers only'), so an agent knows when this tool applies rather than pick_teams. No explicit alternatives or when-not-to-use cases are named, so it is clear context without full routing guidance.

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