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

Annotations already declare a safe, non-destructive, closed-world read, so the bar is lower. The description adds genuinely useful domain behavior not in the schema: the 3–16 team bound and the bye/rest round for odd counts. It stops short of saying what happens for out-of-range input or how the schedule is structured across rounds.

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 front-loaded sentence with no filler; the constraints and behavior are packed densely and nothing is repeated.

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 generator tool with no output schema, the description does not describe the shape of the returned fixture list (rounds, pairings) or error behavior for invalid team counts, leaving an agent to infer the return structure. Acceptable but with a clear gap.

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 100%, so both parameters (teams, homeAndAway) are already documented. The description reinforces the round-robin semantics but adds no format or syntax detail beyond the schema's "true: everyone meets twice."

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 concrete verb+resource ("Make a round-robin fixture list") plus a precise scope (3–16 teams, everyone plays everyone, rest round for odd counts). This is clearly distinct from sibling team-forming tools (make_fair_teams, pick_teams, reshuffle_teams) without needing to name them.

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 3–16 team range and the odd-number rest round imply valid usage, but there is no explicit when-to-use or when-not-to-use guidance and no mention of alternatives such as make_fair_teams or pick_teams for splitting players into sides.

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