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

The description discloses a key behavioral trait: it regenerates an existing unlocked draw, which implies overwriting current pairings. It also states the temporal constraint ('Only before results exist'). This adds context beyond the annotations, which only indicate readOnly=false and destructiveHint=false. No contradiction with annotations.

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?

Two sentences, front-loaded with the core action, followed by key constraints. Every word earns its place; no fluff or repetition. Highly efficient and easy to scan.

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 mutation tool with an output schema and four parameters, the description covers the main functionality, modes, temporal constraints, and regeneration behavior. It does not explain error conditions (e.g., what happens if results exist) or locked draw behavior, but schema and annotations fill some gaps. Overall sufficiently complete for a well-scoped operation.

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?

The description adds meaning to the parameters by explaining the two modes (explicit pairs vs. auto-pair) and clarifies the 'auto' enum values (random/level-balanced). The schema already documents pairs, request_id, and tournament_key, but the description helps disambiguate the auto parameter beyond the schema. Overall it provides useful semantic context.

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 'Fix' with a clear resource ('doubles pairs') and explains two modes: explicit pairs by name or auto-pairing (random/level-balanced). It also states key constraints ('Only before results exist', 'Regenerates an existing unlocked draw') that distinguish it from sibling tools like swap_partners or generate_draw.

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 provides clear context on when to use the tool: only before results exist, and it can regenerate an unlocked draw. However, it does not explicitly mention alternatives or when not to use it compared to related tools such as swap_partners, though the constraints imply some boundaries.

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