Coverage

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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely non-derivable behavior: the call consumes no tokens and requires no API key, which affects an agent's willingness to invoke it repeatedly. It stops short of describing the response shape or pagination beyond the schema's own limit note.

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 tight sentences with zero waste. The core purpose is front-loaded and the cost/key detail is packed into a short trailing clause rather than padding.

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?

With no output schema, the description does carry the return-value burden and largely meets it by explaining that results are bookmaker-by-sport coverage plus market keys. It is nearly complete, missing only an explicit note about row limits or truncation behavior, though the schema's limit description covers that partially.

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%, with per-parameter descriptions for limit, sport, region, product, and bookmaker, so the schema carries the load. The description restates bookmaker/sport filtering without adding format or syntax detail beyond what is already documented, 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?

States a specific verb and resource: shows which bookmakers carry which sports on a product, plus that product's market keys. It implicitly distinguishes itself from the odds and bookmakers siblings by naming market keys as 'the values odds takes as markets', but it never names an alternative tool outright.

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?

Gives filtering guidance ('Filter by bookmaker or sport') and a cost cue ('Costs no tokens and sends no key'), which implies it is cheap to call freely. However, it never says when to reach for this over sports, bookmakers, odds, or event_odds.

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