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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the description's real contribution is the payment mechanism: $0.03 USDC on Base via x402 against POST /v1/game/facts. That is material behavioral context an agent needs to avoid unexpected cost. It does not state what happens on payment failure or rate limits, keeping it below a 5.

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, zero filler. The usage trigger is front-loaded and the pricing/endpoint detail follows in a compact second sentence.

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 usefully enumerates the expected return fields, and it discloses cost and transport. It is slightly thin on response shape (e.g., ranking or no-match behavior) for an open-world lookup tool, but the essentials for correct invocation are present.

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 'query' documented as the game title and 'limit' bounded 1-5 with default 3, so the schema carries the semantics. The description adds only the implicit notion of a title lookup and nothing about match ambiguity or how limit affects results. Baseline 3 is appropriate.

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 names a specific verb+resource ('live game metadata from RAWG') and enumerates the returned data fields (release date, ratings, Metacritic, platforms, genres). An agent can immediately tell this is a title-lookup tool and distinguish it from the unrelated siblings (hook_score, text_analyze, translate_check).

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?

'Use this when you need live game metadata from RAWG' gives an explicit triggering condition, and the pay-per-call pricing tells the agent a decision-relevant constraint before invoking. It stops short of naming when *not* to use it or any alternative source, but the sibling set makes alternatives unnecessary.

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