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

Annotations already declare destructiveHint=true and non-idempotent, so the safety profile is covered. The description adds real value beyond that: the commit-then-settle flow and the specific 403/skill_game_people_only refusal behavior for skill games. It stops short of describing failure modes for insufficient stake or the returned round outcome.

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?

Three compact sentences, front-loaded with the core action before the routing and refusal caveats. Every sentence carries distinct information, though the parenthetical '(commit, then settle)' is slightly terse.

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 no output schema, the description covers the action, routing, and a key error case, and annotations cover the destructive/non-idempotent profile. It could say more about what the round returns or minimum-stake failures, but nothing essential to calling it correctly is missing.

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 id, stake, and clientSeed are all documented in the schema itself (including the 'on its stake menu' note). The description adds no syntax or format detail beyond what the schema provides, so the baseline 3 applies.

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 (plays), resource (invented luck game), and scope (one round, solo, for Luck Points). It also distinguishes itself from the multiplayer sibling (join_room) and from skill games, so an agent can differentiate it without opening schemas.

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?

Explicitly routes multiplayer invented games to join_room and states that skill games are refused (403, skill_game_people_only). The conditions that select this tool versus its alternatives are stated outright, leaving little to inference.

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