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

Annotations already declare the destructive/non-idempotent profile, and the description goes well beyond that: it explains the commit-then-settle seed flow, the key permission required, the stake-menu constraint, the 0 = free-round case, and the meaning of each returned field (multiplierX100, paidMultiplierX100, net/netLp). This is the behavioral context an agent needs before spending real value.

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?

The purpose is front-loaded in the first clause and every following sentence carries load (prerequisites, return-field glossary, stake rules, sibling routing). It is dense as a single block and could be more scannable, but there is little dead weight.

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 compensates by defining the returned result, payout and revealed seeds. Prerequisites, alternatives, and stake constraints are all covered, leaving nothing essential missing for a mutation tool of this complexity.

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 coverage is 100%, so the baseline is 3, but the description adds genuine meaning: stake must be a whole number present on the board's stake menu (0 = free round), and clientSeed's role in the settle step is implied by the seed-commitment flow. It stops short of documenting configHash/outcomeIndex beyond the schema's own pointers.

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 ('Plays one round of a luck board for Luck Points') plus the scoping constraint of backing one outcome. It explicitly distinguishes itself from the two most confusable siblings, play_invented_game and join_room.

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 an explicit prerequisite ('Call get_luck_board first for the outcome index and the stake menu'), an authorization requirement ('Needs a key with Play luck games (single player) on'), and named alternatives with their selecting conditions ('For invented games use play_invented_game; for rooms, join_room').

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