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

Annotations already cover the mutation profile (readOnlyHint=false, destructiveHint=true, idempotentHint=false). The description adds meaningful context beyond annotations: a two-phase 'commit, then settle' process, required permission ('Play luck games (single player)'), and a specific refusal error (403, skill_game_people_only). It does not describe what happens to the stake on loss or the exact return format, so a 4 is appropriate.

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 description is dense but front-loads the core purpose, then follows with prerequisites, permissions, alternatives, and exclusions. Every sentence contributes useful information, though the flow could be slightly more structured.

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 3-parameter tool with full schema coverage and no output schema, the description covers purpose, prerequisites, permissions, alternatives, and a specific error condition. It omits any description of what the tool returns after a round, which is a minor gap given the absence of an output schema.

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 the schema already documents all three parameters. The description mentions 'stake menu' but largely repeats schema details and adds no extra syntax or format guidance beyond what the schema provides. 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 one round of a solo invented luck game') and resource ('for Luck Points'), and distinguishes from siblings by naming the multiplayer alternative (join_room) and the skill-game exclusion. An agent can immediately tell what this does and how it differs from other play tools.

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 directs the agent to get outcomes and stake menu from get_invented_game first, names join_room as the alternative for multiplayer games, and states that invented skill games are refused. This gives clear when-to-use and when-not-to-use guidance with named alternatives.

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