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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false, so side-effect profile is partly covered. The description adds no behavioral context beyond that: it doesn't say whether buying a treat costs resources, whether actions can fail, or whether plays are reversible. For a mutation tool that spends currency, that is a meaningful gap, though not a contradiction.

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 short sentences, front-loaded with the operation and examples, with zero filler. The only weakness is that brevity comes at the cost of substance rather than replacing it.

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?

There is no output schema and no annotation about return values, so the description must explain what a play yields — success text, updated zone state, rewards. It says nothing about results, failure modes, or what 'input' should contain for each action type, leaving an agent guessing about outcomes.

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% and every parameter already has a description (zone, action, input with examples like 'the button id or your answer'). The description merely restates the same examples ('press, buy, answer') without adding format, constraints, or enumerated action values, 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?

The name/title ('play' / 'Do something') are tautological, but the description recovers with concrete examples: 'press a button, buy a treat, answer a riddle.' It identifies the resource (a zone) and the operation (dispatch an action), but never distinguishes this generic dispatcher from specific siblings like give or answer_trade, leaving ambiguity about which to call.

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?

It explicitly routes discovery to a sibling: 'look tells you the actions in each zone,' which tells an agent to call look before play. It gives no when-not guidance, however — nothing says when to prefer give, answer_trade, or talk over this generic action tool.

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