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

readOnlyHint=true already tells the agent this is a safe read. The description adds only that it returns rules plus move format, but says nothing about whether the game must already exist, whether this is static documentation, or how the move format is expressed.

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?

One short sentence with no wasted words, front-loading the returned content. Its terseness is a coverage problem rather than a verbosity problem.

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 one required, undocumented parameter, no output schema, and only a readOnly annotation, the description needs to explain how to identify the game and what the returned rules/move format look like. It gestures at the return contents but leaves the parameter unresolved.

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 0% and the single required parameter 'game' is documented nowhere. The phrase 'of one game' hints the parameter selects a single game, but it does not say whether the value is an ID, a name, or one of the values returned by list_games.

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 fragment names the resource (rules and move format of a game), which is more specific than the title 'Game rules', and it implicitly distinguishes itself from make_move and list_games. However, there is no verb and no explicit statement of what the tool does (retrieve? describe?), leaving the purpose only implied.

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?

No guidance is given about when to call this versus siblings like list_games or get_state, and no preconditions are stated. The agent must infer that this is a lookup to perform before make_move.

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