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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world). The description adds genuinely new behavioral context: the response is structured as titled steps and deliberately excludes puzzle answers, which is a content/return-shape trait the annotations do not express. It stops short of describing length or formatting details, so not a full 5.

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?

Four short sentences, each carrying a distinct load: purpose, output format, argument disambiguation, and sibling routing. The purpose leads and no sentence is redundant.

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 read-only, single-enum-parameter tool with no output schema, the description supplies the missing pieces: what it returns (titled steps), what it withholds (puzzle answers), and how it relates to the other two tools. Coverage is strong, though it says nothing about the step content depth or ordering guarantees.

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?

With a single parameter and 100% schema coverage including an enum, the baseline is 3. The description goes further by disambiguating the argument ('Required game is a game id, not a board'), guarding against a plausible confusion between game identifiers and board identifiers that the schema text only partly addresses.

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 description names a specific verb and resource ('Explain one game's rules and controls') and specifies the output shape ('as titled steps'). It also draws a hard boundary against the sibling tools by clarifying it 'never' returns a puzzle answer, so an agent can tell it apart from open_daily without inspecting 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?

It gives an explicit positive trigger ('Use this to teach a game') and then names both alternatives with their roles: list_dailies to browse today's puzzles and open_daily to play. Nothing about when to prefer this tool over its siblings is left to inference.

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