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), but the description adds real context beyond them: progress stays in the widget and does not sync to the website, and the agent must not reveal solutions. That state-locality and output-constraint disclosure is valuable for a tool whose name could imply a networked fetch.

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?

Three short sentences, front-loaded with the core behavior, then the state caveat, then the routing to alternatives. No filler; every sentence changes agent behavior.

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 one-parameter, zero-required tool with full schema coverage and a rich annotation set, nothing needed to invoke it correctly is missing. The description also covers the non-obvious side effects (local-only progress) that the schema and annotations cannot express.

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% and the single parameter is fully documented with its enum and default in the schema. The description's 'game defaults to hub' and 'pass a game id' restate the schema rather than adding syntax or format detail, 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?

States a specific verb (open) and resource (a playable daily / the thirteen-puzzle hub), and explicitly names the sibling tools it is not (list_dailies, get_rules). An agent can distinguish it from both siblings without opening a schema.

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 gives the conditional: pass a game id to open that board, omit it (or pass 'hub') for the hub. It also states when NOT to use it — use list_dailies to browse and get_rules to explain a game instead of opening it.

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