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

Annotations already declare readOnlyHint=true and openWorldHint=false; the description adds the non-obvious fact that the tool does not write the file itself ('Write it to disk and open it') and that the binding target is stamped in a header comment, which helps the agent verify wiring. It does not state whether the snippet is deterministic across calls or how large the output is, which would be useful for token budgeting.

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 deliverable and its contents, followed by the action ('write it to disk and open it') and a helpful verification detail. No filler, though the final comment sentence could be folded into the first without loss.

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, so the description carries the return-value burden and does so well by describing the artifact's shape, its features, and how to confirm which game it was stamped against. For a two-parameter read-only fetch, nothing an agent needs in order to use the result correctly is missing.

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 both parameters (game, roomName) are documented including the header/primary-game fallback chain. The description adds nothing about parameters, so baseline 3 applies – the schema carries this dimension entirely.

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 ('Returns') and a well-scoped artifact: a complete single-file HTML game wired to the room, enumerating what's included (realtime movement, anonymous claimable player, datastore color, leaderboard). It is distinguishable from most siblings by resource type, but never contrasts with get_sdk_reference, the closest conceptual neighbor, so sibling differentiation is implicit rather than explicit.

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?

'Write it to disk and open it' implies the intended workflow, and the phrase 'wired to this room' implies the tool must be called after a room exists in the current game context. However, there is no explicit when-to-use guidance or instruction to prefer this over get_sdk_reference when the agent actually wants raw API documentation rather than a runnable file.

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