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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent, closed-world operation. The description adds genuine context beyond that: the key relationship (publishable key derived from studio secret key), the exact return payload (publishableKey + wsEndpoint), and how to consume it. It does not warn that repeated calls mint additional distinct games, which is the main behavioral risk given idempotentHint=false.

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 tight sentences: the first defines the operation and its output, the second tells the agent what to do next. No filler, and the core definition is front-loaded.

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-optional-param, no-output-schema tool, the description covers operation, auth model, and return values adequately. It leaves minor gaps: whether 'label' has a default, and whether a studio must exist before calling.

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 optional 'label' parameter is already documented in-schema with an example. The description mentions no parameters at all, so the schema does all the work — this is the baseline case rather than a value-add.

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?

Specific verb+resource ('Mint a new game') with an immediate gloss that resolves ambiguity: a game is a publishable key issued under the studio's secret key. That definition alone separates it from siblings like list_games, publish_game, and set_game_name, which operate on existing games.

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?

The description explains what to do *after* creation — point a client at the key or scope the MCP via the x-mp-game header — which implies when this tool is useful. However, it never states when to prefer create_game over publish_game or claim_studio, nor does it mention prerequisites such as needing an existing studio.

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