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

With destructiveHint=true and readOnlyHint=false already set, the description adds important behavioral context beyond annotations: it opens a real room, people can join immediately, and it consumes one of the team's weekly games. It does not cover auth or rate limits, but the confirmation warning is a meaningful addition.

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?

The description is two tight sentences with the primary purpose and return value front-loaded. The second sentence adds only important side-effect and confirmation context, with no filler.

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?

Given a one-parameter tool with a rich enum schema and an output schema, the description provides everything an agent needs: what it creates, that the room is immediately joinable, that a weekly game is consumed, and that user confirmation is required. Return details are covered by the output schema.

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 game_type enum is fully documented in the schema, including examples and guidance to call funfriday_list_games first. The description adds no additional parameter semantics, so the baseline of 3 is appropriate.

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 states a specific action and resource: 'Start a new Fun Friday game session,' and immediately names the outcome ('room code and join link'). This distinguishes it from sibling read/list tools like funfriday_get_session and funfriday_list_sessions without needing to inspect 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 a clear precondition—'confirm with the user before calling it'—and context that the session uses one of the team's games for the week. It does not explicitly name alternatives or when-not-to-use conditions, though the schema points to funfriday_list_games when unsure.

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