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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds real behavioral value by stating it renders an in-chat arcade with Play buttons and that the games are real and free — information no annotation conveys. It lacks any note on latency, failures, or what happens if an unknown game is passed.

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?

Front-loaded with the core purpose, followed by the game roster and the parameter rule; every sentence is functional. The inline parenthetical game blurbs are slightly dense but earn their place by telling the agent what each option is.

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 single optional enum parameter with no output schema and annotations covering the safety profile, the description supplies triggers, effect, and parameter behavior. Only minor gaps remain (error behavior on invalid input, whether repeated calls open a new instance).

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 coverage is 100% with enum values documented there, but the description still adds meaning: 'Pass `game` to put one game up front; leave it out to show the whole arcade' clarifies that the parameter is a display ordering/featuring choice, not a filter. The parenthetical genre labels also give each enum value semantic context.

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 and resource ('Show the Goatcade arcade in the chat'), enumerates the four games with genre labels, and describes the rendered result (Play button per game). The rendering-oriented framing clearly separates it from the sibling list_games, which by name only lists rather than displays.

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 names trigger conditions ('user wants to play a game, is bored, or asks for Goatcade') and explains the parameter decision: pass `game` to feature one, omit it to show the whole arcade. It does not name list_games as the alternative for a bare listing, so no explicit exclusion is given.

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