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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the safety profile is covered. The description adds the return shape ('what changed and the game's GAMES.GG url') but never states what happens when the game isn't currently saved — the idempotency hint implies a no-op rather than an error, and the description could have confirmed that.

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, front-loaded sentences with the trigger first and the parameter hint second. The trailing sentence about return values is partly redundant with the existing output schema, but it is brief enough not to be noise.

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?

A single required parameter, full schema coverage, rich annotations and an output schema mean the description only needs to supply the trigger and the slug source, both of which it does. Nothing an agent needs to call this 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 coverage is 100% and the schema already says the field is a slug from find_game. The description adds real value by naming my_games as a second valid source of slugs, which the schema does not mention.

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 ('unsave, unfavorite or remove a game from My Games') tied to the user's account, which clearly separates it from save_game and the guide-oriented unsave_guide sibling.

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 opening 'Use when the user asks to...' clause gives explicit trigger conditions and lists the synonymous phrasings an agent might encounter. It stops short of naming siblings like save_game as the inverse operation, but the invocation context is unambiguous.

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