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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so the safety profile is covered by structured data. The description adds context the annotations do not: the action targets the user's own GAMES.GG account (implying authentication is required) and states that the response reports what changed plus the game's URL, which tells the agent this is a recoverable, non-destructive write.

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, each doing distinct work: trigger condition, parameter source, and return shape. The trigger is front-loaded so an agent can decide on the tool in the first sentence.

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-required-parameter tool with full annotation coverage and an output schema, the description supplies everything missing from structured fields: the natural-language triggers, the upstream tool that produces the slug, and a one-line note on the return. No gap remains that would cause a misinvocation.

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 description's only parameter statement, 'game is the slug from find_game', restates the schema's own wording almost verbatim. The one piece of extra value is the implied workflow dependency on the find_game tool, but that is workflow guidance rather than added semantic depth on the parameter itself.

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 pairs the specific verb 'save' with the resource 'game' and the destination 'My Games on their GAMES.GG account', which separates it from save_guide (guides) and unsave_game (the inverse operation). It stops short of naming those siblings explicitly, so differentiation is inferred from the resource noun rather than stated.

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 concrete trigger phrasing: the user asks to 'save, favorite or add a game to My Games', which covers the natural-language variants an agent will encounter. There is no explicit when-not guidance or a pointer to unsave_game for the reverse action, so the routing is clear in one direction only.

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