Add a game to your profile favourites

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

Despite annotations already indicating non-readonly and idempotent behavior, the description adds crucial context: the hard limit of five favourites, rejection of a sixth, and the lack of a removal endpoint. These details go beyond the annotations and help the agent anticipate failure modes.

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 three short sentences, each carrying distinct information: the action, the limit with consequence, and a note about removal. No wasted words.

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-parameter write tool with annotations and a clear schema, the description covers the operational constraints and behavioral expectations completely. No output schema is present, so not describing return values is acceptable.

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?

The schema already fully documents the single 'game' parameter with its accepted formats (title, slug, or ID). The description adds no additional parameter guidance, so a baseline score of 3 is appropriate given the 100% schema coverage.

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 verb ('Pin') and resource ('game to the favourites row on your profile'), clearly distinguishing it from sibling tools like add_game_to_lists. The action is unambiguous and accurately reflects the tool's function.

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 provides implicit usage guidance by noting the five-favourite limit and that removal isn't supported through the server, implying this is the only way to add via API and removal must be done manually. However, it doesn't explicitly name alternatives or state exclusions beyond the removal caveat.

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