etsy_add_to_favorites

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

With no annotations, the description carries the full burden of behavioral disclosure. It reveals the side effect (adding to favorites) and the authentication requirement, but does not mention behavior on duplicate favorites, navigation steps, or error handling. Some behavioral context is provided, but not in depth.

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 short sentences with no redundant wording. The core action is stated first, and the prerequisite follows. Every word earns its place.

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 simple one-parameter mutation tool, the description covers the essential context: the action and the login prerequisite. There is no output schema, but for an add-to-favorites action, return values are less critical. It is slightly incomplete in not addressing duplicate favorites or failure cases, but sufficient for typical agent use.

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 parameter description already specifies 'Full URL of the Etsy listing to favorite.' The tool description adds no additional meaning or format details beyond the schema, so a baseline score 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 clearly uses a specific verb ('Add') and resource ('an item to favorites on Etsy'), which precisely distinguishes it from siblings like etsy_add_to_cart and etsy_get_favorites. The action is unambiguous and the scope is well-defined.

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 states a clear prerequisite: 'Requires being logged in.' This gives context for when the tool can be used, and implies that login should occur first. It does not explicitly name alternatives or when-not-to-use conditions, but the context is clear.

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