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

Annotations already indicate a mutating operation (readOnlyHint: false). The description adds 'Requires authentication,' which is a useful behavioral note, but beyond that it does not disclose edge cases such as what happens when neither parameter is provided.

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 a single, front-loaded sentence that states the action and the auth requirement with no filler or redundancy.

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?

The tool is simple, and the schema plus auth note cover basics, but the description does not clarify that at least one of the two optional parameters should be provided, despite saying 'a product or offer.' No output behavior is described (though no output schema exists).

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 input schema already provides 100% coverage with descriptions for both offer_id and product_id. The description's phrase 'product or offer' simply mirrors the schema, adding no new semantic meaning for the parameters.

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 uses the specific verb 'Add' and identifies the target resource ('product or offer') and destination ('wishlist/bookmarks'), making the tool's purpose immediately clear and distinguishing it from sibling cf_remove_wish.

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 only an authentication prerequisite, implying usage but not explicitly stating when to use this tool versus alternatives like cf_remove_wish or cf_list_wishes. No exclusions or alternative tool references are given.

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