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

Annotations already declare openWorldHint=true and non-idempotent, and the description adds real substance beyond that: the link path causes Wishpile to fetch the page and populate name, price, picture and store, and explicit arguments override page-derived values. It also surfaces the 'own wishlist' authorization scope. It does not address duplicate handling or what is returned, which is a gap for a write tool.

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 sentences, with the core action and scope first, then the link-vs-name behavior and the precedence rule. Every clause carries information an agent needs and nothing is restated from the schema.

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?

No output schema exists, yet the description explains the enrichment side effects well enough for correct invocation. Remaining gaps, such as the return value and whether duplicate items are created, are minor but real for an 8-parameter write tool with openWorldHint.

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?

With 75% schema coverage the baseline is already 3, and the description adds genuine meaning: the conditional requirement that a name is needed when no link is supplied (the schema only marks wishlist_id required), and the precedence rule that explicit values beat scraped ones. It still leaves price/currency/quantity/must_have to the schema, which already documents them.

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 a specific verb and resource ('Adds an item to one of the signed-in person's own wishlists, personal or in a group'), and the ownership/personal-vs-group scope helps distinguish it from generic add tools. It stops short of naming a sibling like add_gift to fully disambiguate, so it is clear but not maximally differentiating.

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 clear operating context: supply a link for automatic enrichment, supply a name when no link is given. That tells an agent how to call it in two distinct modes. It does not state when to prefer this over update_wishlist_item or add_gift, so the guidance is contextual rather than comparative.

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