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

Goes well beyond the annotations: discloses the 50-product cap, that duplicates keep their position but take the new note, that unknown/unavailable/overflow products are reported rather than added, what is returned (items with current prices), and that the token stops working once the list is saved to an account. It corroborates destructiveHint=true (mutates the list) and idempotentHint=true (re-adding is position-stable), so no contradiction.

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?

Four tight sentences, front-loaded with the action and its input, then constraints, then return value, then the token-lifetime caveat. No filler or repetition of the title.

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?

Even though an output schema exists, the description usefully signals the return payload and the partial-failure semantics, and it covers limits, duplicate handling and token expiry. Nothing an agent needs to call this correctly is missing.

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%, so edit_token, items, market, note, slug and product_id are all already documented in the schema, including the token extraction rule and the market default. The description only restates the edit-link/token idea that the schema already carries, so it does not add meaning beyond the structured fields.

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?

States a specific verb and resource ('Adds products to a wishlist') and immediately scopes it to a list 'made earlier', which cleanly separates it from create_wishlist, get_wishlist and remove_from_wishlist. An agent can select it without opening the schema.

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 establishes the prerequisite (the list must exist already, identified by its edit link or token) and implies create_wishlist as the upstream step, but never explicitly names an alternative tool or a when-not-to-use condition. Clear context, no exclusions.

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