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

Annotations only declare readOnlyHint=false and openWorldHint=true; the description goes further by disclosing the auth requirement (editToken from create) and the token-rotation side effect ('Token storage may return a new id — update bookmarks'). That is real mutation context beyond structured fields, though duplicate handling and failure modes are unmentioned.

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 short front-loaded sentences with the action, prerequisite, payload shape and side effect in that order. The trailing 'OpenAPI: addItem.' is the only near-wasteful fragment, and it is one clause.

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?

With 9 parameters, no output schema and an open-world hint, the description covers the mutation path well but omits the emoji parameter and never says what a successful call returns (item id, full item, nothing). Indirectly it notes the token response, which helps but is not a full picture.

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 only 22%, so the description must compensate, and it largely does: it enumerates the identifier options (asin, url, searchKeywords, catalogId), groups name/title as the label pair, and clarifies that url expects a pasted '/dp' link. Only emoji and the explicit role of id are left unexplained.

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 ('Add an item to a wishlist'), which cleanly separates it from create_wishlist and resolve_product. It doesn't explicitly name a sibling it contrasts with, so it stops short of the 5 bar.

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 a concrete precondition ('Requires editToken from create') and lists the accepted identifier forms, which implies the use case of populating an existing list. It never states when not to use it or which sibling handles related tasks such as resolving a product first.

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