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

Annotations already declare readOnlyHint=false and openWorldHint=true, so mutability and external catalog lookups are covered. The description usefully adds that an edit token from a prior create/mutate is needed, but says nothing about duplicate handling, failure modes, or what happens if multiple identifier fields are supplied.

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 first and the auth prerequisite second; no filler. The body enumeration is compressed but dense enough to require re-reading.

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 10-parameter mutation with no output schema and thin schema descriptions, the description covers the essential call path but omits several fields (emoji, notes) and any indication of the response. Adequate to invoke, not enough to invoke correctly on the first try in edge cases.

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 20% (only id and editToken documented), and the description partially compensates by grouping the body fields and implying that asin, url, searchKeywords, or catalogId are alternative product identifiers. It leaves emoji, notes, and the name-vs-title distinction unexplained, and never states that the identifier fields are mutually exclusive.

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") and adds the prerequisite token source. It doesn't differentiate itself from the sibling create_and_fill, which likely also adds items, so the agent must infer the boundary.

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?

Gives one concrete usage condition — an editToken from create is required — which implies this tool is used after a wishlist exists. It never names an alternative (e.g., create_and_fill) or says when not to use it.

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