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

No annotations are provided, so the description carries the behavioral burden. It discloses the mutation ('save it to the row'), the derivation source of the SKU, and the return shape ('the item with its new listing_sku'). It does not cover failure modes (e.g. no SKU convention configured) or idempotency, keeping it short of a 5.

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 sentences, each doing work: what it does, where the id comes from, sequencing, and what comes back. Front-loaded and free of filler, though the parenthetical about title/cost/qty could be tightened.

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 single-parameter mutation tool with no annotations or output schema, the description covers the essentials an agent needs: the argument's provenance, the ordered workflow position, and the return value. Only error/permission behavior is left unstated.

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?

Only one parameter with 0% schema description coverage, so the description must carry it — and it does, explaining that the value is the purchase item id sourced from add_purchase or get_items_purchased. Minor friction: the description calls it 'id' while the schema names it 'item_id', leaving a small ambiguity about whether they are the same field.

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+resource ('Generate a SKU for a purchased item') and immediately scopes it with the inputs it derives from (title/cost/qty using the user's SKU convention) and the persistence step ('save it to the row'). An agent can distinguish this from siblings like create_listing or set_cog 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?

Explicitly tells the agent where the required argument comes from ('the `id` returned by add_purchase or shown in get_items_purchased') and pins the workflow ordering ('Do this before create_listing'). This is concrete when-to-use routing against named siblings.

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