update_cart_item

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

The description notes that setting quantity to 0 removes the item, which is a behavioral trait. However, it does not disclose other behaviors like side effects, permissions, or validation rules. No annotations are present to compensate.

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?

The description is extremely concise, with the purpose front-loaded and the Args section efficiently listing parameters. Every sentence serves a purpose.

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?

The tool is simple and has an output schema (not shown), so return values are covered. However, it lacks context on error handling, prerequisites (e.g., cart must exist), and the effect of updating non-existent items.

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?

The Args section adds meaning to the parameters (e.g., 'quantity: New quantity (0 to remove)'), but the schema coverage is 0%, and the description does not elaborate beyond the obvious purpose of each parameter.

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 clearly states the action ('update the quantity of an item in the cart') and the specific resource (cart item quantity). It distinguishes itself from siblings like add_to_cart (adds new item) and remove_from_cart (removes entire item).

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?

No explicit guidance on when to use this tool versus alternatives. The description does not mention when not to use it or any prerequisites.

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