update_cart

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

Description discloses the key behavior of removing items by setting quantity to 0, but lacks information on idempotency, error handling, or permissions. Since no annotations exist, the description carries the full burden but is minimal.

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 concise sentences with no fluff. The main action is front-loaded, and every word earns its place.

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 mutation tool with no output schema, the description covers the core function and the special removal behavior. It lacks mention of return value or error conditions, but these are partially covered by common REST conventions.

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%. The description adds semantic value by explaining that quantity 0 means removal, which is not obvious from the schema alone. However, it doesn't add further detail about the items array structure beyond what's in the schema.

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?

Description clearly states the verb (update) and resource (quantities of items in shopping cart). It explicitly mentions setting quantity to 0 for removal, distinguishing from add_to_cart and remove_from_cart siblings.

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 guidance on when to use this tool vs alternatives. For example, it doesn't clarify whether to use update_cart vs remove_from_cart for removing items, or when to use update_cart vs add_to_cart for increasing quantities.

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