add_to_cart

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 return behavior ('Returns the updated cart, same shape as get_cart()'), which is useful. It does not mention error handling, persistence side effects, or quantity constraints, but for a simple cart mutation the disclosed behavior is reasonably transparent.

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 two sentences with no filler. The main action and parameter guidance come first, and the return-shape note follows efficiently.

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 two-parameter tool with no output schema and no annotations, the description covers the key inputs, the source of product_id, and the return shape via the get_cart reference. It does not discuss edge cases, but the information needed for normal invocation is largely present.

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 description coverage is 0%, so the description must clarify parameters. It explains that product_id comes from search_products and that count represents units of the product. This adds meaning beyond the bare schema types and names.

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 states a clear action: 'Add `count` units of a product to the cart', which is a specific verb and resource. It also references product_id from search_products, distinguishing this addition tool from siblings like remove_from_cart and clear_cart.

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?

The description implies the tool should be used after search_products by stating 'product_id from search_products', and the return-shape note connects it to get_cart. However, it does not explicitly explain when to use this tool versus alternatives such as remove_from_cart, clear_cart, or get_cart.

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