add_to_cart

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

With no annotations, the description carries full burden for behavioral disclosure. It only states the basic action and quantity parameter, but does not disclose potential side effects, error conditions, behavior for duplicate items, or whether the cart is user-specific. This is a significant gap for a mutation tool.

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 a single, clear sentence that is front-loaded with the action and resource. It contains no wasted words and is immediately understandable.

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 simple two-parameter tool with complete schema documentation, the description is minimally adequate. However, the lack of behavioral context (e.g., what happens if productId is invalid or quantity is beyond stock) and the absence of annotations make it less complete than it could be. It does not explain return values or errors, but since there is no output schema, that responsibility falls to the description.

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 100%, so the schema itself documents both parameters. The description adds minimal value beyond the schema, only echoing 'with specified quantity'. However, since the schema is complete, the baseline score of 3 is appropriate.

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 verb 'Add' and the resource 'product to shopping cart', which directly distinguishes it from sibling tools like remove_from_cart and get_cart_items. It also mentions the key parameter 'quantity'.

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 usage: to add items to the cart. However, it does not explicitly mention when to use it versus alternatives or any exclusions, such as whether the product must exist or whether the cart must be active. The sibling names provide context but the description itself lacks this guidance.

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