PostCartsIdCustomer

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

No annotations are provided, so the description carries full burden. It states this is a mutation operation ('Set'), implying it modifies data, but doesn't disclose behavioral traits like required permissions, whether the operation is idempotent, error conditions, or what happens to existing cart data. For a mutation tool with zero annotation coverage, this leaves significant gaps in understanding how the tool behaves.

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 appropriately sized with two clear sentences. The first sentence states the core purpose, and the second provides contextual usage. There's no wasted text, and information is front-loaded effectively.

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?

Given this is a mutation tool with no annotations, 2 undocumented parameters (0% schema coverage), and no output schema, the description is incomplete. It explains the 'why' but lacks essential details about parameters, behavior, and expected outcomes. The context signals indicate high complexity that isn't adequately addressed.

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 schema provides no parameter documentation. The description mentions no parameters at all, failing to explain what 'id' and 'fields' represent (e.g., cart ID and customer data fields). With 2 undocumented parameters, the description adds zero semantic value beyond what the bare schema provides.

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 ('Set the customer of the cart') and the resource ('cart'), providing a specific verb+resource combination. It distinguishes this tool from siblings like 'PostCarts' (create cart) or 'PostCartsIdComplete' (complete cart) by focusing on customer assignment. However, it doesn't explicitly differentiate from all sibling tools that might modify cart properties.

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 provides an example use case ('when you create the cart for a guest customer, then they log in with their account'), which implies usage context. However, it doesn't explicitly state when NOT to use this tool or name alternatives (e.g., when to use 'PostCustomers' for customer creation instead). The guidance is helpful but incomplete.

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