add_to_cart

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

With no annotations provided, the description bears the full burden but only says 'Add ... locally'. It does not clarify if 'locally' means client-side only, what happens on conflict (e.g., different merchant), or any side effects. Critical behavioral traits are missing.

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 very short (one sentence with two clauses), but it is not well-structured. The constraint about one merchant per cart is appended as a separate thought. While concise, it sacrifices clarity and completeness.

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 the high parameter count, zero schema coverage, and absence of annotations, the description is severely incomplete. It does not explain return values (despite an output schema), error conditions, or prerequisite steps like ensuring a cart exists.

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%, yet the description provides no explanation of the 15 parameters, their roles, defaults, or relationships. The term 'canonical CartRow' is vague and does not compensate for the lack of parameter documentation.

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 'canonical CartRow', and includes the important constraint that a cart may contain only one merchant. This distinguishes it from sibling tools like update_cart_item or 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 mentions the one-merchant constraint, implying when this tool can be used (only with same merchant), but does not explicitly state when to use it versus alternatives like update_cart_item or remove_cart_item. No exclusions or prerequisites are given.

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