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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds valuable context beyond that: the ownership model, token requirement, persistence source, and the need to retain credentials across sessions. This enriches the agent's understanding of the tool's operational requirements.

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, front-loaded with the core purpose, and every sentence contributes essential information. No filler or redundancy.

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?

The description provides a clear and complete picture for a simple read operation, covering purpose, ownership, persistence, and agent responsibilities. The lack of an output schema is not addressed, and the 'meta' parameter is ignored, creating a minor completeness gap, but overall it is well-scoped.

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?

The schema covers 67% of parameters with descriptions. The description reinforces the meaning of cart_access_token by explaining it is returned by create_cart and serves as an owner credential. However, the 'meta' parameter remains undocumented in both schema and description, so the description does not fully compensate for that gap.

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 tool retrieves a Shopify-owned cart by ID, using a specific verb and resource. It distinguishes itself from siblings like update_cart and get_product by emphasizing the owner-bound nature and reliance on a cart_access_token.

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 explicitly states the owner-bound requirement and the need for the cart_access_token from create_cart, giving clear context on when to use this tool. It also advises agents to retain credentials across sessions, but does not explicitly mention alternatives or when not to use it.

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