PostCartsIdShippingMethods

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states this is a write operation ('Add'), implying mutation, but doesn't cover critical aspects like required permissions, whether changes are reversible, rate limits, or what the response looks like. For a mutation tool with zero annotation coverage, this leaves significant gaps.

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 followed by usage context. Every sentence earns its place with no wasted words, making it highly efficient and easy to scan.

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 2 parameters, 0% schema coverage, no annotations, and no output schema, the description is incomplete. It lacks details on parameter usage, behavioral traits (e.g., side effects), and expected outcomes, which are essential for safe and effective tool invocation.

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 compensate for undocumented parameters. It mentions 'cart' (implied for 'id') and 'shipping method' (implied for 'fields'), but doesn't explain what 'fields' should contain (e.g., format, required data) or provide examples. This adds minimal value beyond the bare schema.

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 ('Add a shipping method to a cart') and the resource ('cart'), which is specific and unambiguous. However, it doesn't explicitly differentiate from sibling tools like 'PostCartsIdComplete' or 'PostCartsIdLineItems', which also modify carts but for different purposes.

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 clear context for when to use this tool: 'when the customer chooses their preferred shipping option.' This gives practical guidance, but it doesn't mention when NOT to use it or explicitly name alternatives like 'GetShippingOptions' for browsing options first.

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