ebay_create_fulfillment_policy

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It goes far beyond basic expectations by detailing specific error behavior ('Please select a valid shipping service'), explaining remote validation vs. client duplication (citing DomesticItemShippingService indices), warning about sandbox/production differences, and explicitly listing the required OAuth scope. This gives the agent crucial behavioral insights that cannot be inferred from the schema.

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 longer than the minimum but every section earns its place: the purpose, the critical validation caveat, the working example, the sandbox note, and the OAuth requirement. It is logically organized into a brief summary, a detailed guidance block, and a scope line. It avoids redundancy despite its length.

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 complex create operation with no output schema, the description covers validation, auth, and sandbox nuances, but it does not disclose what the API returns (e.g., policy ID, response object). It also omits explanation of several optional fields (localPickup, freightShipping, etc.). Given the complexity and high parameter count, a note on return value and broader field semantics would make it more complete.

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. It does so effectively by providing a complete known-good example (policy.name, marketplaceId, categoryTypes, handlingTime, shippingOptions) and explaining the most error-prone field, shippingServiceCode. It also warns against invented codes and references GeteBayDetails for discovery. While not every nested field is individually explained, the example and warnings add substantial meaning beyond the raw 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 opens with 'Create a new fulfillment policy,' which is a specific verb + resource statement. It clearly distinguishes this tool from sibling policy-creation tools (e.g., payment policy, return policy) by naming the exact resource type. The rest of the description reinforces this purpose with fulfillment-policy-specific details.

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 the tool (creating a fulfillment policy) but does not explicitly contrast it with alternatives like ebay_create_payment_policy or ebay_create_return_policy. It does include practical usage guidance such as required OAuth scope and how to validate shipping codes, which helps the agent use it correctly, but the when-to-use guidance is implied rather than explicit.

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