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

With no annotations, the description does meaningful lifting: it declares the operation creates an empty container and enumerates the return fields (id, editToken, ownerUrl, shopUrl). However, it omits that editToken is a credential granting edit access, whether the call requires authentication, and whether repeated calls create duplicates — important gaps for an unannotated mutation.

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?

Four short, front-loaded sentences with the core action stated first and returns and prerequisites after. "Requires marketplace + locale" slightly duplicates the schema's required array, but the overall shape is efficient.

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?

Listing return fields is valuable given there is no output schema, but an agent still lacks guidance on the optional personalization parameters and on auth/duplicate behavior for a creation call. Adequate as a minimum-viable definition, not 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 coverage is only 40%, and the description merely restates that marketplace and locale are required, adding no format or meaning beyond the schema's own examples. The three undocumented parameters (ageBand, childName, interests) receive no explanation anywhere, so the description fails to compensate for the coverage 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?

"Create an empty baby registry / wishlist" gives a specific verb and resource, and the word "empty" implicitly separates it from the sibling create_and_fill_registry. It is clear without opening the schema, though the sibling is never named explicitly.

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?

"Start of list-building" hints at the workflow position and "Requires marketplace + locale" states prerequisites, but there is no explicit statement of when to prefer this over create_and_fill_registry or add_registry_item. The agent must infer the contrast from the word "empty".

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