Update Customer Custom Field Values (Bulk)

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

The annotations already indicate a write operation with idempotency, and the description adds valuable behavioral details: partial update semantics (fields not included are left unchanged) and the return format (array of updated field value objects). This goes beyond the structured hints.

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 three sentences long, front-loaded with the endpoint and action, and every sentence provides necessary detail without redundancy. It is highly concise and well-structured.

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 tool with two parameters (one being an array of objects) and no output schema, the description covers the request shape, key field requirements, partial update behavior, and return type. This is complete enough for an agent to invoke it correctly.

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 already provides 100% description coverage for both parameters, including the requirement for 'id' to be the custom field definition ID and the value type rules. The description reinforces this but does not add new semantic meaning beyond what the schema offers, so the baseline of 3 is appropriate.

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 updates multiple custom field values on a customer in a single request, using a specific verb and resource. It distinguishes itself from the singular sibling tool by highlighting the batch nature and the specific endpoint.

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 (to update multiple fields in one request) and explains that omitted fields are left unchanged. However, it does not explicitly name alternatives or say when not to use it, though the bulk vs singular distinction is implied.

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