Update a custom field’s label, selectable options, display order, or required status without changing its key or entity type.
Update a custom field's label, options, or required status. Cannot change the field key or entity type.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Custom field UUID | |
| label | No | Updated label | |
| options | No | Updated options for select/multiselect | |
| sortOrder | No | Updated display order | |
| isRequired | No | Updated required status |
Changes observed during successful MCP inspections.
v4.71.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden and does disclose an important behavioral constraint: key and entity type are immutable. However, it does not mention permissions, whether the update is partial, reversibility, or side effects, leaving meaningful gaps for a mutation tool.
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?
Two tightly written sentences. The mutable fields are front-loaded and the immutability constraint follows immediately, with no wasted wording.
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 simple five-parameter update tool with no output schema, this is nearly complete: it identifies the update target, the mutable fields, and the immutability limits. The main remaining gap is the absence of permission or response context, though the full schema coverage offsets much of that.
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 100%, so the schema already documents all five parameters. The description adds little parameter-specific detail and even omits the sortOrder field, but with full schema coverage 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 states a specific verb and resource ('Update a custom field') and names the mutable fields. It distinguishes itself implicitly from sibling create/delete custom field tools, though it does not name those siblings 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?
Usage is implied: use this to modify an existing custom field. The immutability constraint ('Cannot change the field key or entity type') is useful guidance, but there is no explicit when-to-use versus create/delete or any named alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.