Update a custom field

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=true. The description adds only the vague 'Changes account configuration' and omits that confirm=true may be required for certain changes (as the schema hints) and that non-idempotent updates are not safely retryable — context that matters 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?

Very short and front-loaded, which is good, but the second sentence ('Changes account configuration') is vague filler that does not earn its place — it neither specifies the resource affected nor the effect.

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?

Six parameters including a nested payload object, no output schema, and a mutation that can require confirmation. The description says nothing about the confirm requirement, the payload-vs-body-flags exclusivity, or effect scope, leaving substantial gaps for a non-trivial mutation tool.

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 83%, above the 80% threshold, so the schema already documents account, confirm, payload, payload_file, and custom_field_id. The description adds nothing about parameters, so baseline 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?

States a clear verb+resource ('Update a custom field'), which cleanly separates it from create_custom_field, delete_custom_field, and bulk_create_custom_fields in the sibling list. The second sentence, 'Changes account configuration,' is vague and adds no real specificity about what updating entails.

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?

No indication of when to use this versus create_custom_field, bulk_update_subscriber_custom_field_values, or the payload/payload_file alternatives. No prerequisites or preconditions are stated.

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