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

Annotations already mark this as a non-read-only, destructive mutation, but the description adds real behavioral context beyond them: type immutability after creation, the requirement that select/multi_select keep non-empty select_values, and the non-obvious side effect that setting a default value clears any autofill on the field. It does not warn about what happens to documents that already consume changed select_values, which is the main remaining gap for a destructive update.

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 purpose is front-loaded in the first line and the constraints are grouped into a short list plus one focused paragraph. Every sentence earns its place, though the single-item bullet block and a stray double line break make the layout slightly heavier than the content requires.

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 9-parameter update tool with a published output schema, this covers the load-bearing items: how to discover valid UUIDs (get-template-info with include=["dynamic_fields"]), what can and cannot be modified, partial-update semantics, and value formatting delegation. Return-value explanation is correctly omitted because the output schema handles it.

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 baseline is 3 and the schema already carries most field-level meaning. The description still adds value above that baseline: the distinction that value vs values is driven by multi_select-ness (with format delegated to create-template-dynamic-field), the non-empty select_values constraint for select types, and the autofill-clearing behavior of a default value.

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 a specific verb+resource: 'Update an existing dynamic field on a template.' The verb choice cleanly separates it from the create-template-dynamic-field and delete-template-dynamic-field siblings without needing to name them, and a second sentence enumerates exactly which properties can be changed.

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?

It gives an explicit trigger ('The user wants to change a dynamic field's name, scope, options, default value, or other properties') and an explicit when-not with an alternative path: a field's type cannot be changed, so the agent must 'delete the field and create a new one.' Partial-update semantics ('Only send the fields you want to change') are also stated, which is the key invocation guidance for this tool.

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