set_custom_field_value

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

With no annotations, the description carries full burden. It discloses the mutation behavior ('Set or overwrite') and explains how value is interpreted per field type. However, it omits details about error handling when field type mismatches, permission requirements, or whether setting a value on a non-existent field creates it. This leaves 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?

The description consists of three concise sentences with no wasted words. The first sentence states the purpose, the second lists value shapes in a structured manner, and the third gives a clear usage hint. The information is front-loaded and easy to parse.

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?

Given the complexity (6 parameters, nested objects) and full schema coverage, the description provides near-complete context. It explains value shapes and the prerequisite lookup. However, it does not mention the optional `value_options` parameter, which is documented in the schema but not reinforced in the description. Since the schema covers it, this is a minor gap.

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?

Although schema coverage is 100%, the description adds critical meaning to the `value` parameter by enumerating the exact shape for each field type (primitive, option id, array of option ids, epoch ms, array of user ids). This information is not present in the schema description, which only cross-references the tool description. The added semantics are essential for correct invocation.

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 verb 'Set (or overwrite)' and the resource 'a custom field's value on a task.' It also explains value shape by field type. However, there is a sibling tool 'set_task_custom_field_value' with almost identical name, and the description does not differentiate between them, slightly reducing clarity.

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 a clear prerequisite: 'Look up the field type first with one of the get_*_custom_fields tools.' This guides the agent on proper sequencing. However, it does not explicitly state when to use this tool versus alternatives like 'remove_custom_field_value' or 'set_task_custom_field_value'.

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