Update Custom Field Item

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

With no annotations, the description must carry behavioral disclosure. It discloses a key prerequisite ('Requires Trello Premium or Enterprise') and the mutating nature of the operation via 'Set'. It does not describe overwrite/replace semantics, permissions beyond the plan requirement, or clearing behavior, leaving notable gaps.

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 short sentences with no redundant wording. The action is front-loaded and the licensing requirement is a useful second sentence.

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 four-parameter mutation with no annotations and no output schema, the description is functional but thin. The schema covers parameter semantics, and the description adds the premium prerequisite, but it omits behavioral context such as what happens when a value already exists or how to select between value and idValue for different field types. These gaps prevent it from being fully complete.

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 coverage is 100%; each of the four parameters has an explanatory description in the schema, including the value object and idValue for dropdowns. The tool description itself adds no parameter-level detail, so the baseline 3 applies.

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 concrete action ('Set') on a specific resource ('the value of a custom field on a card'). This clearly separates it from sibling tools such as update_card (card fields) and create_custom_field (field definitions). No ambiguity about the operation's target.

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 gives clear context: this tool is for card custom-field values, not general card updates or custom-field definitions. It does not explicitly name alternatives or state when not to use it, but the scope is specific enough to route an agent correctly.

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