create_labelAdds a new label to a Trello board, with optional color and board ID, so cards can be categorized and filtered.
Create a new label on a board
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | Name of the label | |
| color | No | Color of the label (e.g., "red", "blue", "green", "yellow", "orange", "purple", "pink", "sky", "lime", "black", "null") | |
| boardId | No | ID of the Trello board (uses default if not provided) |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden for a mutation tool, yet it discloses nothing about permissions, whether the board is required or defaulted, whether duplicate names are allowed, or what the result contains. Only the bare mutation intent is conveyed.
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?
A single, front-loaded sentence with no filler, which is appropriately sized for a simple creation tool. It is efficient, though it arguably errs toward under-specification over verbosity.
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?
The low-complexity schema and full parameter coverage mean the description need not re-explain inputs. Still, as a mutation with no annotations and no output schema, it omits behavioral essentials such as default-board resolution and side effects, leaving it only minimally viable.
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 name, color (with example values), and boardId (including its default behavior). The description adds no meaning beyond that, which is the baseline 3 when structured fields do the work.
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 ('Create a new label'), making the action unambiguous. However, it does not differentiate itself from sibling tools like update_label, delete_label, or add_label_to_card, leaving the agent to infer the distinct role from names alone.
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?
There is no guidance on when to use this tool versus update_label or add_label_to_card, nor any note that it only creates the label without attaching it to a card. The agent gets no conditions or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.