Set the brightness level (0-100) for a room or zone to turn lights on or off. Adjust group lighting by specifying a group ID or name and the desired brightness.
Set the brightness (0-100, turns it on; 0 turns it off) of a room or zone.
| Name | Required | Description | Default |
|---|---|---|---|
| group_id | No | ||
| brightness | Yes | ||
| group_name | No |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already disclose idempotent, non-destructive, and non-read-only behavior. The description adds useful behavioral detail beyond annotations: brightness is 0-100, a nonzero value turns the group on, and 0 turns it off.
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 wasted wording. The parenthetical efficiently carries the essential range and on/off behavior.
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 output schema covers return values and the annotations cover safety, but for a three-parameter group-control tool the description omits critical group identification semantics and guidance on alternative tools.
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 0%, so the description must carry parameter meaning. It clarifies brightness range and off behavior, but group_id and group_name are completely undocumented, including how to choose between them or what their empty defaults mean.
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 ("Set the brightness") plus the target scope ("room or zone") and the 0-100 effect. It implicitly distinguishes group control from single-light siblings via "room or zone," but does not explicitly name an alternative tool.
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?
Usage is implied by "room or zone," but there is no explicit guidance on when to use this versus turn_on_group, turn_off_group, or set_brightness. No exclusions or prerequisites are stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.