Control a Shelly roller or cover: open, close, stop, or set position 0–100. Returns updated CoverState and audit-logs the action.
Move a roller/cover: action is open|close|stop, or pass position (0-100) to go to it.
Returns the post-action CoverState. Audit-logged.
| Name | Required | Description | Default |
|---|---|---|---|
| action | Yes | ||
| device | Yes | ||
| channel | No | ||
| position | No |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.3Input schema / additionalPropertiesAdded value: +falsev0.1.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It adds one genuine behavioral fact — 'Audit-logged' — and notes the return is a post-action CoverState, but says nothing about permissions, whether the move is interruptible, or how conflicting action+position inputs are resolved.
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 tight sentences, front-loaded with the action, so the agent gets the core semantics immediately. No filler; every clause carries either parameter meaning or behavioral context.
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?
An output schema exists, so the brief CoverState mention is sufficient rather than redundant. Core invocation semantics are covered, with the only real gap being device/channel resolution that no structured field or description explains.
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 compensates partially by enumerating action values (open|close|stop) and the position range (0-100), which the schema does not express. However, device and channel — including the channel default of 0 — remain undocumented anywhere.
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 specific verb ('Move') and resource ('roller/cover'), making it clearly distinguishable from shelly_switch_set and shelly_light_set which target other device classes. It stops short of explicitly contrasting itself with siblings, but the resource framing is unambiguous.
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 tells the agent the two operating modes (discrete action vs. positional), which implies usage, but offers no when-to-use versus alternatives or exclusions. An agent still has to infer which mode to prefer and whether device types matter.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.