Save a device-specific volume preset (0–100) to the local sidecar, allowing you to recall preferred volume levels for any device.
Store a per-device volume preset (0–100) in the local sidecar.
| Name | Required | Description | Default |
|---|---|---|---|
| device_id | Yes | Device id | |
| volume_percent | Yes | Volume 0–100 | |
| response_format | No | 'concise' = human prose, 'detailed' = more fields in prose, 'json' = raw API object | concise |
Changes observed during successful MCP inspections.
v1.26.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral disclosure burden. It does disclose a meaningful trait: the preset is stored locally in a sidecar rather than applied directly. However, it does not state whether an existing preset is overwritten, whether any validation or Spotify-side effect occurs, or what happens after storage, which are material for a mutation-like 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 is a single sentence that front-loads the core action, the resource kind, and the key constraint. It contains no filler, repetition, or irrelevant detail, earning its place entirely.
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 tool is simple, the schema fully documents all three parameters, and the description supplies the essential storage semantics. The only notable gaps are lack of explicit alternative routing and no statement about overwrite or return behavior, but the schema's response_format description partially covers output expectations.
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 device_id, volume_percent, and response_format. The description adds useful context by framing the action as per-device and confirming the 0–100 range, but it does not add meaning beyond what the schema already provides, so the baseline of 3 is appropriate.
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 names a specific action ('Store'), a specific resource ('per-device volume preset'), and a clear location ('local sidecar'), which clearly distinguishes it from siblings like set_volume or apply_device_presets. It does not explicitly name those alternatives, but the verb and scope are unambiguous enough to prevent basic confusion.
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 about when to use this tool versus alternatives such as apply_device_presets, list_device_presets, set_volume, or volume_ramp. The description implies its purpose but does not state when it should be selected or when it should not, leaving the agent to infer the boundary from the tool name and sibling list.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.