Spotify MCP Server

set_default_device

Set the default Spotify device ID for playback operations to ensure music plays on your preferred speaker or device.

Instructions

Set the default Spotify device ID to use for all playback operations

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "deviceId": "<deviceId>"
    },
    "name": "set_default_device"
  }
}

Input Schema

Name	Required	Description	Default
`deviceId`	Yes	Device ID to set as default

Schema Changelog

Changes observed during successful MCP inspections.

Addedv1.0.0Jan 3, 2026

TDQS

B3.2/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden. It states this is a mutation ('Set'), implying it changes system state, but doesn't disclose behavioral traits like required permissions, whether the change is persistent, error conditions, or side effects. This is a significant gap for a mutation tool with zero annotation coverage.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence with zero waste. It's front-loaded with the core purpose and appropriately sized for a simple tool with one parameter.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given this is a mutation tool with no annotations and no output schema, the description is incomplete. It lacks behavioral context (e.g., what happens on success/failure, whether it affects active playback), and while the parameter is covered, the overall tool behavior is underspecified for safe agent use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

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 the single parameter 'deviceId'. The description adds no additional meaning beyond what the schema provides (e.g., format examples, sourcing instructions, or validation rules). Baseline 3 is appropriate when the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the specific action ('Set') and resource ('default Spotify device ID'), and specifies the scope ('for all playback operations'). It uses precise language that distinguishes it from sibling tools like 'get_devices' or 'control_playback'.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an active device list from 'get_devices'), exclusions, or contextual triggers. The agent must infer usage from the purpose alone.

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

Deploy Server