play_trackPlays a specific Spotify track by URI or bare track ID on a chosen device, or on the currently active device by default, enabling playback control on free Spotify accounts.
Play a raw Spotify track URI on a device.
| Name | Required | Description | Default |
|---|---|---|---|
| uri | Yes | "spotify:track:xxxxx" or a bare track id. | |
| device | No | device name ("" = active device). |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v1.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It does not mention authentication requirements, what happens if no device is active, whether current playback is interrupted, or error behavior for invalid URIs.
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 front-loaded sentence with no wasted text. It is concise, though its brevity contributes to gaps in behavioral and usage guidance rather than being a pure strength.
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, has full schema coverage, and has an output schema, reducing what the description must explain. However, with no annotations, it should at least mention Spotify session requirements or active-device fallback behavior to be fully complete.
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 both the uri and device parameters are already documented in the schema. The description adds no parameter-level meaning beyond those definitions, making the baseline score 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 states a specific verb and resource: 'Play a raw Spotify track URI on a device.' This clearly identifies the operation, but it does not explicitly differentiate this tool from siblings such as play_song or play_liked_song.
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 phrase 'raw Spotify track URI' implies this tool is for callers that already have a track URI, but it never explicitly states when to use it instead of play_song or play_liked_song. Usage is inferable but not directly guided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.