Spotify MCP Server

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 the action ('Play') but lacks critical behavioral details: it does not specify if this requires an active device, what happens if playback is already ongoing, whether it affects shuffle/queue settings, or what the response looks like. This leaves significant gaps for a mutation 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, efficient sentence with zero waste. It is front-loaded with the core purpose and appropriately sized for a simple tool, making it easy to parse quickly.

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?

Given the complexity of a playback mutation tool with no annotations and no output schema, the description is incomplete. It lacks behavioral context (e.g., device requirements, effects on playback state) and does not compensate for the absence of structured fields, making it inadequate for safe and effective use.

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 fully documents the 'uri' parameter with examples. The description adds no additional meaning beyond what the schema provides, such as format nuances or edge cases, but the high schema coverage justifies the baseline score of 3.

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 clearly states the action ('Play') and the target resource ('a specific track'), using a specific verb and resource. However, it does not explicitly differentiate from siblings like 'resume_playback' or 'skip_to_next', which also involve playback control, leaving some ambiguity about when this exact tool is preferred.

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 provides no guidance on when to use this tool versus alternatives. It does not mention prerequisites (e.g., needing an active device), exclusions, or comparisons to sibling tools like 'resume_playback' for general playback or 'search_music' for finding tracks first.

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