Spotify MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It describes basic actions but omits critical details: it doesn't mention authentication requirements, rate limits, error conditions (e.g., what happens if no track is playing for 'skip'), or side effects (e.g., whether 'start' with a URI replaces the current queue). For a mutation-heavy tool (start, pause, skip) with zero annotation coverage, this is a significant gap in transparency.

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 well-structured and front-loaded with the overall purpose, followed by a bulleted list of actions with concise explanations. Each bullet earns its place by clarifying action semantics. However, the repetition of the description in the input schema suggests some redundancy, and it could be slightly more efficient by integrating parameter hints directly.

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 multi-action playback tool with no annotations and no output schema, the description is incomplete. It lacks details on return values (e.g., what 'get' returns), error handling, authentication needs, and behavioral nuances (e.g., interaction between actions). For a tool with 3 parameters and mutation capabilities, this leaves significant gaps for an AI agent to operate effectively.

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 all parameters (action, num_skips, spotify_uri) thoroughly. The description adds minimal value beyond the schema by listing actions but doesn't provide additional syntax, format details, or edge cases. With high schema coverage, the baseline score of 3 is appropriate as the description doesn't compensate with extra semantic insights.

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 tool 'manages current playback' and lists four specific actions (get, start, pause, skip) with brief explanations. It distinguishes itself from siblings like SpotifyGetInfo, SpotifyPlaylist, SpotifyQueue, and SpotifySearch by focusing on playback control rather than information retrieval, playlist management, queue operations, or search. However, it doesn't explicitly contrast with each sibling tool, which prevents a perfect score.

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 implies usage contexts through action descriptions (e.g., 'get' for track info, 'start' to play/resume, 'pause' to stop, 'skip' to advance). However, it lacks explicit guidance on when to choose this tool over alternatives like SpotifyQueue for queue management or SpotifyGetInfo for general info. No when-not-to-use scenarios or prerequisites are mentioned, leaving usage somewhat ambiguous.

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