spotify-mcp

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

With no annotations provided, the description carries the full disclosure burden. It successfully explains the idempotency-like behavior (skipping existing tracks) and the dry_run safety mechanism. It could be improved by mentioning error conditions (e.g., non-existent playlists) or permission requirements, but covers the core behavioral contract well.

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 consists of exactly two high-value sentences with zero redundancy. The first sentence establishes the core operation, while the second provides the critical safety instruction. Every word earns its place in this compact, front-loaded structure.

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?

For a 3-parameter mutation tool with an output schema (per context signals), the description is nearly complete. It covers the safety-critical dry_run default behavior (true) and explains the deduplication logic. Minor gaps include missing error handling or permission notes, but these are acceptable given the output schema handles return value documentation.

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?

Given 0% schema description coverage, the description compensates effectively by mapping 'source playlist' and 'target playlist' to their conceptual roles and explaining the dry_run parameter's function ('Set dry_run=False to apply'). It implicitly clarifies all three parameters despite the schema providing no documentation.

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 operation ('Merge unique tracks'), resources ('source playlist' into 'target playlist'), and deduplication behavior ('Tracks already in target are skipped'). This effectively distinguishes it from siblings like spotify_merge_playlists (which likely creates new playlists) and spotify_add_to_playlist (which likely adds specific tracks rather than bulk merging).

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 critical safety guidance ('Set dry_run=False to apply') which is essential for a mutation tool. However, it lacks explicit guidance on when to choose this over similar tools like spotify_merge_playlists or spotify_interleave_playlists, and omits prerequisites like playlist ownership requirements.

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