Add tracks by ID to a specific Apple Music playlist while automatically skipping songs already present. Use it to build or update playlists without duplicates.
Add tracks (by id) to a playlist. Tracks already in the playlist are skipped.
| Name | Required | Description | Default |
|---|---|---|---|
| playlist | Yes | ||
| track_ids | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It usefully discloses an idempotency-adjacent behavior ('tracks already in the playlist are skipped'), but omits whether the playlist must already exist, required permissions, and whether missing track ids cause failure.
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?
Two short sentences, zero waste, with the core action front-loaded and the dedup caveat following. Appropriately sized for the operation.
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 mutation tool with no annotations, no output schema, and 0% parameter coverage, the description is thinner than ideal. It covers the action and one behavior but leaves error handling, playlist identification, and permissions unaddressed.
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 0%, so the description must compensate. It clarifies that track_ids are IDs, but leaves the 'playlist' parameter ambiguous (name vs. id vs. URI) and says nothing about ID format or playlist resolution.
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?
States a specific verb (add) and resource (tracks to a playlist), clearly distinguishing it from siblings like remove_from_playlist and create_playlist. It doesn't explicitly reference those siblings, but the operation is unambiguous.
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?
There is no guidance on when to use this tool versus alternatives such as create_playlist or remove_from_playlist, nor any prerequisite conditions. The agent must infer usage entirely from the name and description.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.