Append a single track to a laut.fm playlist only if it is not already included. Provide station, playlist, and track IDs to update the playlist.
Append a single track to a playlist. The track must not already be in the playlist.
| Name | Required | Description | Default |
|---|---|---|---|
| track_id | Yes | The track ID to add | |
| station_id | Yes | The station ID | |
| playlist_id | Yes | The playlist ID |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It discloses the duplicate-track precondition, which is useful, but omits mutation side effects, permission requirements, error behavior, and whether the operation is reversible.
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 with zero waste. The core action is front-loaded and the precondition follows efficiently.
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 simple three-parameter mutation with no annotations and no output schema, the description is minimally adequate but incomplete. It does not explain permissions, failure cases, or what the append operation returns, which leaves notable gaps.
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 three parameters. The description does not add syntax, format, or relational meaning beyond what the schema provides, so the baseline 3 is 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: 'Append a single track to a playlist.' It is clear enough to distinguish from read/delete siblings by name and action, though it does not explicitly name or contrast with them.
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?
It provides the precondition that the track must not already be in the playlist, but gives no explicit when-to-use guidance, no alternatives, and no exclusions beyond that single constraint.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.