Add songs by name, URI, or Spotify URL to Liked Songs. Resolves track names automatically, so you can save multiple tracks in one request.
Add songs (names or URIs) to Liked Songs.
| Name | Required | Description | Default |
|---|---|---|---|
| items | Yes | Track names OR URIs OR open.spotify.com URLs — names are auto-resolved. |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden, yet it discloses little beyond the mutation itself. It never states whether duplicates are ignored or rejected, whether there is a per-call item limit, whether authentication is required, or what the call returns. For a library-mutating tool with zero annotation coverage this is a meaningful gap.
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?
A single short sentence with no filler, front-loading the action and the destination collection. Nothing needs to be trimmed.
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 one-parameter tool with full schema coverage and no output schema, the definition is adequate to invoke correctly. It falls short on the mutation-specific context an agent would want (duplicate handling, batch limits), which the absent annotations leave uncovered.
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% and the parameter is documented as accepting track names, URIs, or open.spotify.com URLs with auto-resolution. The description repeats only the names/URIs portion and adds no syntax, batch-size, or resolution-failure guidance beyond the schema, so the baseline of 3 applies.
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 target collection (Liked Songs) with the accepted item forms, so an agent can distinguish it from unsave_tracks and saved_tracks. It doesn't explicitly contrast itself with those siblings, but the direction of the operation (add vs. remove vs. list) 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?
Usage is only implied: the agent must infer that this is the tool for adding to the liked library rather than unsave_tracks or saved_tracks. There is no explicit when-to-use, prerequisite, or routing statement naming an alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.