preview_albumPreview any album from Apple Music WITHOUT adding to library. Use this to sample before committing to add. Returns playable 30-second previews.
| Name | Required | Description | Default |
|---|---|---|---|
| title | Yes | Album title | |
| artist | Yes | Artist name | |
| max_tracks | No | Maximum tracks to preview (default 5) |
| Name | Required | Description | Default |
|---|---|---|---|
| artist | No | ||
| source | No | ||
| tracks | Yes | ||
| cover_url | No | ||
| album_title | Yes | ||
| apple_music_url | No |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "additionalProperties": true,
+ "description": "Album track list with 30-second preview URLs where available.",
+ "properties": {
+ "album_title": {
+ "type": "string"
+ },
+ "apple_music_url": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "artist": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "cover_url": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "source": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "tracks": {
+ "items": {
+ "additionalProperties": true,
+ "properties": {
+ "duration_ms": {
+ "type": [
+ "number",
+ "null"
+ ]
+ },
+ "preview_url": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "title": {
+ "type": "string"
+ },
+ "track_number": {
+ "type": [
+ "number",
+ "null"
+ ]
+ }
+ },
+ "required": [
+ "title"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "album_title",
+ "tracks"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adds real context beyond the annotations: it confirms no library mutation occurs and that results are 30-second playable previews, which the annotation set alone doesn't convey. Minor tension: 'any album from Apple Music' implies querying an external catalog while openWorldHint=false declares a closed domain, though the read-only/idempotent semantics are consistent.
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?
Three short sentences, no filler, and the critical constraint (no library side effect) is placed immediately after the purpose. Every clause earns its place.
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?
An output schema exists, so return-shape explanation is unnecessary, and the description covers the two things an agent most needs: no library mutation and the nature of the returned previews. For a 3-parameter read-only lookup with full schema coverage, nothing essential is missing.
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 title, artist, and max_tracks are already documented with defaults in the schema. The description adds no format guidance (e.g., exact-match vs fuzzy artist names, what happens when title is ambiguous), so the baseline 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?
Specific verb ('Preview') plus resource ('any album from Apple Music'), and it distinguishes itself from the library-mutation siblings by stating 'WITHOUT adding to library'. It does not, however, differentiate itself from the closely related 'get_track_previews' sibling, so an agent cannot fully tell the two apart from the description alone.
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?
'Use this to sample before committing to add' gives a clear situational trigger, effectively routing agents away from add_item/add_to_list for exploratory browsing. It stops short of naming an explicit alternative or a when-not condition (e.g., versus get_track_previews for track-level sampling).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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