Last.fm MCP Server

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

No annotations are provided, so the description carries full burden. It mentions 'Returns: Formatted list of the artist's top albums' but doesn't disclose behavioral traits like rate limits, authentication requirements (though sibling tools suggest an auth system), error conditions, or what 'popular' means (e.g., based on plays, ratings). The description is minimal beyond basic function.

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 is appropriately sized with a clear purpose statement followed by Args/Returns sections. However, the 'Args' and 'Returns' labels are redundant with the schema/context, and some sentences could be more front-loaded (e.g., key constraints like 'limit: 1-50' are buried). It's efficient but not optimally structured.

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?

Given no annotations, 5 parameters with 0% schema coverage, and an output schema exists (so return values needn't be explained), the description is moderately complete. It covers parameter semantics well but lacks behavioral context (e.g., auth, errors) and usage guidelines relative to siblings. For a read-only query tool, it's adequate but has clear 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 0%, so the description must compensate. It adds meaningful semantics for all 5 parameters: explains 'artist' as name, 'mbid' as optional MusicBrainz ID, 'autocorrect' for name correction, 'limit' range and default, and 'page' for pagination. This goes well beyond the bare schema, though it doesn't detail format constraints (e.g., MBID format).

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 tool's purpose: 'Get an artist's most popular albums' with a specific verb ('Get') and resource ('artist's most popular albums'). It distinguishes from siblings like 'get_artist_info' (general info) and 'get_artist_top_tracks' (tracks vs albums), but doesn't explicitly mention these distinctions in the description text itself.

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 no guidance on when to use this tool versus alternatives like 'get_artist_info' or 'search_artists'. It mentions parameters but doesn't explain context for choosing between 'artist' name and 'mbid', or when 'autocorrect' should be enabled. No prerequisites or exclusions are stated.

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