Four well-named tools with clear, actionable descriptions (avg 180 chars). All tools have complete input schemas with proper types, constraints, and parameter descriptions. Naming follows verb_noun pattern (identify_song, search_tracks, get_track_analysis, find_similar_tracks). Parameters are well-constrained (ISRC regex, URL format, numeric bounds). However, output schemas are not documented, LLMs cannot see what fields to expect from responses, forcing inference and risking downstream tool chaining failures. Error handling is present but generic (SongFinderError catch-all). No tool annotations (readOnlyHint, idempotentHint) despite all tools being read-only.

• Document output schemas for all four tools. Add to each tool description: 'Returns: {title (string), artist (string), album (string), isrc (string), streaming_links (array of {platform, url})}' or equivalent. This enables LLMs to plan downstream calls and extract the right fields.
• Add readOnlyHint: true to all tool definitions. Update McpServer.registerTool() calls to include annotations: { readOnlyHint: true }. This signals to agents that these tools are safe to call without side effects.
• Enhance error messages with recovery guidance. Instead of generic 'Unexpected failure', return specific errors: 'Invalid ISRC format (got "ABC123"), must be exactly 12 alphanumeric characters. Try search_tracks() to find the correct ISRC.' This enables self-correction.
• Document identify_song's ISRC resolution fallback. Clarify: 'If ISRC cannot be resolved from the recognized song, the response will include title and artist but no ISRC. Call search_tracks() to look up the ISRC manually.'
• Expand find_similar_tracks 'harmonic' parameter description to: 'When true, restricts results to keys that mix cleanly on the Camelot wheel, use this when building DJ sets or beatmatched playlists. When false, returns similar tracks regardless of key compatibility.'