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1,500 playlists to suit your mood

Reddit · Technical_Noise_9060 · June 13, 2026
A developer created fringefm.net, a website with approximately 1,500 curated playlists generated using Claude AI, allowing users to filter by mood, activity, and musical era with up to 15 tracks per playlist. The project used Claude Opus for playlist creation and Claude Sonnet for generating creative playlist names, completed in about 10 seconds using Anthropic's Batch API at a total cost of approximately $15. The developer discovered notable limitations including Claude's occasional hallucination of non-existent artists and initial misinformation about Spotify's API capabilities.

Detailed Analysis

A developer built FringeFM (fringefm.net), a website hosting approximately 1,500 Spotify playlists curated by Claude Opus, designed to help listeners escape the repetitive loops of algorithmic music recommendation. The project allowed users to filter playlists by mood, activity, and era, with each playlist containing up to 15 tracks and a distinctive name generated by Claude. The entire library of 1,344 playlists was generated via a Python automation script at a cost of roughly $15, leveraging Anthropic's Batch API for a 50% discount and prompt caching to further reduce costs — effectively bringing Opus-level generation down to approximately Sonnet pricing. The speed of generation was notable: all 1,344 playlists were created in approximately 10 seconds, a result the developer initially mistook for a failure.

The technical build offered granular insight into how model selection and temperature settings materially affect output quality for creative tasks. At a temperature of 1.0, Claude produced erratic results — playlists containing tracks of screaming or sound effects — and occasionally hallucinated artists that did not exist on Spotify. Reducing temperature to 0.9 largely eliminated hallucinations while preserving the element of musical surprise the developer sought. Model selection also proved consequential for playlist naming: Haiku generated generic titles like "Late Night Lounge," while Sonnet produced notably better wordplay and humor, and Opus offered diminishing returns on that specific subtask, leading the developer to use Sonnet for naming and reserve Opus for track curation.

The project candidly documented several failure modes that provide practical lessons for developers working with large language models. Claude incorrectly interpreted Spotify's February 2026 API changelog, confidently asserting that playlist creation had been removed entirely — a hallucination that cost the developer approximately three hours before a cross-check with ChatGPT revealed the error. Additionally, Claude lacked knowledge of the Tidal API and was unable to scrape Tidal's documentation due to the structure of their website, requiring the developer to manually locate and paste the relevant documentation into the context window. These episodes illustrate persistent limitations in LLM-assisted development: confident errors on recent or niche technical documentation, and constrained ability to independently retrieve specialized information from dynamically rendered web sources.

The project sits within a broader trend of developers using AI models not merely as coding assistants but as creative collaborators capable of generating large volumes of structured, opinionated content at scale. The combination of Anthropic's Batch API, prompt caching, and tiered model selection represents an increasingly mature cost-optimization strategy that makes large-scale generative projects economically accessible to individual developers. The FringeFM build also reflects growing consumer frustration with closed algorithmic recommendation systems — a sentiment the developer explicitly names as motivation — and positions AI curation as a potential counterweight to personalization systems that reinforce listening habits rather than expand them. The contrast between Spotify's two-week rate-limiting saga and Tidal's twelve-minute API integration, detailed in the developer's full write-up, further underscores how platform infrastructure decisions can dramatically shape the feasibility of third-party AI-driven applications.

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