Show HN: I built a tool to visually manage my LLM prompt templates and save them (promptcanvas.ml4den.com)

A developer released Prompt Canvas, a lightweight visual tool to create, edit and manage reusable LLM prompt templates stored as YAML. The interface includes a Prompt Generator, Schema Editor, template selection, upload/download (including “download with values”), and quick actions like copy and export. Templates carry metadata (name, version, description) and a typed field schema (String, Text, Number, Boolean, List), letting you define input slots for variable substitution. You can upload templates to edit them, add fields through the schema UI, generate a filled prompt, and export the template or a populated YAML file. For the AI/ML community this is a practical utility for prompt engineering hygiene and reproducibility: YAML-backed templates make prompts versionable, shareable, and machine-readable, while typed schemas help validate inputs and reduce ad-hoc prompt drift. The tool is immediately useful for teams building LLM-driven pipelines, experiments, or production integrations because YAML is easy to parse, diff, and include in CI/CD. Technical implications include simpler A/B testing, safer automation of prompt generation, and the potential to extend with value validation, default values, conditional fields, or integrations with model APIs and prompt scoring systems.