Prompty

Prompty is a prompt format and developer toolkit for building AI applications. It keeps prompt text, model settings, inputs and tool definitions in a portable Markdown file that developers can share across editors and language runtimes.

• Reusable prompt files: Jinja2 and Mustache templates let the same prompt work with different inputs, while its settings and tool declarations stay alongside the text.
• VS Code workspace: The extension provides syntax highlighting, autocomplete, live preview and interactive chat with tool calling.
• Execution traces: Inspect model messages, token usage, latency and raw responses in the trace viewer, or send traces to console output, JSON files or OpenTelemetry.
• Agent tools and controls: Prompt files can declare function, MCP and OpenAPI tools, with runtime support for guardrails, cancellation, retries and conversation context management.
• Language runtimes: The same prompt assets work across Python, TypeScript, C#, Rust, Java, Go and Swift runtimes.

The editor and runtimes operate in your development environment. Model requests go to your chosen endpoint: a self-hosted OpenAI-compatible model server, OpenAI, Anthropic or Microsoft Foundry. You can change endpoints without rewriting the prompt body, and custom provider plugins extend the available connections.

Prompty is open source under the MIT license.