flompt

Blocks are automatically ordered following Anthropic's recommended prompt structure.

🚀 Try It Now

flompt.dev, free and open-source, no account needed.

🧩 Browser Extension

Use flompt directly inside ChatGPT, Claude, and Gemini without leaving your tab.

• Injects an Enhance button into the AI chat input
• Bidirectional sync between the sidebar and the chat
• Works on ChatGPT, Claude, and Gemini

🤖 Claude Code Integration (MCP)

flompt exposes its core capabilities as native tools inside Claude Code via the Model Context Protocol (MCP).

Once configured, you can call decompose_prompt, compile_prompt, and list_block_types directly from any Claude Code conversation, no browser, no copy-paste.

Installation

Option 1: CLI (recommended)

claude mcp add --transport http --scope user flompt https://flompt.dev/mcp/

The --scope user flag makes flompt available in all your Claude Code projects.

Option 2: ~/.claude.json

{
  "mcpServers": {
    "flompt": {
      "type": "http",
      "url": "https://flompt.dev/mcp/"
    }
  }
}

Available Tools

Once connected, 3 tools are available in Claude Code:

decompose_prompt(prompt: str)

Breaks down a raw prompt into structured blocks (role, objective, context, constraints, etc.).

• Uses Claude or GPT on the server if an API key is configured
• Falls back to keyword-based heuristic analysis otherwise
• Returns a list of typed blocks + full JSON to pass to compile_prompt

Input:  "You are a Python expert. Write a function that parses JSON and handles errors."
Output: ✅ 3 blocks extracted:
          [ROLE] You are a Python expert.
          [OBJECTIVE] Write a function that parses JSON…
          [CONSTRAINTS] handles errors
        📋 Full blocks JSON: [{"id": "...", "type": "role", ...}, ...]

compile_prompt(blocks_json: str)

Compiles a list of blocks into a Claude-optimized XML prompt.

• Takes the JSON from decompose_prompt (or manually crafted blocks)
• Reorders blocks following Anthropic's recommended structure
• Returns the final XML prompt with an estimated token count

Input:  [{"type": "role", "content": "You are a Python expert", ...}, ...]
Output: ✅ Prompt compiled (142 estimated tokens):

        <role>You are a Python expert.</role>
        <objective>Write a function that parses JSON and handles errors.</objective>

list_block_types()

Lists all 16 available block types with descriptions and the recommended canonical ordering. Useful when manually crafting blocks.

Typical Workflow

1. decompose_prompt("your raw prompt here")
   → get structured blocks as JSON

2. (optionally edit the JSON to add/remove/modify blocks)

3. compile_prompt("<json from step 1>")
   → get Claude-optimized XML prompt, ready to use

Technical Details

| Property | Value | |----------|-------| | Transport | Streamable HTTP (POST) | | Endpoint | https://flompt.dev/mcp/ | | Session | Stateless (each call is independent) | | Auth | None required | | DNS rebinding protection | Enabled (flompt.dev explicitly allowed) |

🛠️ Self-Hosting (Local Dev)

Requirements

• Python 3.12+
• Node.js 18+
• An Anthropic or OpenAI API key (optional, heuristic fallback works without one)

Setup

Backend:

cd backend
python -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt
cp .env.example .env   # add your API key
uvicorn app.main:app --reload --port 8000

App (Frontend):

cd app
cp .env.example .env   # optional: add PostHog key
npm install
npm run dev

Blog:

cd blog
npm install
npm run dev   # available at http://localhost:3000/blog

| Service | URL | |---------|-----| | App | http://localhost:5173 | | Backend API | http://localhost:8000 | | API Docs (Swagger) | http://localhost:8000/docs | | MCP endpoint | http://localhost:8000/mcp/ |

⚙️ AI Configuration

flompt supports multiple AI providers. Copy backend/.env.example to backend/.env:

# Anthropic (recommended)
ANTHROPIC_API_KEY=sk-ant-...
AI_PROVIDER=anthropic
AI_MODEL=claude-3-5-haiku-20241022

# or OpenAI
OPENAI_API_KEY=sk-...
AI_PROVIDER=openai
AI_MODEL=gpt-4o-mini

Without an API key, flompt uses a keyword-based heuristic decomposer and still compiles structured XML.

🚢 Production Deployment

This section documents the exact production setup running at flompt.dev. Everything lives in /projects/flompt.

Architectur