🔁 Loop Demos

Reference demos for capturing and observing LLM traffic with Loop.

This repository illustrates different traffic capture approaches across multiple programming languages and runtimes. The demos are designed to be minimal, readable, and easy to adapt.

Who is this for?

• Developers evaluating Loop
• Experimentation and learning
• Copy–paste starting points for real projects

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🧐 What is Loop?

Loop is an observability and evaluation platform for LLM-powered applications.

Capability	Description
📡 Capture	Intercept and record LLM traffic
🔍 Understand	Analyze prompts and responses
✅ Evaluate	Measure quality and correctness
🔄 Iterate	Improve AI behavior over time

Note: This repository focuses on traffic capture — the first step in the Loop workflow.

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🎯 Demo Approaches

Proxy-based capture

Benefit	Description
🔌 Non-invasive	Intercept traffic without modifying application code
🚫 No code changes	Useful when source modifications are not possible
🏢 Centralized	Single capture point for multiple applications

OpenTelemetry-based capture

Benefit	Description
📊 Rich context	Structured traces with full context
🛠️ SDK integration	Native instrumentation via OpenTelemetry
🎛️ Full control	Best when you own the application code

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📁 Repository Structure

Path	Description
demos/dotnet/proxy/	.NET proxy demo
demos/node/proxy/	Node.js proxy demo
demos/python/proxy/	Python proxy demo

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⚙️ Demos included

Proxy demos (working)

• .NET: demos/dotnet/proxy
• Node.js: demos/node/proxy
• Python: demos/python/proxy

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🚀 Quick start

1. Start Loop (Desktop + Server) and ensure the Loop Proxy endpoint is available.

2. Pick a demo and follow its README:

• demos/dotnet/proxy/README.md
• demos/node/proxy/README.md
• demos/python/proxy/README.md

3. Run the demo and verify:

• you see the response in the terminal
• you see the request/response captured in Loop

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🛠️ Configuration (common)

Most demos use environment variables:

• OPENAI_API_KEY
  API key for the target LLM provider

• LOOP_PROXY_BASE_URL
  Base URL of the Loop Proxy
  Default used by demos: http://localhost:31300/openai

• OPENAI_MODEL
  Model name
  Default used by demos: gpt-4o

Notes:

• Never commit API keys or .env files to Git.
• If you get 401 Unauthorized, verify the API key and proxy configuration.

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📦 Demos Included

Language	Proxy	OpenTelemetry
.NET	✅ demos/dotnet/proxy	🚧 Planned
Node.js	✅ demos/node/proxy	🚧 Planned
Python	✅ demos/python/proxy	🚧 Planned

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🚀 Quick Start

1. Start Loop
   Launch Loop (Desktop + Server) and ensure the Loop Proxy endpoint is available.

2. Pick a demo and follow its README:

   • .NET Proxy Demo
   • Node.js Proxy Demo
   • Python Proxy Demo

3. Verify capture:

   • ✅ Response appears in the terminal
   • ✅ Request/response is captured in Loop

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⚙️ Configuration

All demos use these environment variables:

Variable	Description	Default
OPENAI_API_KEY	API key for the LLM provider	required
LOOP_PROXY_BASE_URL	Base URL of the Loop Proxy	http://localhost:31300/openai
OPENAI_MODEL	Model name to use	gpt-4o

⚠️ Security: Never commit API keys or .env files to Git.

Troubleshooting:

• 401 Unauthorized → Verify your API key and proxy configuration