Coding Agent Explorer

A real-time .NET proxy and dashboard for inspecting Claude Code API calls. Intercept, visualize, and analyze every request and response between Claude Code and the Anthropic API.

Built as a teaching tool for Tore Nestenius' AI agent Workshops and presentations, helping developers understand what happens under the hood when AI coding agents work.

Note: Currently supports Claude Code with the Anthropic API. Support for additional coding agents may be added in the future.

The agentic conversation view allows you to explore the conversation with the LLM models.

The HTTP Inspector view lets you examine every API request and response in detail, including headers, bodies, and streaming SSE events.

What It Does

Coding Agent Explorer sits between your coding agent and the LLM API, capturing all traffic and displaying it in a real-time web dashboard. You can see:

• Every API request and response in real time
• Streaming SSE events as they arrive
• Token usage (input, output, cache creation, cache reads)
• Model selection, timing, and time-to-first-token
• Full request/response headers and bodies
• A conversation view that renders the agent's messages in a chat-style format

Prerequisites

• .NET 10 SDK or later

Getting Started

1. Build and run the proxy

dotnet build
dotnet run

This starts three endpoints:

• Port 8888 - The reverse proxy (HTTP, point your coding agent here)
• Port 5000 - The web dashboard (HTTP)
• Port 5001 - The web dashboard (HTTPS, auto-launches in browser)

2. Configure your coding agent

For Claude Code, set the API base URL to point at the proxy:

# Linux / macOS
export ANTHROPIC_BASE_URL=http://localhost:8888

# Windows (cmd)
set ANTHROPIC_BASE_URL=http://localhost:8888

# Windows (PowerShell)
$env:ANTHROPIC_BASE_URL = "http://localhost:8888"

On Windows, you can also run EnableProxy.bat from the repo root to quickly set the variable. Run DisableProxy.bat to clear it. Both scripts only affect the current cmd session -- the variable is not persisted, so closing the terminal automatically clears it.

Then use Claude Code as you normally would.

3. Open the dashboard

Navigate to https://localhost:5001 in your browser (opens automatically on dotnet run). You'll see two views:

• HTTP Inspector - Table view of all proxied requests with headers, bodies, SSE events, and timing details
• Conversation View - Chat-style display showing messages, tool use, and responses

Architecture

  Coding Agent  ──►  CodingAgentExplorer (port 8888)  ──►  LLM API
                            │
                            ▼
                     Web Dashboard (port 5000/5001)
                     Real-time via SignalR

• ASP.NET Core with YARP reverse proxy
• SignalR for real-time dashboard updates
• Vanilla HTML/JS/CSS frontend (no build step required)
• Single NuGet dependency (Yarp.ReverseProxy)

Project Structure

├── Program.cs                          # App setup: YARP, SignalR, dual-port Kestrel
├── Models/                             # DTOs: ProxiedRequest, ClaudeRequestBody, SseEvent
├── Services/RequestStore.cs            # In-memory circular buffer (max 1000 requests)
├── Proxy/CaptureTransformProvider.cs   # YARP ITransformProvider for request/response capture
├── Hubs/DashboardHub.cs                # SignalR hub for real-time dashboard updates
└── wwwroot/                            # Dashboard SPA (vanilla HTML/JS/CSS)
    ├── index.html                      # Landing page with view selection
    ├── inspector/                      # HTTP Inspector view
    ├── conversation/                   # Conversation view
    ├── css/                            # Stylesheets
    └── js/                             # Dashboard and conversation scripts

Security

• API keys (x-api-key and Authorization headers) are automatically redacted from stored request data
• The proxy only listens on localhost - it is not exposed to the network
• Request data is stored in memory only (max 1000 requests, no persistence)

About the author

This tool was developed by Tore Nestenius, a seasoned .NET instructor and consultant with over 25 years of experience in software development and architecture. With extensive expertise in .NET, Azure, and cloud computing, Tore is passionate about helping developers and organizations build robust software solutions and optimize their development processes. A frequent speaker at conferences and user groups, Tore actively shares his knowledge and insights with the community, fostering learning and growth for developers worldwide.

• Stack Overflow
• LinkedIn
• Blog
• Company

Other Projects by the Author

• CloudDebugger - A .NET web application designed to explore and learn about various Azure services and features, including authentication, configuration, networking, and more.

Want to learn more about AI agents?

Join one of Tore's workshops for programmers at tn-data.se/courses to deepen your understanding of AI coding agents, .NET development, and cloud architecture.

License

This project is licensed under the MIT License.