Claude Code Integration

​

Overview

• Cost tracking - See exactly how much each coding session costs
• Performance monitoring - Track latency and token usage
• Session replay - Review conversations and decisions Claude made
• Error detection - Catch and debug Claude Code issues

​

Quick Start

export ANTHROPIC_BASE_URL=https://anthropic.fallom.com/YOUR_FALLOM_API_KEY

​

Setup

​

1. Get your Fallom API Key

​

2. Set the base URL

# Route Claude Code through Fallom for observability
export ANTHROPIC_BASE_URL=https://anthropic.fallom.com/flm_YOUR_KEY_HERE

​

3. Reload your shell

source ~/.zshrc  # or ~/.bashrc

​

4. Use Claude Code normally

claude "help me refactor this function"

​

How it works

┌──────────────┐
│ Claude Code  │
│  (your CLI)  │
└──────┬───────┘
       │
       │ Your Anthropic API key + Fallom tracking
       │
       ▼
┌──────────────────┐
│  Fallom Proxy    │  ← Logs traces
│  (transparent)   │
└──────┬───────────┘
       │
       │ Forwards to Anthropic
       │
       ▼
┌──────────────────┐
│  Anthropic API   │
└──────────────────┘

1. Receives your Claude Code request
2. Logs the trace to Fallom (async, non-blocking)
3. Forwards to Anthropic API unchanged
4. Streams the response back to you in real-time
5. Logs the final trace with usage data

​

What you’ll see in Fallom

​

Advanced Configuration

​

Custom metadata

# Add Linear issue tracking
export X_FALLOM_LINEAR_ISSUE="LIN-123"

# Add git branch
export X_FALLOM_BRANCH=$(git branch --show-current)

# Add custom customer ID
export X_FALLOM_CUSTOMER_ID="customer-abc"

​

Different environments

# ~/.zshrc or ~/.bashrc

# Development
alias claude-dev='ANTHROPIC_BASE_URL=https://anthropic.fallom.com/flm_dev_key claude'

# Production
alias claude-prod='ANTHROPIC_BASE_URL=https://anthropic.fallom.com/flm_prod_key claude'

# No tracking
alias claude-direct='unset ANTHROPIC_BASE_URL && claude'

​

Disable temporarily

ANTHROPIC_BASE_URL= claude "your prompt"

unset ANTHROPIC_BASE_URL

​

Pricing

• Your Claude Code API usage (to Anthropic)
• Your Fallom plan (for trace storage and analytics)

​

Troubleshooting

​

Claude Code not sending traces

1. Check the environment variable is set:
   echo $ANTHROPIC_BASE_URL
   # Should show: https://anthropic.fallom.com/flm_...
   
2. Verify your Fallom API key:
   • Go to app.fallom.com/settings/api-keys
   • Check that your key is active
3. Check Railway logs:
   • The proxy logs all requests
   • Look for errors in the Railway dashboard

​

Requests failing

1. Remove the base URL temporarily:
   unset ANTHROPIC_BASE_URL
   claude "test"
   
   If this works, the issue is with the proxy.
2. Check your Anthropic API key:
   echo $ANTHROPIC_API_KEY
   # Should be set
   
3. Contact support:
   • Share the error message
   • Include your Fallom API key (first 8 characters only)

​

Traces not appearing in dashboard

1. Check the correct organization:
   • Ensure you’re viewing the right org in Fallom
2. Verify API key permissions:
   • API key might not have trace write permissions
3. Check filters:
   • Clear any filters in the traces view

​

Security

• API keys never logged - Your Anthropic API key is never stored
• TLS encryption - All traffic uses HTTPS
• No data retention - Proxy doesn’t store any request/response data
• Open source - Proxy code is auditable

​

Examples

​

Track costs per project

# Set project in metadata
export X_FALLOM_PROJECT="mobile-app"
claude "help me optimize this React Native component"

# Check costs in Fallom filtered by metadata.project = "mobile-app"

​

Debug a specific session

# Use custom session ID
export X_FALLOM_SESSION_ID="debug-auth-issue"
claude "why is authentication failing?"

# Find traces by session_id in Fallom

​

Monitor token usage

• usage.input_tokens - Tokens in your prompt + context
• usage.output_tokens - Tokens in Claude’s response
• usage.cache_read_input_tokens - Tokens loaded from cache
• usage.cache_creation_input_tokens - New tokens cached

​

Related