[BUG] Claude Code WSL2 Environment API Timeout Issue Report

Claude Code WSL2 Environment API Timeout Issue Report

🖥️ Platform Information

Operating System:

• Windows + WSL2 Environment
• WSL Distribution: Ubuntu
• User Path: /mnt/c/Users/Administrator
• Environment: conda (base) environment

Claude Code Version:

• Version: v1.0.60
• Installation: Claude Max Subscription

Network Environment:

• WSL IP: 172.26.91.225/20
• Gateway: 172.26.80.1
• DNS: 172.26.80.1 (WSL auto-generated)
• Basic network connectivity: Normal (ping, curl tests pass)

🚨 Primary Issues

1. Persistent API Timeout Errors

API Error (Request timed out.) · Retrying in X seconds… (attempt Y/10)

Frequency: Frequent, especially when using tool functions

Impact Scope:

• ✅ Basic conversations: Occasionally works (11 seconds completion)
• ❌ Web search tools: Almost always timeout
• ❌ Complex tool invocations: Frequently fail
• ❌ Recently even basic conversations started timing out

📊 Detailed Error Logs

Typical Error Sequence

> Please search for TSLA stock price today
  ⎿  API Error (Request timed out.) · Retrying in 1 seconds… (attempt 1/10)
  ⎿  API Error (Request timed out.) · Retrying in 1 seconds… (attempt 2/10)
  ⎿  API Error (Request timed out.) · Retrying in 2 seconds… (attempt 3/10)
  ⎿  API Error (Request timed out.) · Retrying in 4 seconds… (attempt 4/10)
  Web Search("TSLA stock price today July 26 2025")
* Conjuring… (70s · ⚒ 12 tokens · esc to interrupt)

Network Diagnostics (Proving Basic Network is Normal)

# IPv4 connectivity normal
PING 8.8.8.8: 3-4ms latency, 0% packet loss

# Direct Anthropic API connection normal
curl https://api.anthropic.com
time_total: 0.235583s
time_connect: 0.005079s
time_namelookup: 0.001225s

Tool Invocation Comparison Test

# Local tool invocation: Normal
claude "search for test" → Successfully found local files (11.25s)

# Web search tool: Immediate timeout
claude "use web search to query test" → Immediate API timeout

🔍 Attempted Solutions

1. Network Configuration Optimization

# DNS configuration
echo "nameserver 8.8.8.8" | sudo tee /etc/resolv.conf

# TCP optimization
sudo sysctl -w net.ipv4.tcp_window_scaling=1

Result: No improvement

2. Claude Code Configuration Adjustments

claude config set http.timeout 180000
claude config set api.timeout 180000

Result: No improvement

3. Using --no-mcp Parameter

claude --no-mcp "test"

Result: Partial improvement, but web search still timeouts

4. WSL Network Reset

# Windows PowerShell (Admin)
wsl --shutdown
netsh winsock reset
netsh int ip reset

Result: No improvement

🎯 Key Findings

1. Network Layer Normal: Basic ping, curl, DNS resolution all working properly
2. Local Tools Normal: grep, ls, find and other local tools work perfectly
3. Web Tool Specific Issue: Only web search tools experience timeout
4. WSL2 Specific Problem: Strong suspicion of WSL2 NAT network incompatibility with Claude Code's web search mechanism

📝 Reproduction Steps

1. Install Claude Code v1.0.60 on Windows + WSL2 environment
2. Run claude to enter interactive mode
3. Execute any command requiring web search functionality
4. Observe "API Error (Request timed out.)" errors

🆘 Suggested Investigation Areas

1. WSL2 Network Compatibility: Claude Code's web search tool behavior in WSL2 NAT environment
2. Error Retry Logic: Why retry mechanisms don't work effectively in WSL environments
3. Network Tool Architecture: How web search tools handle network requests differently from basic API calls

💡 Requested Solutions

1. WSL2 Environment Support: Official guidance for WSL2-specific network configurations
2. Best Practices Documentation: Recommended setup for WSL2 environments
3. Improved Fault Tolerance: Better error handling for web tools in WSL environments
4. Environment Detection: Automatic optimization based on detected environment (WSL2 vs native)

🔬 Technical Analysis

Working Components:

• Basic Claude API communication
• Local file system tools (grep, ls, find, cat)
• Local directory operations
• Basic conversational responses

Failing Components:

• Web search functionality
• External API tool invocations
• Long-running tool operations

Timing Analysis:

• Local tools: 5-15 seconds (normal)
• Web search attempts: Immediate timeout → retry loop → eventual failure

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Report Date: July 26, 2025
Issue Severity: High - Significantly impacts WSL user experience with Claude Code