[BUG] VS Code extension fails to send API requests - messages never reach Claude API (Mac)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The Claude Code VS Code extension panel receives user messages and displays them in the UI, but completely fails to send any requests to api.anthropic.com. No responses are ever received, leaving conversations empty and unusable.

What Should Happen?

The VS Code extension should:

1. Receive user messages in the panel
2. Send HTTP requests to api.anthropic.com/v1/messages
3. Display Claude's responses in real-time
4. Save conversation history
5. Allow continued interaction with Claude

Error Messages/Logs

No error messages appear in:
- VS Code Developer Tools Console (only deprecation warnings)
- Extension Output panel
- Terminal output

The issue is SILENT - no errors, no logs. The extension simply fails to make API calls.

Evidence from Network Tab (VS Code Developer Tools):
- Filter: api.anthropic.com
- Result: 0 of 0 requests
- No HTTP calls are made to Claude's API when sending messages

Steps to Reproduce

1. Install Claude Code VS Code extension (v2.1.3) on macOS
2. Open VS Code (v1.106.3)
3. Open Claude Code panel (Cmd+Shift+P → "Claude Code: Open in New Tab")
4. Type any message (e.g., "hello")
5. Press Send

Expected: Message sent to API, Claude responds
Actual: Message appears in UI but never sent to API (Network tab shows 0 requests)

To verify the bug:

1. Open VS Code Developer Tools (Help → Toggle Developer Tools)
2. Click Network tab
3. Filter for: api.anthropic.com
4. Send a message in Claude panel
5. Observe: 0 of 0 requests shown (NO API calls made)

Contrast with working terminal mode:

1. Open terminal in VS Code (Cmd+`)
2. Run: claude
3. Type: hello
4. Observe: Immediate response (API calls work in terminal)

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.3

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Comprehensive Diagnostic Evidence

1. SMOKING GUN: Network Tab Shows ZERO API Requests

Using VS Code Developer Tools (Help → Toggle Developer Tools):

• Opened Network tab
• Filtered for: api.anthropic.com
• Sent multiple messages in Claude panel
• Result: 0 of 0 requests - NO HTTP calls made to Claude's API
• Screenshot available if needed

2. Network Connectivity Confirmed Working

curl -I https://api.anthropic.com
# Returns: HTTP/2 404, server: cloudflare

✅ System can reach Claude's API
✅ No firewall/proxy blocking
✅ Cloudflare responds normally

3. Terminal Mode Works Perfectly

claude --version  # 2.1.3
claude            # Opens terminal mode
# Messages receive immediate responses

✅ Same Claude Code binary
✅ Same authentication
✅ Same system, same network
✅ API calls succeed in terminal
❌ Only VS Code extension panel fails

4. Usage Limits NOT the Issue

Checked via terminal /usage command:

• Current session: Low usage, plenty available
• Weekly limits: Low usage

✅ Usage limits are not the problem

5. Extensive Troubleshooting Completed

All failed to fix the issue:

• Restarted Extension Host
• Completely uninstalled and reinstalled extension
• Updated from 2.0.64 → 2.1.3
• Disabled ALL other extensions (ruled out conflicts)
• Restarted VS Code multiple times
• Ran /compact command
• Waited for session reset
• Closed and reopened panels

6. Console Shows No Errors

VS Code Developer Tools Console:

• Only deprecation warnings (punycode module)
• No API errors
• No authentication errors
• No blocking errors

The failure is SILENT

7. Comparison: What Works vs. Doesn't

✅ Works:

• Terminal mode (instant responses)
• Network connectivity to api.anthropic.com
• Authentication (proven by terminal)
• Usage limits (plenty available)

❌ Doesn't Work:

• VS Code extension panel (zero API calls)
• No requests to api.anthropic.com
• Messages displayed but never sent
• No responses ever received

Root Cause Analysis

The bug is isolated to the VS Code extension's API communication layer. The extension:

• ✅ Loads and initializes successfully
• ✅ Displays UI correctly
• ✅ Receives user input
• ✅ Shows messages in local UI
• ❌ Fails to make ANY HTTP requests to Claude's API
• ❌ Never calls api.anthropic.com
• ❌ Therefore receives no responses

This is a critical showstopper bug that makes the VS Code extension completely unusable while terminal mode works perfectly.

System Details

• macOS
• VS Code 1.106.3 (Universal)
• Claude Code 2.1.3
• Paid subscription
• No proxy/VPN
• Direct internet connection

Impact

Extension is completely non-functional for visual workflows requiring:

• Screenshot/image sharing for UI design feedback
• Graphical diff reviews
• Easy file referencing

Terminal mode works but lacks:

• Easy image support
• Visual UI
• Safe undo/redo

Request for Priority

This bug is:

1. 100% reproducible on this system
2. Comprehensively diagnosed with definitive evidence
3. Isolated to extension panel (terminal proves everything else works)
4. Blocking productive development work

The Network tab evidence (0 API requests) is definitive proof of the failure point.

Thank you for investigating this critical issue!