Claude Code CLI (OAuth/Claude Pro) requests timeout with 502 (no body) — but API-key requests forward correctly

[PaikyHiean]

Environment

• OS: Windows 11 (10.0.26200)
• headroom-ai: 0.26.0 (reinstalled with uv tool install headroom-ai[all] using uv-managed CPython 3.12.13)
• Claude Code CLI: v2.1.178
• Auth method: Claude Pro subscription (OAuth token, not API key)

What I did

Ran headroom wrap claude from a project directory that has no .claude/settings.json.
Headroom successfully recovered/started the proxy on port 8787 (/readyz → 200, /health → 200).
Sent a message in the Claude Code CLI session.

What happened

After ~3 minutes of waiting, the CLI returned:
502 status code (no body). This is a server-side issue, usually temporary —
try again in a moment. If it persists, check your inference gateway (127.0.0.1:8787).

This happens consistently on every attempt (retried 10/10 times, both attempts failed after 3m 10s and 3m 14s respectively).

What I verified

To rule out a broken proxy, I sent a direct test request to the proxy:

$body = '{"model":"claude-haiku-4-5-20251001","max_tokens":10,"messages":[{"role":"user","content":"hi"}]}'
Invoke-WebRequest -Uri "http://127.0.0.1:8787/v1/messages" -Method POST `
  -Body $body -ContentType "application/json" -Headers @{"x-api-key"="dummy"}

This returned a proper 401 authentication_error: invalid x-api-key from Anthropic immediately — confirming the proxy can forward requests to api.anthropic.com.

The stats endpoint also confirmed the test request was tracked: api_requests: 1, providers: anthropic.

Key observation

No POST requests appear in proxy.log during Claude Code CLI usage, even during the 3-minute timeout window. The log only shows /health and /stats polling from the dashboard browser. This contrasts with the API-key test request, which did produce a log entry.

Question / possible bug

Is this a known limitation on Windows where Claude Code CLI's OAuth-based (Claude Pro) streaming SSE requests are not handled correctly by the proxy? The combination of:

OAuth token auth (not x-api-key)
Streaming SSE response
Windows platform
...seems to be the difference between the working test case and the failing CLI case. Any guidance appreciated.