Remote Control bridge registration returning 502 — server mode unusable

Summary

claude remote-control (server mode) has been unable to register with the bridge API since ~15:44 UTC on April 15, 2026. The POST /v1/environments/bridge endpoint consistently returns 502 Bad Gateway. Regular Claude Code sessions (including those with /remote-control or --rc) work fine — only the server-mode bridge registration is affected.

Environment

• Claude Code version: 2.1.109 (latest)
• OS: Ubuntu Linux (headless server)
• Auth: claude.ai OAuth, Max subscription (confirmed with claude auth status)
• Setup: systemd service running claude remote-control --name "Home Server" --spawn same-dir --permission-mode dontAsk --verbose
• This setup has been working reliably for weeks prior to this incident.

Reproduction

# Direct curl test confirms the endpoint is down:
curl -s -w "\nHTTP_CODE: %{http_code}\n" \
  -X POST https://api.anthropic.com/v1/environments/bridge \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -H "anthropic-beta: environments-2025-11-01" \
  -H "anthropic-version: 2023-06-01" \
  -d '{"machine_name":"test","directory":"/root","branch":"HEAD","max_sessions":32}'
# Returns: 502 Bad Gateway

Meanwhile, the sessions API works fine:

curl -s -X GET https://api.anthropic.com/v1/sessions \
  -H "Authorization: Bearer $TOKEN" \
  -H "anthropic-beta: managed-agents-2026-04-01" \
  -H "anthropic-version: 2023-06-01"
# Returns: 200 OK

Timeline (all times EEST = UTC+3)

1. 15:44 — Running bridge process (PID from previous day) had all 12 active sessions fail simultaneously with timeouts
2. 16:01 — Auto-update installed v2.1.109, service restarted
3. 16:01–16:35 — Service registered but immediately entered reconnection loop (poll timeouts + 503s)
4. 16:35 onwards — Service crashes on startup, unable to register bridge. Restart loop (100+ attempts)
5. 21:15 — Still failing. Confirmed with direct curl: POST /v1/environments/bridge → 502

Debug log output

[bridge:init] apiBaseUrl=https://api.anthropic.com sessionIngressUrl=https://api.anthropic.com
[bridge:api] POST /v1/environments/bridge bridgeId=...
Error: Request failed with status code 502

Alternates between 500, 502, 503, and timeout of 15000ms exceeded.

Impact

Remote Control server mode is the only way to run Claude Code headlessly and spawn sessions from the browser/mobile without an active terminal. This is a key workflow for headless server deployments. The status page (status.claude.com) shows "All Systems Operational" despite this endpoint being down for 5+ hours.

What's NOT the issue

• ✅ Auth is valid (OAuth, Max subscription, correct scopes)
• ✅ No ANTHROPIC_API_KEY set
• ✅ No conflicting env vars (DISABLE_TELEMETRY, CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC, etc.)
• ✅ Network is fine (other API endpoints respond normally)
• ✅ Version is latest (2.1.109)
• ✅ Config matches documentation exactly