[BUG] Claude Code Web: persistent 404 on session_ingress/.../git_proxy/compare — every session fails to initialize

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?

Claude Code Web has been completely non-functional for approximately one month. Every new session fails during initialization with the generic error: "An error occurred while executing Claude Code. You can try again by sending a new message or starting a new session."
A Chromium netlog capture confirms the root cause: after the session is created successfully (POST /v1/sessions → 200), the client immediately calls POST /v1/session_ingress/session/{session_id}/git_proxy/compare, which returns HTTP 404 with x-should-retry: false. This kills the session.
The 404 response includes x-envoy-upstream-service-time: 282, confirming the request reaches Envoy and is routed upstream — but the session's git proxy is not available.
This reproduces 100% of the time, across all platforms (Windows Desktop, macOS, iOS, browser), confirming it is server-side.

What Should Happen?

After the session is created, the git_proxy/compare endpoint should return 200 and the session should initialize successfully, allowing interaction with the cloned repository.

Error Messages/Logs

Netlog: request timeline (30-second capture, Feb 23 2026 10:03 UTC)
✅ POST 200  /api/org/{id}/dust/generate_title_and_branch
✅ POST 200  /api/org/{id}/code/repos/resync
✅ POST 200  /v1/sessions                                          ← session created OK
✅ GET  200  /claude-code-desktop/session_014ECh3TCLSM4xmezt63sZdQ  ← page loads OK
✅ GET  200  /v1/sessions/session_014ECh3TCLSM4xmezt63sZdQ/share-status
✅ POST 200  /api/github/org/{id}/github_batch_branch_status

❌ POST 404  /v1/session_ingress/session/session_014ECh3TCLSM4xmezt63sZdQ/git_proxy/compare
             x-should-retry: false
             request-id: req_011CYQovms1DSSn8pdazDYHv
             x-envoy-upstream-service-time: 282

✅ POST 200  /sentry (two error reports fired immediately after the 404)
✅ GET  101  wss://.../subscribe  ← WebSocket connects, client sends close after 404
Failing request details
POST /v1/session_ingress/session/session_014ECh3TCLSM4xmezt63sZdQ/git_proxy/compare

Request:
  content-type: application/json
  content-length: 93
  anthropic-client-app: com.anthropic.claudefordesktop
  anthropic-client-platform: desktop_app
  anthropic-client-version: 1.1.4010
  x-organization-uuid: [REDACTED-ORG-UUID]

Response:
  HTTP/1.1 404
  x-should-retry: false
  request-id: req_011CYQovms1DSSn8pdazDYHv
  x-envoy-upstream-service-time: 282
  cf-ray: 9d25e46aaf4dfd73-SIN
  server: cloudflare
Sentry trace
sentry-trace: 664d265673194f63bfcf8387ccc2eb8d-a56db1df311229cd
sentry-environment: production
sentry-release: 7bd2e2f0b5bc3ef0bc4a0566fe9ce9809609571c
request-id: req_011CYQovms1DSSn8pdazDYHv
cf-ray: 9d25e46aaf4dfd73-SIN
Additional: UUID validation errors (103 occurrences in claude.ai-web.log)
[REACT_QUERY_CLIENT] QueryClient error: Error: path.conversation_uuid: Input should be a valid UUID,
invalid character: expected an optional prefix of `urn:uuid:` followed by [0-9a-fA-F-], found `l` at 1
Local Code tab session IDs (format local_{uuid}) are being passed to an API endpoint expecting standard conversation UUIDs.

Steps to Reproduce

Steps to Reproduce

Open the Code tab in Claude Desktop for Windows (v1.1.4010), or Claude Desktop for MacOS, or claude.ai in a browser, or the iOS app
Select any environment and any GitHub repository
Wait for initialization — it will show progress labels like "Ideating", "Perusing", "Meandering"
Session fails with: "An error occurred while executing Claude Code. You can try again by sending a new message or starting a new session."
Retrying or starting a new session produces the same result

This is 100% reproducible. Every attempt over the past month has failed, across all platforms.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Approximately late January 2026. The exact version is unknown as the issue is server-side (the git_proxy/compare endpoint), not client-side.

Claude Code Version

This is Claude Code Web (cloud-hosted), not the CLI. Accessed via: Claude Desktop for Windows v1.1.4010 (also reproduced on v1.1.3963, v1.1.3189) claude.ai in browser Claude iOS app

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

Relationship to #22277
This is the same bug as #22277 (filed Feb 1, 2026, still OPEN, labels: bug, area:claude-code-web, area:api). That issue documents the same git_proxy/compare 404 pattern and "Repository or branches not found" errors. The netlog captured here provides the definitive HTTP-level evidence for the root cause.
Also related: #17888 (Jan 13), #18452 (Jan 16, closed as dup), #24215 (Feb 8, Opus stuck on web).
Account details
Account identifiers (org UUID, account UUID, device ID) available on request or via support ticket — not included here as this is a public issue.
What works

Regular Chat tab: fully functional on all platforms
Session creation (POST /v1/sessions): succeeds (200)
All other API calls in the netlog: succeed (200)
Only the git_proxy/compare call fails (404)

Interpretation
The session container is either not being provisioned in time for the git_proxy/compare call, or the git proxy endpoint is not correctly initialized for the session. The 282ms upstream service time suggests the request is being processed (not just rejected at the edge), but the upstream service cannot find the session's git proxy.