Claude shows unauthenticated in T3 on Windows, but `claude auth status` returns loggedIn=true with Vertex

[McNerve]

Summary

T3 Code shows Claude as unauthenticated on Windows, but the local Claude CLI is authenticated and working.

This appears to be a T3-side auth/status bug or stale provider-state issue, not a Claude login failure.

Environment

• T3 Code: v0.0.17
• OS: Windows
• Claude binary path configured in T3: C:\Users\<redacted>\.local\bin\claude.exe

Claude auth status

Running this outside T3:

claude auth status

returns:

{
  "loggedIn": true,
  "authMethod": "third_party",
  "apiProvider": "vertex"
}

What I expected

T3 should recognize Claude as authenticated and allow it to be used.

What happened

T3 still shows Claude as unauthenticated / not logged in.

Additional debugging

A few things suggest this is not a real Claude auth failure:

• claude auth status returns loggedIn: true
• claude --version works
• The Claude Agent SDK can initialize successfully against the same Claude binary and detects apiProvider: "vertex"

Possible cause

This may be a bug in how T3 handles or displays Claude auth state for third_party / vertex auth, or possibly stale local app state.

Related issue: #1807

Repro

1. Configure Claude on Windows using Vertex / third-party auth
2. Verify claude auth status shows:
   • loggedIn: true
   • authMethod: "third_party"
   • apiProvider: "vertex"
3. Open T3 Code
4. Configure Claude binary path to the working Windows binary
5. T3 still reports Claude as unauthenticated

Notes

This does not seem to be a PATH problem.

[tysonwilley]

Experiencing the same behavior on Mac when authenticated through Azure Foundry.

{
  "loggedIn": true,
  "authMethod": "third_party",
  "apiProvider": "foundry"
}

[pahan35]

I have a similar issue on Mac while using apiKey

{
  "loggedIn": true,
  "authMethod": "api_key",
  "apiProvider": "firstParty",
  "apiKeySource": "ANTHROPIC_API_KEY"
}

What's interesting, if I launch t3code server from the repo and add log what's resolved at as

t3code/apps/server/src/provider/Layers/ClaudeProvider.ts

Lines 606 to 607 in ed8e758

	const parsed = parseClaudeAuthStatusFromOutput(authProbe.success.value);
	const authMetadata = claudeAuthMetadata({ subscriptionType, authMethod });

parsed resolves to

{ status: "ready", auth: { status: "authenticated" } }

while from the actual server it looks like it goes with

{
  status: "error",
  auth: { status: "unauthenticated" },
  message: "Claude is not authenticated. Run `claude auth login` and try again.",
}

The issue is reproducible on both v0.0.17 and 0.0.18-nightly.20260416.46

Any idea what might be wrong when actual t3code server app tries to check auth?

[juliusmarminge]

Should hopefully be fixed by #1729 which will be included in the next release