[Bug]: Cursor shows "SDK catalog request failed" when the account plan is rejected (403 plan_required) #15075

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1. 0xKa

   added

   bugSomething is broken or behaving incorrectly.Something is broken or behaving incorrectly.

   needs-triageIssue needs maintainer review and initial categorization.Issue needs maintainer review and initial categorization.

   on Oct 3, 2026
2. juliusmarminge commented on Oct 15, 2026

   

   juliusmarminge

   on Oct 15, 2026

   Member

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   Grok responding on behalf of Julius.

   Carrying over from #19766: the same 403 plan_required also breaks browser sign-in. After login, the verification probe returns auth: unknown (only 401 counts as an auth failure in CursorSdkCatalog), so runLogin in packages/provider-cursor/src/server/auth.ts deletes the new credential and shows the generic "Cursor sign-in failed or expired" instead of the plan error, then the next check reports "Not authenticated". A fix here should surface the plan_required reason both in provider status and in the sign-in failure message. #16224 (Enterprise /v1/me 403) goes through the same path.
3. pancake37 commented on Oct 17, 2026

   

   pancake37

   on Oct 17, 2026

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   Gemini responding on behalf of pancake37.

   Confirmed the same behavior and found a working workaround for free-tier users who want to use Cursor in T3 Code without staying on outdated nightly versions.

   Root Cause Confirmation

   When signing in with a free/hobby Cursor account, @cursor/sdk creates an API key, but Cursor's remote backend rejects Cursor.me / GET /v1/me with:

   {
     "name": "UnknownAgentError",
     "message": "[plan_required] Cloud Agent is not available for free users. Please upgrade to Pro.",
     "code": "plan_required",
     "status": 403
   }

   Because isAuthenticationFailure in packages/provider-cursor/src/server/CursorSdkCatalog.ts only checks for 401 (cause.status === 401), 403 is treated as an unexpected failure. runLogin then immediately executes options.store.clear() and reports "Cursor sign-in failed or expired".

   Working Workaround for Free Accounts: Use Cursor via ACP

   If you have cursor-agent CLI installed locally (~/.local/bin/cursor-agent), it officially supports ACP (cursor-agent acp) and runs against your existing local Cursor session token (no Pro / Cloud Agent subscription required).

   You can register it directly in T3 Code as an ACP provider instance in settings.json:

   "acpRegistry_cursor": {
     "driver": "acpRegistry",
     "displayName": "Cursor Agent (ACP)",
     "enabled": true,
     "config": {
       "agentId": "cursor",
       "commandPath": "/path/to/cursor-agent",
       "distribution": "auto",
       "registryIconUrl": "https://cdn.agentclientprotocol.com/registry/v1/latest/cursor.svg",
       "customModels": []
     }
   }

   This connects to cursor-agent acp via cursor_login auth, discovers all 47 models (Auto, Composer 2.5, Claude Opus 5, Sonnet 5, etc.), and executes prompts cleanly under standard account limits.
4. juliusmarminge

   closed this as completedin #19771on Oct 20, 2026