jwt-403-debug-expert

name: jwt_403_debug_expert description: Diagnose 401/403 responses at the AI Citadel APIM gateway — decode JWT claims, verify Access Contract scope grants, and validate Foundry managed-identity token audience.

jwt_403_debug_expert

When to use

The SRE Agent should invoke this skill when:

• A user reports a 401 or 403 from the Citadel gateway
• A hosted agent's BYOK call returns "Authentication failed with provider … (HTTP 401)" but the underlying provider is the Citadel-routed AOAI
• After running citadel-spoke-onboarding, the new spoke can't reach the gateway

Investigation flow

1. Get the correlation ID of the failing request from the user or from the application's logs.

2. Pull the request from APIM diagnostics:

   ApiManagementGatewayLogs
   | where TimeGenerated > ago(2h)
   | where CorrelationId == "<id>"
   | project TimeGenerated, OperationId, ApiId, ProductId, ResponseCode, BackendStatusReason, LastErrorReason, RequestHeaders, ResponseHeaders
   

3. Decode the JWT if present (claims only — NEVER the signature):

   • aud — must match the gateway URL configured in the Access Contract
   • iss — must be https://login.microsoftonline.com/<tenant>/v2.0
   • oid — the calling principal's object ID
   • scp / roles — must include the operation scope (e.g. llm:read)
   • exp — must not be in the past

4. Match against the Access Contract:

   Symptom	Root cause	Fix
   aud mismatch	Token issued for wrong audience	Re-issue token with correct audience
   Missing scope claim	Access Contract didn't grant this scope	Re-run citadel-spoke-onboarding with the needed scope in gbb_access_contracts
   exp in past	Token expired (default ~1h for MI)	Refresh; check caller's token-cache TTL
   No Authorization header	Caller using product-key path but no key	Set Ocp-Apim-Subscription-Key or switch to JWT
   403 with valid JWT	Per-product policy denies	Check rate-limit-by-key and product subscription state

5. Output: classification, root cause hypothesis, ONE recommended fix and ONE verification step.

Tools

This skill uses:

• RunAzCliReadCommands
• QueryLogAnalyticsByWorkspaceId

Safety

• NEVER display the JWT signature, named-value contents, or any signing material
• Refer to credentials by resource name only (e.g. "Foundry MI on project aifp-pilot")
• Read-only investigation; any RBAC change requires human action