Cloud sessions: non-interactive Azure CLI auth path

Context

I'm using Claude Code on the web (cloud sessions) for a solo build of a healthcare-billing SaaS on Azure. Phase 1 substrate provisioning uses Bicep + GitHub Actions OIDC, which works fine in cloud. Beyond that, every Phase 2+ task that wants ad-hoc Azure CLI introspection from a phone-driven cloud session hits the same wall: there's no path to authenticate az non-interactively in the cloud sandbox.

Cloud sessions can install az (my SessionStart hook handles this), but there's no az login device-code flow available, no service-principal credentials injected into the sandbox env, no federated identity assertion exposed.

Today's workaround stack

• Azure MCP server for read ops (authed via its own MCP-internal flow)
• GitHub Actions OIDC for write ops (deploy via PR + workflow_dispatch)
• Fall back to desktop session for ad-hoc az work

Acceptable for Phase 1 substrate, but Phase 2+ ad-hoc Azure work from a phone-driven cloud session is blocked.

Two viable shapes

1. Federated identity credential — Claude Code on the web exposes an OIDC token issuer for cloud session identity. The user registers a federated credential on a service principal in their tenant trusting that issuer (with a subject claim like claude-cloud-session:<environment-id>). SessionStart hook runs az login --service-principal --federated-token <assertion>. Cleanest — no shared secrets.

1. Environment-injected SP credentials — env-var injection for AZURE_CLIENT_ID / AZURE_TENANT_ID / AZURE_CLIENT_SECRET (or AZURE_FEDERATED_TOKEN_FILE), same mechanism currently used for GH_TOKEN / GITHUB_MCP_PAT. Hook runs az login --service-principal non-interactively.

What I'd like to know

• Does cloud Claude Code expose an OIDC identity-token issuer for session identity (for shape 1)? If yes: issuer URL + subject claim format + audience to use for federation.
• If not, is the existing GH_TOKEN-style env-secret injection extensible to multiple Azure-SP variables (for shape 2)?
• Roadmap timing if neither is available today.

Preference: shape 1 if available; shape 2 acceptable fallback. Both flow through a SessionStart hook (ensure_az_auth parallel to ensure_gh_auth).