ADR-003: Open WebUI as Pipeline Engine
| Field | Value |
|---|---|
| Status | Accepted |
| Date | 2026-03-11 |
| Decision Makers | PO (lead), CA, MEE, IE |
Context
xOps BC1 needs a user-facing interface that serves as both a chat interface AND a pipeline execution engine for CloudOps, DevOps, and FinOps workflows. The interface must support MCP servers, SCIM 2.0 for enterprise SSO, and run entirely on-premise in ap-southeast-2.
Decision
Use Open WebUI 0.8+ as the pipeline engine. Pipelines map directly to ADLC Commands & Hooks — the frontend IS the governance layer.
Key features driving this decision:
- Pipeline engine = ADLC Commands & Hooks (not a separate abstraction)
- Native MCP client (0.8+) + mcpo sidecar for OpenAPI bridge
- SCIM 2.0 → IAM Identity Center user sync
- Built-in RAG: document management + embeddings (zero external vector DB)
- Native Claude API integration (ANTHROPIC_API_KEY)
- 126k+ GitHub stars (strong community, active development)
Consequences
Gains
- Pipeline-as-governance:
/cloudops,/finops,/devopspipelines are ADLC slash commands - Zero custom UI code: No React development needed for BC1
- Sovereign: self-hosted, all data in ap-southeast-2
- Enterprise SSO: SCIM 2.0 auto-provision/deprovision from IAM Identity Center
- Built-in RAG: Document upload + vector search without external infrastructure
Losses
- Customization ceiling: Complex custom UIs require escape to React (AG-UI/CopilotKit for BC2+)
- AG-UI protocol gap: No native AG-UI event support (16 event types for real-time agent progress)
- Dependency on Open WebUI roadmap: Major version changes may require pipeline migration
Alternatives Considered
| Alternative | Score | Verdict | When to Reconsider |
|---|---|---|---|
| Dify | CA: 62% | Workflow builder IDE, not ops command centre | Never for xOps (different paradigm) |
| ChatGPT Teams / Copilot | CA: 0% | APRA CPS 234 data sovereignty breach (blocked) | Never (sovereign requirement non-negotiable) |
| Vercel/chatbot (Next.js) | PO: 68% | Sovereignty concern (Vercel-hosted), no pipeline engine | BC2 Resume Optimizer (non-sovereign workload) |
| AG-UI + CopilotKit | CA: 80% | Best for real-time agent progress panels, but no pipeline engine | BC2+ sidecar alongside Open WebUI |
| Custom React | PO: 45% | 6+ months to build equivalent pipeline engine | Never for BC1 (build vs buy obvious) |
Agent Consensus: 96% (PO 96%, CA 97%, MEE 94%, IE 96%)
Source: xops.jsx FRONTENDS[], LAYERS[id=6]