Runtime plane / Tier 2 / Phase 1
Experience & Interaction
How does a human participate?
The surfaces where people meet the system — and where they steer it: channels, streaming, sessions, clarification, provenance display and the approval moments that make autonomy safe.
- Channels: web, mobile, chat platforms, voice and public API
- Streaming and partial-result rendering so long tasks stay legible
- Session and conversation state at the edge
- Clarification prompts when the task is under-specified
- Approval and review surfaces for human-in-the-loop checkpoints
- Provenance display: what the answer was based on and how confident it is
- Multimodal input and output, and accessibility
every request enters through the gateway
renders approval checkpoints and autonomy state
shows source and lineage behind answers
session continuity across turns
user-visible task status and cost
Product Engineering / Digital Channels, with UX
- Product lead — accountable owner
- Frontend engineer — streaming, sessions, channel adapters
- UX designer — approval, clarification and provenance patterns
- Content designer — the words in the interface
- Accessibility specialist
Architectural recommendation, not a research finding.
Pilot can ship one channel with streaming. Approval and clarification surfaces become mandatory the moment agents can write to production systems.
Signals to watch
- Task completion and abandonment rate
- Clarification rate and its effect on success
- Approval latency and reviewer override rate
- Accessibility conformance
- User-reported trust or satisfaction
- No clarification path, so the agent invents assumptions instead of asking
- Approval fatigue: too many low-stakes confirmations and reviewers stop reading
- Provenance hidden, so users cannot calibrate trust
- Disclosure obligations missed for chatbots regardless of risk tier
Tool and standards snapshot · last reviewed approximately mid-2026
Open source
- AG-UI protocol
- CopilotKit
- Vercel AI SDK
- assistant-ui
- Chainlit
- LiveKit or Pipecat for voice
Managed
- Contact-centre and CPaaS platforms
- Enterprise chat platforms (Teams, Slack) as channels
Standards
- AG-UI for streaming agent interfaces
- Server-Sent Events and WebSocket
- WCAG 2.2 accessibility
- Art. 50 EU AI Act disclosure for machine interaction
This is the harness most often skipped in an architecture diagram and most often blamed in a post-mortem. Autonomy policy is only real if there is a surface where a human can actually intervene in time.