Agent UI

Agent UI is a runtime-first draft standard for agent interaction surfaces. It defines how AI clients project structured agent events, tool calls, human-in-the-loop requests, artifacts, tasks, sessions, teams, and evidence into user-visible UI without turning the UI into a second source of runtime truth.

Agent UI sits between runtime facts and product interaction. It does not own execution, context, storage, policy, or visual components; it defines how facts from those systems become visible, controllable, resumable, editable, and auditable.

Core boundary

Adjacent system	It owns	Agent UI owns
Agent runtime	Runs, turns, tasks, events, snapshots, and authoritative status.	Projection into status, messages, tasks, and controls.
Tools and workflows	Executable actions, connectors, procedures, scripts, and tool results.	Tool progress, safe summaries, recovery states, and user control points.
Context and policy	Facts, sources, memory, permissions, risk, and trust boundaries.	Citations, missing-state UI, approval/input surfaces, and honest fallbacks.
Teams and teammates	Agent identity, parent/child sessions, delegation, work items, handoff, review, remote/background task truth.	Team roster, work board, delegation graph, worker notifications, review lanes, and teammate transcript entrypoints.
Artifacts and evidence	Files, canvases, diffs, traces, reviews, replays, verification, and audit records.	Artifact cards, canvas entrypoints, timelines, evidence surfaces, and handoff states.
Design systems	Visual components, tokens, layout, and responsive behavior.	Surface semantics and behavior-level acceptance checks.

What v0.6 defines

• A runtime event projection contract for lifecycle, text, reasoning, tool, action, queue, artifact, evidence, and session events.
• Core standard surfaces: Composer, Message Parts, Runtime Status, Tool UI, Human-in-the-loop, Task Capsule, Artifact Workspace, Timeline/Evidence, and Session/Tabs.
• Team Workbench surfaces: Team Roster, Work Board, Delegation Graph, Handoff Lane, Worker Notifications, Review Lane, Teammate Transcript, Background Teammate, Remote Teammate, and Team Policy.
• Runtime execution alignment for foreground agent turns, child subagent/teammate turns, automation jobs, external remote tasks, board work items, and queue/parallelism facts.
• A client implementation model for session hydration, progressive rendering, queue vs steer, durable snapshots, and controlled writes.
• Runtime profile test cases that verify Agent Runtime-style events, read models, task snapshots, and evidence packs project into UI without becoming UI-owned truth.
• Performance metrics for first status, first text, delta backlog, history hydration, timeline load, and artifact/evidence offload.
• Acceptance scenarios that prove behavior instead of checking whether a component or file exists, including coordinator teams, parallel workers, handoffs, review teams, human/agent boards, background teammates, and remote teammates.

Runtime architecture

agent runtime events + durable snapshots
  -> projection reducer
  -> UI projection store
  -> Conversation / Process / Task / Artifact Workspace / Evidence surfaces
  -> controlled runtime, artifact, and evidence actions

Compatible implementations should:

1. Consume typed events and snapshots instead of parsing plain assistant text.
2. Keep runtime, artifact, evidence, and UI projection state in separate owners.
3. Show status before first text when the runtime has accepted work.
4. Render text, reasoning, tool calls, action requests, artifacts, and evidence as different message parts or surfaces.
5. Route approvals, interrupts, queue changes, steering, artifact edits, and evidence export through controlled APIs.
6. Hydrate old sessions progressively: shell first, recent messages next, timeline/tool/artifact details on demand.
7. Preserve team/runtime lineage through runtimeEntity, parent/child ids, runtime status, team phase, and queue/parallelism facts when available.
8. Treat UI documentation as guidance only; no Markdown text is allowed to become policy, runtime state, or executable workflow.

Documentation

Key pages:

• Specification
• Runtime standard
• Runtime event projection
• Runtime profile test cases
• Flow and taxonomy
• Source index
• Session hydration
• Queue and steer
• Ecosystem boundaries
• 中文规范

Related Agent standards

• Agent Knowledge - source-grounded knowledge packs.
• Agent UI - interaction surfaces for agent products.
• Agent Runtime - execution facts, controls, tasks, tools, and recovery.
• Agent Evidence - evidence, provenance, verification, review, replay, and export.
• Agent Policy - policy decisions, approvals, permissions, risk, retention, waivers, and traces.
• Agent Artifact - durable deliverables, versions, parts, previews, exports, and handoff packages.
• Agent Tool - tool declarations, surfaces, invocations, progress, results, permissions, and audit refs.
• Agent Context - context surfaces, items, source refs, selection, budgets, assembly, injection, compaction, and missing-context facts.

See the Agent standards ecosystem page for the mutual-link map and future standard candidates.

Local development

npm install
npm run dev

Build

npm run build

The static site is generated at docs/.vitepress/dist.