Glossary

Agent UI

A runtime projection standard for turning structured agent facts into user-visible interaction surfaces and controlled actions.

Runtime fact

A fact owned by an agent runtime or protocol adapter, such as run id, lifecycle state, text delta, tool call, queue state, or action request.

Projection state

UI-owned state derived from facts, such as selected tab, collapsed tool rows, visible message window, focused artifact, or local draft. Projection state is not authoritative runtime truth.

Surface

A user-visible region that answers one class of question. Standard surfaces include Composer, Message Parts, Runtime Status, Tool UI, Human-in-the-loop, Task Capsule, Artifact Workspace, Timeline/Evidence, and Session/Tabs.

Message part

A typed piece of message UI, such as final text, reasoning, tool call, action request, data, artifact reference, or evidence reference.

Runtime status

A short visible state showing whether the agent is submitted, routing, preparing, streaming, calling tools, blocked, retrying, cancelled, failed, or completed.

Tool UI

The surface for tool lifecycle, safe input summaries, progress, output previews, large output offload, and detail inspection.

Human-in-the-loop

A state where the runtime requires user approval, structured input, plan decision, correction, or cancellation before it can continue.

Queue

A user input scheduled to run after the active run finishes.

Steer

A user input intended to affect the currently active run.

Artifact

A generated or edited deliverable such as a document, file, diff, image, table, code object, canvas, or structured output.

Evidence

Trace, citation, verification, replay, review, or audit information that supports or explains an agent run.