The playground

The gateway's home page is a playground around the embeddable widget, and the dev UI: one conversation in the centre (exactly what a host application gets from one <script> tag), the live draft on the right (every value with where it came from), and the trace beside it. Both panes collapse; past chats are in a drawer; the empty state offers the domains' own example openers.

The trace has one entry per turn: who answered (the runtime, or the model, or both when the model answered and the runtime drew the card under it), the route — which domain got the turn, the link that decided (keywords, llm…) and its confidence — the steps the runtime moved (the Details card asked, redrawn, settled; the summary shown), every tool call folded (click one to read the arguments it received and the result it returned), the model's calls with their timings, the usage and the create. A refused create shows as create_ticket with the refusal in its result.

That content — arguments, results, the route — is shown only when the gateway runs with AGENT_DEV_TRACE=true, which a project's .env sets and the hosted copy leaves off (the pane then keeps to who answered, the tools and their time, and says why). It goes to your browser, never to telemetry. The shape is in the client protocol.

A hosted copy runs at https://marg-playground.onrender.com on the mock model with writes off. It sleeps when idle, so the first load takes a moment, and keeps no disk, so a session may be lost on a redeploy. Everything else is the real thing.

What to try

• The opener. "ticket for Northwind: login fails on mobile" — one sentence that names the customer and the problem. The agent resolves the customer, asks the category, draws the Details card.
• Words beside an open ask. While the Details card is open, type "what counts as production?". The model answers in a line; the card is drawn again under it. A typed "yes" while a card is open is never an answer to it.
• A premature yes. Type "yes, create it" while the Details card is open. Nothing is created: the runtime says the card is still open and draws it again, because a typed yes is never an answer to a card, and the create gate requires the summary to have been shown for this draft and the reply to be a plain go-ahead by its whole content. The trace pane shows the turn was the runtime's, with no tool call.
• Change something. On the summary, pick a section; the step's own card re-opens pre-filled; the summary returns.
• Open a tool call. After the opener, click search_customers in the trace: the query it was given and the two customers it found.
• Reload. Refresh the page mid-journey, or open a finished chat from the drawer. The open ask is drawn again from the transcript, the draft comes back with it, and the trace pane has every turn again, from the one history request the page makes.

Embedding the widget

<script src="http://localhost:8787/widget.js" data-agent-auto></script>

Shadow DOM, zero dependencies, streaming replies, chips, forms, cards, tables, media, resume, nudges, voice notes. Or speak the client protocol from your own app.