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The panel is the only Vendo code in your browser. Every turn goes to a route inside your own app and streams back to that panel.

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The path of one question

1

The panel posts the question

The panel sends POST /api/vendo/threads and reads the reply as a stream. baseUrl on the provider is what decides that path.The body carries the question and a snapshot of what the user is looking at. Nothing else leaves the browser.
2

Your route answers who is asking

vendo init wrote one file, and it is ordinary source you can read and change.
app/api/vendo/[...vendo]/route.ts
Init detects Auth.js, Clerk, Supabase, or Auth0 and writes the matching preset. With no library found it writes a principal function for you to fill in instead.Vendo mints no identity of its own. Without one of the two, createVendo throws, and a visitor your resolver cannot place is refused the turn.
3

The turn runs on your server

The harness runs the loop in your own process. Where the prompt goes is set by what your composition selects: pass a model object — models: { default: anthropic("claude-sonnet-4-6") }, which is what vendo init writes when you bring your own key — and the call goes straight to that provider. Leave the slot unset and the VENDO_API_KEY in your environment answers it over the Vendo Cloud gateway. Model credentials covers both.Its tools are your API, extracted into .vendo/tools.json by vendo init and refreshed by vendo sync, plus Vendo’s own tools for building screens.
4

The guard grades every call

Every tool call passes the guard before it runs. Reads run; anything destructive, and anything extraction could not grade, stops and asks.An ask parks the turn on an approval card in the thread, showing the exact request. Approve it and the same turn resumes and the tool runs.
5

Your API runs the call

The call reaches your own endpoint as the person who is signed in. The agent can do what that person could already do by clicking, and nothing more.
6

A screen comes back instead of a paragraph

When the answer is one to look at, the agent calls vendo_make with the request in plain language. Vendo assembles a screen, or builds a small app whose server code runs on a Cloud sandbox.The view streams into the transcript as it forms and lands interactive, bound to live data from your own tools. From there it can be pinned into a VendoSlot on your page.

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What runs where

One key fills the model, store, and sandbox slots your composition left unset. Nothing to provision, and nothing to run.

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What the agent can see

Each send carries a small [Situation] bundle for that turn only. It rides the request and never enters the transcript.
  • The accessibility tree of the visible page, with the URL and title on top, capped at 8 KB.
  • Anything you publish yourself with useVendoContext.
Elements marked data-vendo-ignore are left out of the snapshot, and the panel excludes its own chrome. Pass captureScreen={false} on the provider to turn the page snapshot off entirely.

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What stops a call

The guard’s decision is server-side, so no client can talk it out of one. The default policy runs reads and asks a person about destructive and ungraded calls. Write your own rules in .vendo/policy.json, or pass them to guard() in the route. Approved calls, denials, and everything that ran land in the audit log.

Mount the surface

Every surface the panel is made of, and the props that move them.

API tools

How your endpoints become tools, and how each one gets its risk grade.