Browser runtime

Import the browser-safe facade from smithers-orchestrator/browser. It runs the real Smithers driver, scheduler, renderer, graph extractor, schema validation, and task dependency semantics without pulling Node database, server, CLI-agent, or subprocess code into the bundle.

import React from "react";
import { z } from "zod";
import {
  Task,
  Workflow,
  createBrowserRuntime,
  createBrowserSmithers,
  defineBrowserWorkflow,
} from "smithers-orchestrator/browser";

const resultSchema = z.object({ answer: z.number() });
const workflow = defineBrowserWorkflow(() =>
  React.createElement(
    Workflow,
    { name: "browser-example" },
    React.createElement(
      Task,
      {
        id: "answer",
        output: "results",
        outputSchema: resultSchema,
        agent: {
          async generate() {
            return { answer: 42 };
          },
        },
      },
      "Return the answer.",
    ),
  ),
);

const runtime = createBrowserRuntime();
const smithers = createBrowserSmithers({ workflow, runtime });
const run = await smithers.run({ input: {}, runId: "browser-demo" });

console.log(run.status); // "finished"
console.log(await smithers.getOutputs(run.runId));

createBrowserSmithers creates a fresh driver and scheduler session for every run() call. getRun(runId) and getOutputs(runId) read through the selected runtime storage adapter. runBrowserWorkflow(workflow, options) is the one-shot equivalent when you do not need to retain the Smithers wrapper.

Browser-safe exports

Export	Purpose
`defineBrowserWorkflow(build, options?)`	Define a portable workflow from a context-to-React builder.
`createBrowserRuntime(options?)`	Create the default browser `RuntimeAdapter`.
`createBrowserSmithers({ workflow, runtime?, runtimeOptions? })`	Create a reusable runner with run and output lookup methods.
`runBrowserWorkflow(workflow, options?)`	Run one workflow once.
`Task`, `Workflow`, `Sequence`, `Worktree`	Browser-safe workflow primitives.
`RuntimeCapabilityError`, `RUNTIME_CAPABILITY_UNAVAILABLE`	Typed failure for unavailable host capabilities.
`RuntimeAdapter`, `BrowserRuntimeOptions`, `BrowserWorkflow`, `BrowserRunOptions`, `BrowserSmithers`	Public TypeScript contracts.

Runtime options

The default runtime uses Date, performance, abortable setTimeout, Web Crypto UUIDs, and Map-backed run/output storage. Override any portable seam:

type BrowserRuntimeOptions = {
  clock?: RuntimeClock;
  storage?: RuntimeStorage;
  uuid?: () => string;
  executeTask?: (
    task: TaskDescriptor,
    context: TaskExecutorContext,
  ) => Promise<unknown> | unknown;
};

Provide storage when state must outlive a page refresh. Provide executeTask to route task execution through an application-owned worker, provider client, or policy boundary. The default executor supports static and compute tasks plus in-process agents exposing generate, execute, run, or call. It validates Zod-like outputSchema values before storing outputs.

Capability boundary

The browser adapter intentionally fails closed for filesystem, subprocess, worktree, and sandbox. Calling one of those operations throws a RuntimeCapabilityError with code RUNTIME_CAPABILITY_UNAVAILABLE, the runtime name, capability, and operation. The exported Worktree primitive is portable at graph-render time, but a browser run cannot resolve a real worktree unless the application supplies a custom RuntimeAdapter that owns that capability. The browser facade does not include Node database factories, server helpers, CLI agents, bundled tools, or the full Node component barrel. Use the main smithers-orchestrator entry point for those surfaces.

Source browser engine · Tests browser runtime tests · See also Run workflow, Testing workflows, Package configuration

Overview

Core API

Runtime

Types & errors

Gateway RPC

Browser-safe exports

Runtime options

Capability boundary

​Browser-safe exports

​Runtime options

​Capability boundary

Browser-safe exports

Runtime options

Capability boundary