feat(client): add shared Chromium driver

packages/client/README.md

@@ -16,25 +16,26 @@ The Promise root remains structural and has no Core, Effect, Schema, Protocol, o
 
 ## Node browser attachments
 
-The Node entrypoint owns the control connection, Session lease, authenticated proxy, and network tunnels. Consumers provide a browser adapter once with `BrowserDriver.define`; normal attachment calls only provide a Session ID and that descriptor.
+The Node entrypoint owns the control connection, Session lease, authenticated proxy, and network tunnels. Chromium hosts provide a small platform port once with `BrowserDriver.chromium`; the SDK owns command semantics, CDP input, snapshots, generations, cancellation, and limits.
 
 ```ts
-import { BrowserDriver, BrowserDriverError, OpenCode } from "@opencode-ai/client/node"
+import { BrowserDriver, OpenCode } from "@opencode-ai/client/node"
 
-const driver = BrowserDriver.define(async ({ proxy, signal }) => {
+const driver = BrowserDriver.chromium(async ({ proxy, signal }) => {
-  const browser = await launchBrowser({ proxy, signal })
+  const view = await createChromiumView({ proxy, signal })
   return {
-    resource: browser,
+    resource: view,
-    state: () => browser.state(),
+    state: () => view.state(),
-    subscribe: (listener) => browser.subscribe(listener),
+    subscribe: (listener) => view.subscribe((state, mainDocumentChanged) => listener({ state, mainDocumentChanged })),
-    execute: async (command, options) => {
+    navigate: (url) => view.navigate(url),
-      try {
+    back: () => view.back(),
-        return await browser.execute(command, options)
+    forward: () => view.forward(),
-      } catch (cause) {
+    reload: () => view.reload(),
-        throw new BrowserDriverError("internal", "Browser command failed", { cause })
+    stop: () => view.stop(),
-      }
+    send: (method, params) => view.sendCDP(method, params),
-    },
+    viewport: () => view.viewport(),
-    dispose: () => browser.close(),
+    screenshot: ({ maxDimension }) => view.capturePNG({ maxDimension }),
+    dispose: () => view.close(),
   }
 })
 
@@ -44,6 +45,8 @@ const client = OpenCode.make({
 })
 const attachment = await client.browser.attach({ sessionID, driver })
 
+await attachment.resource.navigate("example.com")
+const view = attachment.resource.resource
 await attachment.close()
 ```
 
@@ -51,7 +54,9 @@ await attachment.close()
 
 Driver factories should return after configuring their resource rather than await a proxied navigation: tunnel dialing is deliberately held behind the first lease acknowledgement, which is published after the driver supplies its initial state.
 
-`BrowserDriver` descriptors are structural factory functions, so adapters remain compatible across duplicate client package instances. The Node entrypoint also re-exports canonical `Browser` contracts. Throw `BrowserDriverError` for typed command failures; structurally equivalent errors are accepted only when their `code` is a valid `Browser.ErrorCode`.
+Port state events set `mainDocumentChanged` only when the main document changes; this advances the public generation and invalidates element refs. `send` must dispatch CDP calls in invocation order. `screenshot` returns PNG bytes and dimensions, proportionally scaled to `maxDimension` without upscaling. The returned controller serializes local navigation with remote commands; `stop` immediately interrupts active work, and controller disposal is idempotent. An aborted or timed-out operation that reached the platform disposes the port so late native completion cannot cross the queue fence.
+
+`BrowserDriver` descriptors are structural factory functions, so adapters remain compatible across duplicate client package instances. The Node entrypoint also re-exports canonical `Browser` contracts. `BrowserDriver.define` remains the advanced escape hatch for non-Chromium semantics; throw `BrowserDriverError` for typed command failures there. Structurally equivalent errors are accepted only when their `code` is a valid `Browser.ErrorCode`.
 
 Effect consumers construct canonical decoded inputs:
 

packages/client/src/node/browser/driver.ts

@@ -1,4 +1,5 @@
 import type { Browser } from "@opencode-ai/schema/browser"
+import { chromiumDriver, type ChromiumDriver, type ChromiumPort } from "./chromium.js"
 
 /** Connection details for the attachment's private authenticated proxy. */
 export interface BrowserProxy {
@@ -50,6 +51,12 @@ export const BrowserDriver = {
     if (typeof create !== "function") throw new TypeError("Browser driver factory must be a function")
     return Object.freeze(create)
   },
+  chromium<Resource>(
+    create: (context: BrowserDriverContext) => PromiseLike<ChromiumPort<Resource>> | ChromiumPort<Resource>,
+  ): ChromiumDriver<Resource> {
+    if (typeof create !== "function") throw new TypeError("Chromium port factory must be a function")
+    return Object.freeze(chromiumDriver(create))
+  },
 }
 
 export function browserDriverFactory<Resource>(driver: BrowserDriver<Resource>) {

packages/client/src/node/index.ts

@@ -23,6 +23,7 @@ export type {
   BrowserDriverInstance,
   BrowserProxy,
 } from "./browser/driver.js"
+export type { ChromiumController, ChromiumDriver, ChromiumPort } from "./browser/chromium.js"
 export type { BrowserAttachment, BrowserAttachOptions, BrowserClient } from "./browser/client.js"
 export type { EventSubscribeOutput as OpenCodeEvent } from "../promise/generated/types.js"
 export type OpenCodeClient = ReturnType<typeof import("./client.js").make>

packages/client/test/node/chromium.test.ts

@@ -0,0 +1,363 @@
+import { describe, expect, test } from "bun:test"
+import {
+  Browser,
+  BrowserDriver,
+  BrowserDriverError,
+  type BrowserDriverContext,
+  type ChromiumPort,
+} from "@opencode-ai/client/node"
+
+type PortListener = Parameters<ChromiumPort<unknown>["subscribe"]>[0]
+type PortState = ReturnType<ChromiumPort<unknown>["state"]>
+
+describe("Chromium browser driver", () => {
+  test("increments generations and invalidates refs only for main-document changes", async () => {
+    const app = await setup()
+    const snapshot = await app.instance.execute(
+      { type: "snapshot", generation: 0 },
+      { signal: new AbortController().signal },
+    )
+    if (snapshot.type !== "snapshot") throw new Error("Expected snapshot result")
+    expect(snapshot.content).toContain('e1 [button] "Save" disabled=false')
+
+    await app.instance.execute(
+      { type: "click", ref: Browser.Ref.make("e1"), generation: 0 },
+      { signal: new AbortController().signal },
+    )
+    app.port.emit({ title: "Updated" }, false)
+    expect(app.controller.state()).toMatchObject({ title: "Updated", generation: 0 })
+
+    app.port.emit({ url: "https://next.example/" }, true)
+    expect(app.controller.state()).toMatchObject({ url: "https://next.example/", generation: 1 })
+    expect(app.port.calls.some((call) => call.method === "Runtime.releaseObject")).toBe(true)
+
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute(
+            { type: "click", ref: Browser.Ref.make("e1"), generation: 1 },
+            { signal: new AbortController().signal },
+          ),
+        ),
+      ),
+    ).toMatchObject({ code: "stale_ref", message: "The element reference is stale. Call browser_snapshot again." })
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute({ type: "snapshot", generation: 0 }, { signal: new AbortController().signal }),
+        ),
+      ),
+    ).toMatchObject({ code: "stale_ref", message: "The browser page changed. Call browser_snapshot again." })
+    await app.controller.dispose()
+  })
+
+  test("parses bounded snapshots and rejects untrusted oversized nodes", async () => {
+    const app = await setup()
+    const result = await app.instance.execute(
+      { type: "snapshot", generation: 0 },
+      { signal: new AbortController().signal },
+    )
+    if (result.type !== "snapshot") throw new Error("Expected snapshot result")
+    expect(result.content).toBe(
+      ["Page: Example", "URL: https://example.com/", "", '  e1 [button] "Save" disabled=false'].join("\n"),
+    )
+    expect(app.port.expressions[0]).toContain("while (visited++ < 500)")
+    expect(app.port.expressions[0]).toContain('editable ? ""')
+    expect(app.port.expressions[0]).not.toContain("textContent")
+    expect(() => new Bun.Transpiler({ loader: "js" }).transformSync(app.port.expressions[0] ?? "")).not.toThrow()
+
+    app.port.snapshotValue = {
+      nodes: Array.from({ length: 501 }, () => ({ role: "button", name: "Save", value: "", depth: 0 })),
+      nextRef: 501,
+    }
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute({ type: "snapshot", generation: 0 }, { signal: new AbortController().signal }),
+        ),
+      ),
+    ).toMatchObject({ code: "internal", message: "Invalid browser snapshot nodes." })
+
+    app.port.snapshotValue = {
+      nodes: [{ token: "e2", role: "bad role", name: "Save", value: "", depth: 0 }],
+      nextRef: 2,
+    }
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute({ type: "snapshot", generation: 0 }, { signal: new AbortController().signal }),
+        ),
+      ),
+    ).toMatchObject({ code: "internal", message: "Invalid browser snapshot nodes." })
+    expect(app.port.calls.filter((call) => call.method === "Runtime.releaseObject").length).toBeGreaterThanOrEqual(2)
+    await app.controller.dispose()
+  })
+
+  test("releases paired input and fences the port when cancellation races a press", async () => {
+    const app = await setup()
+    await app.instance.execute({ type: "snapshot", generation: 0 }, { signal: new AbortController().signal })
+    const abort = new AbortController()
+    const input: string[] = []
+    app.port.onSend = (method, params) => {
+      if (method !== "Input.dispatchMouseEvent") return app.port.response(method, params)
+      if (params?.type === "mousePressed") {
+        input.push("press")
+        abort.abort()
+        return new Promise<never>(() => undefined)
+      }
+      if (params?.type === "mouseReleased") input.push("release")
+      return app.port.response(method, params)
+    }
+
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute({ type: "click", ref: Browser.Ref.make("e1"), generation: 0 }, { signal: abort.signal }),
+        ),
+      ),
+    ).toMatchObject({ code: "aborted", message: "The browser action was aborted." })
+    await app.controller.dispose()
+    expect(input).toEqual(["press", "release"])
+    expect(app.port.stopCount).toBe(1)
+    expect(app.port.disposeCount).toBe(1)
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute({ type: "snapshot", generation: 0 }, { signal: new AbortController().signal }),
+        ),
+      ).code,
+    ).toBe("not_attached")
+  })
+
+  test("serializes local controller work with remote commands", async () => {
+    const app = await setup()
+    const navigation = deferred()
+    const started = deferred()
+    app.port.onNavigate = () => {
+      started.resolve()
+      return navigation.promise
+    }
+
+    const local = app.controller.navigate("example.com")
+    await started.promise
+    const remote = app.instance.execute({ type: "snapshot", generation: 0 }, { signal: new AbortController().signal })
+    await Promise.resolve()
+    expect(app.port.calls.some((call) => call.method === "Runtime.evaluate")).toBe(false)
+    expect(app.port.navigateURLs).toEqual(["https://example.com/"])
+
+    navigation.resolve()
+    await local
+    expect((await remote).type).toBe("snapshot")
+    expect(app.port.calls.some((call) => call.method === "Runtime.evaluate")).toBe(true)
+    await app.controller.dispose()
+  })
+
+  test("maps navigation, CDP, and adapter failures to driver error codes", async () => {
+    const app = await setup()
+    expect(requireDriverError(await rejected(app.controller.navigate("javascript:alert(1)")))).toMatchObject({
+      code: "invalid_url",
+    })
+    expect(app.port.navigateURLs).toEqual([])
+
+    app.port.onNavigate = () => Promise.reject(new Error("net::ERR_NAME_NOT_RESOLVED"))
+    expect(requireDriverError(await rejected(app.controller.navigate("missing.example")))).toMatchObject({
+      code: "navigation_failed",
+      message: "net::ERR_NAME_NOT_RESOLVED",
+    })
+
+    app.port.onSend = () => Promise.reject(new Error("Could not find object with given id"))
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute({ type: "snapshot", generation: 0 }, { signal: new AbortController().signal }),
+        ),
+      ),
+    ).toMatchObject({ code: "stale_ref", message: "The element reference is stale. Call browser_snapshot again." })
+
+    app.port.onSend = () => Promise.reject(new Error("Method not found"))
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute({ type: "snapshot", generation: 0 }, { signal: new AbortController().signal }),
+        ),
+      ),
+    ).toMatchObject({ code: "internal", message: "Method not found" })
+
+    app.port.onSend = () => Promise.reject(new BrowserDriverError("page_crashed", "Renderer gone"))
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute({ type: "snapshot", generation: 0 }, { signal: new AbortController().signal }),
+        ),
+      ),
+    ).toMatchObject({ code: "page_crashed", message: "Renderer gone" })
+    await app.controller.dispose()
+  })
+
+  test("preserves viewport scroll and bounded PNG capture contracts", async () => {
+    const app = await setup()
+    app.port.viewportSize = { width: 101, height: 99 }
+    await app.instance.execute(
+      { type: "scroll", direction: "down", pixels: 5_000, generation: 0 },
+      { signal: new AbortController().signal },
+    )
+    expect(app.port.calls.find((call) => call.params?.type === "mouseWheel")?.params).toEqual({
+      type: "mouseWheel",
+      x: 51,
+      y: 50,
+      deltaX: 0,
+      deltaY: 2_000,
+    })
+
+    const result = await app.instance.execute(
+      { type: "screenshot", generation: 0 },
+      { signal: new AbortController().signal },
+    )
+    if (result.type !== "screenshot") throw new Error("Expected screenshot result")
+    expect(app.port.screenshotLimits).toEqual([2_000])
+    expect(result).toMatchObject({ mediaType: "image/png", width: 100, height: 50 })
+    expect(result.data).toEqual(new Uint8Array([137, 80, 78, 71]))
+
+    app.port.screenshotValue = {
+      data: new Uint8Array(5 * 1_024 * 1_024 + 1),
+      width: 100,
+      height: 50,
+    }
+    expect(
+      requireDriverError(
+        await rejected(
+          app.instance.execute({ type: "screenshot", generation: 0 }, { signal: new AbortController().signal }),
+        ),
+      ),
+    ).toMatchObject({ code: "result_too_large", message: "The browser screenshot exceeds 5 MiB." })
+    await app.controller.dispose()
+  })
+})
+
+class FakeChromiumPort implements ChromiumPort<{ readonly name: string }> {
+  readonly resource = { name: "fake-chromium" }
+  readonly listeners = new Set<PortListener>()
+  readonly calls: Array<{ readonly method: string; readonly params?: Record<string, unknown> }> = []
+  readonly expressions: string[] = []
+  readonly navigateURLs: string[] = []
+  readonly screenshotLimits: number[] = []
+  current: PortState = {
+    url: "https://example.com/",
+    title: "Example",
+    loading: false,
+    canGoBack: false,
+    canGoForward: false,
+  }
+  snapshotValue: unknown = {
+    nodes: [{ token: "e1", role: "button", name: "Save", value: "", depth: 1, disabled: false }],
+    nextRef: 1,
+  }
+  screenshotValue = { data: new Uint8Array([137, 80, 78, 71]), width: 100, height: 50 }
+  viewportSize = { width: 800, height: 600 }
+  onNavigate?: (url: string) => PromiseLike<void> | void
+  onSend?: (method: string, params?: Record<string, unknown>) => unknown
+  stopCount = 0
+  disposeCount = 0
+  private object = 0
+
+  state() {
+    return this.current
+  }
+
+  subscribe(listener: PortListener) {
+    this.listeners.add(listener)
+    return () => {
+      this.listeners.delete(listener)
+    }
+  }
+
+  navigate(url: string) {
+    this.navigateURLs.push(url)
+    return Promise.resolve().then(() => this.onNavigate?.(url))
+  }
+
+  back() {}
+
+  forward() {}
+
+  reload() {}
+
+  stop() {
+    this.stopCount++
+  }
+
+  send(method: string, params?: Record<string, unknown>) {
+    this.calls.push({ method, ...(params ? { params } : {}) })
+    if (method === "Runtime.evaluate" && typeof params?.expression === "string") {
+      this.expressions.push(params.expression)
+    }
+    return Promise.resolve().then(() => (this.onSend ? this.onSend(method, params) : this.response(method, params)))
+  }
+
+  response(method: string, params?: Record<string, unknown>) {
+    if (method === "Runtime.evaluate") return { result: { objectId: `snapshot-${++this.object}` } }
+    if (method !== "Runtime.callFunctionOn") return {}
+    if (params?.functionDeclaration === "function() { return this.result }") {
+      return { result: { value: this.snapshotValue } }
+    }
+    if (typeof params?.functionDeclaration === "string" && params.functionDeclaration.includes("const editable")) {
+      return { result: { value: true } }
+    }
+    return { result: { value: { x: 25, y: 40 } } }
+  }
+
+  viewport() {
+    return this.viewportSize
+  }
+
+  screenshot(options: { readonly maxDimension: number }) {
+    this.screenshotLimits.push(options.maxDimension)
+    return Promise.resolve(this.screenshotValue)
+  }
+
+  dispose() {
+    this.disposeCount++
+  }
+
+  emit(state: Partial<PortState>, mainDocumentChanged: boolean) {
+    this.current = { ...this.current, ...state }
+    this.listeners.forEach((listener) => listener({ state: this.current, mainDocumentChanged }))
+  }
+}
+
+async function setup() {
+  const port = new FakeChromiumPort()
+  const lifetime = new AbortController()
+  const driver = BrowserDriver.chromium(() => port)
+  const instance = await driver({
+    proxy: {
+      url: "https://127.0.0.1:1234",
+      host: "127.0.0.1",
+      port: 1234,
+      credentials: { username: "user", password: "pass" },
+      certificateFingerprint: "fingerprint",
+    },
+    signal: lifetime.signal,
+  } satisfies BrowserDriverContext)
+  return { port, lifetime, instance, controller: instance.resource }
+}
+
+function deferred() {
+  let resolve!: () => void
+  const promise = new Promise<void>((next) => {
+    resolve = next
+  })
+  return { promise, resolve }
+}
+
+function rejected(promise: Promise<unknown>) {
+  return promise.then(
+    () => new Error("Expected operation to reject"),
+    (error: unknown) => error,
+  )
+}
+
+function requireDriverError(input: unknown) {
+  if (!(input instanceof BrowserDriverError)) throw input
+  return input
+}

packages/client/test/node/package-smoke.ts

@@ -127,6 +127,7 @@ function nodeScenario(moduleURL: string) {
 const sdk = await import(${JSON.stringify(moduleURL)})
 if (typeof sdk.OpenCode.make !== "function") throw new Error("Missing OpenCode.make")
 if (typeof sdk.BrowserDriver.define !== "function") throw new Error("Missing BrowserDriver.define")
+if (typeof sdk.BrowserDriver.chromium !== "function") throw new Error("Missing BrowserDriver.chromium")
 if (typeof sdk.BrowserDriverError !== "function") throw new Error("Missing BrowserDriverError")
 if (!sdk.Browser.State) throw new Error("Missing canonical Browser export")
 

packages/client/test/types/node-consumer.ts

@@ -1,4 +1,13 @@
-import { Browser, BrowserDriver, BrowserDriverError, OpenCode, type BrowserAttachment } from "@opencode-ai/client/node"
+import {
+  Browser,
+  BrowserDriver,
+  BrowserDriverError,
+  OpenCode,
+  type BrowserAttachment,
+  type ChromiumController,
+  type ChromiumDriver,
+  type ChromiumPort,
+} from "@opencode-ai/client/node"
 
 const state: Browser.State = {
   url: "about:blank",
@@ -19,6 +28,8 @@ const factory: BrowserDriver<{ readonly proxyURL: string }> = (context) => ({
   dispose: () => undefined,
 })
 const driver = BrowserDriver.define(factory)
+declare const port: ChromiumPort<{ readonly page: true }>
+const chromium: ChromiumDriver<{ readonly page: true }> = BrowserDriver.chromium(() => port)
 
 declare const client: ReturnType<typeof OpenCode.make>
 const attachment: Promise<BrowserAttachment<{ readonly proxyURL: string }>> = client.browser.attach({
@@ -27,3 +38,9 @@ const attachment: Promise<BrowserAttachment<{ readonly proxyURL: string }>> = cl
 })
 
 void attachment
+const chromiumAttachment: Promise<BrowserAttachment<ChromiumController<{ readonly page: true }>>> =
+  client.browser.attach({
+    sessionID: "ses_chromium_type_fixture",
+    driver: chromium,
+  })
+void chromiumAttachment