fix(sdk): bind embedded transport at request time

packages/sdk/src/effect/opencode.ts

@@ -4,7 +4,7 @@ import { OpenCode, type OpenCodeClient } from "@opencode-ai/client/effect"
 import type { Workspace } from "@opencode-ai/core/workspace"
 import { Context, Effect, Layer } from "effect"
 import type { Config, Scope } from "effect"
-import { FetchHttpClient } from "effect/unstable/http"
+import { FetchHttpClient, HttpClient } from "effect/unstable/http"
 import { EmbeddedHost } from "../internal/host"
 import type { SdkInstances } from "../internal/instances"
 
@@ -35,9 +35,12 @@ export const create: <R = never>(
   R = never,
 >(options: CreateOptions<R> = {}, embed: EmbedOptions = {}) {
   const host = yield* Effect.acquireRelease(EmbeddedHost.create(options, embed), (host) => Effect.promise(host.close))
+  const httpClient = yield* HttpClient.HttpClient.pipe(Effect.provide(FetchHttpClient.layer))
   const client = yield* OpenCode.make({ baseUrl: "http://opencode.local" }).pipe(
-    Effect.provide(
-      FetchHttpClient.layer.pipe(Layer.provide(Layer.succeed(FetchHttpClient.Fetch, host.fetch)), Layer.fresh),
+    Effect.provideService(
+      HttpClient.HttpClient,
+      // FetchHttpClient reads Fetch at request time; callers must not replace this host's in-process transport.
+      HttpClient.transformResponse(httpClient, Effect.provideService(FetchHttpClient.Fetch, host.fetch)),
     ),
   )
 

packages/sdk/test/transport.test.ts

@@ -0,0 +1,65 @@
+import { expect } from "bun:test"
+import { Context, Effect, Exit, Layer, Scope, Stream } from "effect"
+import { FetchHttpClient } from "effect/unstable/http"
+import { tmpdirScoped } from "../../core/test/fixture/tmpdir"
+import { testEffect } from "../../core/test/lib/effect"
+import { AbsolutePath, Location, OpenCode, Session } from "../src/effect"
+
+const it = testEffect(Layer.empty)
+
+for (const entrypoint of ["create", "layer"] as const) {
+  it.live(`${entrypoint} keeps requests and streams on its own transport despite an ambient Fetch`, () =>
+    Effect.gen(function* () {
+      const directory = yield* tmpdirScoped()
+      const calls: string[] = []
+      const ambient = Object.assign(
+        (input: RequestInfo | URL) => {
+          calls.push(input instanceof Request ? input.url : String(input))
+          return Promise.reject(new Error("The caller's Fetch must not receive embedded SDK requests"))
+        },
+        { preconnect: () => undefined },
+      )
+      const parent = yield* Effect.scope
+      const scope = yield* Scope.fork(parent)
+      const options: OpenCode.CreateOptions = {
+        app: { version: "transport-test" },
+        config: { directory: directory.path, project: false, content: "{}" },
+        events: { persist: true },
+        models: { fetch: false },
+        fs: { filewatcher: false },
+      }
+      const client = yield* (
+        entrypoint === "create"
+          ? OpenCode.create(options).pipe(Scope.provide(scope))
+          : Layer.buildWithScope(OpenCode.layer(options), scope).pipe(Effect.map(Context.get(OpenCode.Service)))
+      ).pipe(Effect.provideService(FetchHttpClient.Fetch, ambient))
+
+      yield* Effect.gen(function* () {
+        expect(yield* client.health.get()).toMatchObject({ healthy: true, version: "transport-test" })
+        const session = yield* client.sessions.create({
+          location: Location.Ref.make({ directory: AbsolutePath.make(directory.path) }),
+        })
+        expect((yield* client.sessions.get({ sessionID: session.id })).id).toBe(session.id)
+        const events = yield* client.sessions.log({ sessionID: session.id }).pipe(Stream.runCollect)
+        expect(events.some((event) => event.type === "session.created")).toBe(true)
+        expect(yield* client.events.subscribe().pipe(Stream.take(1), Stream.runCollect)).toMatchObject([
+          { type: "server.connected" },
+        ])
+        expect(yield* client.sessions.get({ sessionID: Session.ID.create() }).pipe(Effect.flip)).toMatchObject({
+          _tag: "SessionNotFoundError",
+        })
+        // Binding the SDK's transport must not change the caller's surrounding context.
+        expect(yield* FetchHttpClient.Fetch).toBe(ambient)
+      }).pipe(Effect.provideService(FetchHttpClient.Fetch, ambient))
+      expect(calls).toEqual([])
+
+      yield* Scope.close(scope, Exit.void)
+      expect(
+        Exit.isFailure(
+          yield* client.health.get().pipe(Effect.provideService(FetchHttpClient.Fetch, ambient), Effect.exit),
+        ),
+      ).toBe(true)
+      expect(calls).toEqual([])
+    }),
+  )
+}