diff --git a/packages/opencode/src/effect/bridge.ts b/packages/opencode/src/effect/bridge.ts
index 281cfa010c..3c310129f1 100644
--- a/packages/opencode/src/effect/bridge.ts
+++ b/packages/opencode/src/effect/bridge.ts
@@ -1,4 +1,4 @@
-import { Effect, Fiber } from "effect"
+import { Effect, Exit, Fiber } from "effect"
 import { WorkspaceContext } from "@/control-plane/workspace-context"
 import { Instance, type InstanceContext } from "@/project/instance"
 import type { WorkspaceID } from "@/control-plane/schema"
@@ -9,6 +9,7 @@ import { attachWith } from "./run-service"
 export interface Shape {
   readonly promise: <A, E, R>(effect: Effect.Effect<A, E, R>) => Promise<A>
   readonly fork: <A, E, R>(effect: Effect.Effect<A, E, R>) => Fiber.Fiber<A, E>
+  readonly run: <A, E, R>(effect: Effect.Effect<A, E, R>) => Effect.Effect<A, E>
 }
 
 function restore<R>(instance: InstanceContext | undefined, workspace: WorkspaceID | undefined, fn: () => R): R {
@@ -43,6 +44,14 @@ export function make(): Effect.Effect<Shape> {
         restore(instance, workspace, () => Effect.runPromise(wrap(effect))),
       fork: <A, E, R>(effect: Effect.Effect<A, E, R>) =>
         restore(instance, workspace, () => Effect.runFork(wrap(effect))),
+      run: <A, E, R>(effect: Effect.Effect<A, E, R>) =>
+        Effect.callback<A, E>((resume) => {
+          restore(instance, workspace, () =>
+            Effect.runPromiseExit(wrap(effect)).then((exit) =>
+              resume(Exit.isSuccess(exit) ? Effect.succeed(exit.value) : Effect.failCause(exit.cause)),
+            ),
+          )
+        }),
     } satisfies Shape
   })
 }
diff --git a/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts b/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts
index 39643e35ff..e08e09495a 100644
--- a/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts
+++ b/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts
@@ -18,9 +18,8 @@ import { SessionSummary } from "@/session/summary"
 import { Todo } from "@/session/todo"
 import { MessageID, PartID, SessionID } from "@/session/schema"
 import { NotFoundError } from "@/storage/storage"
-import * as Log from "@opencode-ai/core/util/log"
 import { NamedError } from "@opencode-ai/core/util/error"
-import { Effect, Schema } from "effect"
+import { Cause, Effect, Schema } from "effect"
 import * as Stream from "effect/Stream"
 import { HttpServerRequest, HttpServerResponse } from "effect/unstable/http"
 import { HttpApiBuilder, HttpApiError, HttpApiSchema } from "effect/unstable/httpapi"
@@ -40,8 +39,6 @@ import {
   UpdatePayload,
 } from "../groups/session"
 
-const log = Log.create({ service: "server" })
-
 const mapNotFound = <A, E, R>(self: Effect.Effect<A, E, R>) =>
   self.pipe(
     Effect.catchIf(NotFoundError.isInstance, () => Effect.fail(new HttpApiError.NotFound({}))),
@@ -63,6 +60,7 @@ export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session",
     const statusSvc = yield* SessionStatus.Service
     const todoSvc = yield* Todo.Service
     const summary = yield* SessionSummary.Service
+    const bus = yield* Bus.Service
 
     const list = Effect.fn("SessionHttpApi.list")(function* (ctx: { query: typeof ListQuery.Type }) {
       const instance = yield* InstanceState.context
@@ -264,13 +262,11 @@ export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session",
       const bridge = yield* EffectBridge.make()
       return HttpServerResponse.stream(
         Stream.fromEffect(
-          Effect.promise(() =>
-            bridge.promise(
-              promptSvc.prompt({
-                ...ctx.payload,
-                sessionID: ctx.params.sessionID,
-              }),
-            ),
+          bridge.run(
+            promptSvc.prompt({
+              ...ctx.payload,
+              sessionID: ctx.params.sessionID,
+            }),
           ),
         ).pipe(
           Stream.map((message) => JSON.stringify(message)),
@@ -288,12 +284,12 @@ export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session",
       yield* Effect.sync(() => {
         bridge.fork(
           promptSvc.prompt({ ...ctx.payload, sessionID: ctx.params.sessionID }).pipe(
-            Effect.catchCause((error) =>
-              Effect.sync(() => {
-                log.error("prompt_async failed", { sessionID: ctx.params.sessionID, error })
-                void Bus.publish(Session.Event.Error, {
+            Effect.catchCause((cause) =>
+              Effect.gen(function* () {
+                yield* Effect.logError("prompt_async failed", { sessionID: ctx.params.sessionID, cause })
+                yield* bus.publish(Session.Event.Error, {
                   sessionID: ctx.params.sessionID,
-                  error: new NamedError.Unknown({ message: String(error) }).toObject(),
+                  error: new NamedError.Unknown({ message: Cause.pretty(cause) }).toObject(),
                 })
               }),
             ),