diff --git a/packages/opencode/src/server/routes/instance/httpapi/handlers/session-errors.ts b/packages/opencode/src/server/routes/instance/httpapi/handlers/session-errors.ts
index 0fef2e7763..d4ab0eb599 100644
--- a/packages/opencode/src/server/routes/instance/httpapi/handlers/session-errors.ts
+++ b/packages/opencode/src/server/routes/instance/httpapi/handlers/session-errors.ts
@@ -1,7 +1,13 @@
 import type { NotFoundError as StorageNotFoundError } from "@/storage/storage"
+import type { Session } from "@/session/session"
 import { Effect } from "effect"
+import { HttpApiError } from "effect/unstable/httpapi"
 import * as ApiError from "../errors"
 
 export function mapStorageNotFound<A, R>(self: Effect.Effect<A, StorageNotFoundError, R>) {
   return self.pipe(Effect.mapError((error) => ApiError.notFound(error.message)))
 }
+
+export function mapBusy<A, R>(self: Effect.Effect<A, Session.BusyError, R>) {
+  return self.pipe(Effect.catchTag("SessionBusyError", () => Effect.fail(new HttpApiError.BadRequest({}))))
+}
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 e3f79965da..6509aa2b1f 100644
--- a/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts
+++ b/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts
@@ -58,11 +58,6 @@ export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session",
     const bus = yield* Bus.Service
     const scope = yield* Scope.Scope
 
-    const mapBusy = <A, R>(
-      effect: Effect.Effect<A, Session.BusyError, R>,
-    ): Effect.Effect<A, HttpApiError.BadRequest, R> =>
-      effect.pipe(Effect.catchTag("SessionBusyError", () => Effect.fail(new HttpApiError.BadRequest({}))))
-
     const list = Effect.fn("SessionHttpApi.list")(function* (ctx: { query: typeof ListQuery.Type }) {
       return yield* session.list({
         directory: ctx.query.scope === "project" ? undefined : ctx.query.directory,
@@ -334,7 +329,7 @@ export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session",
       payload: typeof ShellPayload.Type
     }) {
       yield* requireSession(ctx.params.sessionID)
-      return yield* mapBusy(promptSvc.shell({ ...ctx.payload, sessionID: ctx.params.sessionID }))
+      return yield* SessionError.mapBusy(promptSvc.shell({ ...ctx.payload, sessionID: ctx.params.sessionID }))
     })
 
     const revert = Effect.fn("SessionHttpApi.revert")(function* (ctx: {
@@ -342,12 +337,12 @@ export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session",
       payload: typeof RevertPayload.Type
     }) {
       yield* requireSession(ctx.params.sessionID)
-      return yield* mapBusy(revertSvc.revert({ sessionID: ctx.params.sessionID, ...ctx.payload }))
+      return yield* SessionError.mapBusy(revertSvc.revert({ sessionID: ctx.params.sessionID, ...ctx.payload }))
     })
 
     const unrevert = Effect.fn("SessionHttpApi.unrevert")(function* (ctx: { params: { sessionID: SessionID } }) {
       yield* requireSession(ctx.params.sessionID)
-      return yield* mapBusy(revertSvc.unrevert({ sessionID: ctx.params.sessionID }))
+      return yield* SessionError.mapBusy(revertSvc.unrevert({ sessionID: ctx.params.sessionID }))
     })
 
     const permissionRespond = Effect.fn("SessionHttpApi.permissionRespond")(function* (ctx: {
@@ -363,7 +358,7 @@ export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session",
       params: { sessionID: SessionID; messageID: MessageID }
     }) {
       yield* requireSession(ctx.params.sessionID)
-      yield* mapBusy(runState.assertNotBusy(ctx.params.sessionID))
+      yield* SessionError.mapBusy(runState.assertNotBusy(ctx.params.sessionID))
       yield* session.removeMessage(ctx.params)
       return true
     })