diff --git a/packages/api/src/__tests__/timeline-project-procedure-support.test.ts b/packages/api/src/__tests__/timeline-project-procedure-support.test.ts
index 96f5ec1..91b795c 100644
--- a/packages/api/src/__tests__/timeline-project-procedure-support.test.ts
+++ b/packages/api/src/__tests__/timeline-project-procedure-support.test.ts
@@ -41,6 +41,7 @@ import {
 } from "../router/timeline-project-query-support.js";
 import {
   readTimelineProjectBudgetStatusResponse,
+  readTimelineProjectShiftPreview,
   readTimelineProjectShiftPreviewDetail,
 } from "../router/timeline-project-procedure-support.js";
 
@@ -89,6 +90,24 @@ describe("timeline project procedure support", () => {
     });
   });
 
+  it("loads plain shift preview responses through procedure support", async () => {
+    previewTimelineProjectShiftMock.mockResolvedValueOnce({ valid: true } as never);
+
+    await expect(
+      readTimelineProjectShiftPreview({} as never, {
+        projectId: "project_1",
+        newStartDate: new Date("2026-04-03T00:00:00.000Z"),
+        newEndDate: new Date("2026-04-12T00:00:00.000Z"),
+      }),
+    ).resolves.toEqual({ valid: true });
+
+    expect(previewTimelineProjectShiftMock).toHaveBeenCalledWith({}, {
+      projectId: "project_1",
+      newStartDate: new Date("2026-04-03T00:00:00.000Z"),
+      newEndDate: new Date("2026-04-12T00:00:00.000Z"),
+    });
+  });
+
   it("builds budget status responses from project bookings", async () => {
     findTimelineProjectOrThrowMock.mockResolvedValueOnce({
       id: "project_1",
diff --git a/packages/api/src/__tests__/timeline-read-shared.test.ts b/packages/api/src/__tests__/timeline-read-shared.test.ts
index 771b112..2346a81 100644
--- a/packages/api/src/__tests__/timeline-read-shared.test.ts
+++ b/packages/api/src/__tests__/timeline-read-shared.test.ts
@@ -3,6 +3,7 @@ import {
   buildTimelineEntriesDetailInput,
   TimelineDetailFiltersSchema,
   TimelineProjectContextDetailSchema,
+  TimelineProjectIdSchema,
 } from "../router/timeline-read-shared.js";
 
 describe("timeline read shared", () => {
@@ -68,5 +69,11 @@ describe("timeline read shared", () => {
       endDate: "2026-04-20",
       durationDays: undefined,
     });
+
+    expect(TimelineProjectIdSchema.parse({
+      projectId: "project_1",
+    })).toEqual({
+      projectId: "project_1",
+    });
   });
 });
diff --git a/packages/api/src/router/timeline-project-procedure-support.ts b/packages/api/src/router/timeline-project-procedure-support.ts
index d036de1..8e22cc4 100644
--- a/packages/api/src/router/timeline-project-procedure-support.ts
+++ b/packages/api/src/router/timeline-project-procedure-support.ts
@@ -45,6 +45,17 @@ export async function readTimelineProjectShiftPreviewDetail(
   });
 }
 
+export async function readTimelineProjectShiftPreview(
+  db: TimelineProjectProcedureDb,
+  input: {
+    projectId: string;
+    newStartDate: Date;
+    newEndDate: Date;
+  },
+) {
+  return previewTimelineProjectShift(db, input);
+}
+
 export async function readTimelineProjectBudgetStatusResponse(
   db: TimelineProjectProcedureDb,
   projectId: string,
diff --git a/packages/api/src/router/timeline-project-read.ts b/packages/api/src/router/timeline-project-read.ts
index 21f62c0..a4fb489 100644
--- a/packages/api/src/router/timeline-project-read.ts
+++ b/packages/api/src/router/timeline-project-read.ts
@@ -1,9 +1,8 @@
 import { ShiftProjectSchema } from "@capakraken/shared";
-import { z } from "zod";
 import { controllerProcedure } from "../trpc.js";
-import { previewTimelineProjectShift } from "./timeline-project-load-support.js";
 import {
   TimelineProjectContextDetailSchema,
+  TimelineProjectIdSchema,
 } from "./timeline-read-shared.js";
 import {
   readTimelineProjectContextDetailResponse,
@@ -11,12 +10,13 @@ import {
 } from "./timeline-project-context-procedure-support.js";
 import {
   readTimelineProjectBudgetStatusResponse,
+  readTimelineProjectShiftPreview,
   readTimelineProjectShiftPreviewDetail,
 } from "./timeline-project-procedure-support.js";
 
 export const timelineProjectReadProcedures = {
   getProjectContext: controllerProcedure
-    .input(z.object({ projectId: z.string() }))
+    .input(TimelineProjectIdSchema)
     .query(async ({ ctx, input }) => readTimelineProjectContextResponse(ctx.db, input.projectId)),
 
   getProjectContextDetail: controllerProcedure
@@ -25,13 +25,13 @@ export const timelineProjectReadProcedures = {
 
   previewShift: controllerProcedure
     .input(ShiftProjectSchema)
-    .query(async ({ ctx, input }) => previewTimelineProjectShift(ctx.db, input)),
+    .query(async ({ ctx, input }) => readTimelineProjectShiftPreview(ctx.db, input)),
 
   getShiftPreviewDetail: controllerProcedure
     .input(ShiftProjectSchema)
     .query(async ({ ctx, input }) => readTimelineProjectShiftPreviewDetail(ctx.db, input)),
 
   getBudgetStatus: controllerProcedure
-    .input(z.object({ projectId: z.string() }))
+    .input(TimelineProjectIdSchema)
     .query(async ({ ctx, input }) => readTimelineProjectBudgetStatusResponse(ctx.db, input.projectId)),
 };
diff --git a/packages/api/src/router/timeline-read-shared.ts b/packages/api/src/router/timeline-read-shared.ts
index 5c58b41..f8ad155 100644
--- a/packages/api/src/router/timeline-read-shared.ts
+++ b/packages/api/src/router/timeline-read-shared.ts
@@ -60,6 +60,10 @@ export const TimelineProjectContextDetailSchema = z.object({
   durationDays: z.number().int().min(1).max(366).optional(),
 });
 
+export const TimelineProjectIdSchema = z.object({
+  projectId: z.string(),
+});
+
 type TimelineWindowFiltersInput = z.infer<typeof TimelineWindowFiltersSchema>;
 
 export function getAssignmentResourceIds(