diff --git a/CHANGELOG.md b/CHANGELOG.md
index 031c511..2f6d14b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,8 @@ This file is the running release and change log for CODEXIUM. Keep it updated wh
 - Workbench station-to-station rebalance so planners can move an operation onto another active work center and rebuild the downstream chain from the same dispatch surface
 - Workbench drag scheduling in station grouping mode, with draggable operation cards, station drop targets, heatmap-day-aware drop timing, and projected post-drop load cues before the move is committed
 - Workbench station cards now show planned-vs-actual load so planners can compare schedule intent against recorded execution time
+- Work-order `On Hold` quick status changes now require a recorded hold reason and persist the active blocker on the work-order record and audit trail
+- Project milestone cards now support inline quick status actions for start, block, complete, reset, and reopen flows directly from the project detail view
 - Project milestones with status, due dates, notes, and edit-time sequencing inside the project workflow
 - Project-side milestone and work-order rollups surfaced on project list and detail pages
 - Inventory SKU master builder with family-level sequence codes, branch-aware taxonomy management, and generated SKU previews on the item form
diff --git a/README.md b/README.md
index c31294a..cb4fed4 100644
--- a/README.md
+++ b/README.md
@@ -27,8 +27,8 @@ Current foundation scope includes:
 - branded quote, sales-order, and purchase-order PDFs through the shared backend document pipeline
 - purchase-order supporting documents for vendor invoices, acknowledgements, certifications, and backup files
 - shipping shipments linked to sales orders with inventory-backed picking, stock issue posting, packing slips, shipping labels, bills of lading, and logistics attachments
-- projects with customer/commercial/shipment linkage, owners, due dates, milestones, rollups, notes, attachments, reverse-linked quote/sales-order visibility, and downstream project-context carry-through into generated work orders and purchase orders
-- manufacturing work orders with project linkage, station-based operation templates, editable station calendars/capacity settings, calendar-aware operation scheduling, operation execution controls, operator assignment, timer-based and manual labor posting, material issue posting, completion posting, operation rescheduling, and work-order attachments
+- projects with customer/commercial/shipment linkage, owners, due dates, milestones, rollups, inline milestone quick-status actions, notes, attachments, reverse-linked quote/sales-order visibility, and downstream project-context carry-through into generated work orders and purchase orders
+- manufacturing work orders with project linkage, station-based operation templates, editable station calendars/capacity settings, calendar-aware operation scheduling, operation execution controls, operator assignment, timer-based and manual labor posting, required hold reasons for `On Hold` status changes, material issue posting, completion posting, operation rescheduling, and work-order attachments
 - planning workbench with live project/manufacturing schedule data, exception rail, heatmap load view, agenda view, focus drawer, station load grouping, readiness filters, overload visibility, inline dispatch actions, planner-side operation rebalance controls including station-to-station moves, and station-lane drag scheduling
 - sales-order demand planning with multi-level BOM explosion, stock/open-supply netting, and build/buy recommendations
 - planner-assisted conversion of demand-planning recommendations into prefilled work-order and purchase-order drafts
diff --git a/SHIPPED.md b/SHIPPED.md
index 20b5746..30d7acc 100644
--- a/SHIPPED.md
+++ b/SHIPPED.md
@@ -36,10 +36,10 @@ This file tracks roadmap phases, slices, and major foundations that have already
 - Logistics attachments directly on shipment records
 - Projects foundation with customer, quote, sales-order, shipment, owner, due-date, notes, and attachment linkage
 - Reverse project linkage visibility on quote and sales-order detail pages, plus project-context carry-through into generated work orders and purchase orders with sales-order-driven backfill for existing records
-- Project milestones and project-side milestone/work-order rollups
+- Project milestones, inline milestone quick-status actions, and project-side milestone/work-order rollups
 - Project cockpit section on detail pages for commercial, supply, execution, delivery, purchasing, readiness-risk, and cost-snapshot visibility, with direct launch paths into prefilled project work orders and demand-linked purchase orders plus a project activity timeline
 - Project list/detail/create/edit workflows and dashboard program widgets
-- Manufacturing foundation with work orders, project linkage, operation execution controls, operator assignment, timer-based and manual labor posting, material issue posting, completion posting, and work-order attachments
+- Manufacturing foundation with work orders, project linkage, operation execution controls, operator assignment, timer-based and manual labor posting, required hold reasons for `On Hold` status changes, material issue posting, completion posting, and work-order attachments
 - Manufacturing stations, item routing templates, editable station calendars/capacity settings, automatic work-order operation planning, and operation-level rescheduling for the workbench schedule
 - Vendor invoice/supporting-document attachments directly on purchase orders
 - Vendor-detail purchasing visibility with recent purchase-order activity
diff --git a/client/src/components/ConfirmActionDialog.tsx b/client/src/components/ConfirmActionDialog.tsx
index ee7b6d7..2ff98dc 100644
--- a/client/src/components/ConfirmActionDialog.tsx
+++ b/client/src/components/ConfirmActionDialog.tsx
@@ -11,6 +11,12 @@ interface ConfirmActionDialogProps {
   intent?: "danger" | "primary";
   confirmationLabel?: string;
   confirmationValue?: string;
+  extraFieldLabel?: string;
+  extraFieldPlaceholder?: string;
+  extraFieldValue?: string;
+  extraFieldRequired?: boolean;
+  extraFieldMultiline?: boolean;
+  onExtraFieldChange?: (value: string) => void;
   isConfirming?: boolean;
   onConfirm: () => void | Promise<void>;
   onClose: () => void;
@@ -27,6 +33,12 @@ export function ConfirmActionDialog({
   intent = "danger",
   confirmationLabel,
   confirmationValue,
+  extraFieldLabel,
+  extraFieldPlaceholder,
+  extraFieldValue = "",
+  extraFieldRequired = false,
+  extraFieldMultiline = false,
+  onExtraFieldChange,
   isConfirming = false,
   onConfirm,
   onClose,
@@ -44,7 +56,11 @@ export function ConfirmActionDialog({
   }
 
   const requiresTypedConfirmation = Boolean(confirmationLabel && confirmationValue);
-  const isConfirmDisabled = isConfirming || (requiresTypedConfirmation && typedValue.trim() !== confirmationValue);
+  const requiresExtraField = Boolean(extraFieldLabel);
+  const isConfirmDisabled =
+    isConfirming ||
+    (requiresTypedConfirmation && typedValue.trim() !== confirmationValue) ||
+    (requiresExtraField && extraFieldRequired && extraFieldValue.trim().length === 0);
   const confirmButtonClass =
     intent === "danger"
       ? "bg-red-600 text-white hover:bg-red-700"
@@ -81,6 +97,27 @@ export function ConfirmActionDialog({
             />
           </label>
         ) : null}
+        {requiresExtraField ? (
+          <label className="mt-4 block">
+            <span className="mb-2 block text-sm font-semibold text-text">{extraFieldLabel}</span>
+            {extraFieldMultiline ? (
+              <textarea
+                value={extraFieldValue}
+                onChange={(event) => onExtraFieldChange?.(event.target.value)}
+                placeholder={extraFieldPlaceholder}
+                rows={4}
+                className="w-full rounded-[18px] border border-line/70 bg-page px-3 py-2 text-text outline-none"
+              />
+            ) : (
+              <input
+                value={extraFieldValue}
+                onChange={(event) => onExtraFieldChange?.(event.target.value)}
+                placeholder={extraFieldPlaceholder}
+                className="w-full rounded-2xl border border-line/70 bg-page px-3 py-2 text-text outline-none"
+              />
+            )}
+          </label>
+        ) : null}
         <div className="mt-5 flex flex-col-reverse gap-3 sm:flex-row sm:justify-end">
           <button
             type="button"
diff --git a/client/src/lib/api.ts b/client/src/lib/api.ts
index e22307c..ed03845 100644
--- a/client/src/lib/api.ts
+++ b/client/src/lib/api.ts
@@ -75,6 +75,7 @@ import type {
   WorkOrderOperationTimerInput,
   WorkOrderMaterialIssueInput,
   WorkOrderStatus,
+  WorkOrderStatusUpdateInput,
   WorkOrderSummaryDto,
   ManufacturingUserOptionDto,
 } from "@mrp/shared";
@@ -83,6 +84,7 @@ import type {
   ProjectDetailDto,
   ProjectDocumentOptionDto,
   ProjectInput,
+  ProjectMilestoneStatusUpdateInput,
   ProjectOwnerOptionDto,
   ProjectPriority,
   ProjectShipmentOptionDto,
@@ -601,6 +603,13 @@ export const api = {
   updateProject(token: string, projectId: string, payload: ProjectInput) {
     return request<ProjectDetailDto>(`/api/v1/projects/${projectId}`, { method: "PUT", body: JSON.stringify(payload) }, token);
   },
+  updateProjectMilestoneStatus(token: string, projectId: string, milestoneId: string, payload: ProjectMilestoneStatusUpdateInput) {
+    return request<ProjectDetailDto>(
+      `/api/v1/projects/${projectId}/milestones/${milestoneId}/status`,
+      { method: "PATCH", body: JSON.stringify(payload) },
+      token
+    );
+  },
   getProjectCustomerOptions(token: string) {
     return request<ProjectCustomerOptionDto[]>("/api/v1/projects/customers/options", undefined, token);
   },
@@ -667,10 +676,10 @@ export const api = {
   updateWorkOrder(token: string, workOrderId: string, payload: WorkOrderInput) {
     return request<WorkOrderDetailDto>(`/api/v1/manufacturing/work-orders/${workOrderId}`, { method: "PUT", body: JSON.stringify(payload) }, token);
   },
-  updateWorkOrderStatus(token: string, workOrderId: string, status: WorkOrderStatus) {
+  updateWorkOrderStatus(token: string, workOrderId: string, payload: WorkOrderStatusUpdateInput) {
     return request<WorkOrderDetailDto>(
       `/api/v1/manufacturing/work-orders/${workOrderId}/status`,
-      { method: "PATCH", body: JSON.stringify({ status }) },
+      { method: "PATCH", body: JSON.stringify(payload) },
       token
     );
   },
diff --git a/client/src/modules/manufacturing/WorkOrderDetailPage.tsx b/client/src/modules/manufacturing/WorkOrderDetailPage.tsx
index e4c3b7b..fd337b2 100644
--- a/client/src/modules/manufacturing/WorkOrderDetailPage.tsx
+++ b/client/src/modules/manufacturing/WorkOrderDetailPage.tsx
@@ -30,6 +30,7 @@ export function WorkOrderDetailPage() {
   const [operatorOptions, setOperatorOptions] = useState<ManufacturingUserOptionDto[]>([]);
   const [issueForm, setIssueForm] = useState<WorkOrderMaterialIssueInput>(emptyMaterialIssueInput);
   const [completionForm, setCompletionForm] = useState<WorkOrderCompletionInput>(emptyCompletionInput);
+  const [holdReasonDraft, setHoldReasonDraft] = useState("");
   const [status, setStatus] = useState("Loading work order...");
   const [isUpdatingStatus, setIsUpdatingStatus] = useState(false);
   const [isPostingIssue, setIsPostingIssue] = useState(false);
@@ -121,8 +122,12 @@ export function WorkOrderDetailPage() {
     setIsUpdatingStatus(true);
     setStatus("Updating work-order status...");
     try {
-      const nextWorkOrder = await api.updateWorkOrderStatus(token, workOrder.id, nextStatus);
+      const nextWorkOrder = await api.updateWorkOrderStatus(token, workOrder.id, {
+        status: nextStatus,
+        reason: nextStatus === "ON_HOLD" ? holdReasonDraft : null,
+      });
       setWorkOrder(nextWorkOrder);
+      setHoldReasonDraft("");
       setStatus("Work-order status updated. Review downstream planning and shipment readiness if this change affects execution timing.");
     } catch (error: unknown) {
       const message = error instanceof ApiError ? error.message : "Unable to update work-order status.";
@@ -332,6 +337,8 @@ export function WorkOrderDetailPage() {
       impact:
         nextStatus === "CANCELLED"
           ? "Cancelling a work order can invalidate planning assumptions, reservations, and operator expectations."
+          : nextStatus === "ON_HOLD"
+            ? "Putting a work order on hold pauses expected execution and should capture the exact blocker so planning and shop-floor review stay aligned."
           : nextStatus === "COMPLETE"
             ? "Completing the work order signals execution closure and can change readiness views across the system."
             : "This changes the execution state used by planning, dashboards, and downstream operational review.",
@@ -341,6 +348,7 @@ export function WorkOrderDetailPage() {
       confirmationValue: nextStatus === "CANCELLED" ? workOrder.workOrderNumber : undefined,
       nextStatus,
     });
+    setHoldReasonDraft(nextStatus === "ON_HOLD" ? workOrder.holdReason ?? "" : "");
   }
 
   function handleIssueSubmit(event: React.FormEvent<HTMLFormElement>) {
@@ -391,6 +399,12 @@ export function WorkOrderDetailPage() {
             <h3 className="mt-2 text-xl font-bold text-text">{workOrder.workOrderNumber}</h3>
             <p className="mt-1 text-sm text-text">{workOrder.itemSku} - {workOrder.itemName}</p>
             <div className="mt-3"><WorkOrderStatusBadge status={workOrder.status} /></div>
+            {workOrder.status === "ON_HOLD" && workOrder.holdReason ? (
+              <div className="mt-3 max-w-2xl rounded-[18px] border border-amber-300/60 bg-amber-50 px-3 py-3 text-sm text-amber-900">
+                <div className="text-xs font-semibold uppercase tracking-[0.18em]">Current Hold Reason</div>
+                <div className="mt-2 whitespace-pre-line">{workOrder.holdReason}</div>
+              </div>
+            ) : null}
           </div>
           <div className="flex flex-wrap gap-3">
             <Link to="/manufacturing/work-orders" className="inline-flex items-center justify-center rounded-2xl border border-line/70 px-2 py-2 text-sm font-semibold text-text">Back to work orders</Link>
@@ -793,6 +807,12 @@ export function WorkOrderDetailPage() {
         confirmLabel={pendingConfirmation?.confirmLabel ?? "Confirm"}
         confirmationLabel={pendingConfirmation?.confirmationLabel}
         confirmationValue={pendingConfirmation?.confirmationValue}
+        extraFieldLabel={pendingConfirmation?.kind === "status" && pendingConfirmation?.nextStatus === "ON_HOLD" ? "Hold reason" : undefined}
+        extraFieldPlaceholder={pendingConfirmation?.kind === "status" && pendingConfirmation?.nextStatus === "ON_HOLD" ? "Explain the blocker forcing this work order onto hold." : undefined}
+        extraFieldValue={pendingConfirmation?.kind === "status" && pendingConfirmation?.nextStatus === "ON_HOLD" ? holdReasonDraft : undefined}
+        extraFieldRequired={pendingConfirmation?.kind === "status" && pendingConfirmation?.nextStatus === "ON_HOLD"}
+        extraFieldMultiline={pendingConfirmation?.kind === "status" && pendingConfirmation?.nextStatus === "ON_HOLD"}
+        onExtraFieldChange={pendingConfirmation?.kind === "status" && pendingConfirmation?.nextStatus === "ON_HOLD" ? setHoldReasonDraft : undefined}
         isConfirming={
           (pendingConfirmation?.kind === "status" && isUpdatingStatus) ||
           (pendingConfirmation?.kind === "issue" && isPostingIssue) ||
diff --git a/client/src/modules/projects/ProjectDetailPage.tsx b/client/src/modules/projects/ProjectDetailPage.tsx
index 59b3844..0d3a50b 100644
--- a/client/src/modules/projects/ProjectDetailPage.tsx
+++ b/client/src/modules/projects/ProjectDetailPage.tsx
@@ -1,5 +1,5 @@
 import { permissions } from "@mrp/shared";
-import type { WorkOrderSummaryDto } from "@mrp/shared";
+import type { ProjectMilestoneStatus, WorkOrderSummaryDto } from "@mrp/shared";
 import type { ProjectDetailDto } from "@mrp/shared/dist/projects/types.js";
 import type { SalesOrderPlanningDto } from "@mrp/shared/dist/sales/types.js";
 import { useEffect, useState } from "react";
@@ -23,6 +23,7 @@ export function ProjectDetailPage() {
   const [workOrders, setWorkOrders] = useState<WorkOrderSummaryDto[]>([]);
   const [planning, setPlanning] = useState<SalesOrderPlanningDto | null>(null);
   const [status, setStatus] = useState("Loading project...");
+  const [updatingMilestoneId, setUpdatingMilestoneId] = useState<string | null>(null);
 
   const canManage = user?.permissions.includes(permissions.projectsWrite) ?? false;
 
@@ -107,6 +108,50 @@ export function ProjectDetailPage() {
       ? "text-amber-600 dark:text-amber-300"
       : "text-rose-600 dark:text-rose-300";
 
+  async function updateMilestoneStatus(milestoneId: string, nextStatus: ProjectMilestoneStatus) {
+    if (!token || !project) {
+      return;
+    }
+
+    setUpdatingMilestoneId(milestoneId);
+    setStatus("Updating milestone status...");
+    try {
+      const nextProject = await api.updateProjectMilestoneStatus(token, project.id, milestoneId, { status: nextStatus });
+      setProject(nextProject);
+      setStatus("Milestone status updated.");
+    } catch (error: unknown) {
+      const message = error instanceof ApiError ? error.message : "Unable to update milestone status.";
+      setStatus(message);
+    } finally {
+      setUpdatingMilestoneId(null);
+    }
+  }
+
+  function milestoneQuickActions(currentStatus: ProjectMilestoneStatus) {
+    if (currentStatus === "PLANNED") {
+      return [
+        { status: "IN_PROGRESS" as const, label: "Start" },
+        { status: "BLOCKED" as const, label: "Block" },
+        { status: "COMPLETE" as const, label: "Complete" },
+      ];
+    }
+    if (currentStatus === "IN_PROGRESS") {
+      return [
+        { status: "BLOCKED" as const, label: "Block" },
+        { status: "COMPLETE" as const, label: "Complete" },
+        { status: "PLANNED" as const, label: "Reset" },
+      ];
+    }
+    if (currentStatus === "BLOCKED") {
+      return [
+        { status: "IN_PROGRESS" as const, label: "Resume" },
+        { status: "COMPLETE" as const, label: "Complete" },
+        { status: "PLANNED" as const, label: "Reset" },
+      ];
+    }
+    return [{ status: "IN_PROGRESS" as const, label: "Reopen" }];
+  }
+
   return (
     <section className="space-y-4">
       <div className="rounded-[20px] border border-line/70 bg-surface/90 p-4 shadow-panel 2xl:p-5">
@@ -289,7 +334,7 @@ export function ProjectDetailPage() {
           <div><p className="text-xs font-semibold uppercase tracking-[0.24em] text-muted">Milestones</p><p className="mt-2 text-sm text-muted">Track project checkpoints, blockers, and completion progress.</p></div>
           {canManage ? <Link to={`/projects/${project.id}/edit`} className="inline-flex items-center justify-center rounded-2xl border border-line/70 px-2 py-2 text-sm font-semibold text-text">Edit milestones</Link> : null}
         </div>
-        {project.milestones.length === 0 ? <div className="mt-6 rounded-[18px] border border-dashed border-line/70 bg-page/60 px-4 py-8 text-center text-sm text-muted">No milestones are defined for this project yet.</div> : <div className="mt-6 space-y-3">{project.milestones.map((milestone) => (<div key={milestone.id} className="rounded-[18px] border border-line/70 bg-page/60 p-3"><div className="flex flex-wrap items-start justify-between gap-3"><div className="min-w-0"><div className="font-semibold text-text">{milestone.title}</div><div className="mt-2 flex flex-wrap items-center gap-2"><span className={`inline-flex rounded-full px-2 py-1 text-xs font-semibold uppercase tracking-[0.16em] ${projectMilestoneStatusPalette[milestone.status]}`}>{milestone.status.replace("_", " ")}</span><span className="text-xs text-muted">Due {milestone.dueDate ? new Date(milestone.dueDate).toLocaleDateString() : "not scheduled"}</span>{milestone.completedAt ? <span className="text-xs text-muted">Completed {new Date(milestone.completedAt).toLocaleDateString()}</span> : null}</div>{milestone.notes ? <div className="mt-3 whitespace-pre-line text-sm text-text">{milestone.notes}</div> : null}</div></div></div>))}</div>}
+        {project.milestones.length === 0 ? <div className="mt-6 rounded-[18px] border border-dashed border-line/70 bg-page/60 px-4 py-8 text-center text-sm text-muted">No milestones are defined for this project yet.</div> : <div className="mt-6 space-y-3">{project.milestones.map((milestone) => (<div key={milestone.id} className="rounded-[18px] border border-line/70 bg-page/60 p-3"><div className="flex flex-wrap items-start justify-between gap-3"><div className="min-w-0"><div className="font-semibold text-text">{milestone.title}</div><div className="mt-2 flex flex-wrap items-center gap-2"><span className={`inline-flex rounded-full px-2 py-1 text-xs font-semibold uppercase tracking-[0.16em] ${projectMilestoneStatusPalette[milestone.status]}`}>{milestone.status.replace("_", " ")}</span><span className="text-xs text-muted">Due {milestone.dueDate ? new Date(milestone.dueDate).toLocaleDateString() : "not scheduled"}</span>{milestone.completedAt ? <span className="text-xs text-muted">Completed {new Date(milestone.completedAt).toLocaleDateString()}</span> : null}</div>{milestone.notes ? <div className="mt-3 whitespace-pre-line text-sm text-text">{milestone.notes}</div> : null}</div>{canManage ? <div className="flex flex-wrap gap-2">{milestoneQuickActions(milestone.status).map((action) => (<button key={action.status} type="button" onClick={() => void updateMilestoneStatus(milestone.id, action.status)} disabled={updatingMilestoneId === milestone.id} className="rounded-2xl border border-line/70 px-2 py-2 text-xs font-semibold text-text disabled:cursor-not-allowed disabled:opacity-60">{updatingMilestoneId === milestone.id ? "Saving..." : action.label}</button>))}</div> : null}</div></div>))}</div>}
       </section>
       {planning ? (
         <section className="rounded-[20px] border border-line/70 bg-surface/90 p-4 shadow-panel 2xl:p-5">
diff --git a/client/src/modules/workbench/WorkbenchPage.tsx b/client/src/modules/workbench/WorkbenchPage.tsx
index 6054e3e..5c29d91 100644
--- a/client/src/modules/workbench/WorkbenchPage.tsx
+++ b/client/src/modules/workbench/WorkbenchPage.tsx
@@ -300,7 +300,7 @@ export function WorkbenchPage() {
       return;
     }
     if (action.kind === "RELEASE_WORK_ORDER" && action.workOrderId) {
-      await api.updateWorkOrderStatus(token, action.workOrderId, "RELEASED");
+      await api.updateWorkOrderStatus(token, action.workOrderId, { status: "RELEASED" });
       await refreshWorkbench("Workbench refreshed after release.");
       return;
     }
diff --git a/server/prisma/migrations/20260318020000_work_order_hold_reason_and_milestone_quick_status/migration.sql b/server/prisma/migrations/20260318020000_work_order_hold_reason_and_milestone_quick_status/migration.sql
new file mode 100644
index 0000000..8b9ca01
--- /dev/null
+++ b/server/prisma/migrations/20260318020000_work_order_hold_reason_and_milestone_quick_status/migration.sql
@@ -0,0 +1 @@
+ALTER TABLE "WorkOrder" ADD COLUMN "holdReason" TEXT;
diff --git a/server/prisma/schema.prisma b/server/prisma/schema.prisma
index da49bdf..9862303 100644
--- a/server/prisma/schema.prisma
+++ b/server/prisma/schema.prisma
@@ -653,6 +653,7 @@ model WorkOrder {
   warehouseId       String
   locationId        String
   status            String
+  holdReason        String?
   quantity          Int
   completedQuantity Int      @default(0)
   dueDate           DateTime?
diff --git a/server/src/modules/manufacturing/router.ts b/server/src/modules/manufacturing/router.ts
index 98327ac..ac4a720 100644
--- a/server/src/modules/manufacturing/router.ts
+++ b/server/src/modules/manufacturing/router.ts
@@ -59,6 +59,7 @@ const workOrderFiltersSchema = z.object({
 
 const statusUpdateSchema = z.object({
   status: z.enum(workOrderStatuses),
+  reason: z.string().nullable().optional(),
 });
 
 const materialIssueSchema = z.object({
@@ -215,7 +216,7 @@ manufacturingRouter.patch("/work-orders/:workOrderId/status", requirePermissions
     return fail(response, 400, "INVALID_INPUT", "Work-order status payload is invalid.");
   }
 
-  const result = await updateWorkOrderStatus(workOrderId, parsed.data.status, request.authUser?.id);
+  const result = await updateWorkOrderStatus(workOrderId, parsed.data, request.authUser?.id);
   if (!result.ok) {
     return fail(response, 400, "INVALID_INPUT", result.reason);
   }
diff --git a/server/src/modules/manufacturing/service.ts b/server/src/modules/manufacturing/service.ts
index 0ba1369..942ffd9 100644
--- a/server/src/modules/manufacturing/service.ts
+++ b/server/src/modules/manufacturing/service.ts
@@ -15,6 +15,7 @@ import type {
   WorkOrderOperationTimerInput,
   WorkOrderMaterialIssueInput,
   WorkOrderStatus,
+  WorkOrderStatusUpdateInput,
   WorkOrderSummaryDto,
 } from "@mrp/shared";
 
@@ -41,6 +42,7 @@ type WorkOrderRecord = {
   id: string;
   workOrderNumber: string;
   status: string;
+  holdReason: string | null;
   quantity: number;
   completedQuantity: number;
   dueDate: Date | null;
@@ -390,6 +392,7 @@ function mapDetail(
   return {
     ...mapSummary(record),
     notes: record.notes,
+    holdReason: record.holdReason,
     createdAt: record.createdAt.toISOString(),
     itemType: record.item.type,
     itemUnitOfMeasure: record.item.unitOfMeasure,
@@ -1294,12 +1297,18 @@ export async function updateWorkOrder(workOrderId: string, payload: WorkOrderInp
   return workOrder ? { ok: true as const, workOrder } : { ok: false as const, reason: "Unable to load saved work order." };
 }
 
-export async function updateWorkOrderStatus(workOrderId: string, status: WorkOrderStatus, actorId?: string | null) {
+export async function updateWorkOrderStatus(
+  workOrderId: string,
+  payload: WorkOrderStatusUpdateInput,
+  actorId?: string | null
+) {
   const existing = await workOrderModel.findUnique({
     where: { id: workOrderId },
     select: {
       id: true,
+      workOrderNumber: true,
       status: true,
+      holdReason: true,
       quantity: true,
       completedQuantity: true,
     },
@@ -1309,18 +1318,24 @@ export async function updateWorkOrderStatus(workOrderId: string, status: WorkOrd
     return { ok: false as const, reason: "Work order was not found." };
   }
 
-  if (existing.status === "COMPLETE" && status !== "COMPLETE") {
+  if (existing.status === "COMPLETE" && payload.status !== "COMPLETE") {
     return { ok: false as const, reason: "Completed work orders cannot be reopened from quick actions." };
   }
 
-  if (status === "COMPLETE" && existing.completedQuantity < existing.quantity) {
+  if (payload.status === "COMPLETE" && existing.completedQuantity < existing.quantity) {
     return { ok: false as const, reason: "Use the completion action to finish a work order." };
   }
 
+  const nextHoldReason = payload.reason?.trim() ?? "";
+  if (payload.status === "ON_HOLD" && nextHoldReason.length === 0) {
+    return { ok: false as const, reason: "An On Hold reason is required before the work order can be paused." };
+  }
+
   await workOrderModel.update({
     where: { id: workOrderId },
     data: {
-      status,
+      status: payload.status,
+      holdReason: payload.status === "ON_HOLD" ? nextHoldReason : null,
     },
   });
 
@@ -1333,10 +1348,12 @@ export async function updateWorkOrderStatus(workOrderId: string, status: WorkOrd
       entityType: "work-order",
       entityId: workOrderId,
       action: "status.updated",
-      summary: `Updated work order ${workOrder.workOrderNumber} to ${status}.`,
+      summary: `Updated work order ${workOrder.workOrderNumber} to ${payload.status}.`,
       metadata: {
         workOrderNumber: workOrder.workOrderNumber,
-        status,
+        previousStatus: existing.status,
+        status: payload.status,
+        holdReason: payload.status === "ON_HOLD" ? nextHoldReason : null,
       },
     });
   }
diff --git a/server/src/modules/projects/router.ts b/server/src/modules/projects/router.ts
index 0a8bb09..6674cc8 100644
--- a/server/src/modules/projects/router.ts
+++ b/server/src/modules/projects/router.ts
@@ -14,6 +14,7 @@ import {
   listProjectQuoteOptions,
   listProjectShipmentOptions,
   updateProject,
+  updateProjectMilestoneStatus,
 } from "./service.js";
 
 const projectSchema = z.object({
@@ -51,6 +52,10 @@ const projectOptionQuerySchema = z.object({
   customerId: z.string().optional(),
 });
 
+const milestoneStatusSchema = z.object({
+  status: z.enum(projectMilestoneStatuses),
+});
+
 function getRouteParam(value: unknown) {
   return typeof value === "string" ? value : null;
 }
@@ -147,3 +152,23 @@ projectsRouter.put("/:projectId", requirePermissions([permissions.projectsWrite]
 
   return ok(response, result.project);
 });
+
+projectsRouter.patch("/:projectId/milestones/:milestoneId/status", requirePermissions([permissions.projectsWrite]), async (request, response) => {
+  const projectId = getRouteParam(request.params.projectId);
+  const milestoneId = getRouteParam(request.params.milestoneId);
+  if (!projectId || !milestoneId) {
+    return fail(response, 400, "INVALID_INPUT", "Project or milestone id is invalid.");
+  }
+
+  const parsed = milestoneStatusSchema.safeParse(request.body);
+  if (!parsed.success) {
+    return fail(response, 400, "INVALID_INPUT", "Project milestone status payload is invalid.");
+  }
+
+  const result = await updateProjectMilestoneStatus(projectId, milestoneId, parsed.data, request.authUser?.id);
+  if (!result.ok) {
+    return fail(response, 400, "INVALID_INPUT", result.reason);
+  }
+
+  return ok(response, result.project);
+});
diff --git a/server/src/modules/projects/service.ts b/server/src/modules/projects/service.ts
index c9bbe80..fb64088 100644
--- a/server/src/modules/projects/service.ts
+++ b/server/src/modules/projects/service.ts
@@ -11,6 +11,8 @@ import type {
   ProjectInput,
   ProjectMilestoneDto,
   ProjectMilestoneInput,
+  ProjectMilestoneStatus,
+  ProjectMilestoneStatusUpdateInput,
   ProjectOwnerOptionDto,
   ProjectPriority,
   ProjectRollupDto,
@@ -1266,3 +1268,60 @@ export async function updateProject(projectId: string, payload: ProjectInput, ac
   }
   return project ? { ok: true as const, project } : { ok: false as const, reason: "Unable to load saved project." };
 }
+
+export async function updateProjectMilestoneStatus(
+  projectId: string,
+  milestoneId: string,
+  payload: ProjectMilestoneStatusUpdateInput,
+  actorId?: string | null
+) {
+  const existing = await prisma.projectMilestone.findUnique({
+    where: { id: milestoneId },
+    select: {
+      id: true,
+      projectId: true,
+      title: true,
+      status: true,
+      completedAt: true,
+      project: {
+        select: {
+          id: true,
+          projectNumber: true,
+        },
+      },
+    },
+  });
+
+  if (!existing || existing.projectId !== projectId) {
+    return { ok: false as const, reason: "Project milestone was not found." };
+  }
+
+  const nextStatus = payload.status as ProjectMilestoneStatus;
+  await prisma.projectMilestone.update({
+    where: { id: milestoneId },
+    data: {
+      status: nextStatus,
+      completedAt: nextStatus === "COMPLETE" ? existing.completedAt ?? new Date() : null,
+    },
+  });
+
+  const project = await getProjectById(projectId);
+  if (project) {
+    await logAuditEvent({
+      actorId,
+      entityType: "project",
+      entityId: projectId,
+      action: "milestone.status.updated",
+      summary: `Updated milestone ${existing.title} on ${existing.project.projectNumber} to ${nextStatus}.`,
+      metadata: {
+        projectNumber: existing.project.projectNumber,
+        milestoneId,
+        milestoneTitle: existing.title,
+        previousStatus: existing.status,
+        status: nextStatus,
+      },
+    });
+  }
+
+  return project ? { ok: true as const, project } : { ok: false as const, reason: "Unable to load saved project." };
+}
diff --git a/shared/src/manufacturing/types.ts b/shared/src/manufacturing/types.ts
index 2d3c713..cf4da18 100644
--- a/shared/src/manufacturing/types.ts
+++ b/shared/src/manufacturing/types.ts
@@ -157,6 +157,7 @@ export interface WorkOrderCompletionDto {
 
 export interface WorkOrderDetailDto extends WorkOrderSummaryDto {
   notes: string;
+  holdReason: string | null;
   createdAt: string;
   itemType: string;
   itemUnitOfMeasure: string;
@@ -218,3 +219,8 @@ export interface WorkOrderOperationTimerInput {
   action: "START" | "STOP";
   notes: string;
 }
+
+export interface WorkOrderStatusUpdateInput {
+  status: WorkOrderStatus;
+  reason?: string | null;
+}
diff --git a/shared/src/projects/types.ts b/shared/src/projects/types.ts
index 6a7b5a2..7d1988a 100644
--- a/shared/src/projects/types.ts
+++ b/shared/src/projects/types.ts
@@ -189,6 +189,10 @@ export interface ProjectMilestoneInput {
   sortOrder: number;
 }
 
+export interface ProjectMilestoneStatusUpdateInput {
+  status: ProjectMilestoneStatus;
+}
+
 export interface ProjectDetailDto extends ProjectSummaryDto {
   notes: string;
   createdAt: string;