What Is MRP Action Messages?
Also known as: exception messages, MRP exception messages, reschedule in, reschedule out, cancel messages
Definition
MRP action messages are exception prompts generated by the planning run, telling planners to release, reschedule in, reschedule out, change quantity or cancel existing orders so supply matches current demand.
MRP Action Messages Explained
MRP compares existing supply orders against the dates and quantities it now calculates are needed. When they differ, it cannot silently change a released order, so it writes an action message for a planner to review. The usual types are release (a planned order has reached its start date), reschedule in (bring the due date earlier), reschedule out (push it later), increase or decrease quantity, and cancel (no demand remains).
Action messages are the daily worklist of a materials planner or buyer. They are typically filtered by planner code, item class or supplier and prioritized by how close the date is and how large the shortage is. Systems also include warnings for items inside the planning time fence, for missing lead times and for past-due orders.
Where they appear varies. SyteLine surfaces planning exceptions in its planning workbench and MRP exception reports, Infor LN shows action messages in planned order and planning exception sessions, SAP provides the MRP list and stock requirements list with exception codes, and NetSuite presents supply plan recommendations to approve.
The failure mode is overload. If the parameters are wrong, a plant can generate thousands of messages per night, and planners begin to ignore all of them. Tuning time fences, lot sizes and tolerance windows to suppress noise is usually the right fix, rather than adding more people.
Why It Matters
- They are the control point that keeps released orders aligned with demand without MRP overriding commitments.
- Ignored messages are a leading cause of excess inventory, since cancel and reschedule out messages go unactioned.
- Message volume is a direct measure of planning parameter quality.
- Triaging messages by impact is an ideal task for AI assistance with a human making the final change.
In Practice
Example: a purchase order for 500 units is due the 20th, but a sales order cancellation means the need moves to the 10th of next month. MRP raises a reschedule out message. If the supplier cannot move the date, the planner may instead accept the early receipt and note the extra carrying cost.
Frequently Asked Questions
What does reschedule in mean?
It means an existing supply order should arrive earlier because demand now needs it sooner than its current due date.
Why do I get so many MRP messages?
Typically from tight tolerances, noisy forecasts, short time fences, or inaccurate lead times and lot sizes. Tuning parameters usually cuts the volume more effectively than adding review staff.
Does MRP act on the messages automatically?
Usually not. Release of planned orders can be automated in some systems, but changes to released orders normally need planner approval.
Related Terms
MRP (Material Requirements Planning)
MRP (Material Requirements Planning) is the ERP calculation that explodes demand through bills of materials, nets it against on-hand and on-order inventory, and offsets by lead time to produce timed purchase and work order suggestions.
Planned Order
A planned order is a system-generated supply proposal that MRP creates to cover a net requirement. It has a quantity and dates but is not yet a committed job, production order or purchase order, and MRP can delete or reschedule it on every run.
Planning Time Fence
A planning time fence is a number of days from today inside which MRP will not automatically create or change planned supply. Changes in that window need planner approval, which keeps near-term production stable while the outer horizon remains flexible.
Firm Planned Order
A firm planned order (FPO) is a planned order that a planner has frozen so MRP will not delete, resize or reschedule it. It still counts as supply in netting, and it stays a planned order rather than becoming a released production or purchase order.
Go Deeper
MRP Nervousness Assessment
A 10-question diagnostic that scores how badly your MRP plan churns between runs - and pinpoints which levers will stabilize it.
Free ToolSyteLine MRP Health Check
Diagnose why your SyteLine MRP output is noisy or ignored, scoring data accuracy, parameters, and planner behavior across ten dimensions.
SyteLine MRP Parameters Tuning Guide
Optimize SyteLine MRP parameters including order policies, lot sizing, safety stock, and lead times for accurate material requirements planning results.
SyteLine Planning Time Fence Configuration Guide
Configure SyteLine planning time fences with demand fence, planning fence, and frozen zone settings to stabilize production schedules and reduce MRP nervousness.
Working with MRP Action Messages in a live environment? Our engineers do this every day - and our AI agents automate most of it.