Kanban Cards Module

Status: Live (lifecycle redesign in progress). The module ships today; the operational lifecycle described here is being tightened from the looser behavior in the live system. The full engineering reference for what ships today is kept at Kanban Cards (Q2 2026).

Purpose

A kanban card is the pull-replenishment signal for an item: a standing authorization to replenish a specific item in a specific quantity. When stock is drawn down, the card signals the need and travels back toward the point that supplies it; when materials are produced or procured, the card carries them forward to the point of use. It is the shop-floor unit of demand.

The module has two parts:

• The durable card — its identity, its configuration (which item, what quantity), and its printed artifact (with a QR code).
• The cycle — one lap of the replenishment loop: the live operational state of a single round trip. A card runs one cycle at a time and rolls over to a new cycle each time demand is re-triggered.

Main entities

• Kanban card — the durable signal: which item it replenishes, the target quantity, and its print state. It exists independently of whether it is currently circulating.
• Card cycle — one lap of the loop, carrying the operational state and the materials in flight during that lap.

Lifecycle

A card cycle runs a loop: demand travels from the point of use back to the point that supplies it, materials are produced or procured, and they travel forward to be consumed — after which demand is re-triggered and the next lap begins. A card that is not circulating rests at Available.

The lifecycle redesign underway replaces the live system’s loose behavior — which today lets a card move from almost any state to almost any other — with an explicit rule: a card advances forward along the lap (and may skip stages a given site does not perform, such as a site with no formal receiving step), plus a few named exceptions — starting the next lap with a new demand signal (which closes out the current lap; allowed once the card’s materials are ready, from materials ready through fully depleted), pulling a card back out of an order that was never submitted (shelve), and withdrawing a card from circulation (possible at any point in the lap). Backward or arbitrary jumps are no longer allowed.

Operations

Action	What it does	Notes
Request	Puts a card into circulation, or re-triggers demand for a new lap.	Starts a cycle.
Accept	Takes the demand into the order queue.
Shelve	Pulls a card back out of an order that was never submitted.	The corrective exception.
Start / complete replenishment	Advances the card through procurement or production.
Fulfill / receive	Moves materials to the point of use and records their arrival.
Use / deplete	Records consumption until the card is empty.	Ends the lap.
Withdraw	Removes a card from circulation.
Print / reprint / report lost / retire	Manage the card’s printed artifact.	Independent of the operational state.

Guarantees

• One cycle at a time. A card runs a single live cycle; a new lap begins only when demand is re-triggered.
• A lap ends one of two ways, and the two are distinct. A lap either rolls over into the next one (recorded as completed) or is withdrawn (recorded as abandoned); once ended, it is final. A card withdrawn and later re-requested reads as abandoned, not completed.
• Moves are disciplined. Under the redesign, a card advances forward along its lap (skips allowed) plus the few named exceptions — not the anything-goes transitions of the live system.
• Print state is independent. Whether a card is printed, reprinted, lost, or retired is tracked separately from where it is in its replenishment lap.
• A deleted item does not break a card. A card keeps resolving even after the item it references is deleted, showing the item’s last-known name with a deleted marker.

How it relates to its neighbors

• Item — every card replenishes one item.
• Inventory Item — the materials a loaded card carries are inventory holdings.
• Demand — cards are the individual demand signals that the Demand module collates into production requests.
• Processing Network — cards circulate within the loops that connect stations.