On a plant floor the general ledger has to do more than record cash and revenue — it has to track cost as it flows through production. Raw material is received at an actual price but valued in inventory at a standard cost; the difference is a purchase-price variance that belongs in the P&L, not buried in a balance. Inventory then moves into work-in-process, and out again as cost of goods sold. A generic GL has no concept of any of this — it sees a payables entry and an asset, and the variance disappears. This overlay turns the ledger into a cost-accounting ledger: standard-cost variance journals, a cost-center chart of accounts, and inventory that flows Inventory → WIP → COGS while every invariant holds to the cent.

The problem — and the money

The buyer is the plant controller or cost accountant who owns gross margin. If the purchase-price variance isn't isolated to the P&L, margin is wrong and every make-vs-buy and pricing decision downstream is wrong with it; if inventory and WIP don't roll cleanly onto the balance sheet, the plant's working-capital number is fiction. The payoff is concrete: a receipt of 100 units with a standard cost of 100.00 and an actual of 105.00 books inventory at 10000.00, routes the 500.00 variance straight to the P&L, and credits payables at the 10500.00 actual — a balanced journal that keeps the trial balance at 0.00 and lands the variance exactly where a cost accountant needs to see it.

This is the GL suite + the manufacturing overlay. The six base skills — core, journal-entry, financial-reporting and the rest — are unchanged. The overlay only adds one column, one table, four chart-of-accounts leaves, and a variance-journal pattern. Same bucket, one copy of the rows.

What manufacturing adds

A small, additive diff on top of the suite (skill: gl/manufacturing → the gl/overlays/manufacturing contract):

  • One column on the gl/core accounts master — cost_center — added with ALTER TABLE … ADD COLUMN over the pg wire. A column-add, never a second copy.
  • Cost accounts — the chart of accounts gains Inventory (1300) and Work in Process (1350) as assets, COGS (5100) and a Cost Variance / PPV account (5150) as P&L expenses, all tagged cost_center=plant-a and attached to the existing 1000 (assets) / 5000 (expenses) roots.
  • One table — standard_costs (key item_id): the per-item standard vs actual unit cost (qty, std_unit_cost, actual_unit_cost, all money DECIMAL(18,2)) the variance journal reads.
  • One journal pattern — a standard-cost variance journal: DEBIT Inventory at standard, DEBIT Cost Variance by the actual − standard purchase-price variance, CREDIT Accounts Payable at actual. Because standard + variance = actual, it balances. Inventory then flows Inventory → WIP → COGS through two balanced cost-flow journals.

Apply the diff — the ALTER, the cost accounts, the standard-cost table, and the balanced variance journal:

You

In the gl bucket, apply the manufacturing overlay: ALTER accounts ADD cost_center; add the Inventory (1300), WIP (1350), COGS (5100) and Cost Variance/PPV (5150) accounts on plant-a; create standard_costs and seed WIDGET-1 (qty 100, standard 100.00, actual 105.00); then post the standard-cost variance journal — inventory at standard, the variance to the P&L, payables at actual.

DODIL MCP tools called
data_pg→data_table_create→data_table_upsert
Agent

Added cost_center to accounts (ALTER over pg — the master, not a copy). Seeded Inventory/WIP/COGS/Cost-Variance on plant-a. Created standard_costs; WIDGET-1 gives standard 10000.00 vs actual 10500.00 -> a 500.00 variance. Posted journal 2: DEBIT Inventory 10000.00 + DEBIT Cost Variance 500.00 + CREDIT Accounts Payable 10500.00 — balanced, debit=credit=10500.00.

Now the payoff — the variance derived from the standard-cost table, the journal balancing, and the variance landing in the P&L while the balance sheet ties:

You

In gl, derive WIDGET-1's variance from standard_costs (qty x (actual - standard)), confirm the variance journal balances, flow inventory Inventory -> WIP -> COGS, then roll the ledger up by account type and show that the variance hits the P&L and the balance sheet ties.

DODIL MCP tools called
data_pg→data_sql
Agent

WIDGET-1: standard 10000.00, actual 10500.00 -> variance 500.00. Journal 2 balances (debit=credit=10500.00). After the cost-flow journals inventory and WIP net to 0.00 and COGS is 10000.00. Account-type rollup: assets 1000000.00, liabilities 10500.00, equity 1000000.00, expense 10500.00 (COGS 10000.00 + variance 500.00) -> net income -10500.00. Balance sheet ties (assets = liabilities + equity + net income), trial balance 0.00.

The variance is 500.00 because standard + variance = actual (10000.00 + 500.00 = 10500.00), so the journal balances by construction. Inventory and WIP net to 0.00 once production completes; COGS carries 10000.00 and the Cost Variance carries 500.00 — both in the P&L, so net income already absorbs the variance and the balance sheet ties without a plug.

Scaffold it — the one-shot

With the DODIL MCP connected, one prompt composes the suite and this overlay:

Scaffold a GL for my plant — the GL suite plus the manufacturing overlay.
 
Base: the full gl suite (chart of accounts + account-hierarchy graph + journal-entry / period-close /
financial-reporting / subledger-reconciliation / multi-currency) on one bucket, money DECIMAL(18,2),
idempotent ON CONFLICT posting.
 
Then apply the manufacturing overlay on the SAME bucket:
1. ALTER accounts ADD cost_center (pg wire — the master, not a copy).
2. Add Inventory (1300), WIP (1350), COGS (5100), Cost Variance/PPV (5150) on plant-a, under the existing
   asset / expense roots.
3. Create standard_costs (key item_id) — the per-item standard vs actual unit cost.
4. Post a standard-cost variance journal: DEBIT Inventory at standard, DEBIT Cost Variance by
   actual - standard, CREDIT Accounts Payable at actual (balanced); then flow Inventory -> WIP -> COGS.
Seed WIDGET-1 above and show the variance hitting the P&L while the balance sheet ties and the trial
balance stays 0.00.

Verify

Every result below was live-validated on 2026-09-03 (org IHDIASH, throwaway bucket glovlmfg0903, torn down after):

# the column lands (nullable, over the pg wire)
dodil data pg -b "$BUCKET" "ALTER TABLE accounts ADD COLUMN cost_center VARCHAR"
# the variance journal balances: debit = credit = 10500.00
dodil data sql -b "$BUCKET" "SELECT CAST(SUM(debit) AS VARCHAR) d, CAST(SUM(credit) AS VARCHAR) c,
  CAST(SUM(debit)-SUM(credit) AS VARCHAR) imbalance FROM journal_lines WHERE journal_id=2"   # -> 10500.00 | 10500.00 | 0.00
# the variance hits the P&L + the balance sheet ties + trial balance 0.00
dodil data sql -b "$BUCKET" "SELECT a.type, CAST(SUM(l.balance) AS VARCHAR) net FROM ledger l
  JOIN accounts a ON a.account_id=l.account_id GROUP BY a.type ORDER BY a.type"
# a bare re-INSERT of a committed line raises 23505; the ON CONFLICT re-post leaves counts + trial balance unchanged

The ALTER-add, the standard_costs table, the balanced standard-cost variance journal (10500.00 = 10500.00), the Inventory → WIP → COGS cost flow, the variance landing in the P&L (expense net 10500.00 = COGS 10000.00 + variance 500.00), the balance-sheet tie (assets 1000000.00 = liabilities 10500.00 + equity 1000000.00 + net income -10500.00), and the trial balance holding at exactly 0.00 across 7 accounts are all proven live — including an idempotent ON CONFLICT re-post that leaves the journal at 3 lines and the trial balance at 0.00.

Connect your tools

Everything the overlay wrote lives in the one DataK3 bucket, reachable by your own stack — a cost-accounting / MES integration reads standard_costs and the cost accounts over the Postgres wire; a plant-controller dashboard runs the account-type rollup as plain SQL to chart margin and variance. data connect gl prints the endpoints. Full, live-validated walkthrough: Connect your tools.

Composes

This page is not a fork of the GL — it is a composition:

  • Base: the six GL suite skills (gl/core, gl/journal-entry, gl/financial-reporting, …) — the system of record, unchanged.
  • Overlay: gl/overlays/manufacturing — the additive diff above (the cost_center column, the Inventory / WIP / COGS / Cost-Variance accounts, the standard_costs table, the standard-cost variance journal, the Inventory → WIP → COGS cost flow).

Read the base to learn the mechanics; this overlay is the small, industry-specific diff on top.