Add container weight tracking for weigh-based concentrate audits

Record the total weight of a jar (product + container) at acquisition so
audits can be done by simply re-weighing the sealed jar. The tare is
derived (containerWeight − productWeight), and the audit flow offers a
"Weigh container" toggle that auto-calculates remaining product from the
scale reading.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/db.ts

@@ -14,6 +14,7 @@ db.pragma("foreign_keys = ON");
 archiveLegacyIfPresent();
 archiveV1IfPresent();
 migrateAddCheckoutDate();
+migrateAddContainerWeight();
 
 const schema = readFileSync(join(__dirname, "schema.sql"), "utf8");
 db.exec(schema);
@@ -26,6 +27,14 @@ function migrateAddCheckoutDate(): void {
   db.exec(`ALTER TABLE inventory_items ADD COLUMN checkout_date TEXT`);
 }
 
+function migrateAddContainerWeight(): void {
+  const cols = db
+    .prepare(`PRAGMA table_info(inventory_items)`)
+    .all() as { name: string }[];
+  if (cols.length === 0 || cols.some((c) => c.name === "container_weight")) return;
+  db.exec(`ALTER TABLE inventory_items ADD COLUMN container_weight REAL`);
+}
+
 // One-shot migration: the original schema put per-instance fields (weight,
 // bin_id, etc.) directly on `products`. The split schema separates products
 // (catalog) from inventory_items (instance). When we detect the old shape,

server/src/routes/bootstrap.ts

@@ -24,6 +24,7 @@ type InventoryRow = {
   cbd: number;
   total_cannabinoids: number;
   weight: number;
+  container_weight: number | null;
   last_audit_weight: number | null;
   count_original: number;
   count_last_audit: number | null;
@@ -101,6 +102,7 @@ bootstrapRouter.get("/bootstrap", (_req, res) => {
     cbd: i.cbd,
     totalCannabinoids: i.total_cannabinoids,
     weight: i.weight,
+    containerWeight: i.container_weight,
     lastAuditWeight: i.last_audit_weight,
     countOriginal: i.count_original,
     countLastAudit: i.count_last_audit,

server/src/routes/inventory.ts

@@ -15,6 +15,7 @@ type CreateBody = {
   weight?: number;
   countOriginal?: number;
   unitWeight?: number;
+  containerWeight?: number | null;
   purchaseDate: string;
 };
 
@@ -53,14 +54,14 @@ inventoryRouter.post("/inventory", (req, res) => {
        id, asset_id, product_id,
        shop_id, bin_id,
        price, thc, cbd, total_cannabinoids,
-       weight, last_audit_weight,
+       weight, container_weight, last_audit_weight,
        count_original, count_last_audit, unit_weight,
        purchase_date, status
      ) VALUES (
        @id, @assetId, @productId,
        @shopId, @binId,
        @price, @thc, @cbd, @totalCannabinoids,
-       @weight, @lastAuditWeight,
+       @weight, @containerWeight, @lastAuditWeight,
        @countOriginal, @countLastAudit, @unitWeight,
        @purchaseDate, 'active'
      )`,
@@ -75,6 +76,7 @@ inventoryRouter.post("/inventory", (req, res) => {
     cbd: body.cbd ?? 0,
     totalCannabinoids: body.totalCannabinoids ?? 0,
     weight: isDiscrete ? 0 : body.weight ?? 0,
+    containerWeight: isDiscrete ? null : body.containerWeight ?? null,
     lastAuditWeight: isDiscrete ? null : body.weight ?? 0,
     countOriginal: isDiscrete ? body.countOriginal ?? 0 : 0,
     countLastAudit: isDiscrete ? body.countOriginal ?? 0 : null,
@@ -95,6 +97,7 @@ type UpdateBody = Partial<{
   cbd: number;
   totalCannabinoids: number;
   weight: number;
+  containerWeight: number | null;
   countOriginal: number;
   unitWeight: number;
   purchaseDate: string;
@@ -110,6 +113,7 @@ type ItemRow = {
   cbd: number;
   total_cannabinoids: number;
   weight: number;
+  container_weight: number | null;
   last_audit_weight: number | null;
   count_original: number;
   count_last_audit: number | null;
@@ -121,8 +125,8 @@ function doUpdate(id: string, body: UpdateBody): void {
   const existing = db
     .prepare<[string], ItemRow>(
       `SELECT id, shop_id, bin_id, product_id, price, thc, cbd,
-              total_cannabinoids, weight, last_audit_weight, count_original,
-              count_last_audit, unit_weight, purchase_date
+              total_cannabinoids, weight, container_weight, last_audit_weight,
+              count_original, count_last_audit, unit_weight, purchase_date
          FROM inventory_items WHERE id = ?`,
     )
     .get(id);
@@ -161,6 +165,12 @@ function doUpdate(id: string, body: UpdateBody): void {
     !isDiscrete && Number.isFinite(body.weight) && (body.weight as number) >= 0
       ? (body.weight as number)
       : existing.weight;
+  const nextContainerWeight =
+    body.containerWeight === undefined
+      ? existing.container_weight
+      : body.containerWeight != null && Number.isFinite(body.containerWeight)
+        ? body.containerWeight
+        : null;
   const nextCountOriginal =
     isDiscrete && Number.isFinite(body.countOriginal) && (body.countOriginal as number) >= 0
       ? Math.floor(body.countOriginal as number)
@@ -184,6 +194,7 @@ function doUpdate(id: string, body: UpdateBody): void {
        cbd = @cbd,
        total_cannabinoids = @totalCannabinoids,
        weight = @weight,
+       container_weight = @containerWeight,
        last_audit_weight = @lastAuditWeight,
        count_original = @countOriginal,
        count_last_audit = @countLastAudit,
@@ -199,6 +210,7 @@ function doUpdate(id: string, body: UpdateBody): void {
     cbd: nextCbd,
     totalCannabinoids: nextTotalCanna,
     weight: nextWeight,
+    containerWeight: nextContainerWeight,
     lastAuditWeight: nextLastAuditWeight,
     countOriginal: nextCountOriginal,
     countLastAudit: nextCountLastAudit,

server/src/schema.sql

@@ -64,6 +64,7 @@ CREATE TABLE IF NOT EXISTS inventory_items (
   cbd                 REAL DEFAULT 0,
   total_cannabinoids  REAL DEFAULT 0,
   weight              REAL DEFAULT 0,
+  container_weight    REAL,
   last_audit_weight   REAL,
   count_original      INTEGER DEFAULT 0,
   count_last_audit    INTEGER,

web/src/api.ts

@@ -1,7 +1,7 @@
 import type { Bootstrap, AuditMode } from "./types.js";
 
 export type BatchOp =
-  | { action: "update"; id: string; fields: Partial<{ shopId: string | null; binId: string | null; price: number; thc: number; cbd: number; totalCannabinoids: number; purchaseDate: string }> }
+  | { action: "update"; id: string; fields: Partial<{ shopId: string | null; binId: string | null; price: number; thc: number; cbd: number; totalCannabinoids: number; containerWeight: number | null; purchaseDate: string }> }
   | { action: "checkout"; id: string; date: string }
   | { action: "checkin"; id: string; date: string; binId: string }
   | { action: "finish"; id: string; date: string; rating?: number; notes?: string }
@@ -79,6 +79,7 @@ export const api = {
     cbd?: number;
     totalCannabinoids?: number;
     weight?: number;
+    containerWeight?: number | null;
     countOriginal?: number;
     unitWeight?: number;
     purchaseDate: string;
@@ -98,6 +99,7 @@ export const api = {
       cbd: number;
       totalCannabinoids: number;
       weight: number;
+      containerWeight: number | null;
       countOriginal: number;
       unitWeight: number;
       purchaseDate: string;

web/src/components/ProductDetail.tsx

@@ -67,6 +67,12 @@ export function ProductDetail({
       : []),
     ["Purchase date", fmt.date(item.purchaseDate, getStoredTimezone())],
     ["Bin", isCheckedOut ? "In your custody" : bin ? bin.name : <span style={{ color: "var(--ink-3)" }}>—</span>],
+    ...(item.containerWeight != null
+      ? [
+          ["Container weight", `${item.containerWeight.toFixed(2)}g`] as [string, React.ReactNode],
+          ["Tare (empty jar)", `${(item.containerWeight - item.weight).toFixed(2)}g`] as [string, React.ReactNode],
+        ]
+      : []),
     ["Audit cadence", `Every ${cfg?.cadenceDays ?? "—"} days · ${cfg?.auditMode ?? "—"}`],
     [
       "Cost per gram",
@@ -294,6 +300,18 @@ export function ProductDetail({
                   {cfg?.unit}). Re-audit to update.
                 </div>
               )}
+              {item.containerWeight != null && (
+                <div
+                  style={{
+                    fontSize: 11,
+                    color: "var(--ink-3)",
+                    marginTop: 6,
+                    fontStyle: "italic",
+                  }}
+                >
+                  Expected container total: {((item.containerWeight - item.weight) + est).toFixed(2)}g
+                </div>
+              )}
             </div>
           )}
 

web/src/components/modals/AddInventoryFlow.tsx

@@ -382,6 +382,7 @@ function InstanceDetailsStep({
   const [newShopLocation, setNewShopLocation] = useState("");
   const [newBinName, setNewBinName] = useState("");
   const [newBinCapacity, setNewBinCapacity] = useState(10);
+  const [containerWeight, setContainerWeight] = useState("");
   const [error, setError] = useState<string | null>(null);
 
   const update = <K extends keyof typeof form>(k: K, v: (typeof form)[K]) =>
@@ -419,6 +420,7 @@ function InstanceDetailsStep({
         shopId,
         binId,
         weight: isDiscrete ? undefined : form.weight,
+        containerWeight: !isDiscrete && containerWeight !== "" ? parseFloat(containerWeight) : undefined,
         countOriginal: isDiscrete ? 1 : undefined,
         unitWeight: isDiscrete ? form.unitWeight : undefined,
         price: form.price,
@@ -624,6 +626,27 @@ function InstanceDetailsStep({
           </div>
         )}
 
+        {!isDiscrete && cfg?.weighable && (
+          <div style={{ marginTop: 16 }}>
+            <Field label="Container weight (g)" hint="Total weight of jar + lid + product on a scale. Optional — enables weigh-based audits.">
+              <Input
+                type="number"
+                step="0.01"
+                placeholder="—"
+                value={containerWeight}
+                onChange={(e) => setContainerWeight(e.target.value)}
+              />
+            </Field>
+            {containerWeight !== "" && form.weight > 0 && (
+              <div style={{ marginTop: 6, fontSize: 12, color: parseFloat(containerWeight) <= form.weight ? "var(--terracotta)" : "var(--ink-3)" }}>
+                {parseFloat(containerWeight) > form.weight
+                  ? `Tare (empty jar): ${(parseFloat(containerWeight) - form.weight).toFixed(2)}g`
+                  : "Container weight must be greater than product weight"}
+              </div>
+            )}
+          </div>
+        )}
+
         {cfg?.showCannabinoidPct !== false && (
           <>
             <div

web/src/components/modals/AuditFlow.tsx

@@ -55,18 +55,37 @@ export function AuditFlow({
     return helpers.estimatedRemaining(i, getToday(getStoredTimezone())).toFixed(2);
   };
   const [value, setValue] = useState<string>(initialValueFor(item));
+  const [inputMode, setInputMode] = useState<"direct" | "container">(
+    item?.containerWeight != null ? "container" : "direct",
+  );
+  const [containerTotal, setContainerTotal] = useState("");
   const [error, setError] = useState<string | null>(null);
 
   useEffect(() => {
     setValue(initialValueFor(item));
+    setInputMode(item?.containerWeight != null ? "container" : "direct");
+    setContainerTotal("");
   }, [itemId]); // eslint-disable-line react-hooks/exhaustive-deps
 
+  const tare = item ? helpers.tare(item) : null;
+  const derivedRemaining =
+    tare != null && containerTotal !== ""
+      ? parseFloat(containerTotal) - tare
+      : null;
+
+  const effectiveValue =
+    inputMode === "container" && derivedRemaining != null
+      ? derivedRemaining
+      : Number(value);
+  const effectiveMode =
+    inputMode === "container" ? "weigh" : (cfg?.auditMode ?? "weigh");
+
   const audit = useMutation({
     mutationFn: () =>
       api.auditInventoryItem(itemId, {
         date,
-        mode: cfg?.auditMode ?? "weigh",
-        value: Number(value),
+        mode: effectiveMode,
+        value: effectiveValue,
         confirmedBy: cfg?.auditMode === "presence" ? confirmedBy : undefined,
       }),
     onSuccess: () => {
@@ -84,7 +103,9 @@ export function AuditFlow({
   };
 
   const auditMode = cfg?.auditMode ?? "weigh";
-  const ml = AUDIT_MODE_LABELS[auditMode] ?? AUDIT_MODE_LABELS.weigh!;
+  const ml = inputMode === "container"
+    ? { title: "Weigh container", desc: "Place the sealed jar on a scale and enter the total weight. Product remaining is calculated from the tare." }
+    : AUDIT_MODE_LABELS[auditMode] ?? AUDIT_MODE_LABELS.weigh!;
 
   const last = item ? helpers.lastAudit(item) : null;
   const prevValue = item
@@ -95,7 +116,7 @@ export function AuditFlow({
         : item.weight
     : 0;
 
-  const delta = Number(value) - prevValue;
+  const delta = effectiveValue - prevValue;
 
   return (
     <ModalBackdrop onClose={onClose}>
@@ -156,6 +177,23 @@ export function AuditFlow({
                 </div>
               </div>
 
+              {tare != null && (
+                <div style={{ display: "flex", gap: 8, marginTop: 16 }}>
+                  <Btn
+                    variant={inputMode === "container" ? "primary" : "ghost"}
+                    onClick={() => setInputMode("container")}
+                  >
+                    Weigh container
+                  </Btn>
+                  <Btn
+                    variant={inputMode === "direct" ? "primary" : "ghost"}
+                    onClick={() => setInputMode("direct")}
+                  >
+                    Direct entry
+                  </Btn>
+                </div>
+              )}
+
               <div
                 style={{
                   display: "grid",
@@ -164,22 +202,33 @@ export function AuditFlow({
                   marginTop: 24,
                 }}
               >
-                <Field
-                  label={
-                    item.kind === "discrete"
-                      ? `Count now (${cfg?.unit})`
-                      : auditMode === "weigh"
-                        ? `Weight now (${cfg?.unit})`
-                        : `Estimate now (${cfg?.unit})`
-                  }
-                >
-                  <Input
-                    type="number"
-                    step={item.kind === "discrete" ? "1" : "0.1"}
-                    value={value}
-                    onChange={(e) => setValue(e.target.value)}
-                  />
-                </Field>
+                {inputMode === "container" && tare != null ? (
+                  <Field label="Container weight now (g)">
+                    <Input
+                      type="number"
+                      step="0.01"
+                      value={containerTotal}
+                      onChange={(e) => setContainerTotal(e.target.value)}
+                    />
+                  </Field>
+                ) : (
+                  <Field
+                    label={
+                      item.kind === "discrete"
+                        ? `Count now (${cfg?.unit})`
+                        : auditMode === "weigh"
+                          ? `Weight now (${cfg?.unit})`
+                          : `Estimate now (${cfg?.unit})`
+                    }
+                  >
+                    <Input
+                      type="number"
+                      step={item.kind === "discrete" ? "1" : "0.1"}
+                      value={value}
+                      onChange={(e) => setValue(e.target.value)}
+                    />
+                  </Field>
+                )}
                 <Field label="Date">
                   <Input type="date" value={date} onChange={(e) => setDate(e.target.value)} />
                 </Field>
@@ -196,6 +245,17 @@ export function AuditFlow({
                 )}
               </div>
 
+              {inputMode === "container" && tare != null && (
+                <div style={{ marginTop: 8, fontSize: 12, color: "var(--ink-3)" }}>
+                  Tare (empty jar): {tare.toFixed(2)}g
+                  {derivedRemaining != null && (
+                    <span style={{ color: derivedRemaining >= 0 ? "var(--sage)" : "var(--terracotta)" }}>
+                      {" · "}Product remaining: {derivedRemaining.toFixed(2)}g
+                    </span>
+                  )}
+                </div>
+              )}
+
               <div
                 style={{
                   marginTop: 20,
@@ -217,7 +277,7 @@ export function AuditFlow({
                 <div>
                   <div className="smallcaps" style={{ color: "var(--ink-3)" }}>Now</div>
                   <div className="serif" style={{ fontSize: 22, color: "var(--sage)" }}>
-                    {value} {cfg?.unit}
+                    {effectiveValue.toFixed(item.kind === "discrete" ? 0 : 2)} {cfg?.unit}
                   </div>
                 </div>
                 <div>

web/src/components/modals/BulkEditModal.tsx

@@ -1,6 +1,7 @@
 import { useState } from "react";
 import { useMutation, useQueryClient } from "@tanstack/react-query";
 import type { Bootstrap, Item } from "../../types.js";
+import { TYPES } from "../../types.js";
 import { api } from "../../api.js";
 import type { BatchOp } from "../../api.js";
 import { Btn, Field, Input, Select } from "../primitives/index.js";
@@ -26,8 +27,14 @@ export function BulkEditModal({
   const [cbd, setCbd] = useState("");
   const [totalCannabinoids, setTotalCannabinoids] = useState("");
   const [purchaseDate, setPurchaseDate] = useState("");
+  const [containerWeight, setContainerWeight] = useState("");
   const [error, setError] = useState<string | null>(null);
 
+  const hasBulkWeighable = items.some((i) => {
+    const cfg = TYPES.find((t) => t.id === i.type);
+    return i.kind === "bulk" && cfg?.weighable;
+  });
+
   const save = useMutation({
     mutationFn: () => {
       const fields: Record<string, string | number | null> = {};
@@ -38,6 +45,7 @@ export function BulkEditModal({
       if (cbd !== "") fields.cbd = parseFloat(cbd);
       if (totalCannabinoids !== "") fields.totalCannabinoids = parseFloat(totalCannabinoids);
       if (purchaseDate) fields.purchaseDate = purchaseDate;
+      if (containerWeight !== "") fields.containerWeight = parseFloat(containerWeight);
 
       if (Object.keys(fields).length === 0) {
         return Promise.reject(new Error("No fields to update — fill in at least one field."));
@@ -163,6 +171,20 @@ export function BulkEditModal({
             </Field>
           </div>
 
+          {hasBulkWeighable && (
+            <div style={{ display: "grid", gridTemplateColumns: "repeat(5, 1fr)", gap: 16, marginTop: 16 }}>
+              <Field label="Container weight (g)">
+                <Input
+                  type="number"
+                  step="0.01"
+                  placeholder="—"
+                  value={containerWeight}
+                  onChange={(e) => setContainerWeight(e.target.value)}
+                />
+              </Field>
+            </div>
+          )}
+
           {error && (
             <div style={{ marginTop: 14, fontSize: 12, color: "var(--terracotta)" }}>{error}</div>
           )}

web/src/components/modals/EditInventoryFlow.tsx

@@ -38,6 +38,9 @@ export function EditInventoryFlow({
   const [newShopLocation, setNewShopLocation] = useState("");
   const [newBinName, setNewBinName] = useState("");
   const [newBinCapacity, setNewBinCapacity] = useState(10);
+  const [containerWeight, setContainerWeight] = useState(
+    item.containerWeight != null ? String(item.containerWeight) : "",
+  );
   const [error, setError] = useState<string | null>(null);
 
   const update = <K extends keyof typeof form>(k: K, v: (typeof form)[K]) =>
@@ -69,6 +72,7 @@ export function EditInventoryFlow({
         shopId,
         binId,
         weight: isDiscrete ? undefined : form.weight,
+        containerWeight: !isDiscrete ? (containerWeight !== "" ? parseFloat(containerWeight) : null) : undefined,
         unitWeight: isDiscrete ? form.unitWeight : undefined,
         price: form.price,
         thc: form.thc,
@@ -235,6 +239,27 @@ export function EditInventoryFlow({
             </div>
           )}
 
+          {!isDiscrete && cfg?.weighable && (
+            <div style={{ marginTop: 16 }}>
+              <Field label="Container weight (g)" hint="Total weight of jar + lid + product on a scale. Leave blank to clear.">
+                <Input
+                  type="number"
+                  step="0.01"
+                  placeholder="—"
+                  value={containerWeight}
+                  onChange={(e) => setContainerWeight(e.target.value)}
+                />
+              </Field>
+              {containerWeight !== "" && form.weight > 0 && (
+                <div style={{ marginTop: 6, fontSize: 12, color: parseFloat(containerWeight) <= form.weight ? "var(--terracotta)" : "var(--ink-3)" }}>
+                  {parseFloat(containerWeight) > form.weight
+                    ? `Tare (empty jar): ${(parseFloat(containerWeight) - form.weight).toFixed(2)}g`
+                    : "Container weight must be greater than product weight"}
+                </div>
+              )}
+            </div>
+          )}
+
           {cfg?.showCannabinoidPct !== false && (
             <>
               <div

web/src/types.ts

@@ -38,6 +38,7 @@ export interface InventoryItem {
   cbd: number;
   totalCannabinoids: number;
   weight: number;
+  containerWeight: number | null;
   lastAuditWeight: number | null;
   countOriginal: number;
   countLastAudit: number | null;
@@ -183,6 +184,10 @@ export const helpers = {
   typeConfig(id: string): TypeConfig {
     return TYPES.find((t) => t.id === id) ?? TYPES[0]!;
   },
+  tare(item: { containerWeight: number | null; weight: number }): number | null {
+    if (item.containerWeight == null) return null;
+    return item.containerWeight - item.weight;
+  },
   daysSince(iso: string | null, today = TODAY_STR): number {
     if (!iso) return Infinity;
     return Math.floor((+new Date(today) - +new Date(iso)) / 86_400_000);