feat(rules): manual-only rules as one-click quick actions on selected transactions

A rule flagged manual_only never runs in the apply-all pass; instead it shows
as a button in the transactions bulk bar and applies its actions to the current
selection (conditions ignored — the selection is the condition). Recorded as a
rule_apply_run, so it reverts from Rules -> Apply History like any other run.

Motivation: tagging Home + splitting 50/50 with Sonu was two bulk actions every
time. Now it is one click, and any other combo can be defined the same way.

Extracts the action-application and snapshot logic from the apply route into
src/lib/rule-actions.ts so both callers share one implementation — splits upsert
rather than delete+reinsert, so settled flags survive.

prisma/migrations/0012_manual_only_rules/migration.sql

@@ -0,0 +1,10 @@
+-- Manual-only rules ("quick actions"): a rule flagged manual_only is never
+-- picked up by the bulk apply-all run. It exists to be fired by hand against a
+-- selection of transactions from the transactions page, so its conditions are
+-- irrelevant — the selection is the condition.
+
+ALTER TABLE rules
+  ADD COLUMN IF NOT EXISTS manual_only BOOLEAN NOT NULL DEFAULT false;
+
+CREATE INDEX IF NOT EXISTS idx_rules_manual_only
+  ON rules (owner_id, manual_only) WHERE manual_only = true;

prisma/schema.prisma

@@ -98,15 +98,16 @@ model transaction_tags {
 }
 
 model rules {
-  id         Int      @id @default(autoincrement())
-  owner_id   Int
-  name       String
-  conditions Json     @default("[]")
-  actions    Json     @default("{}")
-  enabled    Boolean  @default(true)
-  priority   Int      @default(0)
-  created_at DateTime @default(now())
-  updated_at DateTime @default(now()) @updatedAt
+  id          Int     @id @default(autoincrement())
+  owner_id    Int
+  name        String
+  conditions  Json    @default("[]")
+  actions     Json    @default("{}")
+  enabled     Boolean @default(true)
+  manual_only Boolean @default(false)
+  priority    Int      @default(0)
+  created_at  DateTime @default(now())
+  updated_at  DateTime @default(now()) @updatedAt
 }
 
 model budgets {

src/app/api/rules/[id]/route.ts

@@ -22,6 +22,7 @@ export async function PATCH(req: NextRequest, { params }: { params: Promise<{ id
       ...(body.conditions !== undefined && { conditions: body.conditions }),
       ...(body.actions !== undefined && { actions: body.actions }),
       ...(body.enabled !== undefined && { enabled: body.enabled }),
+      ...(body.manual_only !== undefined && { manual_only: body.manual_only }),
       ...(body.priority !== undefined && { priority: body.priority }),
     },
   });

src/app/api/rules/apply/route.ts

@@ -3,15 +3,7 @@ import { getCurrentUser } from "@/lib/auth";
 import { queryRaw } from "@/lib/db";
 import { getTransactions } from "@/lib/queries";
 import { evaluateCondition, type Condition, type Actions } from "@/lib/rules";
-
-interface SnapshotEntry {
-  transaction_id: number;
-  had_override: boolean;
-  prev_category_override: string | null;
-  prev_merchant_normalized: string | null;
-  prev_tag_ids: number[];
-  prev_splits: { participant_id: number; share_percent: number; settled: boolean }[];
-}
+import { applyRuleActions, captureSnapshot } from "@/lib/rule-actions";
 
 
 export async function GET(req: NextRequest) {
@@ -42,10 +34,16 @@ export async function POST(req: NextRequest) {
   const splitFrom = body.splitFrom || null;
   const ruleId = body.ruleId || null;
 
+  // Manual-only rules ("quick actions") never take part in a condition-matched
+  // run — their conditions are typically empty, so they would match every
+  // transaction. They are fired from the transactions page against a selection.
   const rules = await queryRaw<{ id: number; conditions: unknown; actions: unknown }>(
     ruleId
-      ? `SELECT id, conditions, actions FROM rules WHERE owner_id = $1 AND id = $2`
-      : `SELECT id, conditions, actions FROM rules WHERE owner_id = $1 AND enabled = true ORDER BY priority DESC`,
+      ? `SELECT id, conditions, actions FROM rules
+         WHERE owner_id = $1 AND id = $2 AND manual_only = false`
+      : `SELECT id, conditions, actions FROM rules
+         WHERE owner_id = $1 AND enabled = true AND manual_only = false
+         ORDER BY priority DESC`,
     ruleId ? [user.id, ruleId] : [user.id]
   );
 
@@ -70,51 +68,7 @@ export async function POST(req: NextRequest) {
   }
 
   // --- Capture before-state for all matched transactions (batched) ---
-  const snapshot: SnapshotEntry[] = [];
-  if (matchedIds.size > 0) {
-    const ids = Array.from(matchedIds);
-    const idList = ids.join(",");
-
-    const overrides = await queryRaw<{ transaction_id: number; category_override: string | null; merchant_normalized: string | null }>(
-      `SELECT transaction_id, category_override, merchant_normalized FROM transaction_overrides WHERE transaction_id = ANY($1::int[])`,
-      [ids]
-    );
-    const overrideMap = new Map(overrides.map((o) => [o.transaction_id, o]));
-
-    const tagRows = await queryRaw<{ transaction_id: number; tag_id: number }>(
-      `SELECT transaction_id, tag_id FROM transaction_tags WHERE transaction_id = ANY($1::int[])`,
-      [ids]
-    );
-    const tagMap = new Map<number, number[]>();
-    for (const row of tagRows) {
-      if (!tagMap.has(row.transaction_id)) tagMap.set(row.transaction_id, []);
-      tagMap.get(row.transaction_id)!.push(row.tag_id);
-    }
-
-    const splitRows = await queryRaw<{ transaction_id: number; participant_id: number; share_percent: number; settled: boolean }>(
-      `SELECT transaction_id, participant_id, share_percent, settled FROM transaction_splits WHERE transaction_id = ANY($1::int[])`,
-      [ids]
-    );
-    const splitMap = new Map<number, { participant_id: number; share_percent: number; settled: boolean }[]>();
-    for (const row of splitRows) {
-      if (!splitMap.has(row.transaction_id)) splitMap.set(row.transaction_id, []);
-      splitMap.get(row.transaction_id)!.push({ participant_id: row.participant_id, share_percent: row.share_percent, settled: row.settled });
-    }
-
-    for (const id of ids) {
-      const ov = overrideMap.get(id);
-      snapshot.push({
-        transaction_id: id,
-        had_override: !!ov,
-        prev_category_override: ov?.category_override ?? null,
-        prev_merchant_normalized: ov?.merchant_normalized ?? null,
-        prev_tag_ids: tagMap.get(id) ?? [],
-        prev_splits: splitMap.get(id) ?? [],
-      });
-    }
-
-    void idList; // suppress unused warning
-  }
+  const snapshot = await captureSnapshot(Array.from(matchedIds));
 
   // --- Apply rules ---
   let matched = 0;
@@ -128,45 +82,11 @@ export async function POST(req: NextRequest) {
       matched++;
       affectedIds.add(tx.id);
 
-      if (actions.set_category || actions.set_merchant) {
-        await queryRaw(
-          `INSERT INTO transaction_overrides (transaction_id, category_override, merchant_normalized)
-           VALUES ($1, $2, $3)
-           ON CONFLICT (transaction_id) DO UPDATE SET
-             category_override = COALESCE($2, transaction_overrides.category_override),
-             merchant_normalized = COALESCE($3, transaction_overrides.merchant_normalized),
-             updated_at = NOW()`,
-          [tx.id, actions.set_category || null, actions.set_merchant || null]
-        );
-      }
-
-      if (actions.add_tag_ids?.length) {
-        for (const tagId of actions.add_tag_ids) {
-          await queryRaw(
-            `INSERT INTO transaction_tags (transaction_id, tag_id) VALUES ($1, $2) ON CONFLICT DO NOTHING`,
-            [tx.id, tagId]
-          );
-        }
-      }
-
-      if (actions.apply_split?.length) {
-        if (splitFrom && tx.transaction_date < splitFrom) continue;
-        // Remove only participants no longer in the rule's split, and upsert the
-        // rest — a plain delete+reinsert would reset settled flags on every run.
-        await queryRaw(
-          `DELETE FROM transaction_splits WHERE transaction_id = $1 AND participant_id != ALL($2::int[])`,
-          [tx.id, actions.apply_split.map((s) => s.participant_id)]
-        );
-        for (const s of actions.apply_split) {
-          await queryRaw(
-            `INSERT INTO transaction_splits (transaction_id, participant_id, share_percent)
-             VALUES ($1, $2, $3)
-             ON CONFLICT (transaction_id, participant_id)
-             DO UPDATE SET share_percent = EXCLUDED.share_percent`,
-            [tx.id, s.participant_id, s.share_percent]
-          );
-        }
-      }
+      // splitFrom holds the split back to transactions on/after that date;
+      // category/merchant/tags still apply to everything matched.
+      await applyRuleActions(tx.id, actions, {
+        skipSplit: !!splitFrom && tx.transaction_date < splitFrom,
+      });
     }
   }
 

src/app/api/rules/route.ts

@@ -12,10 +12,11 @@ export async function GET(req: NextRequest) {
     conditions: unknown;
     actions: unknown;
     enabled: boolean;
+    manual_only: boolean;
     priority: number;
     created_at: string;
   }>(
-    `SELECT id, name, conditions, actions, enabled, priority, created_at
+    `SELECT id, name, conditions, actions, enabled, manual_only, priority, created_at
      FROM rules WHERE owner_id = $1 ORDER BY priority DESC, id ASC`,
     [user.id]
   );
@@ -26,7 +27,7 @@ export async function POST(req: NextRequest) {
   const user = await getCurrentUser(req);
   if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 403 });
 
-  const { name, conditions, actions, enabled = true, priority = 0 } = await req.json();
+  const { name, conditions, actions, enabled = true, manual_only = false, priority = 0 } = await req.json();
   if (!name) return NextResponse.json({ error: "name required" }, { status: 400 });
 
   const rule = await prisma.rules.create({
@@ -36,6 +37,7 @@ export async function POST(req: NextRequest) {
       conditions: conditions ?? [],
       actions: actions ?? {},
       enabled,
+      manual_only,
       priority,
     },
   });

src/app/api/transactions/bulk/route.ts

@@ -2,6 +2,8 @@ import { NextRequest, NextResponse } from "next/server";
 import { prisma, queryRaw } from "@/lib/db";
 import { assignTransactionsToTrip, canAccessTransactions } from "@/lib/queries";
 import { getCurrentUser } from "@/lib/auth";
+import { applyRuleActions, captureSnapshot } from "@/lib/rule-actions";
+import type { Actions } from "@/lib/rules";
 
 export async function POST(req: NextRequest) {
   const user = await getCurrentUser(req);
@@ -85,6 +87,37 @@ export async function POST(req: NextRequest) {
     return NextResponse.json({ updated: ids.length });
   }
 
+  // Quick action: fire a saved rule's actions at the current selection. The
+  // selection replaces the rule's conditions, which are not evaluated at all.
+  // Recorded as a rule_apply_run so it can be reverted like any other run.
+  if (action === "apply_rule") {
+    const { rule_id } = body as { rule_id?: number };
+    if (!rule_id) return NextResponse.json({ error: "rule_id required" }, { status: 400 });
+
+    const rules = await queryRaw<{ id: number; name: string; actions: unknown }>(
+      `SELECT id, name, actions FROM rules WHERE id = $1 AND owner_id = $2`,
+      [Number(rule_id), user.id]
+    );
+    if (!rules.length) return NextResponse.json({ error: "Rule not found" }, { status: 404 });
+
+    const actions = (typeof rules[0].actions === "string"
+      ? JSON.parse(rules[0].actions)
+      : rules[0].actions) as Actions;
+
+    const snapshot = await captureSnapshot(ids.map(Number));
+    for (const id of ids) {
+      await applyRuleActions(Number(id), actions);
+    }
+
+    const run = await queryRaw<{ id: number }>(
+      `INSERT INTO rule_apply_runs (owner_id, split_from, matched, transactions_affected, snapshot)
+       VALUES ($1, NULL, $2, $3, $4) RETURNING id`,
+      [user.id, ids.length, ids.length, JSON.stringify(snapshot)]
+    );
+
+    return NextResponse.json({ updated: ids.length, run_id: run[0].id, rule: rules[0].name });
+  }
+
   if (action === "assign_trip") {
     const { trip_id } = body as { ids: number[]; trip_id: number | null };
     await assignTransactionsToTrip(trip_id, ids);

src/app/rules/page.tsx

@@ -86,6 +86,7 @@ export default function RulesPage() {
   const [conditions, setConditions] = useState<Condition[]>([]);
   const [actions, setActions] = useState<Actions>(EMPTY_ACTIONS);
   const [priority, setPriority] = useState(0);
+  const [manualOnly, setManualOnly] = useState(false);
 
   function openNewForm() {
     setEditingId(null);
@@ -93,15 +94,17 @@ export default function RulesPage() {
     setConditions([]);
     setActions(EMPTY_ACTIONS);
     setPriority(0);
+    setManualOnly(false);
     setShowForm(true);
   }
 
-  function openEditForm(rule: { id: number; name: string; conditions: Condition[]; actions: Actions; priority: number }) {
+  function openEditForm(rule: { id: number; name: string; conditions: Condition[]; actions: Actions; priority: number; manual_only?: boolean }) {
     setEditingId(rule.id);
     setName(rule.name);
     setConditions(Array.isArray(rule.conditions) ? rule.conditions : []);
     setActions(rule.actions && typeof rule.actions === "object" ? rule.actions : EMPTY_ACTIONS);
     setPriority(rule.priority);
+    setManualOnly(!!rule.manual_only);
     setShowForm(true);
     window.scrollTo({ top: 0, behavior: "smooth" });
   }
@@ -141,7 +144,7 @@ export default function RulesPage() {
 
   async function handleSubmit(e: React.FormEvent) {
     e.preventDefault();
-    const payload = { name, conditions, actions, enabled: true, priority };
+    const payload = { name, conditions, actions, enabled: true, manual_only: manualOnly, priority };
     if (editingId !== null) {
       await updateRule.mutateAsync({ id: editingId, ...payload });
     } else {
@@ -416,6 +419,20 @@ export default function RulesPage() {
                 className="w-24 bg-zinc-800 border border-zinc-700 rounded-lg px-3 py-2 text-sm"
               />
             </div>
+            <label className="flex items-center gap-2 text-sm text-zinc-400 cursor-pointer select-none pb-2">
+              <input
+                type="checkbox"
+                checked={manualOnly}
+                onChange={(e) => setManualOnly(e.target.checked)}
+                className="accent-amber-500"
+              />
+              <span>
+                Quick action only
+                <span className="block text-xs text-zinc-600">
+                  Never runs automatically — appears as a button on selected transactions
+                </span>
+              </span>
+            </label>
             <button
               type="submit"
               disabled={isPending}
@@ -475,21 +492,35 @@ export default function RulesPage() {
                   <div className="flex-1 min-w-0">
                     <div className="flex items-center gap-3 mb-1">
                       <span className="font-medium text-sm">{rule.name}</span>
+                      {rule.manual_only && (
+                        <span className="text-[10px] uppercase tracking-wide px-1.5 py-0.5 rounded bg-amber-900/40 text-amber-300 border border-amber-800/60">
+                          Quick action
+                        </span>
+                      )}
                       <span className="text-xs text-zinc-500">priority: {rule.priority}</span>
                     </div>
                     <p className="text-xs text-zinc-400">
-                      {conds.length > 0 ? conds.map((c) => humanCondition(c, tagNames)).join(" AND ") : "(matches all)"}
+                      {rule.manual_only
+                        ? "(fired by hand on selected transactions)"
+                        : conds.length > 0
+                        ? conds.map((c) => humanCondition(c, tagNames)).join(" AND ")
+                        : "(matches all)"}
                     </p>
                     <p className="text-xs text-zinc-500 mt-1">{humanAction(acts, tagNames, participantNames)}</p>
                   </div>
                   <div className="flex items-center gap-3 shrink-0">
-                    <button
-                      onClick={() => handleApply(rule.id)}
-                      disabled={applyRules.isPending}
-                      className="text-xs text-emerald-400 hover:text-emerald-300 disabled:opacity-50"
-                    >
-                      Apply
-                    </button>
+                    {/* No Apply for quick actions: their conditions are empty, so a
+                        bulk apply would hit every transaction. They run from the
+                        transactions page against a selection instead. */}
+                    {!rule.manual_only && (
+                      <button
+                        onClick={() => handleApply(rule.id)}
+                        disabled={applyRules.isPending}
+                        className="text-xs text-emerald-400 hover:text-emerald-300 disabled:opacity-50"
+                      >
+                        Apply
+                      </button>
+                    )}
                     <button
                       onClick={() => updateRule.mutate({ id: rule.id, enabled: !rule.enabled })}
                       className={`relative inline-flex h-5 w-9 rounded-full transition-colors ${
@@ -503,7 +534,7 @@ export default function RulesPage() {
                       />
                     </button>
                     <button
-                      onClick={() => openEditForm({ id: rule.id, name: rule.name, conditions: conds as Condition[], actions: acts, priority: rule.priority })}
+                      onClick={() => openEditForm({ id: rule.id, name: rule.name, conditions: conds as Condition[], actions: acts, priority: rule.priority, manual_only: rule.manual_only })}
                       className="text-zinc-400 hover:text-white text-sm"
                     >
                       Edit

src/app/transactions/page.tsx

@@ -2,7 +2,7 @@
 
 import { useState, useCallback, useRef, useEffect, Suspense } from "react";
 import { useSearchParams } from "next/navigation";
-import { useTransactions, useBanks, useUpdateTransaction, useBulkAction, useTags, useStatement, useCreateRule, useParticipants, useRecordPayment, useCurrentUser, useTrips, useAssignTransactionsToTrip } from "@/lib/hooks";
+import { useTransactions, useBanks, useUpdateTransaction, useBulkAction, useTags, useStatement, useCreateRule, useParticipants, useRecordPayment, useCurrentUser, useTrips, useAssignTransactionsToTrip, useRules } from "@/lib/hooks";
 import { CATEGORIES, formatCategory } from "@/lib/categories";
 import { SplitModal } from "@/components/split-modal";
 import { TagPicker } from "@/components/tag-picker";
@@ -10,6 +10,7 @@ import { AddTransactionModal } from "@/components/add-transaction-modal";
 import { EditTransactionModal } from "@/components/edit-transaction-modal";
 import { CsvImportModal } from "@/components/csv-import-modal";
 import type { TransactionRow } from "@/lib/queries";
+import type { RuleRow } from "@/lib/hooks";
 
 function formatDate(d: string) {
   return new Date(d).toLocaleDateString("en-AU", {
@@ -43,6 +44,28 @@ const TYPE_OPTIONS = [
   "debit", "credit", "payment", "refund", "fee", "interest", "transfer",
 ].map((t) => ({ value: t, label: t }));
 
+/** Tooltip text for a quick-action button: what the rule will actually do. */
+function describeActions(
+  actions: RuleRow["actions"],
+  tags: { id: number; name: string }[] = [],
+  participants: { id: number; name: string }[] = []
+): string {
+  const parts: string[] = [];
+  if (actions.set_category) parts.push(`category → ${formatCategory(actions.set_category)}`);
+  if (actions.set_merchant) parts.push(`merchant → ${actions.set_merchant}`);
+  if (actions.add_tag_ids?.length) {
+    const names = actions.add_tag_ids.map((id) => tags.find((t) => t.id === id)?.name ?? `tag#${id}`);
+    parts.push(`tag: ${names.join(", ")}`);
+  }
+  if (actions.apply_split?.length) {
+    const shares = actions.apply_split.map(
+      (s) => `${participants.find((p) => p.id === s.participant_id)?.name ?? `#${s.participant_id}`} ${s.share_percent}%`
+    );
+    parts.push(`split: ${shares.join(" / ")}`);
+  }
+  return parts.join(" · ") || "no actions";
+}
+
 function TypeBadge({ type }: { type: string }) {
   return (
     <span className={`px-2 py-0.5 rounded text-xs font-medium ${TYPE_COLORS[type] || "bg-zinc-800 text-zinc-400"}`}>
@@ -528,6 +551,10 @@ function TransactionsContent() {
   const bulkAction = useBulkAction();
   const { data: trips = [] } = useTrips();
   const assignToTrip = useAssignTransactionsToTrip();
+  const { data: allRules = [] } = useRules();
+  const { data: participants = [] } = useParticipants();
+  const quickActions = allRules.filter((r) => r.manual_only);
+  const [quickResult, setQuickResult] = useState<string | null>(null);
 
   const toggleSelect = useCallback((id: number) => {
     setSelected((prev) => {
@@ -787,6 +814,32 @@ function TransactionsContent() {
           >
             {bulkTripId === "remove" ? "Remove" : "Assign"}
           </button>
+          {quickActions.length > 0 && (
+            <div className="flex items-center gap-2 pl-3 ml-1 border-l border-zinc-700">
+              {quickActions.map((rule) => (
+                <button
+                  key={rule.id}
+                  disabled={bulkAction.isPending}
+                  title={describeActions(rule.actions, tags, participants)}
+                  onClick={() => {
+                    const count = selected.size;
+                    bulkAction.mutate(
+                      { action: "apply_rule", ids: Array.from(selected), rule_id: rule.id },
+                      {
+                        onSuccess: () => {
+                          setSelected(new Set());
+                          setQuickResult(`${rule.name} applied to ${count} transaction${count !== 1 ? "s" : ""}`);
+                        },
+                      }
+                    );
+                  }}
+                  className="px-3 py-1 bg-amber-700/80 hover:bg-amber-600 disabled:opacity-50 rounded text-sm"
+                >
+                  {rule.name}
+                </button>
+              ))}
+            </div>
+          )}
           <button
             onClick={() => setSelected(new Set())}
             className="px-3 py-1 text-zinc-400 hover:text-white text-sm"
@@ -796,6 +849,18 @@ function TransactionsContent() {
         </div>
       )}
 
+      {quickResult && (
+        <div className="flex items-center gap-3 mb-3 px-3 py-2 bg-emerald-900/30 border border-emerald-700 rounded text-sm text-emerald-200">
+          <span>{quickResult}</span>
+          <a href="/rules" className="text-emerald-400 hover:text-emerald-300 underline">
+            undo from Rules → Apply History
+          </a>
+          <button onClick={() => setQuickResult(null)} className="ml-auto text-zinc-400 hover:text-white">
+            dismiss
+          </button>
+        </div>
+      )}
+
       {/* Table */}
       <div className="overflow-x-auto border border-zinc-800 rounded-lg">
         <table className="w-full text-sm min-w-[900px]">

src/lib/hooks.ts

@@ -166,6 +166,7 @@ export function useBulkAction() {
       merchant_normalized?: string;
       splits?: { participant_id: number; share_percent: number }[];
       tag_id?: number;
+      rule_id?: number;
     }) => {
       const res = await fetch("/api/transactions/bulk", {
         method: "POST",
@@ -188,6 +189,16 @@ export function useBulkAction() {
       if (variables.action === "tag" || variables.action === "untag") {
         qc.invalidateQueries({ queryKey: ["tags"] });
       }
+      // A quick action can touch category, tags and splits at once, and records
+      // a revertible run — refresh everything it could have changed.
+      if (variables.action === "apply_rule") {
+        qc.invalidateQueries({ queryKey: ["tags"] });
+        qc.invalidateQueries({ queryKey: ["splits"] });
+        qc.invalidateQueries({ queryKey: ["shared-transactions"] });
+        qc.invalidateQueries({ queryKey: ["participant-balances"] });
+        qc.invalidateQueries({ queryKey: ["analytics"] });
+        qc.invalidateQueries({ queryKey: ["rule-runs"] });
+      }
     },
   });
 }
@@ -459,6 +470,8 @@ export interface RuleRow {
   conditions: { field: string; operator: string; value: string }[];
   actions: { set_category?: string; add_tag_ids?: number[]; set_merchant?: string; apply_split?: { participant_id: number; share_percent: number }[] };
   enabled: boolean;
+  /** Excluded from the apply-all run; fired by hand as a quick action instead. */
+  manual_only?: boolean;
   priority: number;
   created_at: string;
 }

src/lib/rule-actions.ts

@@ -0,0 +1,130 @@
+/**
+ * Applying a rule's `actions` to transactions, and snapshotting the before-state
+ * so a run can be reverted.
+ *
+ * Shared by the two callers that write rule actions:
+ * - `POST /api/rules/apply` — condition-matched bulk run
+ * - `POST /api/transactions/bulk` with `action: "apply_rule"` — quick action
+ *   fired against a hand-picked selection (conditions ignored)
+ */
+
+import { queryRaw } from "@/lib/db";
+import type { Actions } from "@/lib/rules";
+
+export interface SnapshotEntry {
+  transaction_id: number;
+  had_override: boolean;
+  prev_category_override: string | null;
+  prev_merchant_normalized: string | null;
+  prev_tag_ids: number[];
+  prev_splits: { participant_id: number; share_percent: number; settled: boolean }[];
+}
+
+/**
+ * Apply `actions` to one transaction.
+ *
+ * Tags are additive (ON CONFLICT DO NOTHING) — re-running never duplicates and
+ * never removes tags the rule doesn't mention. Splits replace the participant
+ * set but upsert shares, so `settled` flags survive a re-run; a plain
+ * delete+reinsert would silently un-settle reconciled splits.
+ */
+export async function applyRuleActions(
+  transactionId: number,
+  actions: Actions,
+  opts: { skipSplit?: boolean } = {}
+): Promise<void> {
+  if (actions.set_category || actions.set_merchant) {
+    await queryRaw(
+      `INSERT INTO transaction_overrides (transaction_id, category_override, merchant_normalized)
+       VALUES ($1, $2, $3)
+       ON CONFLICT (transaction_id) DO UPDATE SET
+         category_override = COALESCE($2, transaction_overrides.category_override),
+         merchant_normalized = COALESCE($3, transaction_overrides.merchant_normalized),
+         updated_at = NOW()`,
+      [transactionId, actions.set_category || null, actions.set_merchant || null]
+    );
+  }
+
+  if (actions.add_tag_ids?.length) {
+    for (const tagId of actions.add_tag_ids) {
+      await queryRaw(
+        `INSERT INTO transaction_tags (transaction_id, tag_id) VALUES ($1, $2) ON CONFLICT DO NOTHING`,
+        [transactionId, tagId]
+      );
+    }
+  }
+
+  if (actions.apply_split?.length && !opts.skipSplit) {
+    await queryRaw(
+      `DELETE FROM transaction_splits WHERE transaction_id = $1 AND participant_id != ALL($2::int[])`,
+      [transactionId, actions.apply_split.map((s) => s.participant_id)]
+    );
+    for (const s of actions.apply_split) {
+      await queryRaw(
+        `INSERT INTO transaction_splits (transaction_id, participant_id, share_percent)
+         VALUES ($1, $2, $3)
+         ON CONFLICT (transaction_id, participant_id)
+         DO UPDATE SET share_percent = EXCLUDED.share_percent`,
+        [transactionId, s.participant_id, s.share_percent]
+      );
+    }
+  }
+}
+
+/** Capture the overrides / tags / splits of `ids` before a run mutates them. */
+export async function captureSnapshot(ids: number[]): Promise<SnapshotEntry[]> {
+  if (ids.length === 0) return [];
+
+  const overrides = await queryRaw<{
+    transaction_id: number;
+    category_override: string | null;
+    merchant_normalized: string | null;
+  }>(
+    `SELECT transaction_id, category_override, merchant_normalized
+     FROM transaction_overrides WHERE transaction_id = ANY($1::int[])`,
+    [ids]
+  );
+  const overrideMap = new Map(overrides.map((o) => [o.transaction_id, o]));
+
+  const tagRows = await queryRaw<{ transaction_id: number; tag_id: number }>(
+    `SELECT transaction_id, tag_id FROM transaction_tags WHERE transaction_id = ANY($1::int[])`,
+    [ids]
+  );
+  const tagMap = new Map<number, number[]>();
+  for (const row of tagRows) {
+    if (!tagMap.has(row.transaction_id)) tagMap.set(row.transaction_id, []);
+    tagMap.get(row.transaction_id)!.push(row.tag_id);
+  }
+
+  const splitRows = await queryRaw<{
+    transaction_id: number;
+    participant_id: number;
+    share_percent: number;
+    settled: boolean;
+  }>(
+    `SELECT transaction_id, participant_id, share_percent, settled
+     FROM transaction_splits WHERE transaction_id = ANY($1::int[])`,
+    [ids]
+  );
+  const splitMap = new Map<number, { participant_id: number; share_percent: number; settled: boolean }[]>();
+  for (const row of splitRows) {
+    if (!splitMap.has(row.transaction_id)) splitMap.set(row.transaction_id, []);
+    splitMap.get(row.transaction_id)!.push({
+      participant_id: row.participant_id,
+      share_percent: row.share_percent,
+      settled: row.settled,
+    });
+  }
+
+  return ids.map((id) => {
+    const ov = overrideMap.get(id);
+    return {
+      transaction_id: id,
+      had_override: !!ov,
+      prev_category_override: ov?.category_override ?? null,
+      prev_merchant_normalized: ov?.merchant_normalized ?? null,
+      prev_tag_ids: tagMap.get(id) ?? [],
+      prev_splits: splitMap.get(id) ?? [],
+    };
+  });
+}