@@ -0,0 +1,12 @@
+---
+"@objectstack/runtime": patch
+"@objectstack/metadata-protocol": patch
+---
+
+fix: a hook's refusal reached through an action or another hook answers in the hook's own words, and `$top=0` reports the real `total` (#22588)
+
+Clause-②: no
+
+- **A nested sandboxed refusal keeps its sentence (`@objectstack/runtime`).** A script action whose body writes through `ctx.api` and is refused by a sandboxed hook used to answer with the hook's debug wrapper in front of the sentence: `POST /api/v1/actions/:object/:action/:id` → `400 VALIDATION_ERROR` "`hook 'guard' threw: Error: A finished task cannot be reopened.`". It now answers the hook's sentence alone, as `PATCH /api/v1/data/:object/:id` and a declarative `operation: 'update'` action already did. The same holds for a hook that writes another object through `ctx.api` and is refused there: `/data` answers the inner hook's sentence. Status and `code` do not change. The cause was the sandbox's VM hop: a host error crosses into a body's VM as `name` and `message` only, so the refused write's sentence was left behind and the wrapper became the outer error's caller-facing text. The sentence now travels beside the wrapper and is used when the body lets that error escape unchanged. A body that catches the error and throws its own (or rewrites its message first) is still answered in its own words, a nested crash is still a `500`, and the server log still names every frame.
+- **The `/actions` door reads its sentence through `sandboxBusinessMessage`** (`@objectstack/types`), the same read `/data`, the bulk doors and `/analytics/dataset/query` make, instead of its own copy. The wire answer is unchanged.
+- **`$top=0` reports the filtered `total` (`@objectstack/metadata-protocol`).** `limit: 0` asks for no rows, and `findData` treated it as "no limit", so the zero-length page was reported as the total: `GET /api/v1/data/:object?$top=0` answered `total: 0` while `$top=1` answered the real count. The Console reads its list footer's record count from exactly that `$top: 0` request. A zero-row request is now a paged request: it returns no rows and the same `total` as any other page size, filters included. `$count=false` still skips the count and now omits `total` for `$top=0` too, instead of reporting `0`. A `search` query still reports its page-local estimate, as it does at every page size.
@@ -12924,7 +12924,20 @@ export class ObjectStackProtocolImplementation implements
         // reproduced by it, so for those we skip the count and fall back to a
         // page-local estimate (a full page implies there may be more) rather than
         // reporting a wrong total.
-        const pageLimit = typeof options.limit === 'number' && options.limit > 0 ? options.limit : undefined;
+        //
+        // [#22588] `limit: 0` IS a limit. It asks for no rows (objectstack#6485,
+        // the drivers' pagination conformance), so `records.length` is 0 and was
+        // reported as the total: `?$top=0` answered `total: 0` while `?$top=1`
+        // answered the true count, and the Console's footer probe — which sends
+        // exactly `$top: 0` to read the total and nothing else — showed `0` on
+        // every list page. Gated `> 0`, a zero-row page fell into the "no limit,
+        // the full set is the total" arm, which is true of every limit except
+        // this one. So `>= 0`: a zero-row request is a paged request like any
+        // other, and the three arms below keep their meaning for it — the count
+        // runs (`total` is the filtered count, whatever the page size), `$count=false`
+        // still omits `total` instead of reporting the page's 0, and `search`
+        // still reports its page-local estimate rather than a count.
+        const pageLimit = typeof options.limit === 'number' && options.limit >= 0 ? options.limit : undefined;
         const pageOffset = typeof options.offset === 'number' && options.offset > 0 ? options.offset : 0;
         let total: number | undefined = records.length;
         let hasMore = false;
 
@@ -0,0 +1,166 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * #22588 item 2 — a list's `total` is the filtered count whatever the page size,
+ * `$top=0` included.
+ *
+ * ## What was wrong
+ *
+ * `findData` decided "is this a paged request?" with `limit > 0`. `limit: 0`
+ * asks for NO rows (objectstack#6485 — every driver's pagination conformance
+ * pins it), so the gate sent a zero-row request into the "no limit, the whole
+ * result set came back, so its length IS the total" arm — the one arm that is
+ * false for exactly this limit. Measured over HTTP on a booted stack at
+ * `3d0eeefa` (five rows, two of them in stage `b`):
+ *
+ *   GET /data/mz_task?top=0              total 0   ← the defect
+ *   GET /data/mz_task?top=1              total 5
+ *   GET /data/mz_task?top=0&stage=b      total 0   ← the defect
+ *   GET /data/mz_task?top=1&stage=b      total 2
+ *   GET /data/mz_task?top=0&$count=false total 0   ← the opt-out ignored too
+ *
+ * The Console's list footer sends exactly `$top: 0` to read the total and
+ * nothing else, so every list page showed a record count of `0`.
+ *
+ * ## What this suite pins
+ *
+ *  1. `top=0` and `top=1` report the SAME `total`, and `top=0` still returns no
+ *     rows — the engine is asked for `limit: 0`, never for the whole set.
+ *  2. CONTROL — a filter moves both alike. A fix that reported the UNFILTERED
+ *     count for a zero-row page would pass (1) and fail here.
+ *  3. The two neighbouring arms keep their meaning for a zero-row page:
+ *     `$count=false` still issues no COUNT and omits `total` (it no longer
+ *     reports the page's `0` as if it were a count), and `search` still issues
+ *     no COUNT — `engine.count()` cannot reproduce a search, which is why that
+ *     arm reports a page-local estimate at every page size.
+ *  4. Absent a limit nothing moves: no COUNT, `total` is the set's length.
+ */
+
+import { describe, it, expect, vi } from 'vitest';
+import { ObjectStackProtocolImplementation } from './protocol.js';
+
+const SCHEMA = {
+    name: 'mz_task',
+    nameField: 'name',
+    fields: {
+        name: { name: 'name', type: 'text' },
+        stage: { name: 'stage', type: 'text' },
+    },
+};
+
+const ROWS = [
+    { id: 't0', name: 't0', stage: 'a' },
+    { id: 't1', name: 't1', stage: 'a' },
+    { id: 't2', name: 't2', stage: 'a' },
+    { id: 't3', name: 't3', stage: 'b' },
+    { id: 't4', name: 't4', stage: 'b' },
+];
+
+/**
+ * Equality-only `where` — the implicit field filter `?stage=b` lowers to.
+ * Anything else (a combinator, an operator object) is REFUSED rather than
+ * answered silently wrong.
+ */
+function matches(row: Record<string, unknown>, where: unknown): boolean {
+    if (where == null) return true;
+    if (typeof where !== 'object' || Array.isArray(where)) {
+        throw new Error(`test double: unexpected where shape ${JSON.stringify(where)}`);
+    }
+    return Object.entries(where as Record<string, unknown>).every(([k, v]) => {
+        if (k.startsWith('$')) throw new Error(`test double: combinator '${k}' is not implemented`);
+        if (v !== null && typeof v === 'object') throw new Error(`test double: operator on '${k}' is not implemented`);
+        return row[k] === v;
+    });
+}
+
+/**
+ * An engine double that honours `limit` AS WRITTEN — `limit: 0` is no rows,
+ * the drivers' declared contract — and counts over the same `where`.
+ */
+function makeProtocol() {
+    const find = vi.fn(async (_object: string, opts: any = {}) => {
+        const hits = ROWS.filter((r) => matches(r, opts.where));
+        const offset = typeof opts.offset === 'number' ? opts.offset : 0;
+        const sliced = hits.slice(offset);
+        return opts.limit !== undefined ? sliced.slice(0, opts.limit) : sliced;
+    });
+    const count = vi.fn(async (_object: string, opts: any = {}) => ROWS.filter((r) => matches(r, opts.where)).length);
+    const engine = {
+        registry: { getObject: (n: string) => (n === SCHEMA.name ? SCHEMA : undefined) },
+        find,
+        count,
+        aggregate: vi.fn(async () => [] as unknown[]),
+    };
+    return { p: new ObjectStackProtocolImplementation(engine as any), find, count };
+}
+
+async function list(query: Record<string, unknown>) {
+    const h = makeProtocol();
+    const result: any = await h.p.findData({ object: SCHEMA.name, query } as never);
+    return { result, ...h };
+}
+
+describe('[#22588] a zero-row page reports the filtered total', () => {
+    it('top=0 and top=1 report the same total, and top=0 returns no rows', async () => {
+        const zero = await list({ top: '0' });
+        const one = await list({ top: '1' });
+
+        expect(zero.result.total).toBe(5);
+        expect(zero.result.total).toBe(one.result.total);
+        expect(zero.result.records).toEqual([]);
+        // The engine was asked for NO rows — the fix counts, it never widens
+        // the read to the whole set to measure it.
+        expect((zero.find.mock.calls[0] as unknown[])[1]).toMatchObject({ limit: 0 });
+        expect(zero.result.hasMore).toBe(true);
+    });
+
+    it('every spelling of the zero window reaches the same answer', async () => {
+        for (const query of [{ $top: '0' }, { limit: '0' }, { top: 0 }]) {
+            const { result, count } = await list(query);
+            expect(result.total, JSON.stringify(query)).toBe(5);
+            expect(count, JSON.stringify(query)).toHaveBeenCalledTimes(1);
+        }
+    });
+
+    it('CONTROL — a filter changes both alike', async () => {
+        const zero = await list({ top: '0', stage: 'b' });
+        const one = await list({ top: '1', stage: 'b' });
+
+        expect(zero.result.total).toBe(2);
+        expect(one.result.total).toBe(2);
+        expect(zero.result.records).toEqual([]);
+        expect(one.result.records).toHaveLength(1);
+    });
+
+    it('a zero-row page past an offset still reports the whole filtered total', async () => {
+        const { result } = await list({ top: '0', skip: '2' });
+
+        expect(result.total).toBe(5);
+        expect(result.records).toEqual([]);
+        expect(result.hasMore).toBe(true);
+    });
+});
+
+describe('[#22588] the neighbouring arms keep their meaning for a zero-row page', () => {
+    it('$count=false still issues no COUNT — and omits total instead of reporting the page\'s 0', async () => {
+        const { result, count } = await list({ $top: '0', $count: 'false' });
+
+        expect(count).not.toHaveBeenCalled();
+        expect('total' in result).toBe(false);
+    });
+
+    it('search still issues no COUNT — engine.count() cannot reproduce a search', async () => {
+        const { result, count } = await list({ $top: '0', $search: 't' });
+
+        expect(count).not.toHaveBeenCalled();
+        expect(result.records).toEqual([]);
+    });
+
+    it('absent a limit nothing moves: no COUNT, total is the set\'s length', async () => {
+        const { result, count } = await list({ stage: 'b' });
+
+        expect(count).not.toHaveBeenCalled();
+        expect(result.total).toBe(2);
+        expect(result.hasMore).toBe(false);
+    });
+});
@@ -0,0 +1,145 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#22588] Every `/actions` invocation route answers a hook's refusal in the
+ * hook's own words — enumerated from the route ledger, not hand-listed.
+ *
+ * ## What was measured broken
+ *
+ * `POST /api/v1/actions/mz_task/mz_reopen/ID` on a booted stack at `3d0eeefa`:
+ * a script action whose `ctx.api` write a sandboxed `beforeUpdate` hook refused
+ * answered `400 VALIDATION_ERROR` with
+ * `hook 'mz_guard_reopen' threw: Error: A finished task cannot be reopened. …`.
+ * The hotclm browser pass saw the same text in a toast. The producer was the
+ * sandbox's VM hop, repaired in `sandbox/quickjs-runner.ts`; the door now reads
+ * its sentence through `sandboxBusinessMessage`, the read `/data` makes.
+ *
+ * ## Why the ledger, and what the enumeration buys
+ *
+ * The rows are read from {@link ROUTE_LEDGER} — the dispatcher's audited list of
+ * what it serves — so a new `/actions` row is driven here the day it is
+ * ledgered, or fails the completeness case until someone says why it cannot
+ * run an action body. `_activation` is the one such row today.
+ *
+ * Each row is driven through `HttpDispatcher.dispatch()` at a concrete path
+ * built from the row itself, and the refusal each one meets is produced by the
+ * REAL runner at both levels (a hook body refusing under an action body's
+ * `ctx.api` write) — the shape that reached the wire, never a hand-built error.
+ * `executeAction` being called is asserted per row, so a row answered by some
+ * earlier refusal (a missing declaration, the anonymous floor) cannot pass.
+ */
+
+import { describe, it, expect, vi } from 'vitest';
+
+import { HttpDispatcher } from '../http-dispatcher.js';
+import { ROUTE_LEDGER } from '../route-ledger.js';
+import { QuickJSScriptRunner } from '../sandbox/quickjs-runner.js';
+
+const REFUSAL = 'A finished task cannot be reopened. Create a follow-up task instead.';
+const OBJECT = 'mz_task';
+const ACTION = 'mz_reopen';
+const RECORD = 't1';
+
+/**
+ * `/actions` rows that do not invoke an action, with the reason. Closed: a new
+ * row is driven below unless it is named here.
+ */
+const NOT_AN_INVOCATION: ReadonlyMap<string, string> = new Map([
+    ['POST /actions/_activation/:object/:action',
+        'ADR-0126 §8 activation door — writes one sys_metadata_activation row and runs no action body, '
+        + 'so no hook can refuse inside it'],
+]);
+
+const ACTION_ROWS = ROUTE_LEDGER.filter((row) => row.domain === '/actions');
+const INVOCATION_ROWS = ACTION_ROWS.filter((row) => !NOT_AN_INVOCATION.has(row.route));
+
+/** `POST /actions/:object/:action/:recordId` → `/actions/mz_task/mz_reopen/t1`; literals stay. */
+function concretePath(route: string): string {
+    const [, pattern] = route.split(' ');
+    return pattern
+        .replace(':object', OBJECT)
+        .replace(':action', ACTION)
+        .replace(':recordId', RECORD);
+}
+
+const runner = new QuickJSScriptRunner({ hookTimeoutMs: 10_000, actionTimeoutMs: 10_000 });
+
+/**
+ * What an action body's handler throws when its `ctx.api` write is refused by
+ * a sandboxed hook — both levels run by the real runner.
+ */
+async function nestedRefusal(): Promise<unknown> {
+    const hookRefusal = () => runner.runScript(
+        { language: 'js', source: `throw new Error(${JSON.stringify(REFUSAL)});` },
+        { input: {} } as any,
+        { origin: { kind: 'hook', name: 'mz_guard_reopen' } },
+    ).then(() => { throw new Error('the guard hook resolved'); }, (e: unknown) => e);
+    return runner.runScript(
+        {
+            language: 'js',
+            source: `await ctx.api.object('${OBJECT}').update({ id: '${RECORD}', done: false });`,
+            capabilities: ['api.write'],
+        },
+        { input: {}, api: { object: () => ({ update: async () => { throw await hookRefusal(); } }) } } as any,
+        { origin: { kind: 'action', name: ACTION } },
+    ).then(() => { throw new Error('the action body resolved'); }, (e: unknown) => e);
+}
+
+function makeDispatcher() {
+    const declared = { name: ACTION, objectName: OBJECT, type: 'script', target: ACTION };
+    const objectDef = { name: OBJECT, actions: [declared] };
+    const executeAction = vi.fn(async () => { throw await nestedRefusal(); });
+    const ql: any = {
+        executeAction,
+        getSchema: (n: string) => (n === OBJECT ? objectDef : undefined),
+        registry: { getObject: (n: string) => (n === OBJECT ? objectDef : undefined), getItem: () => undefined },
+        find: vi.fn(async () => [{ id: RECORD, done: true }]),
+        insert: vi.fn(), update: vi.fn(), delete: vi.fn(),
+    };
+    // The object-less rows resolve their declaration here: a global action of the same name.
+    const global = (type: string, name: string) =>
+        type === 'action' ? { name, type: 'script', target: name, objectName: 'global' } : null;
+    const metadata: any = {
+        load: vi.fn(async (type: string, name: string) => global(type, name)),
+        loadDiagnosed: vi.fn(async (type: string, name: string) => ({ data: global(type, name), degraded: false, errors: [] })),
+        listObjects: vi.fn(async () => [objectDef]),
+        getObject: vi.fn(async (n: string) => (n === OBJECT ? objectDef : undefined)),
+    };
+    // `/actions` answers an anonymous caller 401 before addressing anything.
+    const auth: any = { api: { getSession: async () => ({ user: { id: 'u1' } }) } };
+    const kernel: any = {
+        context: {
+            getService: (n: string) =>
+                n === 'objectql' || n === 'data' ? ql : n === 'metadata' ? metadata : n === 'auth' ? auth : null,
+        },
+    };
+    return { dispatcher: new HttpDispatcher(kernel) as any, executeAction };
+}
+
+describe('[#22588] the /actions ledger rows, each driven with a real nested hook refusal', () => {
+    it('the ledger has invocation rows to drive, and every exemption names a real row', () => {
+        expect(INVOCATION_ROWS.length).toBeGreaterThanOrEqual(4);
+        for (const route of NOT_AN_INVOCATION.keys()) {
+            expect(ACTION_ROWS.map((r) => r.route), `stale exemption: ${route}`).toContain(route);
+        }
+    });
+
+    for (const row of INVOCATION_ROWS) {
+        it(`${row.route} answers the hook's sentence, not its debug wrapper`, async () => {
+            const { dispatcher, executeAction } = makeDispatcher();
+
+            const res = await dispatcher.dispatch('POST', concretePath(row.route), {}, {}, {
+                request: { headers: {} },
+            });
+
+            // Anti-vacuity: the action body really ran and really refused.
+            expect(executeAction).toHaveBeenCalled();
+            expect(res.response.status).toBe(400);
+            expect(res.response.body.success).toBe(false);
+            expect(res.response.body.error.code).toBe('VALIDATION_ERROR');
+            // The wording IS the defect here, so the sentence is asserted whole.
+            expect(res.response.body.error.message).toBe(REFUSAL);
+            expect(JSON.stringify(res.response.body)).not.toMatch(/threw:|hook '/);
+        }, 60_000);
+    }
+});