diff --git a/‎.changeset/21178-remote-json-column-gate.md‎
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diff --git a/‎packages/drivers/driver-turso/src/remote-transport-compile-refusal-seam.test.ts‎
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@@ -0,0 +1,25 @@
+---
+"@objectstack/driver-turso": minor
+---
+
+fix(driver-turso)!: in remote mode, a filter on a declared JSON-stored field is refused with `INVALID_FILTER` / 400 for every operator the local face refuses there, and `$contains` / `$notContains` answer membership instead of a substring of the stored text (#21178)
+
+Clause-②: yes (narrowing)
+
+<!-- adr-0087: not-required (no-migration-prescription) a refusal of a QUERY shape at the remote transport's filter compiler: the operators refused on a JSON-stored column are exactly the ones driver-sql's where refuses there (and so this driver's local transport), read from the one JSON_COLUMN_INCOMPATIBLE_OPERATORS set @objectstack/core holds, and $contains / $notContains move from a substring test to the membership test the local transport already answers, through the same jsonMembershipPredicate. No authorable key, spelling or stored metadata shape moves: FilterConditionSchema and every object, view and dataset definition parse and save as before, and nothing reads or rewrites a stored row. There is nothing for objectstack migrate meta to rewrite, since what changes is which query this transport answers, not what any metadata says; the refusal itself names the spelling to use. The other categories are closed on facts: the bumped package publishes (not unpublished); no ADR-0087 id covers a filter operator on a JSON-stored column and this diff adds none (not registered / already-registered); and the change is runtime behaviour, with no published export or type narrowed or removed — the one interface change is an ADDED optional method, a widening (not runtime-interface-only / type-surface-only). -->
+
+**BREAKING** (`@objectstack/driver-turso`, remote mode): this narrows what `TursoDriver` answers when its `url` is a remote libSQL endpoint (such as `libsql://` or `https://`), the transport every hosted tenant database runs on, for every door that compiles a `where`: `find`, `findOne`, `count`, `updateMany`, `deleteMany`, `aggregate` and distinct values. It ships as `minor` under the launch-window convention for accept-set narrowings. Local and embedded-replica mode inherit `driver-sql`'s compiler and already answered this way; nothing moves there.
+
+**What is refused.** On a field the object declares JSON-stored (a structured-JSON type such as `json` or `address`, an inherently multi-value option type such as `tags`, `multiselect` or `checkboxes`, or a `select`, `radio`, `lookup`, `user`, `file` or `image` field declared `multiple: true`), a `where` that aims any operator in `@objectstack/core`'s `JSON_COLUMN_INCOMPATIBLE_OPERATORS` at the field is refused with `INVALID_FILTER` / 400, at any depth under `$and` / `$or` / `$not`, before any statement runs: `$eq`, `$ne`, `$gt`, `$gte`, `$lt`, `$lte`, `$between`, `$in`, `$nin`, `$startsWith`, `$endsWith`, `$icontains`, `$like`, `$ilike`, and implicit equality (`{ "owners": "u1" }`), whatever the comparand, `null` included.
+
+**What `$contains` / `$notContains` answer now.** Membership: `{ "owners": { "$contains": "u1" } }` matches the rows whose stored list holds `u1` as an element, so it no longer matches a row holding only `u10`; `$notContains` is its exact complement, a row with no value included; and a structured-JSON object answers no member at all, instead of matching text inside its serialization. On a scalar text field both remain the substring test they were.
+
+**What an author sees now.** The body the local transport answers for the same filter, byte for byte: the filter WAS NOT APPLIED, the comparison can never equal one member of a stored list, and the spelling to use, `{ "FIELD": { "$contains": "a" } }` for membership, or an `$or` of `$contains` for any-of. The field and the operator are withheld from the message, and the full diagnostic, naming both, is written to the driver's logger at `warn`.
+
+**Why.** The remote transport compiles its own SQL and read neither the shared refused set nor the membership construct, so over a `multiple: true` lookup holding `["u1","u2"]`, `["u2"]`, `["u3","u1"]` and `["u10"]` it answered: `$nin: ["u1"]` and `$ne: "u1"` every row, the rows holding `u1` included; `$eq`, `$in` and implicit equality no row; `$lt` / `$lte` a lexicographic verdict over the serialization; `$startsWith: "["` and `$endsWith: "]"` every row with a value; `$contains: "u1"` the row holding only `u10` too. One driver gave two answers to one filter depending only on the connection string, and the exclusion operators failed open.
+
+**Who is affected.** A caller, saved filter, list view, report or read scope that reaches a remote-mode `TursoDriver` with one of those operators on a JSON-stored field and read the rows it got as the answer. Write `$contains` for "holds this member", an `$or` of `$contains` for "holds any of these", `$not` around either for the exclusion, and `$null` / `$exists` / `$empty` for presence.
+
+**New optional API.** `RemoteTransport.setJsonColumnResolver(resolver)` in `@objectstack/driver-turso`, which `TursoDriver` wires to its own `isJsonColumn`, beside `setDeclaredValueShapeResolver`. A `RemoteTransport` driven standalone without it treats no column as JSON-stored and compiles as before.
+
+**Unchanged.** `$contains` and `$notContains` on a scalar field, `$exists`, `$null` and `$empty`; every operator on a field that is not declared JSON-stored; and a table this driver holds no declaration for, where nothing is judged.
@@ -38,6 +38,7 @@ import { readFileSync } from 'node:fs';
 import ts from 'typescript';
 import type { DriverQuery } from '@objectstack/spec/contracts';
 import { lowerFilterCondition, markFilterSubtreeProvenance } from '@objectstack/spec/data';
+import { jsonColumnOperatorRefusalText } from '@objectstack/core';
 import { RemoteTransport } from './remote-transport.js';
 import { TursoDriver } from './turso-driver.js';
 import { asLibsqlClient, makeLibsqlSqliteStub, type LibsqlSqliteStub } from './libsql-sqlite-stub.testkit.js';
@@ -51,6 +52,11 @@ const POLICY_COL = 'secret_policy_col';
 const SECRET = 'PSECRET_LITERAL';
 const SECRET_NUM = 7770123;
 const UNDECLARED_KEY = '$psecret_combinator';
+/**
+ * [#21178] The one column the half-2 transport is told is stored as JSON — the
+ * JSON-column gate's refusal needs the driver's rule injected to be reachable.
+ */
+const POLICY_JSON_COL = 'secret_policy_json_col';
 
 type Door = {
   /** The `RemoteTransport` method this row drives — asserted by the error's stack. */
@@ -171,6 +177,16 @@ const DOORS: readonly Door[] = [
     secrets: [POLICY_COL, SECRET],
     klass: 'a value this transport cannot bind',
   },
+  // ── #21178: the JSON-column gate, born in the seam ─────────────────────────
+  {
+    // The class is read from the shared builder, never spelled here: its words
+    // belong to `@objectstack/core`, and the operator it names in prose
+    // (`$nin`) is the class, not a secret — the FIELD is what is withheld.
+    builder: 'jsonColumnOperator',
+    where: () => ({ [POLICY_JSON_COL]: { $nin: [SECRET] } }),
+    secrets: [POLICY_JSON_COL],
+    klass: jsonColumnOperatorRefusalText(POLICY_JSON_COL, '$nin', false).message,
+  },
 ];
 
 /**
@@ -238,6 +254,19 @@ const ARMS: readonly Door[] = [
     klass: 'A comparand in this filter is undefined',
     label: "{ secret_policy_col: { $in: ['a', undefined] } }",
   },
+  // [#21178] The gate's two bare-equality positions: a value and `null`.
+  {
+    builder: 'jsonColumnOperator',
+    where: () => ({ [POLICY_JSON_COL]: SECRET }),
+    secrets: [POLICY_JSON_COL],
+    klass: jsonColumnOperatorRefusalText(POLICY_JSON_COL, '=', true).message,
+  },
+  {
+    builder: 'jsonColumnOperator',
+    where: () => ({ [POLICY_JSON_COL]: null }),
+    secrets: [POLICY_JSON_COL],
+    klass: jsonColumnOperatorRefusalText(POLICY_JSON_COL, '=', true).message,
+  },
 ];
 
 // ── Half 1: the enumeration ───────────────────────────────────────────────────
@@ -341,6 +370,9 @@ function transport() {
   const t = new RemoteTransport();
   t.setClient(client as any);
   t.setDiagnosticSink((m) => sink.push(m));
+  // [#21178] Only `POLICY_JSON_COL` is a JSON column, so every other row
+  // compiles exactly as it does on a transport handed no rule at all.
+  t.setJsonColumnResolver((_object, field) => field === POLICY_JSON_COL);
   return { t, sink, client };
 }