diff --git a/src/daemon/studio-db-broker.ts b/src/daemon/studio-db-broker.ts
index 30214373..9da624f8 100644
--- a/src/daemon/studio-db-broker.ts
+++ b/src/daemon/studio-db-broker.ts
@@ -12,8 +12,9 @@
  *
  *  1. **Nothing without a live grant.** No grant, an unknown token, a revoked one or an expired one is
  *     refused before a statement is prepared. Read grants cannot write.
- *  2. **Refusals never leave residue.** Every refusal is decided BEFORE the storage is touched, and every
- *     write runs inside one transaction, so an op either completes or leaves the table byte-identical.
+ *  2. **Refusals never leave residue.** Every refusal is decided BEFORE the protected table is touched;
+ *     the schema-skew decision reads only the migration ledger. Every write runs inside one transaction,
+ *     so an op either completes or leaves the table byte-identical.
  *  3. **Identifiers are never interpolated from the wire.** Table names come from the CLOSED contract set;
  *     column names are checked against the table's real columns read from the database itself. Values are
  *     always bound. A wire that names a column the table does not have is a malformed op, not a refusal —
@@ -328,8 +329,9 @@ function isRefusal(value: BrokerGrant | BrokerRefusal): value is BrokerRefusal {
 /**
  * Execute one op against the shared cache.
  *
- * Every decision that can refuse happens above the first prepared statement, and every write runs inside
- * one transaction, so a refused op and a failed op both leave the table exactly as they found it.
+ * Every decision that can refuse protected-table access happens above the first statement against that
+ * table, and every write runs inside one transaction, so a refused op and a failed op both leave the
+ * table exactly as they found it.
  * Reads answer rows; writes answer the rows they wrote — `insert` echoes what landed (so a caller learns
  * the rowid it did not supply), `update` and `delete` answer the affected count as one row, because the
  * count is the only thing SQLite will tell us without a second read the caller did not ask for.
@@ -356,6 +358,15 @@ export function executeBrokerOp(
   const authorized = grants.authorize(op.grant, table, access);
   if (isRefusal(authorized)) return authorized;
 
+  const liveSchemaHead = schemaHead(db);
+  if (liveSchemaHead > authorized.schemaHead) {
+    grants.revoke(authorized.token, 'schema_skew');
+    return { ok: false, reason: 'grant_revoked', table };
+  }
+  // Equality is the schema the grant accepted. A lower live head is not a forward shared-cache
+  // migration, so it remains subject to the broker's normal live-table checks rather than being
+  // mislabeled as schema_skew.
+
   if (op.kind === 'read') {
     if (!Number.isInteger(op.limit) || op.limit <= 0) {
       throw new BrokerOpError('read.limit must be a positive integer');
diff --git a/tests/integration/studio-annotations-broker.test.ts b/tests/integration/studio-annotations-broker.test.ts
index b17228b3..de44f6aa 100644
--- a/tests/integration/studio-annotations-broker.test.ts
+++ b/tests/integration/studio-annotations-broker.test.ts
@@ -6,6 +6,7 @@ import {
   BrokerGrantStore,
   BrokerOpError,
   executeBrokerOp,
+  schemaHead,
 } from '../../src/daemon/studio-db-broker.js';
 import { BROKER_TABLES } from '../../src/companion-contract/index.js';
 import type { BrokerOp, BrokerRefusal, BrokerRow } from '../../src/companion-contract/index.js';
@@ -63,7 +64,7 @@ describe('studio_annotations over the companion broker', () => {
     return grants.issue({
       mode,
       tables: tables as Parameters<BrokerGrantStore['issue']>[0]['tables'],
-      schemaHead: 1,
+      schemaHead: schemaHead(db()),
     }).token;
   }
 
diff --git a/tests/integration/studio-memories-broker.test.ts b/tests/integration/studio-memories-broker.test.ts
index c9af4315..6ce6ab0f 100644
--- a/tests/integration/studio-memories-broker.test.ts
+++ b/tests/integration/studio-memories-broker.test.ts
@@ -6,6 +6,7 @@ import {
   BrokerGrantStore,
   BrokerOpError,
   executeBrokerOp,
+  schemaHead,
 } from '../../src/daemon/studio-db-broker.js';
 import { BROKER_TABLES } from '../../src/companion-contract/index.js';
 import type { BrokerOp, BrokerRefusal, BrokerRow } from '../../src/companion-contract/index.js';
@@ -50,7 +51,7 @@ describe('studio_memories over the companion broker', () => {
     return grants.issue({
       mode,
       tables: tables as Parameters<BrokerGrantStore['issue']>[0]['tables'],
-      schemaHead: 1,
+      schemaHead: schemaHead(db()),
     }).token;
   }
 
diff --git a/tests/integration/studio-sd10-tables-broker.test.ts b/tests/integration/studio-sd10-tables-broker.test.ts
index 12d2063e..d987fea5 100644
--- a/tests/integration/studio-sd10-tables-broker.test.ts
+++ b/tests/integration/studio-sd10-tables-broker.test.ts
@@ -2,7 +2,7 @@ import { afterEach, beforeEach, describe, expect, it } from 'vitest';
 
 import { resetConfig } from '../../src/config.js';
 import { closeDatabase, getDatabase, initDatabase } from '../../src/cache/db.js';
-import { BrokerGrantStore, executeBrokerOp } from '../../src/daemon/studio-db-broker.js';
+import { BrokerGrantStore, executeBrokerOp, schemaHead } from '../../src/daemon/studio-db-broker.js';
 import { BROKER_TABLES } from '../../src/companion-contract/index.js';
 import type { BrokerOp, BrokerRefusal, BrokerRow, BrokerTable } from '../../src/companion-contract/index.js';
 
@@ -81,7 +81,7 @@ describe('the SD10 tables over the companion broker', () => {
   });
 
   function token(tables: readonly BrokerTable[]): string {
-    return grants.issue({ mode: 'readwrite', tables, schemaHead: 1 }).token;
+    return grants.issue({ mode: 'readwrite', tables, schemaHead: schemaHead(getDatabase()) }).token;
   }
 
   function run(op: BrokerOp): ReturnType<typeof executeBrokerOp> {
diff --git a/tests/integration/studio-sd9-tables-broker.test.ts b/tests/integration/studio-sd9-tables-broker.test.ts
index 2b983483..b691f436 100644
--- a/tests/integration/studio-sd9-tables-broker.test.ts
+++ b/tests/integration/studio-sd9-tables-broker.test.ts
@@ -6,6 +6,7 @@ import {
   BrokerGrantStore,
   BrokerOpError,
   executeBrokerOp,
+  schemaHead,
 } from '../../src/daemon/studio-db-broker.js';
 import { BROKER_TABLES } from '../../src/companion-contract/index.js';
 import type { BrokerOp, BrokerRefusal, BrokerRow, BrokerTable } from '../../src/companion-contract/index.js';
@@ -99,7 +100,7 @@ describe('the SD9 tables over the companion broker', () => {
     return grants.issue({
       mode,
       tables: tables as Parameters<BrokerGrantStore['issue']>[0]['tables'],
-      schemaHead: 1,
+      schemaHead: schemaHead(db()),
     }).token;
   }
 
diff --git a/tests/integration/studio-site-profiles-broker.test.ts b/tests/integration/studio-site-profiles-broker.test.ts
index bfd4c3a6..d969dcb7 100644
--- a/tests/integration/studio-site-profiles-broker.test.ts
+++ b/tests/integration/studio-site-profiles-broker.test.ts
@@ -6,6 +6,7 @@ import {
   BrokerGrantStore,
   BrokerOpError,
   executeBrokerOp,
+  schemaHead,
 } from '../../src/daemon/studio-db-broker.js';
 import { BROKER_TABLES } from '../../src/companion-contract/index.js';
 import type { BrokerOp, BrokerRefusal, BrokerRow, BrokerTable } from '../../src/companion-contract/index.js';
@@ -93,7 +94,7 @@ describe('the studio_site_* tables over the companion broker', () => {
     return grants.issue({
       mode,
       tables: tables as Parameters<BrokerGrantStore['issue']>[0]['tables'],
-      schemaHead: 1,
+      schemaHead: schemaHead(db()),
     }).token;
   }
 
diff --git a/tests/unit/daemon/companion-broker.test.ts b/tests/unit/daemon/companion-broker.test.ts
index 2fc153ff..526027ba 100644
--- a/tests/unit/daemon/companion-broker.test.ts
+++ b/tests/unit/daemon/companion-broker.test.ts
@@ -1,7 +1,9 @@
 import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import Database from 'better-sqlite3';
 
 import { resetConfig } from '../../../src/config.js';
 import { initDatabase, getDatabase, closeDatabase } from '../../../src/cache/db.js';
+import { applyMigrations, MIGRATIONS } from '../../../src/cache/migrations/runner.js';
 import {
   BrokerGrantStore,
   BrokerOpError,
@@ -112,6 +114,56 @@ describe('companion broker — grant-scoped table access', () => {
       expect(schemaHead(db())).toBe(0);
     });
 
+    it('revokes a grant when the shared database migrates past its issued head', () => {
+      const migratedDb = new Database(':memory:');
+      try {
+        migratedDb.exec(
+          'CREATE TABLE schema_migrations (name TEXT PRIMARY KEY, applied_at INTEGER NOT NULL)',
+        );
+        const nextMigration = [...MIGRATIONS].reverse().find((migration) => !migration.requiresVec);
+        if (!nextMigration) throw new Error('expected a non-vector migration');
+        const recordMigration = migratedDb.prepare(
+          'INSERT INTO schema_migrations (name, applied_at) VALUES (?, ?)',
+        );
+        for (const migration of MIGRATIONS) {
+          if (migration === nextMigration) break;
+          if (migration.requiresVec) continue;
+          migratedDb.transaction(() => {
+            migratedDb.exec(migration.sql);
+            migration.postStep?.(migratedDb);
+            recordMigration.run(migration.name, 1);
+          })();
+        }
+
+        const issuedHead = schemaHead(migratedDb);
+        const grant = grants.issue({ mode: 'read', tables: ['studio_runs'], schemaHead: issuedHead });
+
+        applyMigrations(migratedDb, { vecLoaded: false });
+        expect(schemaHead(migratedDb)).toBe(issuedHead + 1);
+
+        const op = {
+          grant: grant.token,
+          kind: 'read' as const,
+          table: 'studio_runs' as const,
+          limit: 10,
+        };
+        const first = executeBrokerOp(migratedDb, grants, op);
+
+        expect(refusalOf(first)).toEqual({ ok: false, reason: 'grant_revoked', table: 'studio_runs' });
+        expect(grants.revocationOf(grant.token)).toEqual({
+          token: grant.token,
+          revokedAt: clock,
+          reason: 'schema_skew',
+        });
+
+        const second = executeBrokerOp(migratedDb, grants, op);
+        expect(refusalOf(second)).toEqual({ ok: false, reason: 'grant_revoked', table: 'studio_runs' });
+        expect(grants.revocationOf(grant.token)?.reason).toBe('schema_skew');
+      } finally {
+        migratedDb.close();
+      }
+    });
+
     it('revokes idempotently and keeps the FIRST reason', () => {
       const grant = grants.issue({ mode: 'readwrite', tables: ['studio_runs'], schemaHead: 1 });
 
@@ -283,7 +335,7 @@ describe('companion broker — grant-scoped table access', () => {
     });
 
     it('refuses write_not_granted for a read grant and leaves the table untouched', () => {
-      const grant = grants.issue({ mode: 'read', tables: BROKER_TABLES, schemaHead: 1 });
+      const grant = grants.issue({ mode: 'read', tables: BROKER_TABLES, schemaHead: schemaHead(db()) });
       const before = runRows();
 
       const result = executeBrokerOp(db(), grants, {
@@ -300,7 +352,7 @@ describe('companion broker — grant-scoped table access', () => {
     });
 
     it('refuses row_limit_exceeded above the wire ceiling without running the read', () => {
-      const grant = grants.issue({ mode: 'read', tables: BROKER_TABLES, schemaHead: 1 });
+      const grant = grants.issue({ mode: 'read', tables: BROKER_TABLES, schemaHead: schemaHead(db()) });
 
       const ok = executeBrokerOp(db(), grants, {
         grant: grant.token,
@@ -326,7 +378,7 @@ describe('companion broker — grant-scoped table access', () => {
     });
 
     function grant() {
-      return grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: 1 }).token;
+      return grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: schemaHead(db()) }).token;
     }
 
     it('round-trips insert → read → update → delete on the run projection tables', () => {
@@ -413,7 +465,7 @@ describe('companion broker — grant-scoped table access', () => {
     });
 
     it('rejects a column the table does not have as a malformed op, not a refusal', () => {
-      const token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: 1 }).token;
+      const token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: schemaHead(db()) }).token;
       const before = runRows();
 
       expect(() =>
@@ -432,7 +484,7 @@ describe('companion broker — grant-scoped table access', () => {
     });
 
     it('binds a value that looks like SQL rather than interpolating it', () => {
-      const token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: 1 }).token;
+      const token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: schemaHead(db()) }).token;
 
       executeBrokerOp(db(), grants, {
         grant: token,
@@ -446,7 +498,7 @@ describe('companion broker — grant-scoped table access', () => {
     });
 
     it('refuses an unfiltered update or delete — a whole-table mutation asked for by omission', () => {
-      const token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: 1 }).token;
+      const token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: schemaHead(db()) }).token;
 
       expect(() =>
         executeBrokerOp(db(), grants, { grant: token, kind: 'update', table: 'studio_runs', row: { status: 'x' } }),
@@ -463,7 +515,7 @@ describe('companion broker — grant-scoped table access', () => {
   describe('in-flight atomicity', () => {
     it('leaves the table byte-identical when a write violates a constraint mid-op', () => {
       seedRun();
-      const token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: 1 }).token;
+      const token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: schemaHead(db()) }).token;
       const before = runRows();
 
       // Same primary key as the seeded run: SQLite aborts inside the transaction.
@@ -481,7 +533,11 @@ describe('companion broker — grant-scoped table access', () => {
 
     it('does not roll back an op that already completed when a later one is refused', () => {
       seedRun();
-      const grantRecord = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: 1 });
+      const grantRecord = grants.issue({
+        mode: 'readwrite',
+        tables: BROKER_TABLES,
+        schemaHead: schemaHead(db()),
+      });
 
       const first = executeBrokerOp(db(), grants, {
         grant: grantRecord.token,
diff --git a/tests/unit/daemon/studio-db-broker-bounds.test.ts b/tests/unit/daemon/studio-db-broker-bounds.test.ts
index fe67f0a0..4ae88085 100644
--- a/tests/unit/daemon/studio-db-broker-bounds.test.ts
+++ b/tests/unit/daemon/studio-db-broker-bounds.test.ts
@@ -2,7 +2,12 @@ import { describe, it, expect, beforeEach, afterEach } from 'vitest';
 
 import { resetConfig } from '../../../src/config.js';
 import { initDatabase, getDatabase, closeDatabase } from '../../../src/cache/db.js';
-import { BrokerGrantStore, BrokerOpError, executeBrokerOp } from '../../../src/daemon/studio-db-broker.js';
+import {
+  BrokerGrantStore,
+  BrokerOpError,
+  executeBrokerOp,
+  schemaHead,
+} from '../../../src/daemon/studio-db-broker.js';
 import { BROKER_TABLES, MAX_BROKER_ROWS } from '../../../src/companion-contract/index.js';
 
 /**
@@ -40,7 +45,7 @@ describe('companion broker — the row bound', () => {
     resetConfig();
     initDatabase(':memory:');
     grants = new BrokerGrantStore();
-    token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: 1 }).token;
+    token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: schemaHead(db()) }).token;
   });
 
   afterEach(() => {
diff --git a/tests/unit/daemon/studio-db-broker-run-log.test.ts b/tests/unit/daemon/studio-db-broker-run-log.test.ts
index 66b45141..eea48361 100644
--- a/tests/unit/daemon/studio-db-broker-run-log.test.ts
+++ b/tests/unit/daemon/studio-db-broker-run-log.test.ts
@@ -2,7 +2,7 @@ import { describe, it, expect, beforeEach, afterEach } from 'vitest';
 
 import { resetConfig } from '../../../src/config.js';
 import { initDatabase, getDatabase, closeDatabase } from '../../../src/cache/db.js';
-import { BrokerGrantStore, executeBrokerOp } from '../../../src/daemon/studio-db-broker.js';
+import { BrokerGrantStore, executeBrokerOp, schemaHead } from '../../../src/daemon/studio-db-broker.js';
 import { BROKER_TABLES } from '../../../src/companion-contract/index.js';
 import type { BrokerRow } from '../../../src/companion-contract/index.js';
 
@@ -56,7 +56,7 @@ describe('companion broker — the run-log surface is reachable as table ops', (
     resetConfig();
     initDatabase(':memory:');
     grants = new BrokerGrantStore();
-    token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: 1 }).token;
+    token = grants.issue({ mode: 'readwrite', tables: BROKER_TABLES, schemaHead: schemaHead(db()) }).token;
     op({
       grant: token,
       kind: 'insert',