diff --git a/.changeset/side-effect-free-local-auth.md b/.changeset/side-effect-free-local-auth.md
new file mode 100644
index 00000000..4309acd5
--- /dev/null
+++ b/.changeset/side-effect-free-local-auth.md
@@ -0,0 +1,8 @@
+---
+'@treecrdt/auth': patch
+---
+
+Keep local operation authorization side-effect-free by deferring proof-store publication from
+`verifyOps` to `onVerifiedOps`. Remote sync still invokes `onVerifiedOps` before backend apply,
+preserving proof-first ingestion, while optimistic local backends can verify proposals without
+publishing proof material for a write that has not committed.
diff --git a/packages/treecrdt-auth/src/internal/cose-cwt-auth.ts b/packages/treecrdt-auth/src/internal/cose-cwt-auth.ts
index d89c94a7..3e9ee853 100644
--- a/packages/treecrdt-auth/src/internal/cose-cwt-auth.ts
+++ b/packages/treecrdt-auth/src/internal/cose-cwt-auth.ts
@@ -666,7 +666,6 @@ export function createTreecrdtCoseCwtAuth(opts: TreecrdtCoseCwtAuthOptions): Syn
         throw new Error(`op auth length ${auth.length} does not match ops length ${ops.length}`);
       }
 
-      const toPersist: Array<{ opRef: OpRef; auth: OpAuth }> = [];
       for (let i = 0; i < ops.length; i += 1) {
         const op = ops[i]!;
         const a = auth[i]!;
@@ -719,11 +718,21 @@ export function createTreecrdtCoseCwtAuth(opts: TreecrdtCoseCwtAuthOptions): Syn
           publicKey: replica,
         });
         if (!ok) throw new Error('invalid op signature');
+      }
+    },
+    onVerifiedOps: async (ops, auth, ctx) => {
+      if (ops.length !== auth.length) {
+        throw new Error(`verified auth has ${auth.length} entries for ${ops.length} ops`);
+      }
+      const toPersist: Array<{ opRef: OpRef; auth: OpAuth }> = [];
+      for (let i = 0; i < ops.length; i += 1) {
+        const op = ops[i]!;
+        const entry = auth[i]!;
+        const replica = replicaIdToBytes(op.meta.id.replica);
         const opRef = deriveOpRefV0(ctx.docId, { replica, counter: op.meta.id.counter });
-        opAuthByOpRefHex.set(bytesToHex(opRef), a);
-        if (opts.opAuthStore) toPersist.push({ opRef, auth: a });
+        opAuthByOpRefHex.set(bytesToHex(opRef), entry);
+        if (opts.opAuthStore) toPersist.push({ opRef, auth: entry });
       }
-
       if (opts.opAuthStore && toPersist.length > 0) {
         await ensureOpAuthStoreReady();
         await opts.opAuthStore.storeOpAuth(toPersist);
diff --git a/packages/treecrdt-auth/tests/auth.test.ts b/packages/treecrdt-auth/tests/auth.test.ts
index 52e63864..a404e16c 100644
--- a/packages/treecrdt-auth/tests/auth.test.ts
+++ b/packages/treecrdt-auth/tests/auth.test.ts
@@ -27,7 +27,14 @@ import {
   signTreecrdtOp,
   verifyTreecrdtRevocationRecordV1,
 } from '../dist/treecrdt-auth.js';
-import type { Capability, Filter, Hello, OpRef, SyncBackend } from '@treecrdt/sync-protocol';
+import type {
+  Capability,
+  Filter,
+  Hello,
+  OpAuth,
+  OpRef,
+  SyncBackend,
+} from '@treecrdt/sync-protocol';
 
 ed25519Hashes.sha512 = sha512;
 
@@ -427,6 +434,59 @@ test('auth: signOps selects proof_ref per op when multiple tokens exist', async
   );
 });
 
+test('auth: verifyOps is side-effect-free and onVerifiedOps publishes proof material', async () => {
+  const docId = 'doc-auth-local-proof-staging';
+  const root = '0'.repeat(32);
+  const issuerSk = ed25519Utils.randomSecretKey();
+  const issuerPk = await getPublicKey(issuerSk);
+  const writerSk = ed25519Utils.randomSecretKey();
+  const writerPk = await getPublicKey(writerSk);
+  const token = issueTreecrdtCapabilityTokenV1({
+    issuerPrivateKey: issuerSk,
+    subjectPublicKey: writerPk,
+    docId,
+    actions: ['write_structure'],
+  });
+  const persisted: Array<{ opRef: OpRef; auth: OpAuth }> = [];
+  const auth = createTreecrdtCoseCwtAuth({
+    issuerPublicKeys: [issuerPk],
+    localPrivateKey: writerSk,
+    localPublicKey: writerPk,
+    localCapabilityTokens: [token],
+    opAuthStore: {
+      storeOpAuth: async (entries) => {
+        persisted.push(...entries);
+      },
+      getOpAuthByOpRefs: async (opRefs) => opRefs.map(() => null),
+    },
+  });
+  const signCtx = { docId, purpose: 'local_write' as const, filterId: '__local__' };
+  const ctx = { docId, purpose: 'reconcile' as const, filterId: '__local__' };
+  const firstProposal = makeOp(writerPk, 1, 1, {
+    type: 'insert',
+    parent: root,
+    node: nodeIdFromInt(1),
+    orderKey: orderKeyFromPosition(0),
+  });
+  const retriedProposal = makeOp(writerPk, 1, 2, {
+    type: 'insert',
+    parent: root,
+    node: nodeIdFromInt(2),
+    orderKey: orderKeyFromPosition(1),
+  });
+
+  const firstAuth = (await auth.signOps?.([firstProposal], signCtx))!;
+  await auth.verifyOps?.([firstProposal], firstAuth, ctx);
+  const retriedAuth = (await auth.signOps?.([retriedProposal], signCtx))!;
+  await auth.verifyOps?.([retriedProposal], retriedAuth, ctx);
+  expect(persisted).toHaveLength(0);
+
+  await auth.onVerifiedOps?.([retriedProposal], retriedAuth, ctx);
+  expect(persisted).toHaveLength(1);
+  expect(persisted[0]!.auth.sig).toEqual(retriedAuth[0]!.sig);
+  expect(persisted[0]!.auth.sig).not.toEqual(firstAuth[0]!.sig);
+});
+
 test('auth: restart reuses only a retained proof for the exact local operation', async () => {
   const docId = 'doc-auth-retained-local-proof';
   const issuerSk = ed25519Utils.randomSecretKey();