diff --git a/src/core/Arbiter.js b/src/core/Arbiter.js
index d08a466..6e7c100 100644
--- a/src/core/Arbiter.js
+++ b/src/core/Arbiter.js
@@ -130,7 +130,13 @@ export class Arbiter {
         || 'deterministic',
       reducers: {
         ...(options?.partialGraphPolicy?.reducers || {})
-      }
+      },
+      // Size/reserved limits must survive construction: the partial-graph
+      // context reads them from the policy, and dropping them silently
+      // disabled configured DoS guards (defaults 1000/2000 applied).
+      maxNodes: options?.partialGraphPolicy?.maxNodes,
+      maxRelations: options?.partialGraphPolicy?.maxRelations,
+      reservedRelations: options?.partialGraphPolicy?.reservedRelations
     };
 
     this.snapshotEnabled = false;
diff --git a/src/core/arbiter/ArbiterConfig.js b/src/core/arbiter/ArbiterConfig.js
index 9e349ed..e2e5208 100644
--- a/src/core/arbiter/ArbiterConfig.js
+++ b/src/core/arbiter/ArbiterConfig.js
@@ -62,7 +62,10 @@ export class ArbiterConfig {
 
     this.arbiter.partialGraphPolicy = {
       conflict_mode: conflictMode,
-      reducers
+      reducers,
+      maxNodes: next.maxNodes !== undefined ? next.maxNodes : current.maxNodes,
+      maxRelations: next.maxRelations !== undefined ? next.maxRelations : current.maxRelations,
+      reservedRelations: next.reservedRelations !== undefined ? next.reservedRelations : current.reservedRelations
     };
     return this.arbiter.partialGraphPolicy;
   }
diff --git a/tests/rigor/partial-graph-parity.test.js b/tests/rigor/partial-graph-parity.test.js
index 5431639..0d587ab 100644
--- a/tests/rigor/partial-graph-parity.test.js
+++ b/tests/rigor/partial-graph-parity.test.js
@@ -274,6 +274,46 @@ describe('Partial-graph overlay semantics (rigor)', () => {
     }
   });
 
+  it('POLICY LIMITS: maxNodes/maxRelations enforce and reservedRelations customizes', () => {
+    const four = [
+      { src: 'u:0', relation: 'owner', dst: 'doc:0', possibility: 0.9 },
+      { src: 'u:0', relation: 'owner', dst: 'doc:0', possibility: 0.8 },
+      { src: 'u:0', relation: 'owner', dst: 'doc:0', possibility: 0.7 },
+      { src: 'u:0', relation: 'owner', dst: 'doc:0', possibility: 0.6 }
+    ];
+    const mk = (policy) => {
+      const a = new Arbiter(policy ? { partialGraphPolicy: policy } : {});
+      a.addNode('u:0', 'user');
+      a.addNode('doc:0', 'doc');
+      a.setRelationConfig('can_read', { type: 'direct', relation: 'owner' });
+      return a;
+    };
+    assert.throws(
+      () => mk({ maxRelations: 3 }).check('u:0', 'can_read', 'doc:0', { partialGraph: { relations: four } }),
+      /exceeds max relations/,
+      'constructor maxRelations enforces'
+    );
+    assert.throws(
+      () => mk({ maxNodes: 1 }).check('u:0', 'can_read', 'doc:0', {
+        partialGraph: { nodes: [{ key: 'g:a' }, { key: 'g:b' }], relations: four }
+      }),
+      /exceeds max nodes/,
+      'constructor maxNodes enforces'
+    );
+    const viaSetter = mk();
+    viaSetter.setPartialGraphPolicy({ maxRelations: 2 });
+    assert.throws(
+      () => viaSetter.check('u:0', 'can_read', 'doc:0', { partialGraph: { relations: four } }),
+      /exceeds max relations/,
+      'setter maxRelations enforces'
+    );
+    const customReserved = mk({ reservedRelations: ['owner'] });
+    const r = customReserved.check('u:0', 'can_read', 'doc:0', {
+      partialGraph: { relations: [{ src: 'u:0', relation: 'owner', dst: 'doc:0', possibility: 0.9 }] }
+    });
+    assert.equal(r.possibility, 0, 'custom reservedRelations skips owner');
+  });
+
   it('PROPERTY CAMPAIGN: direct/chain overlay parity under persistent+partial mutations', async () => {
     const result = await rigor.campaign(
       [rigor.object('graph', makeWrapper, [