diff --git a/backend/src/__tests__/networking-aggregate-cache.test.ts b/backend/src/__tests__/networking-aggregate-cache.test.ts
new file mode 100644
index 00000000..63fc000e
--- /dev/null
+++ b/backend/src/__tests__/networking-aggregate-cache.test.ts
@@ -0,0 +1,148 @@
+/**
+ * Networking aggregate memo: read endpoints share one computation per node and
+ * requested variant within the TTL window, a mutation invalidation forces the
+ * next read to recompute, and a base (no-topology) read never satisfies a
+ * topology read. In-flight joining itself is covered by CacheService's own
+ * suite; these tests pin the key derivation this module adds on top.
+ */
+import { describe, it, expect } from 'vitest';
+import {
+  fetchNodeNetworkingAggregateWithMeta,
+  invalidateNodeNetworkingAggregate,
+  networkingAggregateCacheKey,
+} from '../services/network/networkingAggregateCache';
+import type { NetworkingAggregateOptions } from '../services/network/networkingAggregateCache';
+import type { NodeNetworkingAggregate } from '../services/network/networkingTypes';
+
+function fakeAggregate(networkCount: number): NodeNetworkingAggregate {
+  return {
+    overview: {
+      runtimeAvailable: true,
+      networkCount,
+      stackCount: 0,
+      connectedContainerCount: 0,
+      systemNetworkCount: 0,
+      senchoManagedNetworkCount: 0,
+      composeManagedNetworkCount: 0,
+      unmanagedNetworkCount: 0,
+      externalDependencyNetworkCount: 0,
+      exposedStackCount: 0,
+      unknownExposureStackCount: 0,
+      missingExternalCount: 0,
+      networkCollisionCount: 0,
+      findingCount: 0,
+      degradedCache: false,
+      renderFailedStacks: [],
+    },
+    networks: [],
+    findings: [],
+    stackFacts: [],
+    runtimeAvailable: true,
+    recentActivity: [],
+  };
+}
+
+function fakeTopology(): NodeNetworkingAggregate['topology'] {
+  return { networks: [{ id: 'n1', name: 'net', driver: 'bridge', scope: '', stack: null, isSystem: false, ingress: false, ownership: 'unmanaged', declaredByStacks: [], declaredExternalByStacks: [], isExternalDependency: false, findingIds: [], containers: [] }], includeSystem: false };
+}
+
+const NO_OPTIONS: NetworkingAggregateOptions = {};
+
+async function fetchMemo(nodeId: number, options: NetworkingAggregateOptions, compute: () => Promise<NodeNetworkingAggregate>) {
+  const { value } = await fetchNodeNetworkingAggregateWithMeta(nodeId, options, compute);
+  return value;
+}
+
+describe('networkingAggregateCache', () => {
+  it('computes once per TTL window per node and variant', async () => {
+    invalidateNodeNetworkingAggregate(1);
+    let calls = 0;
+
+    const first = await fetchMemo(1, NO_OPTIONS, async () => fakeAggregate(++calls));
+    const second = await fetchMemo(1, NO_OPTIONS, async () => fakeAggregate(++calls));
+
+    expect(first.overview.networkCount).toBe(1);
+    expect(second.overview.networkCount).toBe(1);
+  });
+
+  it('keeps nodes isolated', async () => {
+    invalidateNodeNetworkingAggregate(2);
+    invalidateNodeNetworkingAggregate(3);
+    const [a, b] = await Promise.all([
+      fetchMemo(2, NO_OPTIONS, async () => fakeAggregate(2)),
+      fetchMemo(3, NO_OPTIONS, async () => fakeAggregate(3)),
+    ]);
+    expect(a.overview.networkCount).toBe(2);
+    expect(b.overview.networkCount).toBe(3);
+  });
+
+  it('does not serve a base read to a topology request', async () => {
+    invalidateNodeNetworkingAggregate(5);
+
+    const base = await fetchMemo(5, NO_OPTIONS, async () => fakeAggregate(1));
+    expect(base.topology).toBeUndefined();
+
+    let topologyComputes = 0;
+    const topology = await fetchMemo(5, { includeTopology: true }, async () => {
+      topologyComputes += 1;
+      return { ...fakeAggregate(1), topology: fakeTopology() };
+    });
+    expect(topologyComputes).toBe(1);
+    expect(topology.topology?.networks).toHaveLength(1);
+
+    // The base entry stays warm and is served for base reads.
+    let baseComputes = 0;
+    const warmedBase = await fetchMemo(5, NO_OPTIONS, async () => {
+      baseComputes += 1;
+      return fakeAggregate(99);
+    });
+    expect(baseComputes).toBe(0);
+    expect(warmedBase.overview.networkCount).toBe(1);
+  });
+
+  it('treats includeSystem variants as distinct entries', async () => {
+    invalidateNodeNetworkingAggregate(7);
+    await fetchMemo(7, { includeTopology: true }, async () => fakeAggregate(1));
+
+    let computes = 0;
+    await fetchMemo(7, { includeTopology: true, includeSystem: true }, async () => {
+      computes += 1;
+      return fakeAggregate(1);
+    });
+    expect(computes).toBe(1);
+  });
+
+  it('builds a distinct key per variant', () => {
+    const keys = new Set([
+      networkingAggregateCacheKey(9, {}),
+      networkingAggregateCacheKey(9, { includeTopology: true }),
+      networkingAggregateCacheKey(9, { includeTopology: true, includeSystem: true }),
+      networkingAggregateCacheKey(10, {}),
+    ]);
+    expect(keys.size).toBe(4);
+  });
+
+  it('recomputes after an explicit invalidation (mutation path)', async () => {
+    invalidateNodeNetworkingAggregate(4);
+    let calls = 0;
+
+    await fetchMemo(4, NO_OPTIONS, async () => fakeAggregate(++calls));
+    invalidateNodeNetworkingAggregate(4);
+    const after = await fetchMemo(4, NO_OPTIONS, async () => fakeAggregate(++calls));
+
+    expect(after.overview.networkCount).toBe(2);
+  });
+
+  it('invalidation drops every variant of the node', async () => {
+    invalidateNodeNetworkingAggregate(6);
+    await fetchMemo(6, NO_OPTIONS, async () => fakeAggregate(1));
+    await fetchMemo(6, { includeTopology: true }, async () => fakeAggregate(1));
+
+    invalidateNodeNetworkingAggregate(6);
+
+    let calls = 0;
+    await fetchMemo(6, NO_OPTIONS, async () => { calls += 1; return fakeAggregate(1); });
+    await fetchMemo(6, { includeTopology: true }, async () => { calls += 1; return fakeAggregate(1); });
+    expect(calls).toBe(2);
+  });
+});
diff --git a/backend/src/__tests__/networking-hardening.test.ts b/backend/src/__tests__/networking-hardening.test.ts
new file mode 100644
index 00000000..d70bde53
--- /dev/null
+++ b/backend/src/__tests__/networking-hardening.test.ts
@@ -0,0 +1,151 @@
+/**
+ * Networking hardening integration tests:
+ *  - the aggregate memo serves repeat reads within its TTL,
+ *  - a base (no-topology) read never satisfies a topology request,
+ *  - exposure-intent writes invalidate the memo so the next overview reflects
+ *    them immediately,
+ *  - the delete guard 409s with stack-declaration-unknown for an unlabeled
+ *    external network while a stack fails to render.
+ */
+import { describe, it, expect, beforeAll, afterAll, beforeEach, afterEach, vi } from 'vitest';
+import fs from 'fs';
+import path from 'path';
+import request from 'supertest';
+import jwt from 'jsonwebtoken';
+import { setupTestDb, cleanupTestDb, TEST_USERNAME, TEST_JWT_SECRET } from './helpers/setupTestDb';
+import DockerController from '../services/DockerController';
+import { ComposeService } from '../services/ComposeService';
+import { DatabaseService } from '../services/DatabaseService';
+
+let tmpDir: string;
+let app: import('express').Express;
+let authHeader: string;
+
+const STACK = 'hardnet';
+const NET_ID = 'deadbeefdead';
+
+function stubHealthy() {
+  vi.spyOn(DockerController, 'getInstance').mockReturnValue({
+    getDependencySnapshot: vi.fn().mockResolvedValue({
+      containers: [],
+      networks: [
+        { id: NET_ID, name: 'shared_ext', driver: 'bridge', scope: 'local', isSystem: false, composeProject: null, stack: null },
+      ],
+      volumes: [],
+    }),
+    inspectNetwork: vi.fn().mockResolvedValue({ Id: NET_ID, Name: 'shared_ext', Driver: 'bridge', Scope: 'local', Labels: {}, Containers: {} }),
+    removeNetwork: vi.fn().mockResolvedValue(undefined),
+  } as unknown as DockerController);
+  vi.spyOn(ComposeService, 'getInstance').mockReturnValue({
+    renderConfig: vi.fn().mockResolvedValue({
+      rendered: JSON.stringify({
+        name: STACK,
+        services: { web: { image: 'nginx:latest', ports: ['8080:80'] } },
+        networks: {},
+        volumes: {},
+      }),
+      stderr: '', code: 0, timedOut: false,
+    }),
+  } as unknown as ComposeService);
+}
+
+beforeAll(async () => {
+  tmpDir = await setupTestDb();
+  ({ app } = await import('../index'));
+  authHeader = `Bearer ${jwt.sign({ username: TEST_USERNAME }, TEST_JWT_SECRET, { expiresIn: '5m' })}`;
+});
+
+afterAll(() => cleanupTestDb(tmpDir));
+
+describe('networking hardening', () => {
+  let stackDir: string;
+
+  beforeEach(() => {
+    stackDir = path.join(process.env.COMPOSE_DIR as string, STACK);
+    fs.mkdirSync(stackDir, { recursive: true });
+    fs.writeFileSync(path.join(stackDir, 'compose.yaml'), 'services:\n  web:\n    image: nginx:latest\n');
+    stubHealthy();
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+    fs.rmSync(stackDir, { recursive: true, force: true });
+  });
+
+  it('serves repeat overview reads from one computation within the TTL window', async () => {
+    const first = await request(app).get('/api/networking/overview').set('Authorization', authHeader);
+    expect(first.status).toBe(200);
+
+    const snapshotSpy = DockerController.getInstance(1).getDependencySnapshot as ReturnType<typeof vi.fn>;
+    const callsBefore = snapshotSpy.mock.calls.length;
+
+    const second = await request(app).get('/api/networking/overview').set('Authorization', authHeader);
+    expect(second.status).toBe(200);
+    expect(second.body.schemaVersion).toBe(first.body.schemaVersion);
+    expect(DockerController.getInstance(1).getDependencySnapshot as ReturnType<typeof vi.fn>).toHaveBeenCalledTimes(callsBefore);
+  });
+
+  it('serves real topology data when overview warmed the cache first', async () => {
+    await request(app).get('/api/networking/overview').set('Authorization', authHeader);
+
+    const res = await request(app)
+      .get('/api/networking/topology')
+      .set('Authorization', authHeader);
+    expect(res.status).toBe(200);
+    expect((res.body.networks as Array<{ name: string }>)).toContainEqual(
+      expect.objectContaining({ name: 'shared_ext' }),
+    );
+  });
+  it('reflects an exposure-intent change in the next overview read', async () => {
+    const initial = await request(app).get('/api/networking/overview').set('Authorization', authHeader);
+    expect(initial.status).toBe(200);
+    // The fixture publishes 8080:80 with no intent set, so the pre-write read
+    // must carry the unclassified finding; asserting both directions makes an
+    // invalidation regression loud instead of silently vacuous.
+    const hadUnclassifiedBefore = ((initial.body.findings ?? []) as Array<{ kind: string; stack?: string }>)
+      .some((f) => f.kind === 'exposure-unclassified' && f.stack === STACK);
+    expect(hadUnclassifiedBefore).toBe(true);
+
+    const put = await request(app)
+      .put(`/api/stacks/${STACK}/exposure`)
+      .set('Authorization', authHeader)
+      .send({ service: '', intent: 'internal' });
+    expect(put.status).toBe(200);
+
+    const res = await request(app).get('/api/networking/overview').set('Authorization', authHeader);
+    expect(res.status).toBe(200);
+    const unclassified = (res.body.findings as Array<{ kind: string; stack?: string }>)
+      .find((f) => f.kind === 'exposure-unclassified' && f.stack === STACK);
+    expect(unclassified).toBeUndefined();
+
+    DatabaseService.getInstance().deleteStackExposureIntents(1, STACK);
+  });
+
+  it('409s an unlabeled external network delete while a stack is unrenderable', async () => {
+    (ComposeService.getInstance(1).renderConfig as ReturnType<typeof vi.fn>).mockResolvedValue({
+      rendered: null,
+      stderr: 'redacted render failure',
+      code: 1,
+      timedOut: false,
+    });
+
+    const removeSpy = vi.spyOn(DockerController.getInstance(1), 'removeNetwork');
+    const res = await request(app)
+      .post('/api/system/networks/delete')
+      .set('Authorization', authHeader)
+      .send({ id: NET_ID });
+    expect(res.status).toBe(409);
+    expect(res.body.code).toBe('stack-declaration-unknown');
+    expect(removeSpy).not.toHaveBeenCalled();
+  });
+
+  it('allows deleting the same network once every stack renders again', async () => {
+    const removeSpy = vi.spyOn(DockerController.getInstance(1), 'removeNetwork');
+    const res = await request(app)
+      .post('/api/system/networks/delete')
+      .set('Authorization', authHeader)
+      .send({ id: NET_ID });
+    expect(res.status).toBe(200);
+    expect(removeSpy).toHaveBeenCalledOnce();
+  });
+});
diff --git a/backend/src/__tests__/networking-operator.test.ts b/backend/src/__tests__/networking-operator.test.ts
index 7d2a6f6d..29bf04c1 100644
--- a/backend/src/__tests__/networking-operator.test.ts
+++ b/backend/src/__tests__/networking-operator.test.ts
@@ -12,6 +12,7 @@ import { ComposeService } from '../services/ComposeService';
 import { DatabaseService } from '../services/DatabaseService';
 import { evaluateNetworkDeleteGuard } from '../services/network/networkDeleteGuards';
 import SelfIdentityService from '../services/SelfIdentityService';
+import { invalidateNodeNetworkingAggregate } from '../services/network/networkingAggregateCache';
 
 let tmpDir: string;
 let app: import('express').Express;
@@ -85,6 +86,7 @@ describe('networking operator routes', () => {
 
   afterEach(() => {
     vi.restoreAllMocks();
+    invalidateNodeNetworkingAggregate(1);
     fs.rmSync(stackDir, { recursive: true, force: true });
   });
 
@@ -196,6 +198,19 @@ describe('evaluateNetworkDeleteGuard', () => {
     expect(guard.code).toBe('stack-declaration-unknown');
   });
 
+  it('fails closed for an unlabeled external network while a stack is unrenderable', () => {
+    const snapshot = {
+      containers: [],
+      networks: [{ id: 'n1', name: 'shared_ext', driver: 'bridge', scope: 'local', isSystem: false, composeProject: null, stack: null }],
+      volumes: [],
+    };
+    const guard = evaluateNetworkDeleteGuard('n1', snapshot, [
+      { stack: STACK, renderable: false, renderError: 'compose file invalid', runtime: 'available', networks: [{ key: 'shared_ext', name: 'shared_ext', external: true, internal: false, createdByStack: false }], services: [], drift: { runtimeOnlyAttachments: [], declaredButUnused: [], missingFromRuntime: [], foreignNetworkAttachments: [] }, missingExternalNetworks: [] },
+    ]);
+    expect(guard.blocked).toBe(true);
+    expect(guard.code).toBe('stack-declaration-unknown');
+  });
+
   it('blocks a system network ahead of every other reason', () => {
     const snapshot = {
       containers: [], volumes: [],
diff --git a/backend/src/__tests__/networking-severity.test.ts b/backend/src/__tests__/networking-severity.test.ts
index 624c6772..042679fb 100644
--- a/backend/src/__tests__/networking-severity.test.ts
+++ b/backend/src/__tests__/networking-severity.test.ts
@@ -13,6 +13,7 @@ import { setupTestDb, cleanupTestDb, TEST_USERNAME, TEST_JWT_SECRET } from './he
 import DockerController from '../services/DockerController';
 import { ComposeService } from '../services/ComposeService';
 import { DatabaseService } from '../services/DatabaseService';
+import { invalidateNodeNetworkingAggregate } from '../services/network/networkingAggregateCache';
 
 let tmpDir: string;
 let app: import('express').Express;
@@ -140,6 +141,7 @@ describe('networking collision correctness', () => {
 
   afterEach(() => {
     vi.restoreAllMocks();
+    invalidateNodeNetworkingAggregate(1);
     fs.rmSync(dirA, { recursive: true, force: true });
     fs.rmSync(dirB, { recursive: true, force: true });
   });
diff --git a/backend/src/helpers/cacheInvalidation.ts b/backend/src/helpers/cacheInvalidation.ts
index e78f28f9..cdb04eae 100644
--- a/backend/src/helpers/cacheInvalidation.ts
+++ b/backend/src/helpers/cacheInvalidation.ts
@@ -1,5 +1,6 @@
 import { CacheService } from '../services/CacheService';
 import { StackFileRootsService } from '../services/StackFileRootsService';
+import { invalidateNodeNetworkingAggregate } from '../services/network/networkingAggregateCache';
 
 export const REMOTE_META_NAMESPACE = 'remote-meta';
 
@@ -17,6 +18,11 @@ export function invalidateNodeCaches(nodeId: number): void {
   cache.invalidate(`stats:${nodeId}`);
   cache.invalidate(`stack-statuses:${nodeId}`);
   cache.invalidate('project-name-map');
+  // Stack and container mutations (create/delete/edit/deploy/rename/prune),
+  // auto-created externals during deploy, and network create/delete all reshape
+  // the networking aggregate; drop the memo (every variant) so the next read
+  // reflects the change immediately.
+  invalidateNodeNetworkingAggregate(nodeId);
   StackFileRootsService.invalidateNode(nodeId);
 }
 
diff --git a/backend/src/routes/systemMaintenance.ts b/backend/src/routes/systemMaintenance.ts
index 3263dd4f..5f0f2024 100644
--- a/backend/src/routes/systemMaintenance.ts
+++ b/backend/src/routes/systemMaintenance.ts
@@ -27,6 +27,8 @@ import { requirePermission } from '../middleware/permissions';
 import { buildStackNetworkFacts } from '../services/network/composeNetworkInspector';
 import { evaluateNetworkDeleteGuard } from '../services/network/networkDeleteGuards';
 import { loadNetworkingSnapshot } from '../services/network/networkingAggregate';
+import { mapWithConcurrency } from '../utils/mapWithConcurrency';
+import { withComposeRenderSlot } from '../services/network/composeRenderSemaphore';
 
 // The prune estimate and plan paths are bounded at 12 s. `docker system df`
 // cost scales with image-store size (measured ~7.4 s on a 34 GB store), so
@@ -603,16 +605,28 @@ systemMaintenanceRouter.post('/networks/delete', async (req: Request, res: Respo
     }
     if (rejectIfSelf('network', id, res)) return;
 
+    const guardStartedAt = Date.now();
     const { stacks, snapshot } = await loadNetworkingSnapshot(req.nodeId);
     if (!snapshot) {
       return res.status(503).json({ error: 'Docker networking runtime is unavailable' });
     }
-    const stackFacts = await Promise.all(
-      stacks.map(stack => buildStackNetworkFacts(req.nodeId, stack, snapshot)),
-    );
+    const stackFacts = await mapWithConcurrency(stacks, 4, stack => withComposeRenderSlot(
+      req.nodeId,
+      () => buildStackNetworkFacts(req.nodeId, stack, snapshot),
+    ));
     const baseRow = DockerController.classifySnapshotNetworks(snapshot, stacks)
       .find(n => n.id === id);
     const guard = evaluateNetworkDeleteGuard(id, snapshot, stackFacts, baseRow);
+    if (isDebugEnabled()) {
+      console.debug('[Resources:debug] Network delete guard', {
+        id: id.substring(0, 12),
+        ms: Date.now() - guardStartedAt,
+        stackCount: stacks.length,
+        unrenderableStacks: stackFacts.filter(f => !f.renderable).length,
+        blocked: guard.blocked,
+        code: guard.code ?? null,
+      });
+    }
     if (guard.blocked) {
       return res.status(409).json({ error: guard.error, code: guard.code });
     }
diff --git a/backend/src/services/DatabaseService.ts b/backend/src/services/DatabaseService.ts
index 34efc3e0..eac641dd 100644
--- a/backend/src/services/DatabaseService.ts
+++ b/backend/src/services/DatabaseService.ts
@@ -8,6 +8,7 @@ import { applySuppressions } from '../utils/suppression-filter';
 import { SENCHO_ROLLBACK_HOLD_SQL_LIKE } from '../utils/senchoRollbackHold';
 import type { AuditStatsInput } from './AuditAnomalyService';
 import { EXPOSURE_INTENTS, type ExposureIntent } from './network/types';
+import { invalidateNodeNetworkingAggregate } from './network/networkingAggregateCache';
 import { HIGH_EPSS_THRESHOLD } from './securityPosture';
 import type { BackendScheduledAction } from './scheduledActionRegistry';
 import { stackPatternMatches } from '../helpers/stackPattern';
@@ -3852,11 +3853,13 @@ export class DatabaseService {
             now,
             now
         );
+        invalidateNodeNetworkingAggregate(nodeId);
         return this.getStackDossier(nodeId, stackName) as StackDossier;
     }
 
     public deleteStackDossier(nodeId: number, stackName: string): void {
         this.db.prepare('DELETE FROM stack_dossiers WHERE node_id = ? AND stack_name = ?').run(nodeId, stackName);
+        invalidateNodeNetworkingAggregate(nodeId);
     }
 
     /**
@@ -3947,16 +3950,19 @@ export class DatabaseService {
                 updated_at = excluded.updated_at,
                 updated_by = excluded.updated_by`
         ).run(nodeId, stackName, service, intent, Date.now(), updatedBy);
+        invalidateNodeNetworkingAggregate(nodeId);
     }
 
     /** Clear one intent row, leaving that scope unset; consumers treat a service with no row as inheriting the stack intent. */
     public deleteStackExposureIntent(nodeId: number, stackName: string, service: string): void {
         this.db.prepare('DELETE FROM stack_exposure_intent WHERE node_id = ? AND stack_name = ? AND service = ?').run(nodeId, stackName, service);
+        invalidateNodeNetworkingAggregate(nodeId);
     }
 
     /** Clear every intent row for a stack (used when the stack is deleted). */
     public deleteStackExposureIntents(nodeId: number, stackName: string): void {
         this.db.prepare('DELETE FROM stack_exposure_intent WHERE node_id = ? AND stack_name = ?').run(nodeId, stackName);
+        invalidateNodeNetworkingAggregate(nodeId);
     }
 
     // --- Stack Exposure (Compose reachability descriptor) ---
diff --git a/backend/src/services/network/networkDeleteGuards.ts b/backend/src/services/network/networkDeleteGuards.ts
index a77b49a6..1b4b355f 100644
--- a/backend/src/services/network/networkDeleteGuards.ts
+++ b/backend/src/services/network/networkDeleteGuards.ts
@@ -59,7 +59,10 @@ export function evaluateNetworkDeleteGuard(
     return { blocked: true, code: 'stack-declared', error: 'This network is declared by a Compose stack.' };
   }
 
-  if (hasUnrenderable && (net.composeProject || net.stack)) {
+  // Fail closed while any stack is unrenderable: an external network normally
+  // carries no compose project label, so without this check a broken declaring
+  // stack would let its declared network slip through as "undeclared".
+  if (hasUnrenderable) {
     return {
       blocked: true,
       code: 'stack-declaration-unknown',
diff --git a/backend/src/services/network/networkingAggregate.ts b/backend/src/services/network/networkingAggregate.ts
index 085da359..610e4cc9 100644
--- a/backend/src/services/network/networkingAggregate.ts
+++ b/backend/src/services/network/networkingAggregate.ts
@@ -19,10 +19,40 @@ import { getErrorMessage } from '../../utils/errors';
 import { sanitizeForLog } from '../../utils/safeLog';
 import { mapWithConcurrency } from '../../utils/mapWithConcurrency';
 import { withComposeRenderSlot } from './composeRenderSemaphore';
+import { fetchNodeNetworkingAggregateWithMeta as fetchMemoized, NETWORKING_AGGREGATE_TTL_MS } from './networkingAggregateCache';
+import { isDebugEnabled } from '../../utils/debug';
 
 export async function buildNodeNetworkingAggregate(
   nodeId: number,
   options: { includeTopology?: boolean; includeSystem?: boolean },
+): Promise<NodeNetworkingAggregate> {
+  const startedAt = Date.now();
+  const { value: aggregate, outcome } = await fetchMemoized(nodeId, options, () => computeNodeNetworkingAggregate(nodeId, options));
+  if (outcome === 'stale') {
+    // Stale-on-error fallback: the recompute threw and the memo served the
+    // last good aggregate. Mark it so the UI can say so instead of
+    // presenting confidently stale data as fresh.
+    aggregate.overview.degradedCache = true;
+  }
+  if (isDebugEnabled()) {
+    console.debug('[Networking:debug] Aggregate served', {
+      nodeId,
+      outcome,
+      ms: Date.now() - startedAt,
+      stackCount: aggregate.stackFacts.length,
+      networkCount: aggregate.overview.networkCount,
+      findingCount: aggregate.findings.length,
+      renderFailedStacks: aggregate.overview.renderFailedStacks.length,
+      ttlMs: NETWORKING_AGGREGATE_TTL_MS,
+      variant: options.includeTopology === true ? 'topology' : 'base',
+    });
+  }
+  return aggregate;
+}
+
+async function computeNodeNetworkingAggregate(
+  nodeId: number,
+  options: { includeTopology?: boolean; includeSystem?: boolean },
 ): Promise<NodeNetworkingAggregate> {
   const fsSvc = FileSystemService.getInstance(nodeId);
   const stacks = await fsSvc.getStacks();
@@ -138,6 +168,7 @@ function buildOverview(
       f.kind === 'network-name-collision' || f.kind === 'alias-collision' || f.kind === 'service-name-collision',
     ).length,
     findingCount: findings.length,
+    degradedCache: false,
     renderFailedStacks,
   };
 }
diff --git a/backend/src/services/network/networkingAggregateCache.ts b/backend/src/services/network/networkingAggregateCache.ts
new file mode 100644
index 00000000..e7aa3b79
--- /dev/null
+++ b/backend/src/services/network/networkingAggregateCache.ts
@@ -0,0 +1,39 @@
+/**
+ * Short-TTL memo for the per-node networking aggregate. Read endpoints share one
+ * computation per window instead of re-rendering every stack per request;
+ * mutations invalidate eagerly so deletes and creates never serve a stale view
+ * beyond the request that performed them. Kept as a leaf module so mutation
+ * helpers and services can invalidate without importing the aggregate pipeline
+ * back into themselves.
+ *
+ * The cache key encodes the requested variant (topology / includeSystem) as
+ * well as the node: a plain overview read must never satisfy a topology
+ * request, whose aggregate additionally carries the topology graph.
+ */
+import { CacheService, type CacheFetchOutcome } from '../CacheService';
+import type { NodeNetworkingAggregate } from './networkingTypes';
+
+const NAMESPACE = 'networking-aggregate';
+
+export const NETWORKING_AGGREGATE_TTL_MS = 8_000;
+
+export type NetworkingAggregateOptions = { includeTopology?: boolean; includeSystem?: boolean };
+
+export function networkingAggregateCacheKey(nodeId: number, options: NetworkingAggregateOptions): string {
+  if (options.includeTopology === true) {
+    return `${NAMESPACE}:${nodeId}:topology:${options.includeSystem === true}`;
+  }
+  return `${NAMESPACE}:${nodeId}:base`;
+}
+
+export async function fetchNodeNetworkingAggregateWithMeta(
+  nodeId: number,
+  options: NetworkingAggregateOptions,
+  compute: () => Promise<NodeNetworkingAggregate>,
+): Promise<{ value: NodeNetworkingAggregate; outcome: CacheFetchOutcome }> {
+  return CacheService.getInstance().getOrFetchWithMeta(networkingAggregateCacheKey(nodeId, options), NETWORKING_AGGREGATE_TTL_MS, compute);
+}
+
+export function invalidateNodeNetworkingAggregate(nodeId: number): void {
+  CacheService.getInstance().invalidateNamespace(`${NAMESPACE}:${nodeId}`);
+}
diff --git a/backend/src/services/network/networkingTypes.ts b/backend/src/services/network/networkingTypes.ts
index 40826342..1091a404 100644
--- a/backend/src/services/network/networkingTypes.ts
+++ b/backend/src/services/network/networkingTypes.ts
@@ -138,6 +138,8 @@ export interface NodeNetworkingOverview {
   missingExternalCount: number;
   networkCollisionCount: number;
   findingCount: number;
+  /** True when this aggregate was served from the memo after a recompute failure (stale-on-error fallback). */
+  degradedCache: boolean;
   renderFailedStacks: string[];
 }
 
diff --git a/docs/operations/troubleshooting.mdx b/docs/operations/troubleshooting.mdx
index 41d8af3b..e32f1bfb 100644
--- a/docs/operations/troubleshooting.mdx
+++ b/docs/operations/troubleshooting.mdx
@@ -292,6 +292,14 @@ To re-test connectivity after making changes, open **Settings · Infrastructure
 
 ---
 
+## Network deletion is refused while a stack fails to render
+
+**Symptom:** Deleting an external network returns "Cannot verify stack declarations while one or more stacks failed to render." The delete button may also be disabled with a message about render failures.
+
+**Cause:** Sencho checks every stack's effective Compose model before allowing a network delete, so it never removes a network a stack declares as `external:`. When any stack on the node cannot be rendered (usually a YAML error, an unresolved variable, or a broken include), Sencho cannot prove the network is undeclared and refuses the deletion rather than risk removing a network your stacks depend on.
+
+**Fix:** Find which stack cannot render on the Networking page (the Overview tab lists how many stacks failed), then open that stack and check its Anatomy panels: the Networking panel and the deploy preflight check show the Compose error itself. Fix the YAML (an unresolved variable or a broken include produces the same failure) until the model renders again, then retry the deletion. This is a deliberate safety stop, not a malfunction.
+
 ## Cannot delete a system network (bridge, host, none)
 
 **Symptom:** The delete button is missing or disabled for certain networks.
diff --git a/docs/reference/settings.mdx b/docs/reference/settings.mdx
index 70ccdbd9..8731bcb1 100644
--- a/docs/reference/settings.mdx
+++ b/docs/reference/settings.mdx
@@ -709,7 +709,7 @@ Node-level safety checks and post-deploy observation used during stack deploys a
 | **Observe health after updates** | On | After a stack deploy or update succeeds, watch its containers for the observation window and record a passed or failed verdict on the stack timeline. Observational only: nothing is restarted or rolled back automatically. |
 | **Observation window** | 90 s | How long to watch containers before declaring the update healthy. Raise it for stacks that take a while to settle. Range 15 to 600 seconds. |
 | **Block deploy on missing required env vars** | Off | When on, a deploy or update is refused before it starts if a required `${VAR:?message}` variable is unset or empty, so the stack fails fast with a clear message instead of mid-deploy. |
-| **Automatically create missing external networks during deploy** | Off | When on, safe missing external bridge networks are created automatically before deploy continues. When off, interactive deploy prompts first. Advanced drivers and custom options are never auto-created. |
+| **Automatically create missing external networks during deploy** | Off | When on, safe missing external bridge networks are created automatically before deploy continues. When off, interactive deploy prompts first. Advanced drivers and custom options are never auto-created. Any deploy that triggers an auto-creation records a `network_auto_created` entry in Recent activity, including deploys started by non-admin operators. |
 
 Click **Save settings** to apply.
 
diff --git a/frontend/src/components/networking/NetworkInventoryTable.tsx b/frontend/src/components/networking/NetworkInventoryTable.tsx
index 07d116d1..02589b43 100644
--- a/frontend/src/components/networking/NetworkInventoryTable.tsx
+++ b/frontend/src/components/networking/NetworkInventoryTable.tsx
@@ -57,14 +57,20 @@ function NetworkTableSkeleton({ rows = 5 }: { rows?: number }) {
 /** A network is unsafe to delete without a pre-confirm explanation when it has
  *  connected containers or is declared by a stack's Compose file; the backend
  *  409-guards these, but the UI should explain BEFORE the confirm dialog rather
- *  than let a generic confirmation surprise the user with a rejection. */
-function deleteBlockReason(row: NetworkingNetworkRow): string | null {
+ *  than let a generic confirmation surprise the user with a rejection. When render
+ *  verification is unavailable (a stack failed to render, or the Docker runtime is
+ *  unreachable), declarations cannot be verified at all, so every non-system,
+ *  non-Sencho network is held back the same way the backend does. */
+function deleteBlockReason(row: NetworkingNetworkRow, renderVerificationUnavailable: boolean): string | null {
   if (row.connectedCount > 0) {
     return `Connected to ${row.connectedCount} container${row.connectedCount === 1 ? '' : 's'}; disconnect them first.`;
   }
   if (row.declaredByStacks.length > 0) {
     return `Declared by ${row.declaredByStacks.join(', ')}; remove the declaration first.`;
   }
+  if (renderVerificationUnavailable) {
+    return 'One or more stacks failed to render; stack declarations cannot be verified right now.';
+  }
   return null;
 }
 
@@ -150,6 +156,7 @@ export function NetworkInventoryTable({
   onDelete,
   onOpenStack,
   onFilterTopology,
+  renderVerificationUnavailable,
 }: {
   rows: NetworkingNetworkRow[];
   findings: NetworkingFinding[];
@@ -159,6 +166,7 @@ export function NetworkInventoryTable({
   onDelete: (id: string, name: string) => void;
   onOpenStack: (stack: string) => void;
   onFilterTopology: (name: string) => void;
+  renderVerificationUnavailable: boolean;
 }) {
   const [filter, setFilter] = useState<NetworkFilter>('all');
   const [search, setSearch] = useState('');
@@ -295,7 +303,7 @@ export function NetworkInventoryTable({
                             <TooltipContent>Show in topology</TooltipContent>
                           </Tooltip>
                           {isAdmin && (() => {
-                            const blockReason = deleteBlockReason(row);
+                            const blockReason = deleteBlockReason(row, renderVerificationUnavailable);
                             const protectedReason = row.isSencho
                               ? 'Protected · running Sencho instance'
                               : row.isSystem
diff --git a/frontend/src/components/networking/NetworkingFindingsList.tsx b/frontend/src/components/networking/NetworkingFindingsList.tsx
index 4eafb81c..58bc3428 100644
--- a/frontend/src/components/networking/NetworkingFindingsList.tsx
+++ b/frontend/src/components/networking/NetworkingFindingsList.tsx
@@ -23,6 +23,7 @@ export function NetworkingFindingsList({
   isAdmin,
   onAction,
   disabled = false,
+  nodeId,
 }: {
   findings: NetworkingFinding[];
   loading: boolean;
@@ -30,6 +31,7 @@ export function NetworkingFindingsList({
   isAdmin: boolean;
   onAction: (action: NetworkingRecommendedAction) => void | Promise<void>;
   disabled?: boolean;
+  nodeId: number | null | undefined;
 }) {
   if (loading) return <p className="text-sm text-muted-foreground">Loading findings…</p>;
   if (findings.length === 0) {
@@ -66,7 +68,7 @@ export function NetworkingFindingsList({
                     {items.map((finding, i) => {
                       const sourceLabel = findingSourceLabel(finding);
                       const primary = finding.recommendedActions.find((action) =>
-                        isNetworkingActionVisible(action, isAdmin, (stack) => canEdit('stack:edit', 'stack', stack)),
+                        isNetworkingActionVisible(action, isAdmin, (stack) => canEdit('stack:edit', 'stack', stack, nodeId)),
                       );
                       return (
                         <TableRow
diff --git a/frontend/src/components/networking/NetworkingView.tsx b/frontend/src/components/networking/NetworkingView.tsx
index ba80f605..f9bfe066 100644
--- a/frontend/src/components/networking/NetworkingView.tsx
+++ b/frontend/src/components/networking/NetworkingView.tsx
@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useState, type ReactNode } from 'react';
+import { useCallback, useEffect, useRef, useState, type ReactNode } from 'react';
 import {
   LayoutDashboard, Network, GitBranch, AlertTriangle, RefreshCw, Plus, Unplug,
 } from 'lucide-react';
@@ -14,6 +14,7 @@ import { toast } from '@/components/ui/toast-store';
 import { useAuth } from '@/context/AuthContext';
 import { useNodes } from '@/context/NodeContext';
 import { useIsMobile } from '@/hooks/use-is-mobile';
+import { useDeveloperMode } from '@/hooks/useDeveloperMode';
 import { Masthead, MobileSubTabs, type Tone } from '@/components/mobile/mobile-ui';
 import { springs } from '@/lib/motion';
 import { CreateNetworkDialog } from '@/components/resources/CreateNetworkDialog';
@@ -86,6 +87,11 @@ export function NetworkingView({ headerActions }: NetworkingViewProps) {
   const { isAdmin, can } = useAuth();
   const { activeNode } = useNodes();
   const isMobile = useIsMobile();
+  const developerMode = useDeveloperMode(activeNode?.id);
+  // Read the flag through a ref inside the load effect so flipping it does not
+  // retrigger the overview fetch (the flag only gates debug logging).
+  const developerModeRef = useRef(developerMode);
+  developerModeRef.current = developerMode;
   const nodeId = activeNode?.id;
 
   const [tab, setTab] = useState<NetworkingTab>('overview');
@@ -140,6 +146,7 @@ export function NetworkingView({ headerActions }: NetworkingViewProps) {
     setFindings([]);
     setRecentActivity([]);
     setIsLegacy(false);
+    const startedAt = Date.now();
     const load = async () => {
       try {
         const response = await apiFetch('/networking/overview', { nodeId, signal: controller.signal });
@@ -150,6 +157,13 @@ export function NetworkingView({ headerActions }: NetworkingViewProps) {
         if (!response.ok) throw new Error('Failed to load networking data.');
         const body = await response.json() as Partial<NetworkingOverviewEnvelope>;
         if (stale) return;
+        if (developerModeRef.current) {
+          console.debug('[Networking:debug] overview loaded', {
+            nodeId,
+            ms: Date.now() - startedAt,
+            schemaVersion: body.schemaVersion ?? null,
+          });
+        }
         const adapted = adaptNetworkingOverview(body);
         setIsLegacy(adapted.isLegacy);
         setRuntimeAvailable(adapted.runtimeAvailable);
@@ -292,6 +306,11 @@ export function NetworkingView({ headerActions }: NetworkingViewProps) {
           <CardContent className="p-3 text-sm text-warning">Docker runtime is unavailable. Compose-model signals remain available.</CardContent>
         </Card>
       )}
+      {overview.degradedCache && (
+        <Card className="border-warning/40 bg-warning/5">
+          <CardContent className="p-3 text-sm text-warning">Showing cached results from the last successful refresh; a live refresh failed.</CardContent>
+        </Card>
+      )}
       <div className="grid overflow-hidden rounded-lg border border-card-border bg-card shadow-card-bevel sm:grid-cols-2 xl:grid-cols-4">
         {[
           { label: 'Networks', value: overview.networkCount ?? '—', tab: 'networks' as const },
@@ -526,6 +545,7 @@ export function NetworkingView({ headerActions }: NetworkingViewProps) {
               setPendingTopologyFilter(networkName);
               setTab('topology');
             }}
+            renderVerificationUnavailable={(overview?.renderFailedStacks.length ?? 0) > 0 || !runtimeAvailable}
           />
         </TabsContent>
 
@@ -547,7 +567,7 @@ export function NetworkingView({ headerActions }: NetworkingViewProps) {
         </TabsContent>
 
         <TabsContent value="findings" className="mt-4">
-          <NetworkingFindingsList findings={findings} loading={loading} canEdit={can} isAdmin={isAdmin} onAction={dispatchAction} disabled={isLegacy} />
+          <NetworkingFindingsList findings={findings} loading={loading} canEdit={can} isAdmin={isAdmin} onAction={dispatchAction} disabled={isLegacy} nodeId={nodeId} />
         </TabsContent>
       </Tabs>
 
diff --git a/frontend/src/components/networking/__tests__/NetworkInventoryTable.test.tsx b/frontend/src/components/networking/__tests__/NetworkInventoryTable.test.tsx
index 0746f2d1..f09d03e4 100644
--- a/frontend/src/components/networking/__tests__/NetworkInventoryTable.test.tsx
+++ b/frontend/src/components/networking/__tests__/NetworkInventoryTable.test.tsx
@@ -29,6 +29,7 @@ describe('NetworkInventoryTable', () => {
         onDelete={vi.fn()}
         onOpenStack={vi.fn()}
         onFilterTopology={vi.fn()}
+        renderVerificationUnavailable={false}
       />,
     );
     // Default sort is name ascending, independent of input row order.
@@ -53,6 +54,7 @@ describe('NetworkInventoryTable', () => {
         onDelete={vi.fn()}
         onOpenStack={vi.fn()}
         onFilterTopology={vi.fn()}
+        renderVerificationUnavailable={false}
       />,
     );
     const actionButtons = screen.getAllByRole('button').filter((b) =>
@@ -62,4 +64,40 @@ describe('NetworkInventoryTable', () => {
       'Open app', 'Inspect a-net', 'Show a-net in topology', 'Delete a-net',
     ]);
   });
+
+  it('holds the delete affordance while render verification is unavailable', () => {
+    const unlabeledExternal = row({ id: '1', name: 'shared_ext', composeProject: null, stack: null });
+    render(
+      <NetworkInventoryTable
+        rows={[unlabeledExternal]}
+        findings={[]}
+        loading={false}
+        isAdmin
+        onInspect={vi.fn()}
+        onDelete={vi.fn()}
+        onOpenStack={vi.fn()}
+        onFilterTopology={vi.fn()}
+        renderVerificationUnavailable
+      />,
+    );
+    expect(screen.getByRole('button', { name: 'Delete shared_ext' })).toBeDisabled();
+  });
+
+  it('keeps delete enabled for the same network when renders succeed', () => {
+    const unlabeledExternal = row({ id: '1', name: 'shared_ext', composeProject: null, stack: null });
+    render(
+      <NetworkInventoryTable
+        rows={[unlabeledExternal]}
+        findings={[]}
+        loading={false}
+        isAdmin
+        onInspect={vi.fn()}
+        onDelete={vi.fn()}
+        onOpenStack={vi.fn()}
+        onFilterTopology={vi.fn()}
+        renderVerificationUnavailable={false}
+      />,
+    );
+    expect(screen.getByRole('button', { name: 'Delete shared_ext' })).toBeEnabled();
+  });
 });
diff --git a/frontend/src/components/networking/__tests__/NetworkingFindingsList.test.tsx b/frontend/src/components/networking/__tests__/NetworkingFindingsList.test.tsx
index 95aec545..5723e9a3 100644
--- a/frontend/src/components/networking/__tests__/NetworkingFindingsList.test.tsx
+++ b/frontend/src/components/networking/__tests__/NetworkingFindingsList.test.tsx
@@ -2,7 +2,6 @@ import { describe, it, expect, vi } from 'vitest';
 import { render, screen } from '@testing-library/react';
 import { NetworkingFindingsList } from '../NetworkingFindingsList';
 import type { NetworkingFinding } from '@/types/networking';
-
 function finding(overrides: Partial<NetworkingFinding> = {}): NetworkingFinding {
   return {
     id: overrides.id ?? Math.random().toString(36),
@@ -20,9 +19,18 @@ function finding(overrides: Partial<NetworkingFinding> = {}): NetworkingFinding
 
 const canEdit = () => true;
 
+function exposureFinding(): NetworkingFinding {
+  return finding({
+    id: 'exposure',
+    kind: 'exposure-unclassified',
+    title: 'Unclassified exposure',
+    recommendedActions: [{ kind: 'set-exposure-intent', label: 'Set exposure intent', stack: 'proxy' }],
+  });
+}
+
 describe('NetworkingFindingsList', () => {
   it('shows a calm empty state when there are no findings', () => {
-    render(<NetworkingFindingsList findings={[]} loading={false} canEdit={canEdit} isAdmin onAction={vi.fn()} />);
+    render(<NetworkingFindingsList findings={[]} loading={false} canEdit={canEdit} isAdmin onAction={vi.fn()} nodeId={1} />);
     expect(screen.getByText('No networking issues detected.')).toBeInTheDocument();
   });
 
@@ -38,6 +46,7 @@ describe('NetworkingFindingsList', () => {
         canEdit={canEdit}
         isAdmin
         onAction={vi.fn()}
+        nodeId={1}
       />,
     );
     expect(screen.getByText(/Needs action/)).toBeInTheDocument();
@@ -45,6 +54,18 @@ describe('NetworkingFindingsList', () => {
     expect(screen.getByText(/Informational/)).toBeInTheDocument();
   });
 
+  it('respects node-scoped stack:edit for the primary action', () => {
+    const scopedCanEdit = vi.fn((_action: string, _type?: string, _id?: string, nodeId?: number | null) => nodeId === 7);
+    render(<NetworkingFindingsList findings={[exposureFinding()]} loading={false} canEdit={scopedCanEdit} isAdmin={false} onAction={vi.fn()} nodeId={7} />);
+    expect(screen.getByRole('button', { name: 'Set exposure intent' })).toBeInTheDocument();
+  });
+
+  it('hides the primary action when the node scope does not match', () => {
+    const deniedCanEdit = vi.fn((_action: string, _type?: string, _id?: string, nodeId?: number | null) => nodeId === 8);
+    render(<NetworkingFindingsList findings={[exposureFinding()]} loading={false} canEdit={deniedCanEdit} isAdmin={false} onAction={vi.fn()} nodeId={7} />);
+    expect(screen.queryByRole('button', { name: 'Set exposure intent' })).not.toBeInTheDocument();
+  });
+
   it('shows the merged source label for a card found by both engines', () => {
     render(
       <NetworkingFindingsList
@@ -56,6 +77,7 @@ describe('NetworkingFindingsList', () => {
         canEdit={canEdit}
         isAdmin
         onAction={vi.fn()}
+        nodeId={1}
       />,
     );
     expect(screen.getByText('Live · also found by Doctor')).toBeInTheDocument();
diff --git a/frontend/src/types/networking.ts b/frontend/src/types/networking.ts
index 733cbed9..132b234b 100644
--- a/frontend/src/types/networking.ts
+++ b/frontend/src/types/networking.ts
@@ -128,6 +128,8 @@ export interface NodeNetworkingOverview {
   missingExternalCount: number;
   networkCollisionCount: number;
   findingCount: number;
+  /** Served from the backend memo after a recompute failure; data may lag recent changes. */
+  degradedCache?: boolean;
   renderFailedStacks: string[];
 }