diff --git a/packages/context/src/ingest/isolated-diff/source-routing.test.ts b/packages/context/src/ingest/isolated-diff/source-routing.test.ts
new file mode 100644
index 00000000..75e52a1c
--- /dev/null
+++ b/packages/context/src/ingest/isolated-diff/source-routing.test.ts
@@ -0,0 +1,40 @@
+import { describe, expect, it } from 'vitest';
+import {
+  defaultIsolatedDiffSourceKeys,
+  isIsolatedDiffDirectWriteSourceKey,
+  ISOLATED_DIFF_DIRECT_WRITE_SOURCE_KEYS,
+} from './source-routing.js';
+
+describe('isolated-diff source routing', () => {
+  it('keeps the runner-owned direct-write connector list explicit', () => {
+    expect(ISOLATED_DIFF_DIRECT_WRITE_SOURCE_KEYS).toEqual([
+      'metabase',
+      'notion',
+      'lookml',
+      'looker',
+      'dbt',
+      'metricflow',
+    ]);
+  });
+
+  it('returns a mutable copy for runtime settings', () => {
+    const keys = defaultIsolatedDiffSourceKeys();
+    keys.push('fake');
+
+    expect(defaultIsolatedDiffSourceKeys()).toEqual([
+      'metabase',
+      'notion',
+      'lookml',
+      'looker',
+      'dbt',
+      'metricflow',
+    ]);
+  });
+
+  it('recognizes migrated connector source keys only', () => {
+    expect(isIsolatedDiffDirectWriteSourceKey('notion')).toBe(true);
+    expect(isIsolatedDiffDirectWriteSourceKey('metricflow')).toBe(true);
+    expect(isIsolatedDiffDirectWriteSourceKey('historic-sql')).toBe(false);
+    expect(isIsolatedDiffDirectWriteSourceKey('live-database')).toBe(false);
+  });
+});
diff --git a/packages/context/src/ingest/isolated-diff/source-routing.ts b/packages/context/src/ingest/isolated-diff/source-routing.ts
new file mode 100644
index 00000000..20d63b89
--- /dev/null
+++ b/packages/context/src/ingest/isolated-diff/source-routing.ts
@@ -0,0 +1,22 @@
+export const ISOLATED_DIFF_DIRECT_WRITE_SOURCE_KEYS = [
+  'metabase',
+  'notion',
+  'lookml',
+  'looker',
+  'dbt',
+  'metricflow',
+] as const;
+
+export type IsolatedDiffDirectWriteSourceKey = (typeof ISOLATED_DIFF_DIRECT_WRITE_SOURCE_KEYS)[number];
+
+const ISOLATED_DIFF_DIRECT_WRITE_SOURCE_KEY_SET = new Set<string>(ISOLATED_DIFF_DIRECT_WRITE_SOURCE_KEYS);
+
+export function defaultIsolatedDiffSourceKeys(): string[] {
+  return [...ISOLATED_DIFF_DIRECT_WRITE_SOURCE_KEYS];
+}
+
+export function isIsolatedDiffDirectWriteSourceKey(
+  sourceKey: string,
+): sourceKey is IsolatedDiffDirectWriteSourceKey {
+  return ISOLATED_DIFF_DIRECT_WRITE_SOURCE_KEY_SET.has(sourceKey);
+}
diff --git a/packages/context/src/ingest/local-bundle-runtime.test.ts b/packages/context/src/ingest/local-bundle-runtime.test.ts
index 8287df71..aa4c61e2 100644
--- a/packages/context/src/ingest/local-bundle-runtime.test.ts
+++ b/packages/context/src/ingest/local-bundle-runtime.test.ts
@@ -29,6 +29,14 @@ type RuntimeWithSlValidationDeps = {
   };
 };
 
+type RuntimeWithSettingsDeps = {
+  deps: {
+    settings: {
+      isolatedDiffSourceKeys?: string[];
+    };
+  };
+};
+
 function testAgentRunner(): AgentRunnerPort {
   return { runLoop: vi.fn().mockResolvedValue({ stopReason: 'natural' as const }) };
 }
@@ -258,6 +266,25 @@ describe('createLocalBundleIngestRuntime', () => {
     });
   });
 
+  it('enables isolated-diff routing for direct durable-write connectors', () => {
+    const runtime = createLocalBundleIngestRuntime({
+      project,
+      adapters: [new FakeSourceAdapter()],
+      agentRunner: testAgentRunner(),
+    });
+
+    const settings = (runtime.runner as unknown as RuntimeWithSettingsDeps).deps.settings;
+
+    expect(settings.isolatedDiffSourceKeys).toEqual([
+      'metabase',
+      'notion',
+      'lookml',
+      'looker',
+      'dbt',
+      'metricflow',
+    ]);
+  });
+
   it('accepts a debug LLM request file when constructing the default agent runner', async () => {
     await writeFile(
       join(project.projectDir, 'ktx.yaml'),
diff --git a/packages/context/src/ingest/local-bundle-runtime.ts b/packages/context/src/ingest/local-bundle-runtime.ts
index 74e3bd52..4fccf121 100644
--- a/packages/context/src/ingest/local-bundle-runtime.ts
+++ b/packages/context/src/ingest/local-bundle-runtime.ts
@@ -77,6 +77,7 @@ import { ContextEvidenceIndexService, SqliteContextEvidenceStore } from './conte
 import { DiffSetService } from './diff-set.service.js';
 import { ingestTracePathForJob, type IngestTraceLevel } from './ingest-trace.js';
 import { IngestBundleRunner } from './ingest-bundle.runner.js';
+import { defaultIsolatedDiffSourceKeys } from './isolated-diff/source-routing.js';
 import { PageTriageService } from './page-triage/index.js';
 import { createWarehouseVerificationTools } from './tools/warehouse-verification/index.js';
 import type {
@@ -722,7 +723,7 @@ export function createLocalBundleIngestRuntime(
       workUnitMaxConcurrency: options.project.config.ingest.workUnits.maxConcurrency,
       workUnitStepBudget: options.project.config.ingest.workUnits.stepBudget,
       workUnitFailureMode: options.project.config.ingest.workUnits.failureMode,
-      isolatedDiffSourceKeys: ['metabase'],
+      isolatedDiffSourceKeys: defaultIsolatedDiffSourceKeys(),
       ingestTraceLevel: ingestTraceLevelFromEnv(),
     },
     skillsRegistry: new SkillsRegistryService({ skillsDir, logger }),