diff --git a/docs-site/content/docs/configuration/ktx-yaml.mdx b/docs-site/content/docs/configuration/ktx-yaml.mdx
index a98773dd..182a4bea 100644
--- a/docs-site/content/docs/configuration/ktx-yaml.mdx
+++ b/docs-site/content/docs/configuration/ktx-yaml.mdx
@@ -162,10 +162,12 @@ connections:
 
 Set `scan_enabled: false` to register a warehouse for SQL execution only. The
 connection is usable by `ktx sql` and the agent `sql_execution` tool, but **ktx**
-never introspects, scans, or ingests it — and `ktx setup` validates the
-credential without discovering or scanning its schemas. This is the supported way
-to run read-only queries against shared or public data (for example a BigQuery
-billing project full of unrelated datasets) without making it a context source.
+never introspects, scans, or ingests it: automatic ingest skips it, `ktx setup`
+validates the credential without discovering or scanning its schemas, and even an
+explicit `ktx scan <id>` or `ktx ingest <id>` is refused with guidance. This is
+the supported way to run read-only queries against shared or public data (for
+example a BigQuery billing project full of unrelated datasets) without making it
+a context source.
 
 ```yaml
 connections:
diff --git a/packages/cli/src/ingest.ts b/packages/cli/src/ingest.ts
index 233b1b6e..46b04692 100644
--- a/packages/cli/src/ingest.ts
+++ b/packages/cli/src/ingest.ts
@@ -8,6 +8,7 @@ import type { MemoryFlowEvent, MemoryFlowReplayInput } from './context/ingest/me
 import { renderMemoryFlowReplay } from './context/ingest/memory-flow/render.js';
 import type { KtxSqlQueryExecutorPort } from './context/connections/query-executor.js';
 import { loadKtxProject, type KtxLocalProject } from './context/project/project.js';
+import { isExecuteOnlyConnection } from './context/connections/local-warehouse-descriptor.js';
 import { getKtxCliPackageInfo } from './cli-runtime.js';
 import { resolveProjectEmbeddingProvider } from './embedding-resolution.js';
 import { createKtxCliIngestQueryExecutor } from './ingest-query-executor.js';
@@ -695,6 +696,13 @@ export async function runKtxIngest(
     const project = await loadKtxProject({ projectDir: args.projectDir });
     const env = deps.env ?? process.env;
     if (args.command === 'run') {
+      if (isExecuteOnlyConnection(project.config.connections[args.connectionId])) {
+        io.stderr.write(
+          `Connection '${args.connectionId}' is registered for SQL execution only (scan_enabled: false) and ` +
+            'cannot be ingested. Remove scan_enabled: false to make it a scan/ingest target, or use `ktx sql` to query it.\n',
+        );
+        return 1;
+      }
       const resolveEmbeddingProvider = deps.resolveEmbeddingProvider ?? resolveProjectEmbeddingProvider;
       const resolution = await resolveEmbeddingProvider(project, {
         mode: 'ensure',
diff --git a/packages/cli/src/scan.ts b/packages/cli/src/scan.ts
index 5961e3f1..8169cf08 100644
--- a/packages/cli/src/scan.ts
+++ b/packages/cli/src/scan.ts
@@ -1,6 +1,7 @@
 import type { KtxProgressPort, KtxScanMode, KtxScanReport, KtxScanWarning } from './context/scan/types.js';
 import { runLocalScan } from './context/scan/local-scan.js';
 import { loadKtxProject, type KtxLocalProject } from './context/project/project.js';
+import { isExecuteOnlyConnection } from './context/connections/local-warehouse-descriptor.js';
 import { getKtxCliPackageInfo } from './cli-runtime.js';
 import { resolveProjectEmbeddingProvider } from './embedding-resolution.js';
 import type { KtxCliIo } from './index.js';
@@ -326,6 +327,13 @@ export async function runKtxScan(args: KtxScanArgs, io: KtxCliIo = process, deps
   let project: KtxLocalProject | undefined;
   try {
     project = await loadKtxProject({ projectDir: args.projectDir });
+    if (isExecuteOnlyConnection(project.config.connections[args.connectionId])) {
+      io.stderr.write(
+        `Connection '${args.connectionId}' is registered for SQL execution only (scan_enabled: false) and ` +
+          'cannot be scanned. Remove scan_enabled: false to make it a scan target, or use `ktx sql` to query it.\n',
+      );
+      return 1;
+    }
     const resolveEmbeddingProvider = deps.resolveEmbeddingProvider ?? resolveProjectEmbeddingProvider;
     const resolution = await resolveEmbeddingProvider(project, {
       mode: 'ensure',
diff --git a/packages/cli/test/ingest.test.ts b/packages/cli/test/ingest.test.ts
index c1abfe8b..e2e965d3 100644
--- a/packages/cli/test/ingest.test.ts
+++ b/packages/cli/test/ingest.test.ts
@@ -54,6 +54,40 @@ describe('runKtxIngest', () => {
     await rm(tempDir, { recursive: true, force: true });
   });
 
+  it('refuses to ingest a connection marked execute-only (scan_enabled: false)', async () => {
+    const projectDir = join(tempDir, 'project');
+    await initKtxProject({ projectDir });
+    await writeFile(
+      join(projectDir, 'ktx.yaml'),
+      [
+        'connections:',
+        '  public_bq:',
+        '    driver: bigquery',
+        '    scan_enabled: false',
+        'ingest:',
+        '  adapters:',
+        '    - fake',
+        '  embeddings:',
+        '    backend: none',
+        '',
+      ].join('\n'),
+      'utf-8',
+    );
+    const runLocal = vi.fn();
+    const io = makeIo();
+
+    await expect(
+      runKtxIngest(
+        { command: 'run', projectDir, connectionId: 'public_bq', adapter: 'fake', outputMode: 'plain' },
+        io.io,
+        { runLocalIngest: runLocal },
+      ),
+    ).resolves.toBe(1);
+
+    expect(runLocal).not.toHaveBeenCalled();
+    expect(io.stderr()).toContain('scan_enabled: false');
+  });
+
   it('runs local ingest and reads status', async () => {
     const projectDir = join(tempDir, 'project');
     await writeWarehouseConfig(projectDir);
diff --git a/packages/cli/test/scan.test.ts b/packages/cli/test/scan.test.ts
index 51c55498..2396dc7b 100644
--- a/packages/cli/test/scan.test.ts
+++ b/packages/cli/test/scan.test.ts
@@ -332,6 +332,35 @@ describe('runKtxScan', () => {
     await rm(tempDir, { recursive: true, force: true });
   });
 
+  it('refuses to scan a connection marked execute-only (scan_enabled: false)', async () => {
+    await initKtxProject({ projectDir: tempDir });
+    await writeFile(
+      join(tempDir, 'ktx.yaml'),
+      ['connections:', '  public_bq:', '    driver: bigquery', '    scan_enabled: false', ''].join('\n'),
+      'utf-8',
+    );
+    const runLocalScan = vi.fn();
+    const io = makeIo();
+
+    await expect(
+      runKtxScan(
+        {
+          command: 'run',
+          projectDir: tempDir,
+          connectionId: 'public_bq',
+          mode: 'structural',
+          detectRelationships: false,
+          dryRun: false,
+        },
+        io.io,
+        { runLocalScan, createLocalIngestAdapters: noLocalIngestAdapters },
+      ),
+    ).resolves.toBe(1);
+
+    expect(runLocalScan).not.toHaveBeenCalled();
+    expect(io.stderr()).toContain('scan_enabled: false');
+  });
+
   it('runs structural scans and prints a dev-friendly plain summary', async () => {
     await initKtxProject({ projectDir: tempDir });
     const runLocalScan = vi.fn(