diff --git a/src/commands/metrics/index.ts b/src/commands/metrics/index.ts
index 25b6bc9..ee8c1c4 100644
--- a/src/commands/metrics/index.ts
+++ b/src/commands/metrics/index.ts
@@ -7,7 +7,7 @@ import {
   printResult,
   withErrorHandling,
 } from '../../lib/utils/api-helper.js';
-import { parseMetricId } from '../../lib/utils/validators.js';
+import { parseMetricId, parseDatasourceId } from '../../lib/utils/validators.js';
 import type { MetricId } from '../../lib/api/branded-types.js';
 import { summarizeMetricRow } from '../../api-client/entity-summary.js';
 import { createListCommand } from '../../lib/utils/list-command.js';
@@ -173,6 +173,11 @@ function addMetricFieldOptions(cmd: Command): Command {
       )
       .option('--custom-sql <sql>', 'custom SQL (required for custom_sql type)')
       .option('--custom-statistics-type <type>', 'custom statistics type (continuous, binomial)')
+      .option(
+        '--datasource-id <id>',
+        'datasource ID the custom SQL runs against (custom_sql)',
+        parseDatasourceId
+      )
       .option('--vr-lookback-interval <interval>', 'VR lookback interval (1w, 2w, 3w, 4w)')
       .option('--relation-kind <kind>', 'goal relation kind (refund, replacement)')
       .option('--relation-refund-operation <op>', 'refund operation (add, subtract)')
@@ -264,6 +269,7 @@ async function resolveMetricFieldsFromOptions(
     activityInterval: options.activityInterval as string | undefined,
     customSql: options.customSql as string | undefined,
     customStatisticsType: options.customStatisticsType as string | undefined,
+    datasourceId: options.datasourceId as number | undefined,
     vrLookbackInterval: options.vrLookbackInterval as string | undefined,
     relationKind: options.relationKind as string | undefined,
     relationRefundOperation: options.relationRefundOperation as string | undefined,
diff --git a/src/commands/metrics/metrics.test.ts b/src/commands/metrics/metrics.test.ts
index f221fc0..8727b8a 100644
--- a/src/commands/metrics/metrics.test.ts
+++ b/src/commands/metrics/metrics.test.ts
@@ -388,6 +388,86 @@ describe('metrics command', () => {
     );
   });
 
+  it('should create a custom_sql metric pinned to a datasource via --datasource-id', async () => {
+    await metricsCommand.parseAsync([
+      'node',
+      'test',
+      'create',
+      '--name',
+      'BQ conversions',
+      '--type',
+      'custom_sql',
+      '--description',
+      'BigQuery conversions',
+      '--custom-sql',
+      'SELECT 1',
+      '--custom-statistics-type',
+      'binomial',
+      '--datasource-id',
+      '10',
+    ]);
+
+    expect(mockClient.createMetric).toHaveBeenCalledWith(
+      expect.objectContaining({
+        type: 'custom_sql',
+        custom_sql: 'SELECT 1',
+        datasource_id: 10,
+      })
+    );
+  });
+
+  it('should use the last --datasource-id when the flag is repeated, not a radix-confused value', async () => {
+    await metricsCommand.parseAsync([
+      'node',
+      'test',
+      'create',
+      '--name',
+      'BQ conversions',
+      '--type',
+      'custom_sql',
+      '--description',
+      'BigQuery conversions',
+      '--custom-sql',
+      'SELECT 1',
+      '--custom-statistics-type',
+      'binomial',
+      '--datasource-id',
+      '16',
+      '--datasource-id',
+      '10',
+    ]);
+
+    expect(mockClient.createMetric).toHaveBeenCalledWith(
+      expect.objectContaining({
+        datasource_id: 10,
+      })
+    );
+  });
+
+  it('should reject a --datasource-id with trailing non-numeric characters', async () => {
+    await expect(
+      metricsCommand.parseAsync([
+        'node',
+        'test',
+        'create',
+        '--name',
+        'BQ conversions',
+        '--type',
+        'custom_sql',
+        '--description',
+        'BigQuery conversions',
+        '--custom-sql',
+        'SELECT 1',
+        '--custom-statistics-type',
+        'binomial',
+        '--datasource-id',
+        '10x',
+      ])
+    ).rejects.toThrow();
+
+    expect(mockClient.createMetric).not.toHaveBeenCalled();
+  });
+
   it('should create a goal_ratio metric with numerator and denominator types', async () => {
     await metricsCommand.parseAsync([
       'node',
@@ -807,6 +887,41 @@ describe('metrics command', () => {
     expect(mockClient.activateMetric).not.toHaveBeenCalled();
   });
 
+  it('should pass --datasource-id through to the version payload', async () => {
+    await metricsCommand.parseAsync([
+      'node',
+      'test',
+      'version',
+      '1',
+      '--reason',
+      'pin to bigquery',
+      '--datasource-id',
+      '10',
+    ]);
+
+    expect(mockClient.createMetricVersion).toHaveBeenCalledWith(
+      1,
+      { datasource_id: 10 },
+      'pin to bigquery'
+    );
+  });
+
+  it('should omit datasource_id from the version payload when --datasource-id is not passed', async () => {
+    await metricsCommand.parseAsync([
+      'node',
+      'test',
+      'version',
+      '1',
+      '--reason',
+      'rename',
+      '--name',
+      'x',
+    ]);
+
+    const payload = mockClient.createMetricVersion.mock.calls[0]![1] as Record<string, unknown>;
+    expect(payload).not.toHaveProperty('datasource_id');
+  });
+
   it('should support `new-version` alias', async () => {
     await metricsCommand.parseAsync([
       'node',
diff --git a/src/core/metrics/payload.ts b/src/core/metrics/payload.ts
index 26c6f3e..78e56a4 100644
--- a/src/core/metrics/payload.ts
+++ b/src/core/metrics/payload.ts
@@ -27,6 +27,7 @@ export interface MetricFields {
   activityInterval?: string | undefined;
   customSql?: string | undefined;
   customStatisticsType?: string | undefined;
+  datasourceId?: number | undefined;
   vrLookbackInterval?: string | undefined;
   relationKind?: string | undefined;
   relationRefundOperation?: string | undefined;
@@ -81,6 +82,7 @@ export function buildMetricPayload(fields: MetricFields): Record<string, unknown
   set('activity_interval', fields.activityInterval);
   set('custom_sql', fields.customSql);
   set('custom_statistics_type', fields.customStatisticsType);
+  set('datasource_id', fields.datasourceId);
   set('vr_lookback_interval', fields.vrLookbackInterval);
   set('relation_kind', fields.relationKind);
   set('relation_refund_operation', fields.relationRefundOperation);