diff --git a/CLAUDE.md b/CLAUDE.md
index 196b678e..038202ac 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -120,7 +120,8 @@ Required:
 Optional (infrastructure):
 - `PORT` - Server port (default: 3000)
 - `LOG_LEVEL` - Logging level (default: info)
-- `DATABASE_SSL` - Set to `false` to disable SSL for local PostgreSQL (default: enabled)
+- `DATABASE_SSL` - Set to `false` to disable SSL for local PostgreSQL (default: enabled with certificate validation)
+- `DATABASE_CA_CERT` - Path to a PEM-encoded CA certificate file for managed databases that use a private CA (e.g., AWS RDS, Azure Database, GCP Cloud SQL). When set, the certificate is read and passed as the `ca` option to `pg.Pool`, enabling TLS certificate validation against the specified CA. Example: `DATABASE_CA_CERT=/etc/ssl/certs/rds-ca.pem`
 - `CLAUDE_CODE_OAUTH_TOKEN` - For Claude Code engine (subscription auth)
 - `CREDENTIAL_MASTER_KEY` - 64-char hex string (32-byte AES-256 key) for encrypting credentials at rest. Generate with `npm run credentials:generate-key`. When set, all new/updated credentials are encrypted automatically; existing plaintext credentials continue to work.
 - `WEBHOOK_CALLBACK_BASE_URL` - Base URL for webhook callbacks (e.g., `https://cascade.example.com`). Used by `tools/setup-webhooks.ts` and the `cascade webhooks create` CLI command to construct the full webhook URL.
diff --git a/src/db/client.ts b/src/db/client.ts
index 52dc1336..b4aea43a 100644
--- a/src/db/client.ts
+++ b/src/db/client.ts
@@ -1,3 +1,4 @@
+import fs, { existsSync } from 'node:fs';
 import { drizzle } from 'drizzle-orm/node-postgres';
 import pg from 'pg';
 import * as schema from './schema/index.js';
@@ -28,13 +29,28 @@ function getDatabaseUrl(): string {
 	throw new Error('DATABASE_URL or CASCADE_POSTGRES_HOST must be set');
 }
 
+function getSslConfig(): false | { rejectUnauthorized: boolean; ca?: string } {
+	if (process.env.DATABASE_SSL === 'false') {
+		return false;
+	}
+	const sslConfig: { rejectUnauthorized: boolean; ca?: string } = { rejectUnauthorized: true };
+	if (process.env.DATABASE_CA_CERT) {
+		const certPath = process.env.DATABASE_CA_CERT;
+		if (!existsSync(certPath)) {
+			throw new Error(`DATABASE_CA_CERT file not found: ${certPath}`);
+		}
+		sslConfig.ca = fs.readFileSync(certPath, 'utf8');
+	}
+	return sslConfig;
+}
+
 export function getDb(): ReturnType<typeof drizzle<typeof schema>> {
 	if (_testDbOverride) return _testDbOverride;
 	if (!db) {
 		pool = new pg.Pool({
 			connectionString: getDatabaseUrl(),
 			max: 5,
-			ssl: process.env.DATABASE_SSL === 'false' ? false : { rejectUnauthorized: false },
+			ssl: getSslConfig(),
 		});
 		db = drizzle(pool, { schema });
 	}
diff --git a/tests/unit/db/client.test.ts b/tests/unit/db/client.test.ts
index f95d26cb..f0196f56 100644
--- a/tests/unit/db/client.test.ts
+++ b/tests/unit/db/client.test.ts
@@ -4,10 +4,12 @@ import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 // vi.mock factories are hoisted to the top of the file, so any variables they
 // reference must also be hoisted via vi.hoisted().
 
-const { mockPoolEnd, mockPoolConstructor } = vi.hoisted(() => {
+const { mockPoolEnd, mockPoolConstructor, mockReadFileSync, mockExistsSync } = vi.hoisted(() => {
 	const mockPoolEnd = vi.fn().mockResolvedValue(undefined);
 	const mockPoolConstructor = vi.fn().mockImplementation(() => ({ end: mockPoolEnd }));
-	return { mockPoolEnd, mockPoolConstructor };
+	const mockReadFileSync = vi.fn().mockReturnValue('mock-ca-cert-content');
+	const mockExistsSync = vi.fn().mockReturnValue(true);
+	return { mockPoolEnd, mockPoolConstructor, mockReadFileSync, mockExistsSync };
 });
 
 vi.mock('pg', () => ({
@@ -20,6 +22,13 @@ vi.mock('drizzle-orm/node-postgres', () => ({
 	drizzle: vi.fn().mockReturnValue({ __isMockDrizzle: true }),
 }));
 
+vi.mock('node:fs', () => ({
+	default: {
+		readFileSync: mockReadFileSync,
+	},
+	existsSync: mockExistsSync,
+}));
+
 // ── Imports (after mocks) ─────────────────────────────────────────────────────
 
 import { _setTestDb, closeDb, getDb } from '../../../src/db/client.js';
@@ -150,22 +159,56 @@ describe('getDb', () => {
 
 	it('creates pool with SSL disabled when DATABASE_SSL=false', () => {
 		vi.stubEnv('DATABASE_SSL', 'false');
+		vi.stubEnv('DATABASE_CA_CERT', '');
 
 		getDb();
 
 		expect(mockPoolConstructor).toHaveBeenCalledWith(expect.objectContaining({ ssl: false }));
 	});
 
-	it('creates pool with rejectUnauthorized:false by default (DATABASE_SSL not set)', () => {
+	it('creates pool with rejectUnauthorized:true by default (DATABASE_SSL not set)', () => {
 		vi.stubEnv('DATABASE_SSL', '');
+		vi.stubEnv('DATABASE_CA_CERT', '');
 
 		getDb();
 
 		expect(mockPoolConstructor).toHaveBeenCalledWith(
-			expect.objectContaining({ ssl: { rejectUnauthorized: false } }),
+			expect.objectContaining({ ssl: { rejectUnauthorized: true } }),
 		);
 	});
 
+	it('creates pool with custom CA cert when DATABASE_CA_CERT is set', () => {
+		vi.stubEnv('DATABASE_SSL', '');
+		vi.stubEnv('DATABASE_CA_CERT', '/path/to/ca.pem');
+
+		getDb();
+
+		expect(mockReadFileSync).toHaveBeenCalledWith('/path/to/ca.pem', 'utf8');
+		expect(mockPoolConstructor).toHaveBeenCalledWith(
+			expect.objectContaining({
+				ssl: { rejectUnauthorized: true, ca: 'mock-ca-cert-content' },
+			}),
+		);
+	});
+
+	it('throws a descriptive error when DATABASE_CA_CERT path does not exist', () => {
+		vi.stubEnv('DATABASE_SSL', '');
+		vi.stubEnv('DATABASE_CA_CERT', '/nonexistent/ca.pem');
+		mockExistsSync.mockReturnValueOnce(false);
+
+		expect(() => getDb()).toThrow('DATABASE_CA_CERT file not found: /nonexistent/ca.pem');
+	});
+
+	it('DATABASE_CA_CERT is ignored when DATABASE_SSL=false', () => {
+		vi.stubEnv('DATABASE_SSL', 'false');
+		vi.stubEnv('DATABASE_CA_CERT', '/path/to/ca.pem');
+
+		getDb();
+
+		expect(mockReadFileSync).not.toHaveBeenCalled();
+		expect(mockPoolConstructor).toHaveBeenCalledWith(expect.objectContaining({ ssl: false }));
+	});
+
 	it('returns singleton — second call returns same instance', () => {
 		const first = getDb();
 		const second = getDb();
diff --git a/tools/migrate-hooks.ts b/tools/migrate-hooks.ts
index 8e754c94..6d35549c 100644
--- a/tools/migrate-hooks.ts
+++ b/tools/migrate-hooks.ts
@@ -8,6 +8,7 @@
  *   npx tsx tools/migrate-hooks.ts --apply    # Apply changes
  */
 
+import { existsSync, readFileSync } from 'node:fs';
 import pg from 'pg';
 
 const DATABASE_URL = process.env.DATABASE_URL ?? '';
@@ -16,6 +17,21 @@ if (!DATABASE_URL) {
 	process.exit(1);
 }
 
+function getSslConfig(): false | { rejectUnauthorized: boolean; ca?: string } {
+	if (process.env.DATABASE_SSL === 'false') {
+		return false;
+	}
+	const sslConfig: { rejectUnauthorized: boolean; ca?: string } = { rejectUnauthorized: true };
+	if (process.env.DATABASE_CA_CERT) {
+		const certPath = process.env.DATABASE_CA_CERT;
+		if (!existsSync(certPath)) {
+			throw new Error(`DATABASE_CA_CERT file not found: ${certPath}`);
+		}
+		sslConfig.ca = readFileSync(certPath, 'utf8');
+	}
+	return sslConfig;
+}
+
 const dryRun = !process.argv.includes('--apply');
 
 interface LegacyBackend {
@@ -124,7 +140,7 @@ async function main() {
 	const pool = new pg.Pool({
 		connectionString: DATABASE_URL,
 		max: 2,
-		ssl: process.env.DATABASE_SSL === 'false' ? false : { rejectUnauthorized: false },
+		ssl: getSslConfig(),
 	});
 
 	try {