diff --git a/apps/api/src/lib/config.ts b/apps/api/src/lib/config.ts
index daa7fc3..3d77d25 100644
--- a/apps/api/src/lib/config.ts
+++ b/apps/api/src/lib/config.ts
@@ -8,6 +8,24 @@
  */
 import { z } from 'zod';
 
+/**
+ * Parse a boolean from an environment variable.
+ *
+ * NOT `z.coerce.boolean()`, which calls `Boolean(value)` — so the string
+ * `"false"` becomes `true`, along with `"0"`, `"no"` and `"off"`. Every
+ * feature flag set to `false` would silently be on, which is exactly the
+ * class of bug that gets discovered in production by reading a startup
+ * warning that should not have appeared.
+ */
+const envBoolean = (defaultValue: boolean) =>
+  z
+    .string()
+    .optional()
+    .transform((value) => {
+      if (value == null || value.trim() === '') return defaultValue;
+      return ['1', 'true', 'yes', 'on'].includes(value.trim().toLowerCase());
+    });
+
 const schema = z.object({
   DATABASE_URL: z.string().min(1, 'DATABASE_URL is required.'),
 
@@ -24,10 +42,10 @@ const schema = z.object({
 
   PRIME_API_KEY: z.string().optional(),
   PRIME_API_BASE: z.string().default('https://api.primeintellect.ai'),
-  PRIME_SYNC_ENABLED: z.coerce.boolean().default(false),
+  PRIME_SYNC_ENABLED: envBoolean(false),
   PRIME_SYNC_INTERVAL_MINUTES: z.coerce.number().int().positive().default(30),
 
-  PIGGY_ENABLED: z.coerce.boolean().default(false),
+  PIGGY_ENABLED: envBoolean(false),
   ANTHROPIC_API_KEY: z.string().optional(),
   PIGGY_MODEL: z.string().default('claude-sonnet-5'),
   PIGGY_LEASE_SECONDS: z.coerce.number().int().positive().default(300),