diff --git a/.server-changes/trigger-worker-queue-db-error-leak.md b/.server-changes/trigger-worker-queue-db-error-leak.md
new file mode 100644
index 00000000000..9725ef9f2eb
--- /dev/null
+++ b/.server-changes/trigger-worker-queue-db-error-leak.md
@@ -0,0 +1,6 @@
+---
+area: webapp
+type: fix
+---
+
+Stop `trigger()` from leaking raw database connection errors to API clients during a database outage; infrastructure errors now return a generic, retryable 500.
diff --git a/apps/webapp/app/runEngine/concerns/queues.server.ts b/apps/webapp/app/runEngine/concerns/queues.server.ts
index 2fc35fc8435..dce74d7d1a9 100644
--- a/apps/webapp/app/runEngine/concerns/queues.server.ts
+++ b/apps/webapp/app/runEngine/concerns/queues.server.ts
@@ -15,6 +15,7 @@ import type { RunEngine } from "~/v3/runEngine.server";
 import { env } from "~/env.server";
 import { tryCatch } from "@trigger.dev/core/v3";
 import { ServiceValidationError } from "~/v3/services/common.server";
+import { isInfrastructureError } from "~/utils/prismaErrors";
 import { createCache, createLRUMemoryStore, DefaultStatefulContext, Namespace } from "@internal/cache";
 import { singleton } from "~/utils/singleton";
 import type { TaskMetadataCache, TaskMetadataEntry } from "~/services/taskMetadataCache.server";
@@ -394,6 +395,17 @@ export class DefaultQueueManager implements QueueManager {
     );
 
     if (error) {
+      // getDefaultWorkerGroupForProject queries the writer DB. A Prisma
+      // infrastructure error (e.g. P1001 "Can't reach database server", whose
+      // message carries the DB hostname) must NOT be promoted into a
+      // client-facing ServiceValidationError: that leaks internal infra detail
+      // to the API client (the SDK echoes it into the run view) and
+      // mis-classifies a transient outage as a non-retryable 422. Let it
+      // propagate to the route's generic 500 handler (scrubbed + retryable);
+      // only wrap genuine domain failures.
+      if (isInfrastructureError(error)) {
+        throw error;
+      }
       throw new ServiceValidationError(error.message);
     }
 
diff --git a/apps/webapp/app/utils/prismaErrors.ts b/apps/webapp/app/utils/prismaErrors.ts
new file mode 100644
index 00000000000..b8262ed3d1f
--- /dev/null
+++ b/apps/webapp/app/utils/prismaErrors.ts
@@ -0,0 +1,39 @@
+import { Prisma } from "@trigger.dev/database";
+
+// Prisma connectivity / infrastructure error codes — engine- and
+// connection-level failures, not query- or validation-level ones. When the
+// database is unreachable, Prisma 6.x throws a PrismaClientKnownRequestError
+// carrying one of these codes (e.g. P1001 "Can't reach database server").
+const INFRASTRUCTURE_PRISMA_CODES = new Set([
+  "P1001", // Can't reach database server
+  "P1002", // Database server reached but timed out
+  "P1008", // Operations timed out
+  "P1017", // Server has closed the connection
+]);
+
+/**
+ * True when `error` is a Prisma infrastructure/connectivity failure (DB
+ * unreachable, timed out, connection dropped) rather than a query- or
+ * validation-level error.
+ *
+ * These errors carry internal infrastructure detail (e.g. the database
+ * hostname) in their `.message`, so they must never be surfaced to API
+ * clients — callers should let them propagate to the generic 5xx handler
+ * (which both scrubs the message and is retryable by the SDK) instead of
+ * folding `.message` into a client-facing error.
+ */
+export function isInfrastructureError(error: unknown): boolean {
+  if (
+    error instanceof Prisma.PrismaClientInitializationError ||
+    error instanceof Prisma.PrismaClientRustPanicError ||
+    error instanceof Prisma.PrismaClientUnknownRequestError
+  ) {
+    return true;
+  }
+
+  if (error instanceof Prisma.PrismaClientKnownRequestError) {
+    return INFRASTRUCTURE_PRISMA_CODES.has(error.code);
+  }
+
+  return false;
+}
diff --git a/apps/webapp/test/prismaErrors.test.ts b/apps/webapp/test/prismaErrors.test.ts
new file mode 100644
index 00000000000..48af6c829c7
--- /dev/null
+++ b/apps/webapp/test/prismaErrors.test.ts
@@ -0,0 +1,32 @@
+import { describe, expect, it } from "vitest";
+import { Prisma } from "@trigger.dev/database";
+import { isInfrastructureError } from "../app/utils/prismaErrors.js";
+
+describe("isInfrastructureError", () => {
+  it("treats a P1001 'can't reach database server' (KnownRequestError) as infrastructure", () => {
+    // Prisma 6.x reports P1001 as a PrismaClientKnownRequestError with code P1001 —
+    // this is the exact production shape that leaked the RDS hostname to a customer.
+    const err = new Prisma.PrismaClientKnownRequestError(
+      "Invalid `prisma.project.findFirst()` invocation: Can't reach database server at host:5432",
+      { code: "P1001", clientVersion: "6.14.0" }
+    );
+    expect(isInfrastructureError(err)).toBe(true);
+  });
+
+  it("treats a PrismaClientInitializationError as infrastructure", () => {
+    const err = new Prisma.PrismaClientInitializationError("init failed", "6.14.0");
+    expect(isInfrastructureError(err)).toBe(true);
+  });
+
+  it("does NOT treat a query/validation error (P2002 unique constraint) as infrastructure", () => {
+    const err = new Prisma.PrismaClientKnownRequestError("Unique constraint failed", {
+      code: "P2002",
+      clientVersion: "6.14.0",
+    });
+    expect(isInfrastructureError(err)).toBe(false);
+  });
+
+  it("does NOT treat a plain domain Error as infrastructure", () => {
+    expect(isInfrastructureError(new Error("Project not found."))).toBe(false);
+  });
+});