diff --git a/src/app/(dashboard)/dashboard/providers/components/onboarding/ProviderOnboardingWizard.tsx b/src/app/(dashboard)/dashboard/providers/components/onboarding/ProviderOnboardingWizard.tsx
index af3196ebd0..65510ef0ce 100644
--- a/src/app/(dashboard)/dashboard/providers/components/onboarding/ProviderOnboardingWizard.tsx
+++ b/src/app/(dashboard)/dashboard/providers/components/onboarding/ProviderOnboardingWizard.tsx
@@ -260,9 +260,9 @@ function ResultSummary({
         )}
 
         <div className="flex flex-wrap gap-2">
-          {connection?.provider && (
+          {connection?.id && (
             <Link
-              href={`/dashboard/providers/${connection.provider}`}
+              href={`/dashboard/providers/${connection.id}`}
               className="inline-flex items-center justify-center rounded-lg bg-primary px-4 py-2 text-sm font-medium text-white transition-colors hover:bg-primary/90"
             >
               {providerText(t, "onboardingOpenProviderDetails", "Open provider details")}
diff --git a/tests/unit/onboarding-wizard-details-link-6145.test.ts b/tests/unit/onboarding-wizard-details-link-6145.test.ts
new file mode 100644
index 0000000000..78ff6c67a7
--- /dev/null
+++ b/tests/unit/onboarding-wizard-details-link-6145.test.ts
@@ -0,0 +1,37 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { dirname, join } from "node:path";
+
+// Regression guard for #6145: the onboarding success-screen "Open provider
+// details" link must route by `connection.id` (the node id the
+// `/dashboard/providers/[id]` route expects), NOT `connection.provider` (the
+// provider slug/type). The old code produced `/dashboard/providers/<provider-slug>`
+// which 404s for openai-compatible / anthropic-compatible providers.
+
+const here = dirname(fileURLToPath(import.meta.url));
+const repoRoot = join(here, "..", "..");
+const wizard = readFileSync(
+  join(
+    repoRoot,
+    "src/app/(dashboard)/dashboard/providers/components/onboarding/ProviderOnboardingWizard.tsx"
+  ),
+  "utf8"
+);
+
+test("#6145: provider-details link routes by connection.id (matches the [id] route)", () => {
+  assert.match(
+    wizard,
+    /href=\{`\/dashboard\/providers\/\$\{connection\.id\}`\}/,
+    "the details link must build the URL from connection.id"
+  );
+});
+
+test("#6145: provider-details link must NOT use connection.provider (404s for compat providers)", () => {
+  assert.doesNotMatch(
+    wizard,
+    /href=\{`\/dashboard\/providers\/\$\{connection\.provider\}`\}/,
+    "connection.provider is the slug/type, not the node id — it 404s"
+  );
+});