From fd7bafe392057c4e188e01b8d443d2a269ff252b Mon Sep 17 00:00:00 2001
From: diegosouzapw <diego.souza.pw@gmail.com>
Date: Thu, 21 May 2026 23:58:02 -0300
Subject: [PATCH] fix(validation): strip trailing /models in Gemini validator
 to avoid /models/models 404 (#2545)

---
 src/lib/providers/validation.ts               |  6 ++++-
 .../provider-validation-hardening.test.ts     | 25 +++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/lib/providers/validation.ts b/src/lib/providers/validation.ts
index b36c209e34..41b00aa5df 100644
--- a/src/lib/providers/validation.ts
+++ b/src/lib/providers/validation.ts
@@ -741,11 +741,15 @@ async function validateGeminiLikeProvider({
       return { valid: false, error: "Missing base URL" };
     }
 
+    // Strip a trailing /models before appending — the default Gemini registry baseUrl is
+    // `.../v1beta/models` (for the chat urlBuilder), so naively appending /models produced
+    // `.../v1beta/models/models` → upstream 404 on connection validation (#2545).
+    const baseForModels = baseUrl.replace(/\/models\/?$/, "");
     const requestUrl =
       typeof providerSpecificData?.modelsUrl === "string" &&
       providerSpecificData.modelsUrl.trim() !== ""
         ? providerSpecificData.modelsUrl.trim()
-        : `${baseUrl}/models`;
+        : `${baseForModels}/models`;
 
     const urlWithKey =
       authType === "query" ? `${requestUrl}?key=${encodeURIComponent(apiKey)}` : requestUrl;
diff --git a/tests/unit/provider-validation-hardening.test.ts b/tests/unit/provider-validation-hardening.test.ts
index 8858c87dbd..9bbeba99e9 100644
--- a/tests/unit/provider-validation-hardening.test.ts
+++ b/tests/unit/provider-validation-hardening.test.ts
@@ -163,3 +163,28 @@ test("#2463 openai-compatible validation does not throw on non-string modelsUrl"
   });
   assert.equal(typeof result.valid, "boolean");
 });
+
+// Regression for #2545: the default Gemini (AI Studio) base URL ends in /v1beta/models,
+// so the validator must not append a second /models (which produced /models/models → 404).
+test("#2545 gemini validation does not produce /models/models", async () => {
+  const calls: string[] = [];
+  globalThis.fetch = async (url: any) => {
+    calls.push(String(url));
+    return new Response(JSON.stringify({ models: [] }), { status: 200 });
+  };
+  const result = await validateProviderApiKey({
+    provider: "gemini",
+    apiKey: "AIzaTestKey",
+    providerSpecificData: {},
+  });
+  assert.equal(typeof result.valid, "boolean");
+  assert.ok(calls.length > 0, "validator must make a request");
+  assert.ok(
+    !calls.some((u) => u.includes("/models/models")),
+    `outbound URL must not contain /models/models — got ${calls.join(", ")}`
+  );
+  assert.ok(
+    calls.some((u) => /\/v1beta\/models(\?|$)/.test(u)),
+    `outbound URL must hit a single /models segment — got ${calls.join(", ")}`
+  );
+});