From 6b4bbc36741919bdd90cd68a49641309ca7d6bec Mon Sep 17 00:00:00 2001
From: Saleh Alghusson <1331721+qirh@users.noreply.github.com>
Date: Mon, 19 Oct 2026 20:49:06 +0000
Subject: [PATCH] fix: preserve PERPLEXITY_BASE_URL query parameters when
 joining paths

---
 src/index.test.ts | 21 +++++++++++++++++++++
 src/server.ts     |  4 +++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/index.test.ts b/src/index.test.ts
index e08c59c..782b7f1 100644
--- a/src/index.test.ts
+++ b/src/index.test.ts
@@ -579,6 +579,27 @@ describe("Perplexity MCP Server", () => {
       }
     });
 
+    it("should keep PERPLEXITY_BASE_URL path and query on the agent path", async () => {
+      vi.resetModules();
+      process.env.PERPLEXITY_BASE_URL = "https://proxy.example.com/api/?key=x";
+      try {
+        const serverModule = await import("./server.js");
+        global.fetch = vi
+          .fn()
+          .mockResolvedValue(sseResponse([completedEvent("ok")]));
+
+        await serverModule.performAgentResponse(TEST_MESSAGES, "fast");
+
+        expect(global.fetch).toHaveBeenCalledWith(
+          "https://proxy.example.com/api/v1/agent?key=x",
+          expect.anything()
+        );
+      } finally {
+        delete process.env.PERPLEXITY_BASE_URL;
+        vi.resetModules();
+      }
+    });
+
     it("should skip malformed stream chunks and still complete", async () => {
       const payload =
         "data: this-is-not-json\n\n" +
diff --git a/src/server.ts b/src/server.ts
index 0c1941a..b6ec968 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -94,7 +94,9 @@ async function makeApiRequest(
   // Read timeout fresh each time to respect env var changes
   const TIMEOUT_MS = parseInt(process.env.PERPLEXITY_TIMEOUT_MS || "300000", 10);
 
-  const url = new URL(`${PERPLEXITY_BASE_URL}/${endpoint}`);
+  // Append to the base path so a query string in the base URL is preserved.
+  const url = new URL(PERPLEXITY_BASE_URL);
+  url.pathname = `${url.pathname.replace(/\/$/, "")}/${endpoint}`;
   const controller = new AbortController();
   const timeoutId = setTimeout(() => controller.abort(), TIMEOUT_MS);
   // An abort from the caller's signal also tears down an in-flight body stream.