From 65c84b8a4edc8fc5a744f51334573805f0669e64 Mon Sep 17 00:00:00 2001
From: Saleh Alghusson <1331721+qirh@users.noreply.github.com>
Date: Mon, 19 Oct 2026 20:49:02 +0000
Subject: [PATCH] fix: preserve base URL query parameters when joining paths

---
 src/client.ts     |  9 +++++++--
 src/index.test.ts | 14 ++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/client.ts b/src/client.ts
index 6437da4..6bbd98a 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -256,12 +256,17 @@ export class Perplexity implements SdkTransport {
     defaultBaseURL?: string | undefined,
   ): string {
     const baseURL = (!this.#baseURLOverridden() && defaultBaseURL) || this.baseURL;
+    // Join paths without the base query so it cannot absorb the request path.
+    const baseQueryIndex = baseURL.indexOf('?');
+    const basePath = baseQueryIndex === -1 ? baseURL : baseURL.slice(0, baseQueryIndex);
+    const baseQuery =
+      isAbsoluteURL(path) || baseQueryIndex === -1 ? {} : Object.fromEntries(new URL(baseURL).searchParams);
     const url = isAbsoluteURL(path)
       ? new URL(path)
-      : new URL(baseURL + (baseURL.endsWith('/') && path.startsWith('/') ? path.slice(1) : path));
+      : new URL(basePath + (basePath.endsWith('/') && path.startsWith('/') ? path.slice(1) : path));
 
     const defaultQuery = this.defaultQuery();
-    const pathQuery = Object.fromEntries(url.searchParams);
+    const pathQuery = { ...baseQuery, ...Object.fromEntries(url.searchParams) };
     if (!isEmptyObj(defaultQuery) || !isEmptyObj(pathQuery)) {
       query = { ...pathQuery, ...defaultQuery, ...query };
     }
diff --git a/src/index.test.ts b/src/index.test.ts
index 06bc586..54e6e70 100644
--- a/src/index.test.ts
+++ b/src/index.test.ts
@@ -402,6 +402,20 @@ describe('instantiate client', () => {
       assert.deepStrictEqual(client.buildURL('/foo', null), 'http://localhost:5000/custom/path/foo');
     });
 
+    it('query parameters', () => {
+      for (const baseURL of [
+        'http://localhost:5000/custom/path?key=x',
+        'http://localhost:5000/custom/path/?key=x',
+      ]) {
+        const client = new Perplexity({ baseURL, apiKey: 'My API Key' });
+        assert.deepStrictEqual(client.buildURL('/foo', null), 'http://localhost:5000/custom/path/foo?key=x');
+        assert.deepStrictEqual(
+          client.buildURL('/foo?bar=1', { key: 'y', baz: 2 }),
+          'http://localhost:5000/custom/path/foo?key=y&bar=1&baz=2',
+        );
+      }
+    });
+
     afterEach(() => {
       process.env['PERPLEXITY_BASE_URL'] = undefined;
     });