From 4a4c85a425f647d983cd890d990e0a6cf620d168 Mon Sep 17 00:00:00 2001
From: Federico Biccheddu <service+git@f15u.dev>
Date: Fri, 5 Dec 2025 01:12:30 +0100
Subject: [PATCH 1/3] feat: support `URL` in `HttpClientRequest.prependUrl`

---
 packages/platform/src/HttpClientRequest.ts        |  4 ++--
 .../platform/src/internal/httpClientRequest.ts    | 15 +++++++++------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/packages/platform/src/HttpClientRequest.ts b/packages/platform/src/HttpClientRequest.ts
index c79db130e29..a51ea28b028 100644
--- a/packages/platform/src/HttpClientRequest.ts
+++ b/packages/platform/src/HttpClientRequest.ts
@@ -211,8 +211,8 @@ export const setUrl: {
  * @category combinators
  */
 export const prependUrl: {
-  (path: string): (self: HttpClientRequest) => HttpClientRequest
-  (self: HttpClientRequest, path: string): HttpClientRequest
+  (path: string | URL): (self: HttpClientRequest) => HttpClientRequest
+  (self: HttpClientRequest, path: string | URL): HttpClientRequest
 } = internal.prependUrl
 
 /**
diff --git a/packages/platform/src/internal/httpClientRequest.ts b/packages/platform/src/internal/httpClientRequest.ts
index 73d0132ce2a..05311b9ee6d 100644
--- a/packages/platform/src/internal/httpClientRequest.ts
+++ b/packages/platform/src/internal/httpClientRequest.ts
@@ -264,19 +264,22 @@ export const appendUrl = dual<
 
 /** @internal */
 export const prependUrl = dual<
-  (path: string) => (self: ClientRequest.HttpClientRequest) => ClientRequest.HttpClientRequest,
-  (self: ClientRequest.HttpClientRequest, path: string) => ClientRequest.HttpClientRequest
->(2, (self, url) =>
-  makeInternal(
+  (path: string | URL) => (self: ClientRequest.HttpClientRequest) => ClientRequest.HttpClientRequest,
+  (self: ClientRequest.HttpClientRequest, path: string | URL) => ClientRequest.HttpClientRequest
+>(2, (self, url) => {
+  const clone = typeof url === "string" ? url : url.toString()
+
+  return makeInternal(
     self.method,
-    url.endsWith("/") && self.url.startsWith("/") ?
+    clone.endsWith("/") && self.url.startsWith("/") ?
       url + self.url.slice(1) :
       url + self.url,
     self.urlParams,
     self.hash,
     self.headers,
     self.body
-  ))
+  )
+})
 
 /** @internal */
 export const updateUrl = dual<

From dadecb172224b54f5e0a0936737dc76e470cc325 Mon Sep 17 00:00:00 2001
From: Federico Biccheddu <service+git@f15u.dev>
Date: Fri, 5 Dec 2025 01:12:57 +0100
Subject: [PATCH 2/3] test: support `URL` in `HttpClientRequest.prependUrl`

---
 .../platform/test/HttpClientRequest.test.ts   | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 packages/platform/test/HttpClientRequest.test.ts

diff --git a/packages/platform/test/HttpClientRequest.test.ts b/packages/platform/test/HttpClientRequest.test.ts
new file mode 100644
index 00000000000..0cabc6b66a3
--- /dev/null
+++ b/packages/platform/test/HttpClientRequest.test.ts
@@ -0,0 +1,19 @@
+import * as HttpClientRequest from "@effect/platform/HttpClientRequest"
+import { describe, it } from "@effect/vitest"
+import { deepStrictEqual } from "@effect/vitest/utils"
+
+describe("HttpClientRequest", () => {
+  const intialRequest = HttpClientRequest.make("GET")("/test")
+
+  it("prependUrl with a string", () => {
+    const result = intialRequest.pipe(HttpClientRequest.prependUrl("https://example.com"))
+
+    deepStrictEqual(result.url, "https://example.com/test")
+  })
+
+  it("prependUrl with an URL instance", () => {
+    const result = intialRequest.pipe(HttpClientRequest.prependUrl(new URL("https://example.com")))
+
+    deepStrictEqual(result.url, "https://example.com/test")
+  })
+})

From 374dcb6c46f9bb68696366fe11cb35be1864c3b0 Mon Sep 17 00:00:00 2001
From: Federico Biccheddu <service+git@f15u.dev>
Date: Fri, 5 Dec 2025 01:17:44 +0100
Subject: [PATCH 3/3] docs: add changeset

---
 .changeset/light-comics-rest.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/light-comics-rest.md

diff --git a/.changeset/light-comics-rest.md b/.changeset/light-comics-rest.md
new file mode 100644
index 00000000000..845683c53df
--- /dev/null
+++ b/.changeset/light-comics-rest.md
@@ -0,0 +1,5 @@
+---
+"@effect/platform": minor
+---
+
+Support `URL` in `HttpClientRequest.prependUrl` parameter