From 63958bb19567e84dcde4bd4bb5253b6529e3cb2b Mon Sep 17 00:00:00 2001
From: Wauplin <lucainp@gmail.com>
Date: Wed, 6 Aug 2025 14:39:33 +0200
Subject: [PATCH 1/3] Forward user headers

---
 src/routes/responses.ts | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/routes/responses.ts b/src/routes/responses.ts
index efaae7d..fa4a058 100644
--- a/src/routes/responses.ts
+++ b/src/routes/responses.ts
@@ -35,6 +35,17 @@ class StreamingError extends Error {
 type IncompleteResponse = Omit<Response, "incomplete_details" | "output_text" | "parallel_tool_calls">;
 const SEQUENCE_NUMBER_PLACEHOLDER = -1;
 
+// All headers are forwarded by default, except these ones.
+const NOT_FORWARDED_HEADERS = [
+	"accept",
+	"accept-encoding",
+	"authorization",
+	"connection",
+	"content-length",
+	"content-type",
+	"host",
+];
+
 export const postCreateResponse = async (
 	req: ValidatedRequest<CreateResponseParams>,
 	res: ExpressResponse
@@ -169,6 +180,11 @@ async function* innerRunStream(
 		return;
 	}
 
+	// Forward headers (except authorization handled separately)
+	const defaultHeaders = Object.fromEntries(
+		Object.entries(req.headers).filter(([key]) => !NOT_FORWARDED_HEADERS.includes(key.toLowerCase()))
+	) as Record<string, string>;
+
 	// Return early if not supported param
 	if (req.body.reasoning?.summary && req.body.reasoning?.summary !== "auto") {
 		throw new Error(`Not implemented: only 'auto' summary is supported. Got '${req.body.reasoning?.summary}'`);
@@ -429,7 +445,7 @@ async function* innerRunStream(
 	do {
 		previousMessageCount = currentMessageCount;
 
-		for await (const event of handleOneTurnStream(apiKey, payload, responseObject, mcpToolsMapping)) {
+		for await (const event of handleOneTurnStream(apiKey, payload, responseObject, mcpToolsMapping, defaultHeaders)) {
 			yield event;
 		}
 
@@ -499,11 +515,13 @@ async function* handleOneTurnStream(
 	apiKey: string | undefined,
 	payload: ChatCompletionCreateParamsStreaming,
 	responseObject: IncompleteResponse,
-	mcpToolsMapping: Record<string, McpServerParams>
+	mcpToolsMapping: Record<string, McpServerParams>,
+	defaultHeaders: Record<string, string>
 ): AsyncGenerator<PatchedResponseStreamEvent> {
 	const client = new OpenAI({
 		baseURL: process.env.OPENAI_BASE_URL ?? "https://router.huggingface.co/v1",
 		apiKey: apiKey,
+		defaultHeaders,
 	});
 	const stream = await client.chat.completions.create(payload);
 	let previousInputTokens = responseObject.usage?.input_tokens ?? 0;

From 1703c3d1131778f0bfe9b036f3d0e104cbb9defa Mon Sep 17 00:00:00 2001
From: Wauplin <lucainp@gmail.com>
Date: Wed, 6 Aug 2025 14:47:24 +0200
Subject: [PATCH 2/3] complete list

---
 src/routes/responses.ts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/routes/responses.ts b/src/routes/responses.ts
index fa4a058..0b0884b 100644
--- a/src/routes/responses.ts
+++ b/src/routes/responses.ts
@@ -44,6 +44,12 @@ const NOT_FORWARDED_HEADERS = [
 	"content-length",
 	"content-type",
 	"host",
+	"keep-alive",
+	"te",
+	"trailer",
+	"trailers",
+	"transfer-encoding",
+	"upgrade",
 ];
 
 export const postCreateResponse = async (

From f8ae9683bdc6b1114705c8fd33649563139c6dce Mon Sep 17 00:00:00 2001
From: Wauplin <lucainp@gmail.com>
Date: Wed, 6 Aug 2025 14:50:23 +0200
Subject: [PATCH 3/3] use set for O(1) search

---
 src/routes/responses.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/routes/responses.ts b/src/routes/responses.ts
index 0b0884b..d61206b 100644
--- a/src/routes/responses.ts
+++ b/src/routes/responses.ts
@@ -36,7 +36,7 @@ type IncompleteResponse = Omit<Response, "incomplete_details" | "output_text" |
 const SEQUENCE_NUMBER_PLACEHOLDER = -1;
 
 // All headers are forwarded by default, except these ones.
-const NOT_FORWARDED_HEADERS = [
+const NOT_FORWARDED_HEADERS = new Set([
 	"accept",
 	"accept-encoding",
 	"authorization",
@@ -50,7 +50,7 @@ const NOT_FORWARDED_HEADERS = [
 	"trailers",
 	"transfer-encoding",
 	"upgrade",
-];
+]);
 
 export const postCreateResponse = async (
 	req: ValidatedRequest<CreateResponseParams>,
@@ -188,7 +188,7 @@ async function* innerRunStream(
 
 	// Forward headers (except authorization handled separately)
 	const defaultHeaders = Object.fromEntries(
-		Object.entries(req.headers).filter(([key]) => !NOT_FORWARDED_HEADERS.includes(key.toLowerCase()))
+		Object.entries(req.headers).filter(([key]) => !NOT_FORWARDED_HEADERS.has(key.toLowerCase()))
 	) as Record<string, string>;
 
 	// Return early if not supported param