From a2436bc50bd8d2cc1288ddb3a6829b10e48d3fc7 Mon Sep 17 00:00:00 2001
From: diegosouzapw <diegosouzapw@users.noreply.github.com>
Date: Mon, 13 Apr 2026 14:58:37 -0300
Subject: [PATCH] fix(gemini): harden schema sanitizing and streaming defaults

Remove unsupported Gemini schema fields including vendor-prefixed
`x-` properties so translated tool definitions avoid rejected keywords.

Emit an empty `content` field with the initial assistant role delta to
keep OpenAI-compatible streaming output consistent for clients that
expect content on the first chunk.

Also force undici's fetch whenever a dispatcher is provided and treat
`onRequestStart` version mismatches as fatal instead of falling back to
native fetch, preventing broken proxy requests under mixed undici
versions.
---
 open-sse/translator/helpers/geminiHelper.ts      |  7 ++++---
 open-sse/translator/response/gemini-to-openai.ts |  2 +-
 open-sse/utils/proxyFetch.ts                     | 14 +++++++++++++-
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/open-sse/translator/helpers/geminiHelper.ts b/open-sse/translator/helpers/geminiHelper.ts
index cd6eb63538..a0c671917b 100644
--- a/open-sse/translator/helpers/geminiHelper.ts
+++ b/open-sse/translator/helpers/geminiHelper.ts
@@ -42,6 +42,7 @@ export const UNSUPPORTED_SCHEMA_CONSTRAINTS = [
   "contentMediaType",
   "contentEncoding",
   // Non-standard schema fields (not recognized by Gemini API)
+  "deprecated",
   "optional",
   // UI/Styling properties (from Cursor tools - NOT JSON Schema standard)
   "cornerRadius",
@@ -185,9 +186,9 @@ function removeUnsupportedKeywords(obj, keywords) {
     }
   } else {
     // Delete unsupported keys at current level
-    for (const keyword of keywords) {
-      if (keyword in obj) {
-        delete obj[keyword];
+    for (const key of Object.keys(obj)) {
+      if (keywords.includes(key) || key.startsWith("x-")) {
+        delete obj[key];
       }
     }
     // Recurse into remaining values
diff --git a/open-sse/translator/response/gemini-to-openai.ts b/open-sse/translator/response/gemini-to-openai.ts
index bc6d6bb877..b13cf46695 100644
--- a/open-sse/translator/response/gemini-to-openai.ts
+++ b/open-sse/translator/response/gemini-to-openai.ts
@@ -28,7 +28,7 @@ export function geminiToOpenAIResponse(chunk, state) {
         choices: [
           {
             index: 0,
-            delta: { role: "assistant" },
+            delta: { role: "assistant", content: "" },
             finish_reason: null,
           },
         ],
diff --git a/open-sse/utils/proxyFetch.ts b/open-sse/utils/proxyFetch.ts
index ff0a2de58a..ccbb986a81 100644
--- a/open-sse/utils/proxyFetch.ts
+++ b/open-sse/utils/proxyFetch.ts
@@ -165,6 +165,9 @@ export async function runWithProxyContext(proxyConfig, fn) {
 
 async function patchedFetch(input: RequestInfo | URL, options: FetchWithDispatcherOptions = {}) {
   if (options?.dispatcher) {
+    // When a dispatcher is present, we MUST use the undici library fetch
+    // to ensure version compatibility. Node 22 built-in fetch (undici v6)
+    // is incompatible with undici v8 dispatchers (missing onRequestStart, etc.)
     return (undiciFetch as unknown as (...args: unknown[]) => Promise<Response>)(input, options);
   }
 
@@ -206,7 +209,16 @@ async function patchedFetch(input: RequestInfo | URL, options: FetchWithDispatch
         dispatcher: getDefaultDispatcher(),
       });
     } catch (dispatcherError) {
-      const msg = dispatcherError instanceof Error ? dispatcherError.message : String(dispatcherError);
+      const msg =
+        dispatcherError instanceof Error ? dispatcherError.message : String(dispatcherError);
+      // CAUTION: Do NOT fallback to native fetch if the error is a version mismatch (invalid onRequestStart)
+      // because the native fetch will definitely fail with the undici v8 dispatcher.
+      if (msg.includes("onRequestStart")) {
+        console.error(
+          `[ProxyFetch] Fatal version mismatch: Dispatcher (v8) vs Fetch (v6/native). Hardware upgrade or SOCKS5 config isolation required. Error: ${msg}`
+        );
+        throw dispatcherError;
+      }
       // Only fallback for connection/dispatcher errors, not HTTP errors
       if (msg.includes("fetch failed") || msg.includes("ECONNREFUSED") || msg.includes("UND_ERR")) {
         console.warn(`[ProxyFetch] Undici dispatcher failed, falling back to native fetch: ${msg}`);