Fix : Antigravity MITM

src/mitm/handlers/antigravity.js

@@ -1,19 +1,31 @@
-const { err } = require("../logger");
+const { err, createResponseDumper } = require("../logger");
 const { fetchRouter, pipeSSE } = require("./base");
 
 /**
- * Intercept Antigravity (Gemini) request — replace model and forward to router
+ * Intercept Antigravity request — forward Gemini body as-is to /v1/chat/completions.
+ * Router auto-detects format via body.userAgent==="antigravity" + body.request.contents,
+ * runs antigravity→openai→provider→openai→antigravity translators internally.
  */
 async function intercept(req, res, bodyBuffer, mappedModel) {
+  const dumper = createResponseDumper(req, "intercept-antigravity");
+  const isStream = req.url.includes(":streamGenerateContent");
   try {
     const body = JSON.parse(bodyBuffer.toString());
-    body.model = mappedModel;
+    if (body.model) body.model = mappedModel;
+
     const routerRes = await fetchRouter(body, "/v1/chat/completions", req.headers);
-    await pipeSSE(routerRes, res);
+    await pipeSSE(routerRes, res, dumper);
   } catch (error) {
     err(`[antigravity] ${error.message}`);
-    if (!res.headersSent) res.writeHead(500, { "Content-Type": "application/json" });
-    res.end(JSON.stringify({ error: { message: error.message, type: "mitm_error" } }));
+    if (dumper) { dumper.writeChunk(`\n[ERROR] ${error.message}\n`); dumper.end(); }
+    // For stream endpoint, send SSE error chunk so SDK doesn't hang waiting
+    if (isStream) {
+      if (!res.headersSent) res.writeHead(200, { "Content-Type": "text/event-stream" });
+      res.end(`data: ${JSON.stringify({ error: { message: error.message } })}\r\n\r\n`);
+    } else {
+      if (!res.headersSent) res.writeHead(500, { "Content-Type": "application/json" });
+      res.end(JSON.stringify({ error: { message: error.message, type: "mitm_error" } }));
+    }
   }
 }