fix(antigravity): preserve uploaded file references

Keep original file paths and metadata instead of decoding every small upload as UTF-8. This accepts attachments without losing binary contents or requiring file reads during prompt encoding.

Co-authored-by: ax <chinaszlcx@gmail.com>

plugins/antigravity-provider/server/internal/prompt.ts

@@ -1,5 +1,5 @@
 import { randomUUID } from "node:crypto";
-import { chmod, mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
+import { chmod, mkdtemp, rm, writeFile } from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 import type { ProviderPrompt } from "@getpaseo/plugin/server/provider";
@@ -10,8 +10,6 @@ interface EncodedPrompt {
   nativeText: string;
 }
 
-const MAX_INLINE_FILE_BYTES = 2 * 1024 * 1024; // 2 MB
-
 export class PromptFiles {
   private directory: string | null = null;
 
@@ -22,16 +20,19 @@ export class PromptFiles {
       prompt.outputSchema !== undefined
     )
       throw new AntigravityError("Antigravity supports messages only");
-
+    const parts = prompt.input.content.map((part) => {
+      if (part.type === "text" || part.type === "uploaded_file") return part;
+      if (part.type === "image") return { ...part, extension: imageExtension(part.mimeType) };
+      throw new AntigravityError("Antigravity supports text, image and uploaded file content only");
+    });
     const text: string[] = [];
     const native: string[] = [];
-
-    for (const part of prompt.input.content) {
+    for (const part of parts) {
       if (part.type === "text") {
         text.push(part.text);
         native.push(part.text);
       } else if (part.type === "image") {
-        const extension = imageExtension(part.mimeType);
+        const extension = part.extension;
         if (this.directory === null) {
           this.directory = await mkdtemp(path.join(os.tmpdir(), "paseo-antigravity-images-"));
           await chmod(this.directory, 0o700);
@@ -41,31 +42,20 @@ export class PromptFiles {
         await chmod(file, 0o600);
         native.push(`Attached image: ${file}`);
       } else if (part.type === "uploaded_file") {
-        if (part.mimeType && part.mimeType.startsWith("image/")) {
+        if (part.mimeType.startsWith("image/")) {
           native.push(`Attached image: ${part.path}`);
-        } else if (part.size > MAX_INLINE_FILE_BYTES) {
-          const notice = `[Attached large file: ${part.fileName} at ${part.path} (${part.size} bytes)]`;
-          text.push(notice);
-          native.push(notice);
         } else {
-          try {
-            const content = await readFile(part.path, "utf8");
-            const fileBlock = `[File: ${part.fileName}]\n${content}`;
-            text.push(fileBlock);
-            native.push(fileBlock);
-          } catch {
-            const notice = `[Attached file: ${part.fileName} at ${part.path}]`;
-            text.push(notice);
-            native.push(notice);
-          }
+          const reference = [
+            `Uploaded file: ${part.fileName}`,
+            `Path: ${part.path}`,
+            `MIME: ${part.mimeType}`,
+            `Size: ${part.size} bytes`,
+          ].join("\n");
+          text.push(reference);
+          native.push(reference);
         }
-      } else {
-        throw new AntigravityError(
-          `Antigravity does not support content type: ${(part as { type?: string }).type ?? "unknown"}`,
-        );
       }
     }
-
     return { text: text.join("\n"), nativeText: native.join("\n") };
   }
 

plugins/antigravity-provider/server/provider.test.ts

@@ -775,7 +775,7 @@ describe("image prompts", () => {
 });
 
 describe("uploaded file prompts", () => {
-  it("inlines readable text files and references uploaded images and large files", async () => {
+  it("references uploaded text, images and large files without changing their bytes", async () => {
     const h = await harness();
     await h.open();
     const txtFile = path.join(h.cwd, "notes.txt");
@@ -815,8 +815,10 @@ describe("uploaded file prompts", () => {
 
     const sent = (await h.records()).find((entry) => entry.input).input.message.content;
     expect(sent).toBe(
-      `SYSTEM PREFIX\n\nPlease review these attachments:\n[File: notes.txt]\nexport const meaning = 42;\nAttached image: ${imgFile}\n[Attached large file: dataset.bin at /tmp/dataset.bin (3145728 bytes)]`,
+      `SYSTEM PREFIX\n\nPlease review these attachments:\nUploaded file: notes.txt\nPath: ${txtFile}\nMIME: text/plain\nSize: 26 bytes\nAttached image: ${imgFile}\nUploaded file: dataset.bin\nPath: /tmp/dataset.bin\nMIME: application/octet-stream\nSize: 3145728 bytes`,
     );
+    expect(await readFile(txtFile, "utf8")).toBe("export const meaning = 42;");
+    expect(await readFile(imgFile, "utf8")).toBe("png bytes");
   });
 });
 
@@ -835,3 +837,29 @@ it.runIf(process.platform === "win32")(
     });
   },
 );
+
+it("preserves a usable reference for an uploaded binary file", async () => {
+  const h = await harness();
+  await h.open();
+  const file = path.join(h.cwd, "document.pdf");
+  const bytes = Buffer.from([0x25, 0x50, 0x44, 0x46, 0x00, 0xff, 0xfe]);
+  await writeFile(file, bytes);
+  await h.completed(
+    await h.message([
+      { type: "text", text: "Read the attachment" },
+      {
+        type: "uploaded_file",
+        id: "pdf-upload",
+        fileName: "document.pdf",
+        mimeType: "application/pdf",
+        size: 7,
+        path: file,
+      },
+    ]),
+  );
+  const sent = (await h.records()).find((entry) => entry.input).input.message.content;
+  expect(sent).toContain(file);
+  expect(sent).not.toContain("\u0000");
+  expect(sent).not.toContain("\ufffd");
+  expect(await readFile(file)).toEqual(bytes);
+});