fix(antigravity): support uploaded_file attachments in prompt encoding

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

@@ -1,5 +1,5 @@
 import { randomUUID } from "node:crypto";
-import { chmod, mkdtemp, rm, writeFile } from "node:fs/promises";
+import { chmod, mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 import type { ProviderPrompt } from "@getpaseo/plugin/server/provider";
@@ -10,6 +10,8 @@ interface EncodedPrompt {
   nativeText: string;
 }
 
+const MAX_INLINE_FILE_BYTES = 2 * 1024 * 1024; // 2 MB
+
 export class PromptFiles {
   private directory: string | null = null;
 
@@ -20,19 +22,16 @@ export class PromptFiles {
       prompt.outputSchema !== undefined
     )
       throw new AntigravityError("Antigravity supports messages only");
-    const parts = prompt.input.content.map((part) => {
-      if (part.type === "text") return part;
-      if (part.type === "image") return { ...part, extension: imageExtension(part.mimeType) };
-      throw new AntigravityError("Antigravity supports text and image content only");
-    });
+
     const text: string[] = [];
     const native: string[] = [];
-    for (const part of parts) {
+
+    for (const part of prompt.input.content) {
       if (part.type === "text") {
         text.push(part.text);
         native.push(part.text);
       } else if (part.type === "image") {
-        const extension = part.extension;
+        const extension = imageExtension(part.mimeType);
         if (this.directory === null) {
           this.directory = await mkdtemp(path.join(os.tmpdir(), "paseo-antigravity-images-"));
           await chmod(this.directory, 0o700);
@@ -41,8 +40,32 @@ export class PromptFiles {
         await writeFile(file, Buffer.from(part.data, "base64"), { flag: "wx", mode: 0o600 });
         await chmod(file, 0o600);
         native.push(`Attached image: ${file}`);
+      } else if (part.type === "uploaded_file") {
+        if (part.mimeType && 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);
+          }
+        }
+      } 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

@@ -774,6 +774,52 @@ describe("image prompts", () => {
   });
 });
 
+describe("uploaded file prompts", () => {
+  it("inlines readable text files and references uploaded images and large files", async () => {
+    const h = await harness();
+    await h.open();
+    const txtFile = path.join(h.cwd, "notes.txt");
+    await writeFile(txtFile, "export const meaning = 42;");
+    const imgFile = path.join(h.cwd, "photo.png");
+    await writeFile(imgFile, "png bytes");
+
+    await h.completed(
+      await h.message([
+        { type: "text", text: "Please review these attachments:" },
+        {
+          type: "uploaded_file",
+          id: "upload-txt-1",
+          fileName: "notes.txt",
+          mimeType: "text/plain",
+          size: 26,
+          path: txtFile,
+        },
+        {
+          type: "uploaded_file",
+          id: "upload-img-1",
+          fileName: "photo.png",
+          mimeType: "image/png",
+          size: 9,
+          path: imgFile,
+        },
+        {
+          type: "uploaded_file",
+          id: "upload-big-1",
+          fileName: "dataset.bin",
+          mimeType: "application/octet-stream",
+          size: 3 * 1024 * 1024,
+          path: "/tmp/dataset.bin",
+        },
+      ]),
+    );
+
+    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)]`,
+    );
+  });
+});
+
 it.runIf(process.platform === "win32")(
   "launches an Antigravity command shim for probes and conversation startup",
   async () => {