Prepare prompt file attachments for future UI (#1376)

* Support file uploads to agents

* Harden prompt file upload handling

* Fix duplicate upload retry handling

* Update relay reconnect tests for queued messages

* Make upload timeout track idle progress

* Clean failed upload directories

packages/protocol/src/binary-frames/demux.test.ts

@@ -0,0 +1,53 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  decodeBinaryFrame,
+  encodeFileTransferFrame,
+  encodeTerminalStreamFrame,
+  FileTransferOpcode,
+  TerminalStreamOpcode,
+} from "./index.js";
+
+describe("binary frame demux", () => {
+  it("routes terminal frames by opcode", () => {
+    expect(
+      decodeBinaryFrame(
+        encodeTerminalStreamFrame({
+          opcode: TerminalStreamOpcode.Input,
+          slot: 7,
+          payload: "ls",
+        }),
+      ),
+    ).toEqual({
+      kind: "terminal",
+      frame: {
+        opcode: TerminalStreamOpcode.Input,
+        slot: 7,
+        payload: new TextEncoder().encode("ls"),
+      },
+    });
+  });
+
+  it("routes file-transfer frames by opcode", () => {
+    expect(
+      decodeBinaryFrame(
+        encodeFileTransferFrame({
+          opcode: FileTransferOpcode.FileChunk,
+          requestId: "req-upload",
+          payload: new TextEncoder().encode("hello"),
+        }),
+      ),
+    ).toEqual({
+      kind: "file_transfer",
+      frame: {
+        opcode: FileTransferOpcode.FileChunk,
+        requestId: "req-upload",
+        payload: new TextEncoder().encode("hello"),
+      },
+    });
+  });
+
+  it("rejects unknown binary opcodes", () => {
+    expect(decodeBinaryFrame(new Uint8Array([0xff, 0]))).toBeNull();
+  });
+});

packages/protocol/src/binary-frames/demux.ts

@@ -0,0 +1,35 @@
+import {
+  decodeFileTransferFrame,
+  FileTransferOpcode,
+  type FileTransferFrame,
+} from "./file-transfer.js";
+import {
+  decodeTerminalStreamFrame,
+  TerminalStreamOpcode,
+  type TerminalStreamFrame,
+} from "./terminal.js";
+
+export type BinaryFrame =
+  | { kind: "terminal"; frame: TerminalStreamFrame }
+  | { kind: "file_transfer"; frame: FileTransferFrame };
+
+export function decodeBinaryFrame(bytes: Uint8Array): BinaryFrame | null {
+  switch (bytes[0]) {
+    case TerminalStreamOpcode.Output:
+    case TerminalStreamOpcode.Input:
+    case TerminalStreamOpcode.Resize:
+    case TerminalStreamOpcode.Snapshot:
+    case TerminalStreamOpcode.Restore: {
+      const frame = decodeTerminalStreamFrame(bytes);
+      return frame ? { kind: "terminal", frame } : null;
+    }
+    case FileTransferOpcode.FileBegin:
+    case FileTransferOpcode.FileChunk:
+    case FileTransferOpcode.FileEnd: {
+      const frame = decodeFileTransferFrame(bytes);
+      return frame ? { kind: "file_transfer", frame } : null;
+    }
+    default:
+      return null;
+  }
+}

packages/protocol/src/binary-frames/file-transfer.ts

@@ -14,6 +14,7 @@ export const FileBeginMetadataSchema = z.object({
   size: z.number().int().nonnegative(),
   encoding: z.enum(["utf-8", "binary"]),
   modifiedAt: z.string(),
+  fileName: z.string().optional(),
 });
 
 export interface FileBegin {

packages/protocol/src/binary-frames/index.ts

@@ -1,2 +1,3 @@
+export * from "./demux.js";
 export * from "./file-transfer.js";
 export * from "./terminal.js";