fix: bound model streaming

src/main/agent/bounded-response.ts

@@ -0,0 +1,54 @@
+export type BoundedResponseTextOptions = {
+  maxBytes: number
+  missingBodyMessage?: string
+  tooLargeMessage: string
+}
+
+export async function readBoundedResponseText(
+  response: Response,
+  options: BoundedResponseTextOptions
+): Promise<string> {
+  const declaredLength = response.headers.get('content-length')
+  if (declaredLength !== null) {
+    const parsedLength = Number(declaredLength)
+    if (
+      !Number.isSafeInteger(parsedLength) ||
+      parsedLength < 0 ||
+      parsedLength > options.maxBytes
+    ) {
+      await response.body?.cancel().catch(() => undefined)
+      throw new Error(options.tooLargeMessage)
+    }
+  }
+  if (!response.body) {
+    if (options.missingBodyMessage) {
+      throw new Error(options.missingBodyMessage)
+    }
+    return ''
+  }
+
+  const reader = response.body.getReader()
+  const chunks: Uint8Array[] = []
+  let completed = false
+  let total = 0
+  try {
+    while (true) {
+      const { done, value } = await reader.read()
+      if (done) {
+        completed = true
+        break
+      }
+      total += value.byteLength
+      if (total > options.maxBytes) {
+        throw new Error(options.tooLargeMessage)
+      }
+      chunks.push(value)
+    }
+  } finally {
+    if (!completed) {
+      await reader.cancel().catch(() => undefined)
+    }
+    reader.releaseLock()
+  }
+  return Buffer.concat(chunks, total).toString('utf8')
+}