HeadersTimeoutError after 5 minutes when using @opencode-ai/sdk versions > 1.3.3 #20119

Description

When using @opencode-ai/sdk version 1.3.4 or higher (up to the current latest 1.3.7), the SDK fails with a HeadersTimeoutError after approximately 5 minutes of operation. This issue does not occur in version 1.3.3, which works correctly.

The error occurs during SDK operations (specifically when calling client.session.prompt()), suggesting a timeout configuration change or network handling regression was introduced after version 1.3.3.

code = 'UND_ERR_HEADERS_TIMEOUT'
message = 'Headers Timeout Error'
name = 'HeadersTimeoutError'
stack = 'HeadersTimeoutError: Headers Timeout Error
    at FastTimer.onParserTimeout [as _onTimeout] (node:internal/deps/undici/undici:6827:32)
    at Timeout.onTick [as _onTimeout] (node:internal/deps/undici/undici:528:17)
    at listOnTimeout (node:internal/timers:608:17)
    at process.processTimers (node:internal/timers:543:7)'

• Affected versions: 1.3.4, 1.3.5, 1.3.6, 1.3.7 (all versions > 1.3.3)
• Working version: 1.3.3
• tested: @opencode-ai/sdk@1.3.3-7 and opencode-ai@1.3.3-7

Plugins

No response

OpenCode version

1.3.4, 1.3.5, 1.3.6, 1.3.7 (all versions > 1.3.3)

Steps to reproduce

• Install @opencode-ai/sdk version 1.3.4 or higher
• Create an OpenCode server and client:

import { createOpencodeClient, createOpencodeServer } from "@opencode-ai/sdk";

const server = await createOpencodeServer({
  hostname: "127.0.0.1",
  port: 4096,
});

const client = createOpencodeClient({
  baseUrl: "http://127.0.0.1:4096",
  directory: "/path/to/project",
  throwOnError: true,
});

• Create a session and send a prompt:

const session = await client.session.create({
  body: { title: "My session" },
});

const result = await client.session.prompt({
  path: { id: session.data.id },
  body: {
    model: { providerID: "sap-ai-core", modelID: "anthropic--claude-4.5-haiku" },
    parts: [{ type: "text", text: "Hello!" }],
  },
});

• Wait approximately 5 minutes
• Observe the HeadersTimeoutError

Expected behavior: The operation should complete successfully (as it does in version 1.3.3)

Actual behavior After ~5 minutes, the operation fails with HeadersTimeoutError

Screenshot and/or share link

No response

Operating System

macOS Tahoe

Terminal

No response