Introduction

The built-in web_search tool in DeepSeek Harness (DSH) calls Anthropic-compatible Messages endpoints. When the provider points to OpenCode Go / Zen, the gateway requires requests to include the x-opencode-session header. Missing this header causes the request to be rejected and returns a MissingSessionID error.

dsh-web-search-opencode-go is a plugin that fixes routing issues with DSH’s built-in web_search on OpenCode Go / Zen by automatically injecting the required routing headers.

What It Is

This is a Drop-in patched fork designed to allow DSH’s web_search tool to work correctly through the OpenCode Go / Zen gateway without modifying the official DSH installation.

  • Owner: leeyoung1
  • License: MIT

Core Features

  • Automatic header injection: Automatically adds the x-opencode-session and x-opencode-client: dsh headers.
  • Routing issue fix: Resolves OpenCode Go / Zen rejecting requests due to a missing session ID.
  • Installation modes: Supports DSH Bundle (recommended) and Drop-in copy installation modes.
  • Configurable headers: Supports custom headers by configuring headers and sessionId.
  • Plug-and-play: No modification to the official DSH installation is required. After installation, restart dsh web to use it.

Installation and Enablement

Bundle mode installation is recommended.

  1. Run the installation command:
    dsh plugin --profile web add github:leeyoung1/dsh-web-search-opencode-go

The installation command adds the plugin to `dsh.profile.bundles` and automatically handles the patch configuration.
  1. Restart the dsh web process to load the new plugin.

Typical Usage

After installing and restarting dsh web, configure baseURL and set the API Key environment.

  1. Configure the provider to point to OpenCode Go in ~/.dsh/settings.yaml:
    web-search-deepseek:
      baseURL: https://opencode.ai/zen/go/v1
      apiKeyEnv: DEEPSEEK_API_KEY

(Note: `apiKeyEnv` can also be set to `OPENCODE_GO_API_KEY`)
  1. Search using natural language in the conversation, or invoke the tool directly:
    web_search: DeepSeek Harness GitHub

Configuration Details

In addition to the basic baseURL and apiKeyEnv, optional headers and sessionId can be configured.

Optional Configuration Items

web-search-deepseek:
  baseURL: https://opencode.ai/zen/go/v1
  # 自定义 x-opencode-session 头部
  headers:
    x-opencode-session: my-fixed-session
  # 显式指定会话 ID
  sessionId: my-fixed-session

Header Priority

If not explicitly configured, the plugin determines the session ID in the following order:
1. Explicitly configured headers['x-opencode-session']
2. Explicitly configured sessionId
3. Current DSH agent session ID
4. Provider-level UUID (used for non-agent calls)

Notes

  • Runtime environment: Requires Node.js 20+ or pnpm.
  • Restart mechanism: dsh web must be restarted after installation for changes to take effect.
  • Platform support: Supports macOS, Linux, and Windows.
  • Official package protection: The plugin works as a Drop-in copy or Bundle and does not modify the official profile package in the DSH installation directory.

Summary

This plugin resolves routing errors when DSH uses OpenCode Go / Zen as the search provider. By using the standard installation command and configuration file changes, the normal functionality of the web_search tool can be restored.