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DeepSeek Harness vs OpenCode: which fits your workflow?
DeepSeek Harness and OpenCode can both support AI coding. Your task scope, extension needs and existing environment help determine which to try. OneLLM provides separate phone connection modules for both: configure the service on your computer, then connect from an iPhone or iPad.
Published by OneLLM using the official sources below and this site’s connection workflow. OneLLM is independent of DeepSeek and OpenCode. This is not a controlled benchmark of speed, cost or code quality.
DeepSeek Harness vs OpenCode
Swipe horizontally to view the full table.
| Area | DeepSeek Harness | OpenCode |
|---|---|---|
| Focus | An open-source agent harness. Official examples cover everyday work, coding and research. | An open-source AI coding agent for understanding repositories, changing code and development tasks. |
| Interfaces | An official desktop preview and a Web UI launched from npm. | Terminal, desktop and IDE interfaces, plus documented Web and standalone server access. |
| Extensions | A Cordis-based plugin architecture for composing an agent environment. | Plugins with event hooks, external integrations and custom tools. It should not be described as lacking plugins. |
| OneLLM phone module | Use DS Harness and scan its matching connection code. | Use OpenCode and scan its matching connection code. |
| Version compatibility | Still labeled a preview; interfaces and plugins may undergo breaking changes. | Separate documentation exists for OpenCode 1 and 2. Installation, service protocols and client compatibility should not be assumed identical across versions. |
This table describes workflows, not model rankings. Results also depend on the selected model, context, tools and how you review the output.
Choose by your task and existing setup
You already have an OpenCode project and conversations
Keep that environment and follow the OpenCode mobile guide to add phone access. A mobile interface alone need not trigger a project migration. Before upgrading the computer service, check the connector’s supported version and release notes.
You want to explore a composable agent environment
Start with the DeepSeek Harness preview and plugin documentation. Use a small task to confirm the tools you need are available. A plugin architecture offers a way to extend functionality; specific file formats and task outcomes still need verification in your configuration.
You mainly want to compare coding results
Use equivalent project copies, the same problem and the same acceptance criteria. Record model versions, tool permissions, elapsed time and actual model usage, then inspect the changes and test results. Differences in models or context should not automatically be attributed to the harness.
Connect either service through OneLLM
- Prepare the computer service.Follow the connection page to install the OneLLM Connect preview and its dependencies. Select OpenCode or DS Harness, the project directory, and a LAN or Tailscale address.
- Configure the model account.Complete the selected service’s model setup on the computer. Click Connect and wait for Ready to scan. Model usage is billed separately.
- Scan in the matching module.Open OneLLM → OpenCode or DS Harness → Scan connection code. The modules use different connections; their codes are not interchangeable.
- Confirm the conversation and scope.Check the project and start with a small, verifiable task. Keep the computer running and reachable from your phone.
OneLLM’s mobile app is for iPhone and iPad. Remote access does not run either computer service locally on the phone, and is separate from offline inference with downloaded OneLLM models.
Check these results in your first trial
- Does the computer service work independently with its configured model account?
- Can the phone open the intended conversation and operate in the correct directory?
- Do changes come with reviewable file differences, test results and unfinished items?
- Can you reconnect after switching networks or waking the computer? Use connection codes only on your own devices.
Official sources and setup guides
- DeepSeek Harness overview: task examples and desktop preview.
- DeepSeek Harness repository: plugin architecture, startup and preview status.
- OpenCode introduction: interfaces, model configuration and versions.
- OpenCode plugins and server documentation: extensions and client access.