"Everything is a Plugin": DeepSeek Hands Tasks to Codex and Claude Code
A pre-release of DeepSeek Harness lets its agent delegate independent coding tasks to rivals' locally installed tools. The design separates each task from the main conversation, with no follow-up messages.
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Oct 30, 06:00 UTC ·
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DeepSeek has added an experimental tool to its Harness coding agent that can hand independent tasks to locally installed Codex or Claude command-line tools, opening a route to rival systems. [1]
The feature arrived in v0.2.2-alpha.2, a pre-release published on October 28, 2026. DeepSeek calls the plugin subagent_oar and explicitly labels it experimental. [1]
Harness is the software around an AI agent that connects it to tools and manages its work. Here, DeepSeek is adding a way for that software to delegate tasks to coding tools associated with OpenAI and Anthropic, rather than requiring the main agent to do everything itself. [1][2]
DeepSeek describes Harness's design with the slogan "Everything is a Plugin." Its official repository identifies it as an open-source agent harness built around plugins, and warns that it remains in developer preview, with changes possible that could break compatibility. [3]
The unusual move is the choice of helpers. An agent using tools is routine. DeepSeek's own harness offering a route to competing coding agents makes the surrounding software a place where developers can combine systems from different companies. The practical value will depend on how well those handoffs work.
A complete brief, then a separate agent
Codex CLI and Claude Code are coding tools operated through a terminal, where users give instructions through text commands. CLI stands for command-line interface. The integration described in the release notes calls on these external tools locally, so a developer needs the relevant tool installed as well as Harness. [1]
The implementation describes a deliberately bounded job. The main agent supplies a complete task prompt and selects a configured external provider. The child agent works in its own context, cannot see the parent conversation and cannot receive follow-up messages. [2]
That puts a burden on the handoff. If an instruction depends on something discussed earlier, the parent must include that information in the task itself. A request such as fixing a narrowly defined problem would need enough detail for the child to work without asking the main agent what it meant.
This is delegation by written brief, rather than a shared conversation.
The call returns a child identifier, while the child's final answer is delivered later. The code also allows the caller to specify a working directory, giving the delegated task a location in which to operate. [2]
The identifier lets the caller distinguish one delegated job from another. Receiving it is different from receiving completed work: the interface separates starting the task from getting its answer. A working directory, meanwhile, tells the child where to work, rather than supplying the missing history of the parent conversation. [2]
Those choices explain why DeepSeek describes the feature as suited to independent tasks. A job that can be separated cleanly from the rest of the work fits this design. A job that needs repeated clarification from the parent conversation does not fit it nearly as well.
The implementation details come from the repository's current master branch, rather than a version-pinned copy of the October 28 release. Supported CLI versions, authentication requirements, permissions, approval handling and error recovery have not been established.
There are also no independent tests or user results showing that delegation makes coding faster or more reliable. The integration does not establish that rival tools have been incorporated into a DeepSeek model, or that their underlying models run on the user's computer. [1][2]
A bridge between products
The plugin architecture gives this addition a specific place in Harness. A plugin is a separately defined component that adds a capability to the surrounding software. Here, the experimental component supplies a way to ask an external agent to do a job, with provider selection handled through configuration. [2][3]
For developers deciding what to try, that changes which system can be asked to handle part of a project. Any gain would have to justify the work of preparing a self-contained brief and managing the result when it comes back.
For DeepSeek, the design makes room for its harness to remain useful even when a developer wants another company's coding tool to do part of the work. That is a practical bet on the value of coordinating agents, rather than keeping every task inside a single provider's software.
The same pre-release also lists experimental statistics tools and tools for viewing change requests, proposed sets of code edits awaiting review, and worktrees, the separate working copies developers use to manage code changes. Delegation is one addition within a broader set of updates. [1]
Harness is available under the MIT License, making its code open for developers to inspect and modify. DeepSeek's developer-preview warning still applies to the project as a whole. [3]
The next useful milestone is a documented, reproducible handoff: how to configure a provider, what access the child receives, and what happens when its work fails or conflicts with the parent task. Developers need to establish how safely and reliably they can use it.
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