DeepSeek Launches Open-Source Alternative to Claude Code and Releases V4 Pro

DeepSeek has launched Harness v0.1, an open-source platform for AI agents, alongside its finalized V4 Pro model. Available on GitHub under the MIT license, Harness serves as an alternative to Claude Code, enabling developers to build AI agents that can generate and execute code autonomously.

The new development environment enhances large language models (LLMs) with tools for interacting with codebases, terminals, and external applications. DeepSeek positions Harness as a minimalist framework that can be customized for specific tasks and integrated with various models.

In conjunction with the Harness launch, DeepSeek has released the final version of V4 Pro, which boasts improved performance in agent tasks and now supports the OpenAI Responses API. The model can be accessed via applications, web platforms, and API, and features selectable reasoning modes: low, high, and max.

Performance Highlights of V4 Pro

Tests indicate V4 Pro's effectiveness, achieving scores of 87.9 in Terminal Bench 2.1, 62.7 in DeepSWE, and 74.1 in Toolathlon-Verified. The company claims that these enhancements will help agents utilize tools more efficiently and perform complex sequences of actions.

Revised API Pricing Structure

Following this full release, DeepSeek will implement a new pricing model for its API, featuring variable rates based on peak and off-peak usage, with discounts during non-peak hours. This pricing adjustment will come into effect on August 16.