Cline on May 13 introduced Cline SDK and described the release as a rebuild of its agent runtime around a standalone, pluggable package, @cline/sdk, rather than an embedded IDE extension. The company states that the new architecture is meant to let the runtime operate as a shared service across surfaces such as VS Code, JetBrains and the CLI, while supporting longer-running sessions and more portable workflows.
In the post, Cline argues that the earlier extension-first design became harder to maintain and reuse as the product gained terminal integration, computer use, subagents, multi-agent teams and custom tools. The company presents the SDK rewrite as a way to separate the low-level agent loop from the product layer around it, with the runtime staying "stateless and reusable" while the surrounding infrastructure becomes durable enough to survive UI restarts and move across interfaces.
Cline also claims work on the runtime improved the harness itself. The post lists rewritten prompts, a simplified loop, tighter context management, better feedback loops, improved error handling and reworked tool definitions as part of Cline 2.0. Those changes, the company says, apply across its surfaces because they live in the runtime rather than a single app.
The company pairs that pitch with benchmark tables comparing Cline CLI with other tools on Terminal Benchmark. In its frontier-model table, Cline lists a 74.2% score on claude-opus-4.7 and 73.0% on gpt-5.3-codex; for open-weight models, it lists 55.1% on kimi-k2.6, 53.9% on deepseek-v4-pro and 49.4% on glm-5.1. The post notes that these are pass@1 scores and that some competitor combinations have no published runs, so the comparisons appear limited to the data Cline included.
Beyond performance claims, the SDK adds several extensibility layers. Cline says plugins can register tools, observe lifecycle events, add rules and commands, and shape what the agent sees. It also describes support for custom tools, MCPs and skills, plus native agent teams and subagents that can delegate tasks and exchange handoff notes without requiring a separate orchestration layer.
The provider layer is another focus. Cline says @cline/llms keeps model catalogs and provider settings out of the agent loop, and the SDK supports Anthropic, OpenAI, Google, AWS Bedrock, Mistral, LiteLLM and OpenAI-compatible endpoints such as vLLM, Together and Fireworks. To add a custom provider, the post says developers can implement an ApiHandler and register it with llms.registerHandler("my-provider", handler).
Cline also says it is migrating its own products to the new stack. The post states that its CLI and kanban already use the latest SDK, while its VS Code and JetBrains extensions are in the process of moving over. It also mentions experimental connector channels for Telegram, WhatsApp, Slack and other platforms through cline connect.
The company closes by pointing to examples, docs and a quick-start path that includes npm install @cline/sdk, npm i -g @cline and npx skills add cline/sdk-skill. It also situates the release as a continuation of the project’s earlier agentic tooling work, while acknowledging that Cline 2.0 reflects "learnings, inspirations, failures, and growth" from the broader coding-agent ecosystem.
Source: Cline
