Cline

Cline is an AI coding agent distributed across several open-source surfaces sharing one engine: a VS Code extension, a terminal CLI, a headless mode for CI/CD, a web-based Kanban board for running many agents in parallel, and an SDK for building custom agents on the same core. A JetBrains plugin also exists but is not currently open-sourced.

The agent reads project structure, makes coordinated multi-file edits, monitors linter and compiler output as it works, and executes shell commands directly in your terminal — including long-running processes like dev servers, reacting to new output as it appears. Every file edit and command requires explicit approval by default (with an auto-approve toggle for autonomous runs), and edits show as reviewable diffs tracked with checkpoints so any step can be undone.

Cline supports Plan/Act mode switching (explore and strategize before executing), project-specific .clinerules for coding standards and conventions, MCP server integration, and works with models from Anthropic, OpenAI, Google, and other providers rather than being locked to one. Both the VS Code extension and the CLI/Kanban/SDK products are Apache-2.0 licensed.

What You Get

• A VS Code extension and terminal CLI sharing the same underlying agent engine, distributed under Apache-2.0
• A web-based Kanban board (cline/kanban) for running many agents in parallel, each with its own git worktree and auto-commits
• An SDK (@cline/sdk) for building custom agents, multi-agent teams, and scheduled automations on the same core
• Plan/Act mode switching, .clinerules for project-specific conventions, and MCP server support

Common Use Cases

• Driving multi-file code changes in VS Code with every edit shown as a reviewable diff before it’s applied
• Running headless coding agent tasks from a terminal or CI/CD pipeline via the CLI
• Orchestrating multiple agents in parallel on different tasks using the Kanban board, each isolated in its own git worktree
• Building custom AI coding tools or multi-agent workflows on top of the same engine via the SDK

Under The Hood

Architecture Cline’s repository is organized as a monorepo under apps/ (vscode, cli, cline-hub) plus a top-level sdk/, with the VS Code extension’s src/ split into core, integrations, services, hosts, and standalone — the hosts/standalone split suggests the same agent core is designed to run inside the VS Code extension host or as a standalone process for the CLI and other surfaces. The separately maintained cline/kanban repository builds on this shared engine rather than duplicating agent logic, using per-task git worktrees to isolate parallel agent runs.

Tech Stack TypeScript throughout, distributed as a VS Code Marketplace extension, an npm-installable CLI (npm i -g cline) and Kanban tool (npm i -g kanban), and an SDK package (@cline/sdk) for programmatic use. Model access is provider-agnostic, supporting Anthropic, OpenAI, Google, and others rather than a single hardcoded backend.

Code Quality Over 150 test files were found under the VS Code extension’s src/ alone, and the project separates __tests__ directories per concern (core, integrations, etc.), consistent with a mature, actively maintained codebase backed by very active recent commit history.

What Makes It Unique Cline’s default posture is human-in-the-loop by design — every edit and command needs approval unless you explicitly opt into auto-approve — and that same reviewed, checkpointed engine is exposed consistently across an editor extension, a CLI, a multi-agent Kanban board, and an SDK, rather than each surface reimplementing its own agent logic.

Self-Hosting

Licensing Model Apache-2.0 for the VS Code extension, CLI, Kanban board, and SDK. The JetBrains plugin is explicitly not open-sourced, per the project’s own README — it’s a closed-source client talking to the same shared agent core.

Self-Hosting Restrictions None found for the open-source surfaces; there’s no separate paid tier gating features in the VS Code extension, CLI, or SDK.

License Key Required No, for the open-source products. The JetBrains plugin’s distribution model is separate and not covered by the open-source license.