What is Cline?
Open-source, agent-first, lives inside VS Code. Cline (formerly Claude Dev) skips the completion-and-chat model most AI coding tools use and builds around an agent loop instead. It plans a task, edits multiple files, runs terminal commands, and uses a built-in browser to check its own work. Every step has a human approval gate, so nothing happens behind your back.
Key Features
- Multi-file agentic edits: plans changes, edits, and verifies across the workspace
- Terminal and browser integration: runs commands and inspects rendered output for self-correction
- Human-in-the-loop by default: every file write and shell command is reviewable before execution
- Bring-your-own-key model routing: works with Anthropic, OpenAI, Google, OpenRouter, local Ollama, and more
- Open-source: Apache 2.0 license, with a transparent agent loop you can fork or audit
Who is it for?
Developers who want an agent loop inside VS Code without adopting a closed-source IDE fork like Cursor. The Apache 2.0 license is the decisive feature, not a footnote: it means the agent loop is auditable and forkable, which is why BYO-key clears security and finance review where a closed fork with opaque server-side prompt construction does not. The fit inverts for teams that need SSO, policy controls, and GitHub-native PR integration; Cline has none of those and Copilot's depth wins that case regardless of license.
Pricing
The extension is free; you pay your model provider directly at their list rates, with no platform markup. The tradeoff is structural, not incidental: BYO-key has no flat ceiling, so heavy frontier-model use can exceed a fixed $20 Cursor or $10 Copilot subscription. What you buy for that is auditability. Every dollar maps to a provider invoice line you control, and you set the model, context window, and system prompt instead of accepting a vendor's gated defaults. That trade favors Cline below the crossover (light-to-moderate frontier use) and favors a flat plan above it.