Cline

Cline is an open-source AI coding agent that runs as a VS Code / Cursor extension. All config happens inside the IDE plugin UI — platform-independent.

Get an API key first — see Common setup.

Install the extension

In VS Code / Cursor:

1. Open Extensions (Cmd/Ctrl + Shift + X)
2. Search cline
3. Install Cline (prev. Claude Dev)

Configure PrimeRouter

1. Open the Cline sidebar (robot icon on the left)

2. Top-right ⚙️ → Settings

3. API Provider → OpenAI Compatible

4. Fill:

   Base URL:  https://primerouter.ai/v1
   API Key:   sk-your-primerouter-key
   Model ID:  claude-sonnet-4-6

5. Enable "Enable streaming"

6. Enable tool-use related toggles for agent behavior

7. Save

Recommended setup

Plan / Act with different models

Cline supports separate Plan and Act models:

Mode	Model	Why
Plan	claude-opus-4-7	complex reasoning + long context, worth the tokens
Act	claude-sonnet-4-6	fast and cheap, single-step actions

Context window

Cline defaults to 200K, which works fine for the Claude family.

Custom Instructions

Use Cline's Custom Instructions to add project-level rules ("tests use jest", "frontend uses Semi") so you don't repeat yourself.