Know What Each Extension Is For
| Extension | Strength |
|---|---|
| GitHub Copilot | Best-in-class inline completion + integrated chat and edits |
| Continue | Open-source, bring-your-own-model (local or API), highly configurable |
| Cline | Autonomous agent that plans, edits files, and runs commands |
| Sourcegraph Cody | Codebase-aware chat with strong whole-repo context |
Run Local Models with Continue
If privacy or cost matters, Continue lets you point the editor at a local model (via Ollama or similar) or any API you choose. You give up some quality versus frontier models, but for completion and routine refactors on sensitive code, keeping everything on your machine is a real advantage.
Reach for an Agent Extension on Big Tasks
Completion extensions help you type; agent extensions like Cline do the task. For "scaffold a new module" or "migrate these files to the new API", an agent that edits across files and runs your tests will outpace line-by-line completion — just review its diffs carefully.
Avoid Stacking Completion Engines
Two inline-completion extensions active at once produce flickering, duplicated, or conflicting ghost text. Pick one for inline completion (Copilot or Continue), and add others only for non-overlapping roles like agentic edits or codebase chat.
Give Extensions Project Context
Most AI extensions read repo-level instruction files or settings. Whether it's Copilot's instructions file or Continue's config, spend ten minutes describing your stack and conventions — every extension that reads it gets better, and you stop repeating yourself in chat.
AI extensions grab shortcuts like Tab, Cmd-K, and Cmd-I. If completions stop accepting or chat won't open, check Keyboard Shortcuts for conflicts before assuming the extension is broken.
Match the Tool to the Sensitivity of the Code
Use a frontier cloud model for greenfield and public code; switch to a local model for anything under NDA or covered by data-residency rules. Configuring two profiles up front saves you from leaking the wrong thing in a hurry.
Frequently Asked Questions
Can I run Copilot and Continue together?
Yes, but don't enable inline completion in both — pick one for ghost-text completion to avoid conflicts, and use the other for chat or local-model tasks.
Which extension is best for private code?
Continue with a local model (e.g., via Ollama) keeps code on your machine. Cody and enterprise Copilot also offer stronger data controls than consumer tiers.
Do I need an agent extension if I have Copilot?
Copilot now includes edit/agent modes, so often no. Standalone agents like Cline are worth adding if you want a different model or more autonomous behavior.