Side-by-side
MCP Builder vs Copilot Extensions Preview SDK (JS)
MCP Builder (7.7/10) wins on maintenance and adoption; Copilot Extensions Preview SDK (JS) (7.5/10) leads on safety.
Both are scored on the same rubric (safety 35%, maintenance 25%, documentation 20%, adoption 20%) so every comparison below is apples-to-apples. How we score.
Choose
MCP Builder
Choose MCP Builder if you weight maintenance and adoption most.
Choose
Copilot Extensions Preview SDK (JS)
Choose Copilot Extensions Preview SDK (JS) if you weight safety most.
Effectively tied on: documentation.
| Dimension | MCP Builderanthropics | Copilot Extensions Preview SDK (JS)GitHub copilot-extensions |
|---|---|---|
| Skill score (overall) | 7.7 | 7.5 |
| Safety sub-score | 55/100 | 95/100 |
| Maintenance sub-score | 92/100 | 54/100 |
| Documentation sub-score | 85/100 | 88/100 |
| Adoption sub-score | 91/100 | 52/100 |
| Community rating | No ratings yet | No ratings yet |
| Platforms | Claude Skill | Copilot |
| Primary platform | Claude Skills | GitHub Copilot Extensions |
| Vendor | anthropics | GitHub copilot-extensions |
| Primary category | Engineering and Development | Engineering and Development |
| License | Apache-2.0 | MIT |
| GitHub stars | 139.7K | 87 |
| Last commit | 5 days ago | 3 months ago |
| Last verified | May 24, 2026 | May 24, 2026 |
| Open flags | None | None |