GitHub Copilot Review (August 2026): Agent Plugins 1.0, Grok 4.6, and Whether Slack Changes the Verdict
GitHub Copilot shipped Agent Plugins 1.0, Grok 4.6, Kimi K3, MAI-Code image understanding, and Slack plus Teams agents in August 2026. Here is what changed, which model to default for your team, and whether the 4.4 rating moves.
- ✓Agent Plugins 1.0 is GA across VS Code, Copilot CLI, the Copilot SDK, and the Copilot app on all plans, so one plugin.json ports across tools instead of a per-client rebuild (per GitHub changelog, Aug 12 2026)
- ✓The picker gained three models in one week: Kimi K3 (all paid plans), MAI-Code-1.1-Flash with native image understanding, and Grok 4.6 for agentic reasoning (per GitHub changelog, Aug 13 and 14 2026)
- ✕Agent mode still trails Cursor Composer on whole-repo multi-file refactors, the gap that has held since June (comparison carried from our July review)
- ✕The Slack integration is gated to Copilot Business and Enterprise; Pro and Pro+ seats cannot use it (per GitHub changelog, Aug 21 2026)
For a solo developer, Pro+ at $39 is the working tier and the August model breadth (Grok 4.6 for long agent runs, Kimi K3 for cheap routine work, MAI-Code for screenshots) buys more at the same price, but if your day is all-day multi-file agent editing, Cursor's Composer still edits cleaner. For a small team on Business at $19/user, the Slack and Teams agents are the reason to standardize here: triage-to-PR now happens in the channel, gated to Business and above. For an enterprise on Enterprise at $39/user, Agent Plugins 1.0 going GA removes the ecosystem-lock-in objection, since one plugin.json now runs in Cursor's client and Copilot's alike under your existing governance.