Copilot CLI Weekly: Safety, Personal Hooks, and GPT-5.4

The Week After GA GitHub Copilot CLI hit general availability last week , marking the end of public preview and the start of enterprise production commitments. This week brought three releases— v0.0.421 (March 3), v0.0.422 (March 5), and v0.0.423 (March 6)—that shift the focus from shipping features to hardening the foundation. The pattern is clear: safety guardrails, UX polish, and extensibility depth. These aren't headline features, but they're exactly the kind of work you'd expect from a team that just made production promises to enterprise customers. Let me walk through what matters. Shell Command Safety Prompts The most significant change this week landed in v0.0.423: users are now prompted for shell commands with potentially dangerous expansion or substitution use cases . The release notes call this "additional guardrails for malicious exploits." Here's why this matters. Copilot CLI can execute shell commands autonomously in autopilot mode. If an LLM hallucinates a command with r