The CLI does `keyenv pull` to fetch encrypted secrets from the server, then `keyenv run` injects them as environment variables into your process. No .env file written, no plaintext ever touches disk, and your app reads process.env exactly like before.
The advantage over 1Password's approach (mentioned in another comment) is that KeyEnv is purpose-built for dev teams: secrets are scoped per project and environment (dev/staging/prod), team members get granular access, and there's a full audit trail. 1Password is great for personal secrets but gets awkward when you need per-project scoping across a team.
For the shell history concern someone raised: `keyenv run` never exposes the actual secret values to the shell — they go straight into the child process environment.