Skill: direnv

Guidance for using direnv to securely maintain credentials and load environment variables without exposing them in agent outputs.

Core Process

1. Setup Environment: Copy .env.example to .env if .env does not exist and needs configuration.
2. Authorize Directory: Run direnv allow <path-to-env-dir> to approve the environment variables.
3. Export Variables: Run eval "$(direnv export bash)" to inject the variables into the current session.

Core Principles

• Security Focus: Never print, echo, or expose API keys and secrets in the terminal output.
• Session Persistence: Always follow direnv allow with eval "$(direnv export bash)" to ensure the agent's shell session properly loads the variables, as standard direnv shell hooks may not be active.

When to Use

• When you need to automatically load environment variables upon entering a specific project directory.
• To safely manage API keys and secrets in local development without committing them to version control.
• When an agent needs to execute commands that depend on project-specific credentials stored in .env.

When Not to Use

• In production CI/CD pipelines where secrets are securely injected by the runner environment (like GitHub Actions secrets).
• For managing global, system-wide environment variables (use ~/.bashrc or ~/.profile instead).
• When running commands in isolated, ephemeral Docker containers where environment variables are passed via --env-file.

Common Pitfalls

• Forgetting to Eval: Running direnv allow but forgetting to run eval "$(direnv export bash)", meaning the variables never actually load into the agent's current shell session.
• Committing Secrets: Adding sensitive keys to .env but failing to ensure .env is listed in the project's .gitignore.
• Assuming Global State: Expecting direnv variables to persist if the agent changes directories (cd ..), which naturally unloads them.

Commands / Usage Patterns

To authenticate when API keys are missing (e.g., loading from ../../):

direnv allow ../../
eval "$(direnv export bash)"

Full Workflow Example

Example usage for maintaining credentials and running commands from a subdirectory:

cp ../../.env.example ../../.env
# Edit ../../.env and set real values using file editing tools
direnv allow ../../
eval "$(direnv export bash)"

What to Avoid

• Do not manually source or cat .env files.
• Do not run direnv allow without immediately running eval "$(direnv export bash)" within the same execution context.