pi-psst

A pi extension for psst — automatic secret injection and scrubbing for AI agents.

What it does

• Injects psst vault secrets as environment variables into every bash command
• Scrubs secret values from all tool output — bash, read, grep, everything the LLM sees
• Tells the LLM which secrets are available via the system prompt
• Never exposes secret values to the agent's context

You: "deploy using the stripe key"

Agent runs: curl -H "Authorization: Bearer $STRIPE_KEY" https://api.stripe.com
Agent sees: HTTP 200 OK, Authorization: Bearer [REDACTED:STRIPE_KEY]

Install

# Requires psst-cli
npm install -g psst-cli

# Install the extension
pi install npm:@miclivs/pi-psst
# or
pi install git:github.com/Michaelliv/pi-psst

Setup

# Create a vault and add secrets
psst init
psst set STRIPE_KEY
psst set DATABASE_URL

# Start pi — secrets are automatically available
pi

Commands

How it works

1. On each bash call, the extension reads secrets from the local psst vault via the SDK
2. Secrets are injected into the subprocess environment via spawnHook
3. After any tool completes, tool_result scrubs secret values from the output
4. before_agent_start adds secret names to the system prompt so the LLM knows to use $SECRET_NAME

The agent orchestrates. psst handles the secrets. The values never touch the context window.

License

MIT