Secret

Let coding agents use your credentials without reading them.

When your coding agent reads an environment file to deploy your app, the token can end up in its conversation.

Secret is a local CLI that runs your program with selected credentials and redacts their literal values from its output, with an optional names-only MCP server and guard hook.

Accident prevention, not a sandbox. Transformed output and arbitrary child behavior remain outside that protection.

Before and after

Today: The agent reads the file. The value is now in its context.
$ cat .env
API_TOKEN=synthetic-token

Illustrative transcripts. Whatever the command prints becomes part of the conversation.

With Secret: You stash the value once. The agent selects the key by name.
$ secret stash ~/.secrets.env API_TOKEN
API_TOKEN: 
stored API_TOKEN in /home/you/.secrets.env
$ secret run -f ~/.secrets.env \
    --key API_TOKEN -- ./deploy.sh
API_TOKEN=<redacted>

API_TOKEN reaches deploy.sh through its environment; if the script echoes the loaded literal value, run prints <redacted> instead. The optional Claude Code or Codex plugin's guard also denies reading the store file itself, as accident prevention.

Install

Linux/macOS

curl -fsSL https://raw.githubusercontent.com/avhn/secret/v0.6.0/install.sh | sh

Windows PowerShell

irm https://raw.githubusercontent.com/avhn/secret/v0.6.0/install.ps1 | iex

Both scripts install the latest release by default and print the executable's absolute path. No GitHub account or gh is needed; rerunning updates the installation. Neither reads stores, registers MCP, installs hooks or edits clients. See setup for pins, rollback, paths and the trust boundary.

Three commands

Example paths. You enter values in your own terminal; agents use show and run.

secret stash ~/.secrets.env API_TOKEN

Reads the value from a hidden prompt and writes the store with a private atomic replacement.

secret show ~/.secrets.env

Prints key names with masked byte lengths, such as API_TOKEN=<40 bytes>, never values.

secret run -f ~/.secrets.env --key API_TOKEN -- ./deploy.sh

Exports only the selected keys to the child's environment and replaces every loaded literal value with <redacted> on its stdout and stderr.

Clients

Setup guides for Claude Code, Claude Desktop via MCPB, Codex, and other local MCP stdio clients. The names-only MCP tools list, show, diff and health never return values, value hashes or lengths; the optional Claude Code and Codex plugins install the Bash guard that denies known store-reading operations.

Guides