Holster MCP
Local-first secret scanning, rotation, vault, and audit-log tools for AI agents.
Install
Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).
holster-mcpclaude mcp add holster-mcp -- uvx holster-mcp==0.1.1
{
"mcpServers": {
"holster-mcp": {
"command": "uvx",
"args": [
"holster-mcp==0.1.1"
]
}
}
}
Documentation
From the project's README on GitHub, refreshed weekly. Links open on GitHub.
Contents
Holster
Local-first API key manager for AI developers.
Install
macOS Apple Silicon (M-series)
- Download
holster-cli-macos-arm64.tar.gz+.sha256from the latest release: https://github.com/nauta-ai/holster/releases/latest - Extract:
tar xzf holster-cli-macos-arm64.tar.gz - Verify:
shasum -a 256 -c holster-cli-macos-arm64.tar.gz.sha256 - Install:
sudo mv holster-cli /usr/local/bin/ - If macOS blocks first run:
xattr -d com.apple.quarantine /usr/local/bin/holster-cli - Verify:
holster-cli --version
macOS Intel (x86_64, since v0.7.0)
- Download
holster-cli-macos-x86_64.tar.gz+.sha256from the latest release. - Same extract / verify / install steps as above.
Linux x86_64
- Download
holster-cli-linux-x86_64.tar.gz+.sha256from the latest release. - Extract:
tar xzf holster-cli-linux-x86_64.tar.gz - Verify:
shasum -a 256 -c holster-cli-linux-x86_64.tar.gz.sha256 - Install:
sudo mv holster-cli /usr/local/bin/ - Verify:
holster-cli --version
Password handling on Linux: macOS Keychain is not available. Use --password-env <ENV_NAME> to read the vault password from an environment variable, or --password-stdin to pipe it via stdin.
Windows x86_64 (since v0.7.0)
- Download
holster-cli-windows-x86_64.zip+.sha256from the latest release. - Verify: in PowerShell,
(Get-FileHash -Algorithm SHA256 holster-cli-windows-x86_64.zip).Hashshould match the value in the.sha256file. - Extract:
Expand-Archive holster-cli-windows-x86_64.zip -DestinationPath . - Move
holster-cli.exesomewhere on$env:Path(e.g.C:\Users\<you>\bin\after adding that folder to PATH). - Verify:
holster-cli.exe --version
Password handling on Windows: macOS Keychain is not available. Use --password-env <ENV_NAME> or --password-stdin.
Rotating the master password (since v0.7.0)
Holster lets you change the vault's master password without re-creating the vault or losing entries:
holster-cli rotate-master /path/to/vault
# Prompts for OLD master, then NEW master twice (confirm)
This re-encrypts every entry under the new master and regenerates the vault salt under a single SQLite transaction. If the rotation fails or is interrupted, the vault remains intact under the old master.
If you cache the master password in macOS Keychain (common for daemon usage), pass --keychain-update SERVICE,ACCOUNT to update the cached entry in the same command:
holster-cli rotate-master /path/to/vault \
--keychain-update holster-personas-vault,admin
For unattended / scripted rotation:
# OLD pw from Keychain, NEW pw from env
holster-cli rotate-master /path/to/vault \
--old-password-keychain-service holster-personas-vault \
--old-password-keychain-account admin \
--new-password-env NEW_HOLSTER_MASTER
# Both from stdin (one line each, OLD first then NEW)
printf '%s\n%s\n' "$OLD_PW" "$NEW_PW" | \
holster-cli rotate-master /path/to/vault \
--old-password-stdin --new-password-stdin
Rotate the master password:
- After any suspected credential exposure
- After a team member who knew the master leaves
- Quarterly as routine hygiene
- Whenever the master appears in plaintext somewhere (logs, configs, transcripts)
Password sources (since v0.7.0)
get, add, rotate-master, and exec-env now accept the master password from multiple sources. Precedence (first non-None wins):
--password-env <NAME>— read from an environment variable--password-stdin— read first line of stdin--password-keychain-service <SVC> [--password-keychain-account <ACCT>]— macOS Keychain- Interactive TTY prompt (fallback)
This makes Holster scriptable from CI, launchd, systemd, and daemon contexts without requiring an interactive TTY.
Documentation
Read docs/framework/00_README.md to start.
holster guard
holster guard . preflights a repo before you run an AI agent against it or share/commit it. It prints a local RUN verdict, a SHARE verdict, and a ranked fix list without exposing raw secret values.
RUN VERDICT: CAUTION
SHARE VERDICT: RISKY
Why:
1. [SHARE/RISK] OPENAI_API_KEY in .env.local:3
2. [SHARE/RISK] .env.local not gitignored — will be committed
3. [RUN/CAUTION] MCP server "cursor" inherits full shell environment
Fix order:
1. Add .env.local and *.pem to .gitignore
2. Move live keys into the Holster vault (holster add ...)
3. Pin or approve the MCP wrapper command
For a redacted report that is safe to paste into a review thread:
holster guard . --share-report holster-guard-report.md
Status
v0.7.0 — early access. Holster includes the local vault CLI, rotate-master, scriptable password sources, Windows/macOS-x86_64 builds, and early holster guard preflight checks. Vault crate stable since M1.
Frequently asked questions
What is Holster MCP?
Local-first secret scanning, rotation, vault, and audit-log tools for AI agents.
How do I install Holster MCP?
It runs on your machine. In Claude Code: claude mcp add holster-mcp -- uvx holster-mcp==0.1.1. For other clients, paste the JSON configuration from this page into their MCP settings.
Does Holster MCP need an API key?
Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.
Is Holster MCP open source?
Yes. Its code is on GitHub under the MIT license.
Who maintains Holster MCP?
It is published by nauta-ai. AI.tn lists it but does not maintain or endorse it.
From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.