psamvault-mcp

v0.4.0 — MCP server for psamvault.

Lets AI agents use your stored credentials without ever seeing their plaintext values. Also integrates with pv-dotenv for runtime credential resolution in your .env files.

Features

New in v0.4.0: use_credential, run_with_credential, scan_and_protect, capture_stripe_credentials, list_api_keys, single-process browser architecture (no fragile subprocess daemon), auto-restart on crash.

Related MCP server: DelineaMCP

How it works

Browser login flow (browser_login)

When an AI agent needs to log you into a website, psamvault opens a real Chromium browser, navigates to the site, and fills in the credentials directly inside that browser process.

The agent never sees the credentials. It only sees whether the login succeeded.

Agent: "Log me into kaggle.com"
         ↓
psamvault opens Chromium → navigates to kaggle.com → finds the login page
         ↓
psamvault decrypts credential locally
         ↓
psamvault fills username + password fields directly in the browser
         ↓
If a CAPTCHA appears, psamvault takes a screenshot, pauses automation,
and tells you to solve the CAPTCHA and click Sign in manually
         ↓
Agent receives:
         {
           "success": true,
           "message": "Logged in to github.com successfully.",
           "steps_count": 8,
           "url": "https://github.com/dashboard",
           "captcha_detected": false
         }
         ↓
Browser stays open — you take over from there.
The browser session is saved and reused on subsequent calls to the same site.

API credential flow (use_credential)

When an AI agent needs to make an authenticated API call on your behalf:

Agent: "Get my top 10 starred repos"
         ↓
use_credential("github.com", target_url="api.github.com/users/psam-717/starred")
         ↓
psamvault decrypts the API key locally, makes the HTTP request,
returns only the response — the credential is NEVER in the agent's context

Supports three injection modes:

• Bearer token — Authorization: Bearer ***

• API key header — <custom-header>: <key>

• Basic auth — Authorization: Basic base64(user:pass)

The fields parameter lets you return only the response keys you need, reducing token usage.

CLI command flow (run_with_credential)

When an agent needs to run a CLI tool that requires a credential (upload to PyPI, push to a private git repo, log into Docker, publish an npm package):

Agent: "Upload my package to PyPI"
         ↓
run_with_credential("pypi", "twine upload dist/*",
                    inject_as="env", env_var_name="TWINE_PASSWORD")
         ↓
psamvault decrypts the credential locally, spawns the subprocess
with the credential injected as an env var (or piped via stdin)
         ↓
All stdout and stderr is scanned for the credential value
and redacted before being returned
         ↓
Agent receives only the redacted output — the credential NEVER
appears in the agent's context

Supports two injection modes:

• env (default) — credential set as an environment variable (e.g. TWINE_PASSWORD, GITHUB_TOKEN, NPM_TOKEN). When TWINE_PASSWORD is used, TWINE_USERNAME=__token__ is set automatically.

• stdin — credential piped via stdin (e.g. for docker login).

Use cases include: twine upload, git push, docker login, npm publish, pip install (private repos), and any CLI tool that needs an API key or password.

Protecting your .env files (scan_and_protect)

Agent: "Protect the secrets in my project"
         ↓
scan_and_protect scans the project directory for .env files
         ↓
Detects API keys, passwords, tokens (pattern matching)
         ↓
Encrypts each secret into the psamvault vault
         ↓
Replaces plaintext with "psamvault:KEY_NAME" placeholders
         ↓
Your app resolves them at runtime with pv-dotenv

Secrets can be stored under a project namespace by passing project_name:

• Keys stored as project_name/.env/KEY_NAME for clean per-project organisation

• When omitted, keys are stored as env/.env/KEY_NAME (backwards-compatible)

• Use list_api_keys(project_name="myproject") to view only that project's keys

After protecting, pair with pv-dotenv — a drop-in replacement for python-dotenv that resolves psamvault: placeholders at runtime. No code changes needed beyond the import:

# Before:
from dotenv import load_dotenv

# After:
from pv_dotenv import load_dotenv

Prerequisites

• Python ≥ 3.11

• psamvault installed and logged in

pipx install psamvault
psamvault configure
psamvault login

• Playwright Chromium browser

playwright install chromium

Installation

pipx install psamvault-mcp

Transport modes

psamvault-mcp primarily uses stdio transport (the MCP standard for desktop agents). HTTP/SSE transport is also available as an option.

stdio (default — for Hermes, Goose, Claude Desktop, Cline)

psamvault-mcp

Starts the MCP server over stdin/stdout. This is the default mode and works with all major MCP desktop clients.

HTTP/SSE (for custom clients, remote setups, or network-accessible deployments)

psamvault-mcp --http --port 8433

Starts an HTTP server with Server-Sent Events (SSE) transport.

Goose setup

Option A — One-click deeplink

Click or paste this URL into your browser while Goose Desktop is running:

goose://extension?cmd=psamvault-mcp&timeout=300&id=psamvault&name=psamVault&description=Use%20stored%20credentials%20without%20exposing%20them%20to%20the%20agent

Goose will prompt you to confirm, then the extension is added instantly.

Option B — Goose Desktop UI

1. Open Goose Desktop.

2. Click the sidebar button (top-left) → Extensions.

3. Click Add custom extension.

4. Fill in the form:

   Field	Value
   Type	Standard IO
   ID	psamvault
   Name	psamVault
   Description	Use stored credentials without exposing them to the agent
   Command	psamvault-mcp
   Timeout	300

5. Click Add.

The extension appears in your Extensions list — toggle it on to activate it.

Option C — Config file (advanced)

Edit ~/.config/goose/config.yaml and add the following under extensions::

extensions:
  psamvault:
    name: psamVault
    cmd: psamvault-mcp
    args: []
    enabled: true
    type: stdio
    timeout: 300

Save the file and restart Goose (or reload the session).

Verifying the extension works

Once added, start a Goose session and try:

What credentials do I have stored in my vault?

Goose will call list_vault_sites via psamvault-mcp. If you see your stored sites, everything is working.

Hermes setup

Connect to psamvault-mcp via stdio transport (default). Add this block to ~/.hermes/config.yaml under mcp_servers:

mcp_servers:
  psamvault:
    command: psamvault-mcp
    enabled: true

If you need HTTP/SSE transport instead (e.g. for remote access), start the server with --http and point Hermes at the SSE endpoint:

mcp_servers:
  psamvault:
    url: "http://127.0.0.1:8433/sse"
    enabled: true

psamvault-mcp --http --port 8433

Restart or reload Hermes — the tools will be discovered automatically.

Claude Desktop setup

Config file location:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\\Claude\\claude_desktop_config.json

{
  "mcpServers": {
    "psamvault": {
      "command": "psamvault-mcp"
    }
  }
}

Restart Claude Desktop after saving.

Other MCP clients

Any MCP client supporting stdio transport can use psamvault-mcp:

{
  "mcpServers": {
    "psamvault": {
      "command": "psamvault-mcp"
    }
  }
}

For HTTP/SSE support, point the client at http://127.0.0.1:8433/sse.

Configuration

psamvault-mcp reads its backend URL from ~/.psamvault/config.env, written automatically by psamvault configure.

To point at a self-hosted backend, set the variable in ~/.psamvault/config.env:

PSAMVAULT_API_URL=https://your-backend.example.com

Available tools

Architecture

The MCP server manages a single Playwright Chromium instance in-process. No subprocess daemon is used — the browser lives in the same process as the MCP server. If the browser crashes, it is automatically restarted on the next browser_login call.

This eliminates the fragile 3-process chain (MCP → CLI daemon → browser) that caused connection errors with certain MCP clients (e.g. Goose's ECONNREFUSED on internal proxy ports).

Example agent prompts

Once connected, you can ask your agent things like:

• "What credentials do I have stored in my vault?"

• "What API keys do I have stored?"

• "Log me into kaggle.com"

• "Open github.com and log me in"

• "Check if I have a credential stored for z.ai"

• "Get my top 10 starred repos from GitHub"

• "Upload my package to PyPI"

• "Push to my private repo"

• "Protect the secrets in my project directory"

Related projects

Testing

# From the repo root
pytest

Tests live in tests/ and cover crypto primitives, session management, consent logic, the API client (with httpx mocking), and MCP tool behaviour. The test suite requires no real network access or OS keychain — all external dependencies are mocked.

Security

• Credentials are decrypted locally on your machine — never sent to the agent

• The agent only receives HTTP responses or redacted CLI output, never credential values

• All communication with the psamvault backend uses HTTPS

• The browser is managed in-process — no subprocess daemon or internal HTTP proxy

• CLI command output is scanned for the credential value and redacted before returning to the agent

License

MIT — see LICENSE.