mcp-client

README

mcp

Run MCP servers without blindly trusting them.

---

The problem

Every time you run an MCP server, you're executing arbitrary code with your full system permissions:

uvx some-mcp-server       # What does this code actually do?
npx @someone/mcp-tool     # Can it read your SSH keys? Yes.

No verification. No limits. No sandboxing. No audit trail. For production environments connected to internal databases and APIs, this is an unacceptable risk.

What mcp does

mcp is a drop-in replacement for uvx/npx that adds the security layer they don't have:

1. Verifies every package against its SHA-256 digest before execution
2. Sandboxes processes with CPU, memory, network, and filesystem limits
3. Enforces certification policies (only run code that passed security analysis)
4. Audits every execution with structured logs and automatic secret redaction

Packages are analyzed upstream by MCP Hub Platform for 14 classes of security vulnerabilities and assigned a certification level (0-3) before they ever reach your machine.

uvx/npx vs mcp

	uvx / npx	mcp
Integrity verification	None	SHA-256 on every artifact
Security analysis	None	14 vulnerability classes, cert levels 0-3
Sandboxing	None (full system access)	CPU, memory, PID, FD limits
Network	Unrestricted	Default-deny (Linux)
Filesystem	Full access	Confined to workdir (Linux)
Secret handling	Visible in env/logs	Automatically redacted
Audit trail	None	Structured JSON logs

---

Install

Homebrew (recommended)

brew install mcp-hub-corp/tap/mcp

Binary

Download from Releases:

# macOS (Apple Silicon)
curl -sSL -o mcp https://github.com/mcp-hub-corp/mcp-client/releases/latest/download/mcp_*_darwin_arm64.tar.gz
tar xzf mcp_*_darwin_arm64.tar.gz && sudo mv mcp /usr/local/bin/

# macOS (Intel)
curl -sSL -o mcp https://github.com/mcp-hub-corp/mcp-client/releases/latest/download/mcp_*_darwin_amd64.tar.gz
tar xzf mcp_*_darwin_amd64.tar.gz && sudo mv mcp /usr/local/bin/

# Linux (amd64)
curl -sSL -o mcp https://github.com/mcp-hub-corp/mcp-client/releases/latest/download/mcp_*_linux_amd64.tar.gz
tar xzf mcp_*_linux_amd64.tar.gz && sudo mv mcp /usr/local/bin/

# Linux (arm64)
curl -sSL -o mcp https://github.com/mcp-hub-corp/mcp-client/releases/latest/download/mcp_*_linux_arm64.tar.gz
tar xzf mcp_*_linux_arm64.tar.gz && sudo mv mcp /usr/local/bin/

From source

go install github.com/mcp-hub-corp/mcp-client/cmd/mcp@latest

Verify

mcp --version
mcp doctor     # shows which security features your system supports

---

Usage

# Run a certified MCP server
mcp run acme/hello-world@1.2.3

# Run latest version
mcp run acme/tool@latest

# Run by exact digest (immutable)
mcp run acme/tool@sha256:a1b2c3...

# Pre-download for CI/CD
mcp pull acme/tool@1.2.3

# Inspect before running
mcp info acme/tool@1.2.3

# Manage cache
mcp cache ls
mcp cache rm --all

Authentication

mcp login --token YOUR_TOKEN
# or
export MCP_REGISTRY_TOKEN=YOUR_TOKEN

---

Configuration

Create ~/.mcp/config.yaml:

registry_url: "https://registry.mcp-hub.info"
timeout: 5m
max_memory: "512M"
max_cpu: 1000              # millicores (1000 = 1 core)
log_level: "info"

audit_enabled: true
audit_log_file: "~/.mcp/audit.log"

policy:
  min_cert_level: 1        # reject uncertified packages (0-3)
  cert_level_mode: strict  # strict | warn | disabled
  allowed_origins:         # empty = allow all
    - official
    - verified

CLI flags override config. Environment variables use MCP_ prefix (MCP_REGISTRY_URL, MCP_CACHE_DIR, etc.).

---

Platform support

	Linux	macOS	Windows
Resource limits	cgroups v2	rlimits	Job Objects
Network isolation	namespaces	--	--
Filesystem isolation	Landlock	--	--
Audit logging	full	full	full
Production ready	Yes	No	No

For production with untrusted MCP servers, use Linux or Docker. Run mcp doctor to check your system.

---

Documentation

Architecture	How the pieces fit together
Security model	Threat model and invariants
Examples	Usage patterns and CI/CD integration
Linux sandbox	cgroups, namespaces, Landlock, seccomp
Config reference	All available options
Contributing	Development guidelines

---

License

MIT -- see LICENSE.

---

Part of MCP Hub Platform -- trust infrastructure for MCP servers.