Env Validator

env-validator-mcp

An MCP (Model Context Protocol) server that inspects your local development environment and reports missing dependencies, version mismatches, and misconfigured environment variables to any MCP-compatible AI assistant.

Works with Claude Desktop, Cursor, Gemini CLI, and any other client that supports stdio-transport MCP servers.

---

Features

MCP Tool	What it does
check_tool_version	Checks if a CLI tool is installed; optionally validates a semver constraint (e.g. >=1.21.0)
check_env_vars	Verifies environment variables are set, non-empty, and/or match a regex pattern
check_config_files	Confirms files/directories exist; optionally validates JSON files and checks for required keys
validate_environment	Full sweep: tools + env vars + config files, returns a structured JSON report
list_checks	Lists everything this server can inspect

Supported CLI tools: go, node, npm, docker, git, python3, pip3, make, curl, jq, kubectl, terraform, helm, rustc, java

---

Quick Start

1. Build

git clone https://github.com/pouyasadri/env-validator-mcp.git
cd env-validator-mcp
make build
# → bin/env-validator-mcp

2. Configure Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "env-validator": {
      "command": "/Users/pouyasadri/Desktop/Projects/env-validator-mcp/bin/env-validator-mcp"
    }
  }
}

Restart Claude Desktop. You can now ask:

"Check if Go, Docker and Node are installed and meeting my minimum version requirements"

"Is my DATABASE_URL environment variable set?"

"Run a full environment validation and tell me what's missing"

3. Configure Cursor / other MCP clients

Most clients support the same JSON config format. Point command at the binary path.

---

Example Responses

validate_environment

{
  "results": [
    {
      "name": "go",
      "status": "ok",
      "found_version": "1.24.2",
      "expected_range": ">=1.21.0",
      "message": "go 1.24.2 is installed and satisfies >=1.21.0"
    },
    {
      "name": "docker",
      "status": "missing",
      "message": "docker is not found or not executable: executable file not found in $PATH"
    },
    {
      "name": "HOME",
      "status": "ok",
      "message": "environment variable HOME is set"
    }
  ],
  "summary": "6 OK, 2 issue(s) found",
  "ok_count": 6,
  "issue_count": 2
}

check_tool_version

// Arguments: { "tool": "node", "constraint": ">=18.0.0" }
{
  "name": "node",
  "status": "outdated",
  "found_version": "16.0.0",
  "expected_range": ">=18.0.0",
  "message": "node 16.0.0 does not satisfy constraint >=18.0.0"
}

---

Semver Constraint Syntax

Operator	Example	Meaning
>=	>=1.21.0	Version must be 1.21.0 or newer
>	>1.20.0	Version must be strictly newer than 1.20.0
<=	<=3.0.0	Version must be 3.0.0 or older
<	<3.0.0	Version must be strictly older than 3.0.0
=	=1.24.2	Version must match exactly
(empty)	""	Any version — just check if installed

---

Development

Prerequisites

• Go 1.24+

Commands

make build      # Compile binary to bin/
make test       # Run all tests
make test-race  # Run with race detector
make coverage   # Generate HTML coverage report
make lint       # Run golangci-lint
make clean      # Remove build artifacts

Project Structure

env-validator-mcp/
├── cmd/server/          # Entry point (main.go)
├── internal/
│   ├── checker/         # Tool, env, and file checkers (interfaces + implementations)
│   ├── report/          # Result and Report types
│   └── semver/          # Version extraction and constraint checking
├── mcp/                 # MCP server setup and tool handlers
├── Makefile
└── go.mod

Architecture: Dependency Injection for TDD

All external effects are hidden behind interfaces:

Commander   → exec.Command (real) / MockCommander (tests)
EnvReader   → os.LookupEnv (real) / MockEnvReader (tests)
FileSystem  → os.Stat/ReadFile (real) / MockFileSystem (tests)

This allows every checker to be tested in complete isolation — no spawned processes, no real environment, no filesystem I/O.

---

License

MIT