mcp-tester-helper

A unified MCP (Model Context Protocol) server for multi-stand infrastructure testing: REST APIs, PostgreSQL databases, and OpenSearch — all through a single config file.

Built for DevOps, QA, and developers who need AI-assisted testing across multiple environments (stands).

Features

• 🔀 Multi-stand — switch between dev / test / prod environments via config
• 🔒 Secure auth — OAuth tokens and DB credentials stay server-side, never exposed in AI chat
• 🌐 REST API — test any microservice endpoint with auto-authentication
• 🐘 PostgreSQL — run SQL queries with connection pooling and read-only safety
• 🔍 OpenSearch — search logs, list indices, inspect mappings via Query DSL
• 📋 Service Discovery — AI can list available stands and services
• ❤️ Health Checks — verify stand infrastructure availability

Quick Start

npx -y mcp-tester-helper --config ./config.json

Configuration

MCP Client Setup

Add to your MCP client configuration (Claude Desktop, Antigravity, Cursor, etc.):

{
  "mcpServers": {
    "infra": {
      "command": "npx",
      "args": ["-y", "mcp-tester-helper", "--config", "/path/to/config.json"],
      "env": {
        "STAGING_USERNAME": "admin",
        "STAGING_PASSWORD": "secret",
        "REST_ENABLE_SSL_VERIFY": "false"
      }
    }
  }
}

Config File (config.json)

{
  "stands": {
    "dev": {
      "auth": {
        "url": "https://auth.dev.example.com/oauth/token",
        "type": "json",
        "user": "DEV_USERNAME",
        "pass": "DEV_PASSWORD"
      },
      "elastic": {
        "url": "https://opensearch.dev.example.com:9200",
        "user": "DEV_ELASTIC_USER",
        "pass": "DEV_ELASTIC_PASS"
      },
      "database": {
        "host": "db.dev.example.com",
        "port": 5432,
        "db": "dev_db",
        "user": "DEV_DB_USER",
        "pass": "DEV_DB_PASS"
      },
      "services": {
        "billing": {
          "url": "https://billing.dev.example.com/api",
          "openapi": "api-docs/billing.json"
        }
      }
    }
  }
}

Note: user and pass fields contain environment variable names, not actual credentials. Actual values come from .env file or MCP client env config.

Auth Types

Type	Description	Content-Type
json (default)	{"username":"...","password":"..."}	application/json
oauth2	grant_type=password&username=...&password=...	x-www-form-urlencoded

Environment Variables

Variable	Description	Default
REST_RESPONSE_SIZE_LIMIT	Max response body size in bytes	10000
REST_ENABLE_SSL_VERIFY	Set to false to skip SSL cert verification	true

Tools Reference

test_request — HTTP API Calls

Test a REST API endpoint with auto-authentication.

{
  "stand": "staging",
  "service": "orders",
  "method": "GET",
  "endpoint": "/api/v1/health"
}

Parameter	Required	Description
stand	✅	Target stand name
service	✅	Service name from config, or "elastic" for OpenSearch
method	✅	GET, POST, PUT, DELETE, PATCH
endpoint	✅	Path (e.g. /api/v1/users)
body		Request body (for POST/PUT/PATCH)
headers		Extra headers (don't pass Authorization)

db_query — PostgreSQL Queries

Execute read-only SQL queries with connection pooling.

{ "stand": "staging", "query": "SELECT * FROM schema.table LIMIT 10" }

All queries run inside BEGIN TRANSACTION READ ONLY — data modifications are blocked.

os_search — OpenSearch Query DSL

Search OpenSearch indices using the full Query DSL.

{
  "stand": "staging",
  "index": "app-logs-*",
  "query_body": {
    "query": { "match": { "level": "ERROR" } },
    "size": 10,
    "sort": [{ "@timestamp": "desc" }]
  },
  "fields": ["@timestamp", "message", "level"]
}

os_indices — List OpenSearch Indices

{ "stand": "staging", "index_pattern": "app-logs-*" }

os_mappings — Index Mappings

{ "stand": "staging", "index": "app-logs-2025.07" }

list_services — Service Discovery

{ "stand": "staging" }

Returns all services, database, and OpenSearch info for the stand.

health — Infrastructure Health Check

{ "stand": "staging", "target": "all" }

Pings services, OpenSearch, and PostgreSQL. Returns status and timing for each.

Security

• 🔐 Auth tokens are obtained automatically and cached server-side (with TTL)
• 🚫 Credentials never appear in tool responses sent to the AI
• 🔄 Automatic token refresh on 401 responses
• 📖 All SQL queries are wrapped in read-only transactions
• ✂️ Response bodies are truncated to prevent token overflow

Credits & Attribution

This project is built upon and inspired by the following open-source projects:

• dkmaker/mcp-rest-api (MIT License) — REST API testing MCP server, used as the foundation for HTTP client and MCP server structure.

• modelcontextprotocol/servers — server-postgres (MIT License) — Official PostgreSQL MCP reference implementation. Connection pooling and read-only transaction patterns.

• elastic/mcp-server-elasticsearch (Apache-2.0 License) — Official Elasticsearch MCP server. Tool design for search, indices, and mappings (reimplemented from Rust to TypeScript for OpenSearch compatibility).

License

MIT