mcp-test-servers

MCP Test Servers

A collection of test servers implementing the Model Context Protocol (MCP).

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Manual Installation

npx -y @msfeldstein/mcp-test-servers <server>

Available Servers

• all-types: Demonstrates various tool parameter types supported by MCP
• bad-param: Server with an intentionally malformed parameter name
• big-response: Server that returns large responses
• broken-tool: Server with intentionally broken tool
• broken-schema: Server with invalid JSON schema using oneOf/allOf/anyOf at top level
• broken-schema-fastmcp: FastMCP server with genuinely broken schemas using oneOf/allOf/anyOf at top level
• crash-on-startup: Server that crashes on startup
• combined: Server with tools and resources
• duplicate-names: Server with duplicate names for resources
• elicitation: Server demonstrating MCP elicitation feature - requests user information (name, age, contact details, preferences) through structured forms
• enum-param: Tool has enum string parameter
• env-check: Checks for SHOULD_RUN environment variable being passed properly
• env-echo: Echoes the environment variables
• gpt5-breaker: Server with SQL query execution tool using complex parameter validation
• headers: FastMCP server that safely returns HTTP header information
• instructions: Server with instructions and a makeRequest tool that returns success for value 42
• image: Tool returns an image of sonic the hedgehog
• long-description: Publicize a very long description configured via env var
• long-running: Server that sends progress notifications every 2 seconds for a 20-second task
• many-resources: Server with multiple resources
• many-tools: Server with 100 tools that each return 'ack'
• math: Server with basic math function tools (add, subtract, multiply, divide, power, sqrt, factorial)
• missing-type: Server with tools missing the required 'type' field in parameter schemas
• missing-type-fastmcp: FastMCP server with genuinely missing 'type' fields in tool schemas
• named: Server with configurable name via MCP_SERVER_NAME environment variable
• notion-gemini-repro: Server with complex nested schema that breaks on some models (Notion API reproduction case) - inline schema
• notion-gemini-repro-raw: Server with complex nested schema that breaks on some models (Notion API reproduction case) - exact raw schema object
• number-param: Tool with a number parameter
• oauth-repro: Reproduces OAuth 2.0 flow issues with proper discovery endpoints - runs resource server on port 3001 and auth server on port 3002
• optional-param: Tool has an optional param
• pattern-param: Tool has a parameter with a pattern match
• ping: A simple server that responds with 'pong'
• prompts: Server with two prompts - one static greeting and one dynamic story generator with character name and location parameters
• raw-broken: Raw JSON-RPC MCP server with genuinely broken schemas (no framework validation)
• resource: Resource server implementation
• resource-lister: Server that publishes 5 resources and has a tool to list them
• roots-echo: Server that demonstrates MCP roots functionality by echoing back the roots provided by the client
• session-management: HTTP server that implements MCP session management behavior - assigns session IDs, requires them in requests, returns 404 for terminated sessions
• stderr: Server that logs to stderr
• structured-output: Demonstrates structuredContent responses with a simple echo tool

Remote Servers

# Streamable HTTP
npm run http-ping

# SSE
npm run sse-ping