MCP Inspector provides a web interface for exploring and testing MCP server tools without an AI client. The interface displays available tools with their parameters and allows manual execution to verify behavior before integrating with Claude Code or other clients.
Start MCP Inspector
MCP Inspector runs via npx and requires Node.js 18 or later. Verify the installation with node --version, then start the inspector:
npx @modelcontextprotocol/inspector
http://localhost:6274 and opens a browser window automatically.
Connect to Gcore MCP Server
MCP Inspector supports two connection methods: stdio transport through the UI configuration, and HTTP transport for debugging scenarios where server logs need monitoring.
Stdio transport
The stdio method launches the server directly from the Inspector interface.
-
Set Transport Type to
STDIO.
-
Enter the command:
- Enter the arguments:
--from gcore-mcp-server@git+https://github.com/G-Core/gcore-mcp-server.git gcore-mcp-server
- Expand Environment Variables and add:
| Variable | Value |
|---|
GCORE_API_KEY | API token |
GCORE_TOOLS | cdn.* (or other filter pattern) |
- Click Connect.
HTTP transport
HTTP mode allows monitoring server logs in a separate terminal.
- Start the server with HTTP transport:
GCORE_API_KEY=your-key GCORE_TOOLS="cdn.*" gcore-mcp-server --http
-
In the Inspector, set Transport Type to
SSE.
-
Enter the URL:
http://localhost:8000/sse
- Click Connect.
After connecting, the Inspector displays three tabs: Tools (available MCP tools), Resources (MCP resources if configured), and Prompts (MCP prompts if configured). Selecting a tool reveals its description, input schema with required and optional parameters, and a test interface for manual execution.
The tool list reflects the GCORE_TOOLS filter. Setting GCORE_TOOLS="cdn.*" shows CDN-related tools, while GCORE_TOOLS="cloud.instances.*" displays Cloud instance tools. Multiple products can be combined with GCORE_TOOLS="cdn.*,dns.*".
Setting GCORE_TOOLS=* loads all 720 tools. The Inspector interface may become slow or unresponsive with this configuration. Filter to specific products for responsive navigation.
GCORE_TOOLS="cdn.*", select cdn.cdn_resources.list from the tools list, and execute without parameters. The response contains an array of CDN resource objects with their configuration details.
Retrieving DNS zone details demonstrates a parameterized call: connect with GCORE_TOOLS="dns.*", select dns.zones.get, enter the zone name in the parameter field, and execute. The response contains the zone configuration including records, TTL settings, and status.
Tool schemas define the expected input format and appear in the Input Schema section when selecting a tool. Each field includes its data type (string, number, object, or array), whether it is required, a description of its purpose, and default values if applicable. Expanding nested objects reveals all available configuration options.
Schema exploration helps understand exact parameter names and formats before constructing requests in Claude Code or other clients.
Debug execution errors
The Inspector displays the full JSON-RPC request sent to the server, the response with results or errors, and execution timing. This visibility helps diagnose issues that produce generic errors in AI clients.
Authentication errors (401) indicate an invalid or expired API key—generate a new token in the Gcore Customer Portal. Permission errors (403) indicate the token lacks required permissions for the operation. Resource not found errors (404) indicate incorrect parameter values such as nonexistent IDs or zone names. Validation errors indicate missing required parameters or incorrect types—check the tool schema for the expected format. Practical applications
MCP Inspector serves as a reference tool when documenting or integrating Gcore MCP Server. Exploring tools reveals exact names, parameter requirements, types, and response structures. Testing filter patterns confirms that GCORE_TOOLS values match the intended tool set before configuring production clients. When Claude Code reports errors, replicating the tool call in the Inspector reveals the exact request and full error response for debugging. 
