MCP Tester
Test NextX's MCP server right in your browser: is it up, is your key/sign-in valid, which tools can the AI see and why tool X is missing, and what a call returns. Keys and tokens stay in this tab only.
https://mcp.nextx.vn/mcpJust like when an AI assistant (ChatGPT, Claude, Gemini, Grok…) connects: pick a workspace, tick permissions, then come back here.
Check results
- 1
Server is up (/health)
- 2
OAuth discovery (Protected Resource Metadata)
- 3
Handshake (initialize)
- 4
List tools (tools/list)
- 5
Compare permissions with the catalog
This session
Auth: Sign in with NextX (OAuth)
Protocol: 2025-06-18
Server: —
Visible tools: —
Attach when asking for support. Contains no key or token.
Client configuration
URL only — the assistant opens the sign-in page, you pick a workspace and tick permissions.
{
"url": "https://mcp.nextx.vn/mcp",
"transport": "streamable-http"
}Common errors
| Symptom | Cause | Fix |
|---|---|---|
| 401 at initialize | Wrong / revoked / expired key, or the sign-in token expired | Create a new key in the app or sign in again. Sandbox keys do not work on production. |
| 403 insufficient_scope on a tool call | The connection was not granted that tool's scope | Reconnect and tick the extra permission; for API keys add the scope to the key in the app. |
| 404 on /health or /mcp | Wrong server address (missing /mcp or wrong environment) | Use the exact address shown in Server above. |
| 429 | Rate limit exceeded | Wait a few minutes and retry; call less often. |
| Immediate network error | A self-hosted server has no CORS for this page, or the network blocks it | Allow CORS for the developer portal, or test with an MCP client outside the browser. |
| Over 30 seconds | Server overloaded or an incident is ongoing | Check System status and retry later. |
| 0 tools | The key/connection has no scope matching any tool | Add a read scope to the key or tick permissions when connecting. |
| Production works, Sandbox 401 (or vice versa) | Keys and tokens belong to ONE environment | Create a separate key in the sandbox app for the sandbox server. |
JSON-RPC log
No calls yet.