Parser failures
Invalid JSON, smart quotes, Windows backslash escapes, trailing commas and a practical subset of Codex MCP TOML.
Local diagnostic tool · 本地诊断
Stop guessing why your MCP config fails.
Paste JSON or Codex TOML. Get exact, actionable diagnostics for wrapper names, transports, arguments, URLs and exposed credentials—then convert the working config to another client.
粘贴 MCP 配置，定位格式与安全问题，并在 Claude、Cursor、VS Code、Codex、Gemini CLI 之间转换。数据不离开浏览器。
- 6 clients
- JSON ↔ TOML
- Secret leak warnings
- No signup
- No upload
1. Paste configuration
Processed only in this tab. Do not paste live secrets into any website.
2. Corrected conversion
ReadyNothing leaves this browser
- Paste a config and run the doctor.
Build a clean MCP config from scratch
No existing file? Enter one server below. Put each command argument on its own line so spaces inside paths and values are preserved. For credentials, reference an environment variable instead of inserting the real token.
One protocol, several incompatible config shapes
MCP standardizes how clients talk to servers; it does not standardize every application's local settings file. Copying a valid snippet into the wrong wrapper or filename is one of the most common setup failures.
| Client | Project config | Top-level shape | Remote HTTP field | What this tool handles |
|---|---|---|---|---|
| Claude Code | .mcp.json | mcpServers | type: "http" + url | Validate + convert |
| Claude Desktop | User app config | mcpServers | url | Validate + convert |
| Cursor | .cursor/mcp.json | mcpServers | url | Validate + convert |
| VS Code | .vscode/mcp.json | servers | type: "http" + url | Validate + convert |
| Codex | .codex/config.toml | [mcp_servers.name] | url = "…" | TOML + JSON conversion |
| Gemini CLI | .gemini/settings.json | mcpServers | httpUrl | Validate + convert |
What the doctor checks
Client wrapper mismatch
Detects the servers versus mcpServers problem and converts to the selected client's structure.
Transport conflicts
Flags definitions that combine command and url, malformed URLs, insecure remote HTTP and legacy SSE.
Wrong value types
Finds comma-separated argument strings, non-object environment blocks and incomplete server definitions.
Credential exposure
Warns when token, key, password or authorization fields appear to contain literal credentials rather than variable references.
Startup friction
Catches easy-to-miss issues such as interactive npx installation prompts and Claude Code's reserved workspace server name.
How to troubleshoot after the file validates
Run the command directly
Copy the command and arguments into a terminal. Package-not-found, permission and runtime errors happen before MCP negotiation and cannot be fixed by changing the JSON wrapper.
Use the client's MCP view
Claude Code exposes /mcp and claude mcp list; Codex exposes /mcp and codex mcp list; Gemini CLI exposes /mcp and gemini mcp list.
Separate config from connection
A structurally valid file can still fail because the executable is absent, the URL is unreachable, OAuth is incomplete, the working directory is wrong or the server writes logs to stdout.
Specification sources and scope
This tool's client mappings were checked against first-party documentation on July 31, 2026. It validates configuration structure; it does not execute an untrusted MCP server or claim that a remote endpoint is reachable.
MCP config FAQ
Cursor commonly reads server definitions from mcpServers. VS Code's mcp.json uses a top-level servers object. A simple copy can therefore be valid JSON and still be invalid for the target client. Choose VS Code as the output above to change the wrapper and transport fields.
Use ~/.codex/config.toml for user-wide settings or .codex/config.toml for a trusted project. The ChatGPT desktop app, Codex CLI and IDE extension share the configuration for the same Codex host. You can also add servers with codex mcp add.
No. It proves that the supported configuration shape is parseable and checks likely mistakes. Only the target client can start or contact the server, negotiate the protocol, complete authentication and list tools. Use the client's status screen and logs after validation.
Replace the literal with a client-supported environment reference or secure input mechanism. If the credential was committed to Git, pasted into a ticket or otherwise exposed, revoke and rotate it. Removing the string from the current file does not erase it from history.
SSE is still accepted by some clients, but current Claude Code guidance labels it deprecated and recommends Streamable HTTP for remote servers where available. The warning does not automatically rewrite an SSE endpoint because the server must actually support the newer transport.
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