mcp-config-check
A small Python linter for Model Context Protocol config files used by Claude Desktop, Cursor, Cline, Windsurf, and Zed.
It catches common footguns before you start a broken MCP server:
- missing or conflicting transport (no
commandand nourl, or both set) - malformed
command/args/envshapes - hardcoded API keys in
envorargs(Anthropic, OpenAI, AWS, GitHub, Stripe, Slack, Google, HuggingFace, and more) - placeholder values left in (
"<your-api-key>","replace-me", etc.) - URLs with embedded credentials (
https://user:pass@...) - auth headers sent over plain HTTP
autoApprove: ["*"]/alwaysAllow: ["*"]wildcards that silently disable tool confirmation- case-insensitive duplicate server names
- unknown fields in a server entry
Supports both the Claude/Cursor/Cline/Windsurf shape (mcpServers) and the Zed shape (context_servers).
Install
pip install mcp-config-check
Usage
mcp-config-check path/to/mcp.json
Multiple files:
mcp-config-check ~/Library/Application\ Support/Claude/claude_desktop_config.json ~/.cursor/mcp.json
Only show errors (no OK lines, no warnings):
mcp-config-check --quiet path/to/mcp.json
Exit status: 0 on no errors, 1 on any errors.
Use as a library
from mcp_config_check import validate_config_file
result = validate_config_file("path/to/mcp.json")
if not result.ok:
for issue in result.errors:
print(issue.code, issue.server, issue.message)
Issue codes
| Code | Severity | Meaning |
|---|---|---|
| E000 | error | file-level problem (missing, empty, not JSON, wrong root shape) |
| E001 | error | server has no transport (command or url required) |
| E002 | error | server declares both command and url |
| E003 | error | command is not a non-empty string |
| E004 | error | args is not an array of strings |
| E005 | error | hardcoded secret detected in args |
| E006 | error | env is not a string-valued object |
| E007 | error | hardcoded secret detected in env value |
| E008 | error | env value is an obvious placeholder |
| E020 | error | url is invalid or has a non-http(s) scheme |
| E021 | error | url has embedded credentials |
| E022 | error | Authorization header sent over plain HTTP |
| E030 | error | no mcpServers or context_servers container found |
| E031 | error | case-insensitive duplicate server name |
| E100 | error | autoApprove / alwaysAllow contains "*" |
| W030 | warning | server container is empty |
| W900 | warning | unknown field on a server entry |
Development
pip install -e '.[dev]'
pytest
License
MIT
1 maintainer
Metadata
1 maintainer
Release files for mcp-config-check 0.1.0
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Total release size: 16.9 kB
Release files / mcp_config_check-0.1.0.tar.gz
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