GitHub - mcpcustoms/mcp-customs: Inspect an MCP server before you let it through. Offline, zero telemetry. · GitHub
/" data-turbo-transient="true" />
Skip to content
Search or jump to...
Search code, repositories, users, issues, pull requests...
-->
Search
Clear
Search syntax tips
Provide feedback
--><br>We read every piece of feedback, and take your input very seriously.
Include my email address so I can be contacted
Cancel
Submit feedback
Saved searches
Use saved searches to filter your results more quickly
-->
Name
Query
To see all available qualifiers, see our documentation.
Cancel
Create saved search
Sign in
/;ref_cta:Sign up;ref_loc:header logged out"}"<br>Sign up
Appearance settings
Resetting focus
You signed in with another tab or window. Reload to refresh your session.<br>You signed out in another tab or window. Reload to refresh your session.<br>You switched accounts on another tab or window. Reload to refresh your session.
Dismiss alert
{{ message }}
mcpcustoms
mcp-customs
Public
Notifications<br>You must be signed in to change notification settings
Fork
Star
main
BranchesTags
Go to file
CodeOpen more actions menu
Folders and files<br>NameNameLast commit message<br>Last commit date<br>Latest commit
History<br>2 Commits<br>2 Commits
.github/workflows
.github/workflows
bin
bin
examples
examples
src
src
LAUNCH_POST.md
LAUNCH_POST.md
LICENSE
LICENSE
PROJECT_OVERVIEW.md
PROJECT_OVERVIEW.md
README.md
README.md
package.json
package.json
View all files
Repository files navigation
mcp-customs
Inspect an MCP server for common security risks before you install it.<br>Runs fully offline. No telemetry, no cloud upload, no account.
npx mcp-customs scan ./some-mcp-server
──────────────────────────────────────────────────────<br>MCP-CUSTOMS INSPECTION REPORT<br>──────────────────────────────────────────────────────<br>target ./some-mcp-server<br>files scanned 14<br>score 62 / 100<br>stamp [ REVIEW ]<br>──────────────────────────────────────────────────────<br>[HIGH] MCP002 — Unsanitized file path (possible path traversal)<br>server.js:41 return fs.readFileSync(userPath, 'utf8');<br>fix: Resolve the path against an allowed base directory ...
Why
Developers install MCP servers the way they used to install npm packages —<br>quickly, trusting the name, and moving on. An MCP server can read your<br>files, call your APIs, and execute commands on your behalf. Almost nobody<br>checks what it can actually do before connecting it to their agent.
mcp-customs is the "audit before install" step, run locally, in seconds.
What it checks (v0.1)
Rule<br>Severity<br>What it looks for
MCP001<br>critical<br>Shell command execution with unsanitized interpolation
MCP002<br>high<br>File reads/writes without a path-traversal guard
MCP003<br>critical<br>eval() / dynamic code execution
MCP004<br>high<br>Hardcoded API keys / credentials
MCP005<br>critical<br>Tool descriptions containing hidden-instruction language (prompt injection via the tool's own metadata)
MCP006<br>medium<br>Outbound network calls combined with environment-variable reads (possible exfiltration)
MCP007<br>low<br>No permissions/scopes declared in the manifest
These are heuristic, regex-based checks — fast and fully auditable in one<br>sitting, not a dataflow analysis. They will produce false positives and<br>will miss things a deeper analysis would catch. Treat a CLEARED stamp as<br>"nothing obvious," not "verified safe."
CI usage
# .github/workflows/mcp-customs.yml<br>- run: npx mcp-customs scan . --sarif results.sarif --fail-on high<br>- uses: github/codeql-action/upload-sarif@v3<br>with:<br>sarif_file: results.sarif
Get a badge for your README
npx mcp-customs scan . --badge --name your-server-name
Roadmap
Publish scan results to a public registry (mcp-customs.dev) with searchable trust scores
Dynamic/sandboxed analysis (catch what static checks miss)
Python-specific AST checks (current Python rules are regex-only)
Community flagging / verification on registry entries
License
Apache-2.0. No open-core trap — this CLI stays free either way. If a<br>hosted registry/dashboard ships later, that's a separate paid product;<br>this tool's local scanning will never require it.
About
Inspect an MCP server before you let it through. Offline, zero telemetry.
Resources
Readme
License
Apache-2.0 license
Uh oh!
There was an error while loading. Please reload this page.
Activity
Stars
stars
Watchers
watching
Forks
forks
Report repository
Releases
No releases published
Packages
Uh oh!
There was an error while loading. Please reload this page.
Contributors
Uh oh!
There was an error while loading. Please reload this page.
Languages
JavaScript<br>100.0%
You can’t perform that action at this time.