MCP Scanner CLI
mcp-scanner
A scanner from Cisco AI Defense: checks MCP servers and their tools for threats with three engines, YARA rules, a model and the Cisco API
- 1,096 ★ on the repository
- Last commit
- Apache-2.0
Extended access
Why this level
- Connects to the servers it checks
- May pass tool descriptions to external analysis services
Install
In your terminal, with SkillFoxx CLI
npx skillfoxx add cli/mcp-scannerDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- Connects to the servers it checks
- May pass tool descriptions to external analysis services
This is third-party code. Review the repository files before installing.
What it does
MCP Scanner connects to MCP servers and checks their tool descriptions for threats. There are three engines: YARA rules, language model analysis and the Cisco AI Defense API with the `MCP_SCANNER_API_KEY` key. For model analysis you set `MCP_SCANNER_LLM_API_KEY` (Bedrock, OpenAI and others), and `VIRUSTOTAL_API_KEY` is optional. The project is in Python, version 4.8.6 from 02.10.2026, from the Cisco AI Defense organization.
Who it is for. For developers and security specialists who connect other people's MCP servers and want to check them before use.
Good fit when
- You need to check a third-party MCP server before connecting it to an agent
- You need to find suspicious instructions in tool descriptions
- You need regular checks of servers you already use
Not a fit when
- You cannot send tool descriptions to external analysis services
- You need to check the server's own code: the scanner looks at tool descriptions
Example request
Scan this MCP server and list which tools the engines considered suspicious and whyLimitations
The scanner connects to the servers it checks and may pass tool descriptions to external analysis services (a model, the Cisco API, VirusTotal), so do not use it on servers whose descriptions cannot be shared. Some engines need keys. No findings do not guarantee the server is safe.
How to disable. Remove the package with pip uninstall and revoke the keys you set for the engines.
FAQ
What does the scanner check?
The tool descriptions of MCP servers for threats with three engines: YARA, a model and the Cisco AI Defense API.
Are keys needed?
The Cisco API needs MCP_SCANNER_API_KEY and the model engine needs MCP_SCANNER_LLM_API_KEY. VIRUSTOTAL_API_KEY is optional.
Does no findings guarantee safety?
No, the scanner checks tool descriptions rather than the whole server code.
Discussion
No questions or reviews yet.
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Comparison with similar tools
Entries that share the main search query, and how they differ.
| Entry | Official | Repository stars | Main difference |
|---|---|---|---|
| MCP Scanner (this entry) | yes | 1,096 | |
| HOL Guard | yes | 964 | checks commands, secrets and package installs before they run |
| AgentShield | no | 1,311 | agentShield audits the .claude folder for plaintext keys |
| Agentic Radar | yes | 1,058 | agentic Radar analyzes multi-agent code on LangGraph |
README in short
The README describes the Cisco AI Defense MCP server scanner with three engines, keys and run modes. Apache-2.0 license.