Bawbel never executes your MCP servers. Snyk's agent-scan does.

pip install "bawbel-scanner[all]"
bawbel scan ./skills/        # scan skill files
bawbel ssc https://server    # scan MCP server without starting it

Why Bawbel

How it works

System overview

How a scan flows from your file to an AIVSS-scored finding:

  your file
      |
      v
  [ Pre-processing ]
    code fence stripping
    negation context detection
      |
      v
  [ Detection engines ]  (run in parallel)
    1a  Pattern    40 regex rules, stdlib only, always on
    1b  YARA       39 binary/behavioral rules
    1c  Semgrep    41 structural rules
    2   LLM        semantic analysis via LiteLLM
    3   Sandbox    Docker behavioral sandbox
      |
      v
  [ Deduplication ]
    merge by (ave_id, line)
    pattern > yara > semgrep > llm > sandbox priority
      |
      v
  [ Toxic flow analysis ]
    map findings to capability tags
    check all pairs against 12 chain definitions
      |
      v
  [ ScanResult ]
    findings[]          active findings, sorted by severity
    suppressed_findings[]
    accepted_findings[] new in v1.2.0
    toxic_flows[]
    risk_score          max(findings, toxic_flows)
    aivss_score         OWASP AIVSS v0.8

Detection stages

Six engines run in parallel. Results merge before toxic flow analysis:

  Stage 1a   Pattern engine
             40 regex rules, no deps, < 5ms
             always active

  Stage 1b   YARA engine
             39 rules, multi-condition matching
             pip install "bawbel-scanner[yara]"

  Stage 1c   Semgrep engine
             41 structural rules, multi-line context
             pip install "bawbel-scanner[semgrep]"

  Stage 2    LLM engine
             semantic analysis, catches synonym attacks
             pip install "bawbel-scanner[llm]" + API key

  Stage 3    Sandbox engine
             dynamic behavioral analysis in Docker
             BAWBEL_SANDBOX_ENABLED=true

             +-----------+
  All  ----> | dedup     |

... [View full README on GitHub](https://github.com/bawbel/bawbel-scanner#readme)