Jupyterlab Rtc — the complete, unedited output of the deterministic mcptrustchecker engine v1.9.0, scanned . Every finding, capability tag and score component below is exactly what the engine produced — no AI, no post-processing.
{
"tool": {
"name": "mcptrustchecker",
"version": "1.9.0",
"methodologyVersion": "mcptrustchecker-1.9"
},
"target": {
"id": "jupyterlab-rtc-mcp",
"source": {
"kind": "package",
"origin": "jupyterlab-rtc-mcp"
},
"server": {
"name": "jupyterlab-rtc-mcp"
}
},
"grade": "A",
"score": {
"score": 93,
"threatScore": 100,
"grade": "A",
"band": "A",
"categorySubtotals": {
"injection": 0,
"exfiltration": 0,
"permissions": 0,
"supply-chain": 0,
"network": 0,
"hygiene": 0
},
"vector": [
{
"kind": "client",
"term": "capability-exposure",
"level": "high",
"label": "capability blast radius (high) — client exposure if the model is manipulated",
"appliedPenalty": 6
},
{
"kind": "client",
"term": "verification-discount",
"level": "repo",
"label": "publisher verification (public source) — no provenance, but the source is public and inspectable",
"appliedPenalty": 1
},
{
"kind": "client",
"term": "coverage-honesty",
"level": "source",
"label": "inspection depth (source) — how much of the target the scan could see",
"appliedPenalty": 0
}
],
"gatesFired": [],
"methodologyVersion": "mcptrustchecker-1.9"
},
"capability": {
"level": "high",
"reasons": [
"can create, modify or delete files",
"can execute shell commands or code"
],
"tags": [
"file-write",
"code-exec"
]
},
"coverage": {
"level": "source",
"inputs": {
"toolSurface": true,
"implementationSource": true,
"packageMetadata": true,
"liveTransport": false
},
"caveats": [
"Tools were statically extracted from the published source (28 recovered), not enumerated from a running server. Tool-poisoning, Unicode-smuggling, capability and toxic-flow analysis ran on this inferred surface, but a mis-parsed registration could be missed or mis-attributed, so tool-derived findings are capped below “confirmed”. To grade the real runtime surface, scan the running server: --command \"npx -y <package>\"."
]
},
"findings": [
{
"ruleId": "MTC-SRC-001",
"title": "Dynamic code execution in server code (bundle/jupyterlab-rtc-mcp.mjs)",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "In the server's implementation (`bundle/jupyterlab-rtc-mcp.mjs:6`): Evaluating strings as code is the most direct RCE primitive; if any tool input reaches it, the server executes attacker-chosen code. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.",
"remediation": "Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.",
"location": {
"kind": "server",
"name": "bundle/jupyterlab-rtc-mcp.mjs"
},
"evidence": "ee,E));var X;try{var de=new Function(\"self\",\"RULES\",\"formats\",\"root\",\"refVal\",\"defaults\",\"customRules\",\"equal\",\"ucs2leng",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-001",
"file": "bundle/jupyterlab-rtc-mcp.mjs",
"line": 6,
"nonRuntime": false
}
},
{
"ruleId": "MTC-CAP-002",
"title": "Tool \"overwrite_document\" can modify the filesystem",
"category": "permissions",
"severity": "medium",
"confidence": "strong",
"description": "Tool \"overwrite_document\" can write, overwrite or delete files (keyword \"overwrite\" in tool name). Verify it is scoped to a safe directory.",
"remediation": "Constrain file operations to an explicit, non-sensitive root; reject path traversal.",
"location": {
"kind": "tool",
"name": "overwrite_document"
},
"data": {
"tags": [
"file-write"
]
}
},
{
"ruleId": "MTC-CAP-005",
"title": "Mutating tool \"overwrite_document\" declares no destructiveHint",
"category": "hygiene",
"severity": "low",
"confidence": "heuristic",
"description": "Tool \"overwrite_document\" can mutate/egress but declares no destructiveHint. Clients that don't default to spec-safe behavior may not prompt before running it.",
"remediation": "Declare accurate annotations, and gate destructive tools on user confirmation regardless.",
"location": {
"kind": "tool",
"name": "overwrite_document"
},
"data": {
"tags": [
"file-write"
]
}
}
],
"toxicFlows": [],
"capabilities": [
{
"tool": "get_base_url",
"tags": [],
"reasons": {}
},
{
"tool": "nb_path_from_url",
"tags": [],
"reasons": {}
},
{
"tool": "query_nb_sessions",
"tags": [],
"reasons": {}
},
{
"tool": "end_nb_session",
"tags": [],
"reasons": {}
},
{
"tool": "list_nbs",
"tags": [],
"reasons": {}
},
{
"tool": "create_notebook",
"tags": [],
"reasons": {}
},
{
"tool": "get_nb_stat",
"tags": [],
"reasons": {}
},
{
"tool": "read_nb_cells",
"tags": [],
"reasons": {}
},
{
"tool": "modify_nb_cells",
"tags": [],
"reasons": {}
},
{
"tool": "insert_nb_cells",
"tags": [],
"reasons": {}
},
{
"tool": "delete_nb_cells",
"tags": [],
"reasons": {}
},
{
"tool": "execute_nb_cells",
"tags": [],
"reasons": {}
},
{
"tool": "restart_nb_kernel",
"tags": [],
"reasons": {}
},
{
"tool": "list_available_kernels",
"tags": [],
"reasons": {}
},
{
"tool": "assign_nb_kernel",
"tags": [],
"reasons": {}
},
{
"tool": "list_documents",
"tags": [],
"reasons": {}
},
{
"tool": "create_document",
"tags": [],
"reasons": {}
},
{
"tool": "get_document_info",
"tags": [],
"reasons": {}
},
{
"tool": "delete_document",
"tags": [],
"reasons": {}
},
{
"tool": "rename_document",
"tags": [],
"reasons": {}
},
{
"tool": "copy_document",
"tags": [],
"reasons": {}
},
{
"tool": "overwrite_document",
"tags": [
"file-write"
],
"reasons": {
"file-write": [
"keyword \"overwrite\" in tool name"
]
}
},
{
"tool": "get_document_content",
"tags": [],
"reasons": {}
},
{
"tool": "insert_document_text",
"tags": [],
"reasons": {}
},
{
"tool": "delete_document_text",
"tags": [],
"reasons": {}
},
{
"tool": "replace_document_text",
"tags": [],
"reasons": {}
},
{
"tool": "end_document_session",
"tags": [],
"reasons": {}
},
{
"tool": "query_document_session",
"tags": [],
"reasons": {}
}
],
"surfaceDigest": "5da5d54f18bed49171ea6f90f35faae79451f68b4d528a508fd94e673894fc80",
"stats": {
"tools": 28,
"prompts": 0,
"resources": 0,
"findingsBySeverity": {
"critical": 0,
"high": 1,
"medium": 1,
"low": 1,
"info": 0
}
}
}