Guesty — the complete, unedited output of the deterministic mcptrustchecker engine v1.13.0, scanned . Every finding, capability tag and score component below is exactly what the engine produced — no AI, no post-processing.
{
"tool": {
"name": "mcptrustchecker",
"version": "1.13.0",
"methodologyVersion": "mcptrustchecker-1.13"
},
"target": {
"id": "guesty-mcp-server",
"source": {
"kind": "package",
"origin": "guesty-mcp-server"
},
"server": {
"name": "guesty-mcp-server"
}
},
"grade": "A",
"score": {
"score": 96,
"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": "moderate",
"label": "capability blast radius (moderate) — client exposure if the model is manipulated",
"appliedPenalty": 3
},
{
"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-1.13"
},
"capability": {
"level": "moderate",
"reasons": [
"ingests untrusted external content (a prompt-injection entry point)",
"can send data / act on an external service"
],
"tags": [
"untrusted-input",
"external-sink"
]
},
"coverage": {
"level": "source",
"inputs": {
"toolSurface": true,
"implementationSource": true,
"packageMetadata": true,
"liveTransport": false
},
"caveats": [
"Tools were statically extracted from the published source (43 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-FLOW-005",
"title": "Untrusted input can drive an external action",
"category": "exfiltration",
"severity": "medium",
"confidence": "strong",
"description": "Untrusted-input tools ([get_reservations, get_listing, get_conversations, get_financials, get_reviews, get_calendar, get_owner_statements, get_expenses, get_tasks, get_photos, get_guests, get_custom_fields]) co-exist with external-action tools ([create_webhook, delete_webhook]). A prompt injection could cause unwanted external actions, though no direct sensitive-data leak path was found.",
"remediation": "Require confirmation for state-changing/egress actions triggered after processing untrusted content.",
"location": {
"kind": "flow",
"name": "get_reservations → create_webhook"
},
"evidence": "untrusted [get_reservations, get_listing, get_conversations, get_financials, get_reviews, get_calendar, get_owner_statements, get_expenses, get_tasks, get_photo",
"owasp": "LLM06:2025 Excessive Agency",
"references": [],
"data": {
"untrusted": [
"get_reservations",
"get_listing",
"get_conversations",
"get_financials",
"get_reviews",
"get_calendar",
"get_owner_statements",
"get_expenses",
"get_tasks",
"get_photos",
"get_guests",
"get_custom_fields"
],
"sinks": [
"create_webhook",
"delete_webhook"
]
}
},
{
"ruleId": "MTC-SRC-003",
"title": "Hardcoded egress to an external endpoint (src/cli.js)",
"category": "exfiltration",
"severity": "medium",
"confidence": "strong",
"description": "In the server's implementation (`src/cli.js:18`): A hardcoded outbound call to a fixed external host inside server code is a classic exfiltration/telemetry channel — especially paired with reads of local data. 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": "src/cli.js"
},
"evidence": ") { const res = await fetch(\"https://open-api.guesty.com/oauth2/token\", { method: \"POST\", headers: { \"Content-",
"owasp": "LLM02:2025 Sensitive Information Disclosure",
"data": {
"rule": "MTC-SRC-003",
"file": "src/cli.js",
"line": 18,
"nonRuntime": false
}
},
{
"ruleId": "MTC-SRC-003",
"title": "Hardcoded egress to an external endpoint (src/server.js)",
"category": "exfiltration",
"severity": "medium",
"confidence": "strong",
"description": "In the server's implementation (`src/server.js:51`): A hardcoded outbound call to a fixed external host inside server code is a classic exfiltration/telemetry channel — especially paired with reads of local data. 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": "src/server.js"
},
"evidence": "n; const res = await fetch(\"https://open-api.guesty.com/oauth2/token\", { method: \"POST\", headers: { \"Content-",
"owasp": "LLM02:2025 Sensitive Information Disclosure",
"data": {
"rule": "MTC-SRC-003",
"file": "src/server.js",
"line": 51,
"nonRuntime": false
}
}
],
"toxicFlows": [
{
"id": "flow-1",
"severity": "medium",
"confidence": "strong",
"untrustedInput": [
"get_reservations",
"get_listing",
"get_conversations",
"get_financials",
"get_reviews",
"get_calendar",
"get_owner_statements",
"get_expenses",
"get_tasks",
"get_photos",
"get_guests",
"get_custom_fields"
],
"sensitiveSource": [],
"externalSink": [
"create_webhook",
"delete_webhook"
],
"selfContained": false,
"description": "Untrusted input can drive an external action even though no sensitive source is exposed."
}
],
"capabilities": [
{
"tool": "get_property_health",
"tags": [],
"reasons": {}
},
{
"tool": "submit_checkout_photos",
"tags": [],
"reasons": {}
},
{
"tool": "get_maintenance_alerts",
"tags": [],
"reasons": {}
},
{
"tool": "get_readiness_score",
"tags": [],
"reasons": {}
},
{
"tool": "get_reservations",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "get_listing",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "get_conversations",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "send_guest_message",
"tags": [],
"reasons": {}
},
{
"tool": "get_financials",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "update_pricing",
"tags": [],
"reasons": {}
},
{
"tool": "create_reservation",
"tags": [],
"reasons": {}
},
{
"tool": "get_reviews",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "get_calendar",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "update_calendar",
"tags": [],
"reasons": {}
},
{
"tool": "respond_to_review",
"tags": [],
"reasons": {}
},
{
"tool": "get_owner_statements",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "get_expenses",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "get_channels",
"tags": [],
"reasons": {}
},
{
"tool": "get_tasks",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "get_photos",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "update_photos",
"tags": [],
"reasons": {}
},
{
"tool": "get_calendar_blocks",
"tags": [],
"reasons": {}
},
{
"tool": "create_expense",
"tags": [],
"reasons": {}
},
{
"tool": "get_guests",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "get_guest_by_id",
"tags": [],
"reasons": {}
},
{
"tool": "update_listing",
"tags": [],
"reasons": {}
},
{
"tool": "get_automation_rules",
"tags": [],
"reasons": {}
},
{
"tool": "create_task",
"tags": [],
"reasons": {}
},
{
"tool": "update_reservation",
"tags": [],
"reasons": {}
},
{
"tool": "get_supported_languages",
"tags": [],
"reasons": {}
},
{
"tool": "search_reservations",
"tags": [],
"reasons": {}
},
{
"tool": "get_listing_occupancy",
"tags": [],
"reasons": {}
},
{
"tool": "get_revenue_summary",
"tags": [],
"reasons": {}
},
{
"tool": "get_webhooks",
"tags": [],
"reasons": {}
},
{
"tool": "create_webhook",
"tags": [
"external-sink"
],
"reasons": {
"external-sink": [
"keyword \"webhook\""
]
}
},
{
"tool": "delete_webhook",
"tags": [
"external-sink"
],
"reasons": {
"external-sink": [
"keyword \"webhook\""
]
}
},
{
"tool": "get_custom_fields",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "get_account_info",
"tags": [],
"reasons": {}
},
{
"tool": "get_reservation_financials",
"tags": [],
"reasons": {}
},
{
"tool": "create_reservation_note",
"tags": [],
"reasons": {}
},
{
"tool": "get_listing_pricing",
"tags": [],
"reasons": {}
},
{
"tool": "update_listing_pricing",
"tags": [],
"reasons": {}
},
{
"tool": "get_license_info",
"tags": [],
"reasons": {}
}
],
"surfaceDigest": "ffebd68c33ece2a9e444c94e3d0be0efd572bef989c5d5dd666f6f85e91fd415",
"stats": {
"tools": 43,
"prompts": 0,
"resources": 0,
"findingsBySeverity": {
"critical": 0,
"high": 0,
"medium": 3,
"low": 0,
"info": 0
}
}
}