Simple Mail Sender — the complete, unedited output of the deterministic mcptrustchecker engine v1.8.0, scanned . Every finding, capability tag and score component below is exactly what the engine produced — no AI, no post-processing.
{
"tool": {
"name": "mcptrustchecker",
"version": "1.8.0",
"methodologyVersion": "mcptrustchecker-1.8"
},
"target": {
"id": "mcp-simple-mail-sender",
"source": {
"kind": "package",
"origin": "mcp-simple-mail-sender"
},
"server": {
"name": "mcp-simple-mail-sender"
}
},
"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-1.8"
},
"capability": {
"level": "high",
"reasons": [
"can send data / act on an external service",
"reads sensitive or local data",
"has a read → egress path (a data-exfiltration surface)"
],
"tags": [
"external-sink",
"sensitive-source"
]
},
"coverage": {
"level": "source",
"inputs": {
"toolSurface": true,
"implementationSource": true,
"packageMetadata": true,
"liveTransport": false
},
"caveats": [
"Tools were statically extracted from the published source (4 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-003",
"title": "Read-and-egress in one tool: \"send_email\"",
"category": "exfiltration",
"severity": "high",
"confidence": "strong",
"description": "Tool \"send_email\" can both read sensitive data and send data to an external destination. Even without an explicit untrusted-input leg, this is a single-call data-exfiltration path if the model is ever manipulated.",
"remediation": "Separate reading from sending; require explicit user confirmation before egress of file/secret contents.",
"location": {
"kind": "flow",
"name": "send_email"
},
"owasp": "LLM02:2025 Sensitive Information Disclosure",
"references": [],
"data": {
"tags": [
"external-sink",
"sensitive-source"
]
}
},
{
"ruleId": "MTC-FLOW-004",
"title": "Sensitive-source and external-sink co-exist",
"category": "exfiltration",
"severity": "high",
"confidence": "strong",
"description": "Tools that read sensitive data ([send_email]) and tools that can send data out ([send_email, send_email_json_arg, send_email_flat_args]) are exposed together. An agent can move private data to the sink.",
"remediation": "Keep secret-reading and egress capabilities on separate, separately-approved servers.",
"location": {
"kind": "flow",
"name": "send_email → send_email_json_arg"
},
"evidence": "sources [send_email] → sinks [send_email, send_email_json_arg, send_email_flat_args]",
"owasp": "LLM02:2025 Sensitive Information Disclosure",
"references": [],
"data": {
"sources": [
"send_email"
],
"sinks": [
"send_email",
"send_email_json_arg",
"send_email_flat_args"
]
}
},
{
"ruleId": "MTC-CAP-008",
"title": "Unconstrained path parameter \"filename\" on \"send_email\"",
"category": "permissions",
"severity": "low",
"confidence": "heuristic",
"description": "Tool \"send_email\" takes a path parameter \"filename\" with no constraint. Without a canonicalize-and-contain check (not visible statically), this permits ../ traversal outside the intended root.",
"remediation": "Resolve and verify the path stays within an allowed root; reject traversal sequences.",
"location": {
"kind": "tool",
"name": "send_email",
"field": "inputSchema.properties.filename"
},
"data": {
"param": "filename"
}
}
],
"toxicFlows": [
{
"id": "flow-1",
"severity": "high",
"confidence": "strong",
"untrustedInput": [],
"sensitiveSource": [
"send_email"
],
"externalSink": [
"send_email"
],
"selfContained": true,
"description": "Tool \"send_email\" both reads sensitive data and can send it externally."
},
{
"id": "flow-2",
"severity": "high",
"confidence": "strong",
"untrustedInput": [],
"sensitiveSource": [
"send_email"
],
"externalSink": [
"send_email",
"send_email_json_arg",
"send_email_flat_args"
],
"selfContained": false,
"path": [
"send_email",
"send_email_flat_args"
],
"pathWired": true,
"description": "A sensitive-source → external-sink chain exists: send_email ⇒ send_email_flat_args."
}
],
"capabilities": [
{
"tool": "mcp-simple-mail-sender",
"tags": [],
"reasons": {}
},
{
"tool": "send_email",
"tags": [
"external-sink",
"sensitive-source"
],
"reasons": {
"external-sink": [
"keyword \"send_email\""
],
"sensitive-source": [
"parameter \"filename\""
]
}
},
{
"tool": "send_email_json_arg",
"tags": [
"external-sink"
],
"reasons": {
"external-sink": [
"keyword \"send_email\""
]
}
},
{
"tool": "send_email_flat_args",
"tags": [
"external-sink"
],
"reasons": {
"external-sink": [
"keyword \"send_email\""
]
}
}
],
"surfaceDigest": "6dd482aef21544cfa4eb2918b1c1ea89be57495d15fa0353992b81ddfd2b065a",
"stats": {
"tools": 4,
"prompts": 0,
"resources": 0,
"findingsBySeverity": {
"critical": 0,
"high": 2,
"medium": 0,
"low": 1,
"info": 0
}
}
}