Langflow Builder — the complete, unedited output of the deterministic mcptrustchecker engine v1.7.0, scanned . Every finding, capability tag and score component below is exactly what the engine produced — no AI, no post-processing.
{
"tool": {
"name": "mcptrustchecker",
"version": "1.7.0",
"methodologyVersion": "mcptrustchecker-1.7"
},
"target": {
"id": "langflow-builder-mcp",
"source": {
"kind": "package",
"origin": "langflow-builder-mcp"
},
"server": {
"name": "langflow-builder-mcp"
}
},
"grade": "B",
"score": {
"score": 85,
"threatScore": 96,
"grade": "B",
"band": "B",
"categorySubtotals": {
"injection": 4.5,
"exfiltration": 0,
"permissions": 0,
"supply-chain": 0,
"network": 0,
"hygiene": 0
},
"vector": [
{
"kind": "threat",
"ruleId": "MTC-INJ-AUTH-1",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"rawWeight": 3,
"confidenceMult": 0.4,
"diminishingFactor": 1,
"appliedPenalty": 1.2
},
{
"kind": "threat",
"ruleId": "MTC-INJ-AUTH-1",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"rawWeight": 3,
"confidenceMult": 0.4,
"diminishingFactor": 0.5,
"appliedPenalty": 0.6
},
{
"kind": "threat",
"ruleId": "MTC-INJ-AUTH-1",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"rawWeight": 3,
"confidenceMult": 0.4,
"diminishingFactor": 0.25,
"appliedPenalty": 0.3
},
{
"kind": "threat",
"ruleId": "MTC-INJ-CAPS",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"rawWeight": 3,
"confidenceMult": 0.4,
"diminishingFactor": 1,
"appliedPenalty": 1.2
},
{
"kind": "threat",
"ruleId": "MTC-INJ-SEQ-2",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"rawWeight": 3,
"confidenceMult": 0.4,
"diminishingFactor": 1,
"appliedPenalty": 1.2
},
{
"kind": "client",
"term": "capability-exposure",
"level": "critical",
"label": "capability blast radius (critical) — client exposure if the model is manipulated",
"appliedPenalty": 10
},
{
"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-1.7"
},
"capability": {
"level": "critical",
"reasons": [
"ingests untrusted external content (a prompt-injection entry point)",
"reads sensitive or local data",
"has a read → egress path (a data-exfiltration surface)",
"can execute shell commands or code",
"untrusted input can reach code execution"
],
"tags": [
"untrusted-input",
"sensitive-source",
"code-exec"
]
},
"coverage": {
"level": "source",
"inputs": {
"toolSurface": true,
"implementationSource": true,
"packageMetadata": true,
"liveTransport": false
},
"caveats": [
"Tools were statically extracted from the published source (37 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-002",
"title": "Shell/command execution in server code (src/langflow_builder_mcp/source_repo.py)",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "In the server's implementation (`src/langflow_builder_mcp/source_repo.py:43`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. 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/langflow_builder_mcp/source_repo.py"
},
"evidence": "subprocess.run(",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-002",
"file": "src/langflow_builder_mcp/source_repo.py",
"line": 43
}
},
{
"ruleId": "MTC-INJ-AUTH-1",
"title": "Authority framing in tool metadata",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"description": "Authority framing in tool metadata detected in the description of tool \"update_node\". Instruction-like content in tool metadata is executed by the model, not the human, and is the primary tool-poisoning vector.",
"remediation": "Tool descriptions should describe behavior, not instruct the assistant. Treat imperative / secrecy / sequencing language in metadata as hostile.",
"location": {
"kind": "tool",
"name": "update_node",
"field": "description"
},
"evidence": "IMPORTANT",
"owasp": "LLM01:2025 Prompt Injection",
"data": {
"kind": "authority"
}
},
{
"ruleId": "MTC-INJ-AUTH-1",
"title": "Authority framing in tool metadata",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"description": "Authority framing in tool metadata detected in the description of tool \"set_tool_mode\". Instruction-like content in tool metadata is executed by the model, not the human, and is the primary tool-poisoning vector.",
"remediation": "Tool descriptions should describe behavior, not instruct the assistant. Treat imperative / secrecy / sequencing language in metadata as hostile.",
"location": {
"kind": "tool",
"name": "set_tool_mode",
"field": "description"
},
"evidence": "IMPORTANT",
"owasp": "LLM01:2025 Prompt Injection",
"data": {
"kind": "authority"
}
},
{
"ruleId": "MTC-INJ-AUTH-1",
"title": "Authority framing in tool metadata",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"description": "Authority framing in tool metadata detected in the description of tool \"langflow_concepts\". Instruction-like content in tool metadata is executed by the model, not the human, and is the primary tool-poisoning vector.",
"remediation": "Tool descriptions should describe behavior, not instruct the assistant. Treat imperative / secrecy / sequencing language in metadata as hostile.",
"location": {
"kind": "tool",
"name": "langflow_concepts",
"field": "description"
},
"evidence": "IMPORTANT",
"owasp": "LLM01:2025 Prompt Injection",
"data": {
"kind": "authority"
}
},
{
"ruleId": "MTC-INJ-CAPS",
"title": "Excessive ALL-CAPS emphasis in metadata",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"description": "A run of shouted words is a common way to give injected instructions false authority.",
"location": {
"kind": "tool",
"name": "langflow_concepts",
"field": "description"
},
"evidence": "Get quick reference information about Langflow concepts.\n\n READ THIS FIRST before creating custom components or makin"
},
{
"ruleId": "MTC-INJ-SEQ-2",
"title": "Conditional behavior directive",
"category": "injection",
"severity": "low",
"confidence": "heuristic",
"description": "Conditional behavior directive detected in the description of tool \"list_flows\". Instruction-like content in tool metadata is executed by the model, not the human, and is the primary tool-poisoning vector.",
"remediation": "Tool descriptions should describe behavior, not instruct the assistant. Treat imperative / secrecy / sequencing language in metadata as hostile.",
"location": {
"kind": "tool",
"name": "list_flows",
"field": "description"
},
"evidence": "When call",
"owasp": "LLM01:2025 Prompt Injection",
"data": {
"kind": "sequencing"
}
},
{
"ruleId": "MTC-SUP-012",
"title": "Package has no license",
"category": "hygiene",
"severity": "info",
"confidence": "strong",
"description": "\"langflow-builder-mcp\" has no declared license. This is a legal/reuse concern, not a security finding.",
"location": {
"kind": "package",
"name": "langflow-builder-mcp"
}
}
],
"toxicFlows": [],
"capabilities": [
{
"tool": "list_component_categories",
"tags": [],
"reasons": {}
},
{
"tool": "list_components",
"tags": [],
"reasons": {}
},
{
"tool": "get_component_schema",
"tags": [],
"reasons": {}
},
{
"tool": "search_components",
"tags": [],
"reasons": {}
},
{
"tool": "list_flows",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "list_all_flows",
"tags": [],
"reasons": {}
},
{
"tool": "get_flow",
"tags": [],
"reasons": {}
},
{
"tool": "create_flow",
"tags": [],
"reasons": {}
},
{
"tool": "delete_flow",
"tags": [],
"reasons": {}
},
{
"tool": "duplicate_flow",
"tags": [],
"reasons": {}
},
{
"tool": "build_flow",
"tags": [],
"reasons": {}
},
{
"tool": "build_node",
"tags": [],
"reasons": {}
},
{
"tool": "get_build_status",
"tags": [],
"reasons": {}
},
{
"tool": "add_node",
"tags": [],
"reasons": {}
},
{
"tool": "add_custom_component",
"tags": [],
"reasons": {}
},
{
"tool": "update_node",
"tags": [],
"reasons": {}
},
{
"tool": "set_tool_mode",
"tags": [],
"reasons": {}
},
{
"tool": "remove_node",
"tags": [],
"reasons": {}
},
{
"tool": "get_node_details",
"tags": [],
"reasons": {}
},
{
"tool": "list_nodes",
"tags": [],
"reasons": {}
},
{
"tool": "move_node",
"tags": [],
"reasons": {}
},
{
"tool": "add_note",
"tags": [],
"reasons": {}
},
{
"tool": "update_note",
"tags": [],
"reasons": {}
},
{
"tool": "analyze_flow_layout",
"tags": [],
"reasons": {}
},
{
"tool": "auto_arrange_flow",
"tags": [],
"reasons": {}
},
{
"tool": "move_nodes_batch",
"tags": [],
"reasons": {}
},
{
"tool": "get_layout_suggestions",
"tags": [],
"reasons": {}
},
{
"tool": "connect_nodes",
"tags": [],
"reasons": {}
},
{
"tool": "disconnect_nodes",
"tags": [],
"reasons": {}
},
{
"tool": "list_connections",
"tags": [],
"reasons": {}
},
{
"tool": "validate_connection",
"tags": [],
"reasons": {}
},
{
"tool": "find_compatible_connections",
"tags": [],
"reasons": {}
},
{
"tool": "setup_langflow_source",
"tags": [],
"reasons": {}
},
{
"tool": "explore_langflow",
"tags": [],
"reasons": {}
},
{
"tool": "read_langflow_file",
"tags": [],
"reasons": {}
},
{
"tool": "list_langflow_directory",
"tags": [
"sensitive-source"
],
"reasons": {
"sensitive-source": [
"keyword \"list_files\""
]
}
},
{
"tool": "langflow_concepts",
"tags": [],
"reasons": {}
}
],
"surfaceDigest": "315f0611256ecb0edc545d183ff43d33b146f8d1a2201d5e7dc2e922364b878c",
"stats": {
"tools": 37,
"prompts": 0,
"resources": 0,
"findingsBySeverity": {
"critical": 0,
"high": 1,
"medium": 0,
"low": 5,
"info": 1
}
}
}