Foxbridge — 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": "foxbridge-mcp",
"source": {
"kind": "package",
"origin": "foxbridge-mcp"
},
"server": {
"name": "foxbridge-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-1.13"
},
"capability": {
"level": "high",
"reasons": [
"ingests untrusted external content (a prompt-injection entry point)",
"can execute shell commands or code"
],
"tags": [
"code-exec",
"untrusted-input"
]
},
"coverage": {
"level": "source",
"inputs": {
"toolSurface": true,
"implementationSource": true,
"packageMetadata": true,
"liveTransport": false
},
"caveats": [
"Tools were statically extracted from the published source (52 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-CAP-001",
"title": "Tool \"eval_js\" exposes command/code execution",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "Tool \"eval_js\" appears to run shell commands or evaluate code (keyword \"eval\" in tool name). Arbitrary execution driven by model input is one of the most dangerous MCP capabilities; combined with any untrusted input it becomes RCE.",
"remediation": "Sandbox execution, allowlist commands/arguments, and never pass model output to a shell unescaped.",
"location": {
"kind": "tool",
"name": "eval_js"
},
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"tags": [
"code-exec"
]
}
},
{
"ruleId": "MTC-CAP-001",
"title": "Tool \"ff_eval\" exposes command/code execution",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "Tool \"ff_eval\" appears to run shell commands or evaluate code (keyword \"eval\" in tool name). Arbitrary execution driven by model input is one of the most dangerous MCP capabilities; combined with any untrusted input it becomes RCE.",
"remediation": "Sandbox execution, allowlist commands/arguments, and never pass model output to a shell unescaped.",
"location": {
"kind": "tool",
"name": "ff_eval"
},
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"tags": [
"code-exec"
]
}
},
{
"ruleId": "MTC-SRC-001",
"title": "Dynamic code execution in server code (dist/driver.js)",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "In the server's implementation (`dist/driver.js:275`): 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": "dist/driver.js"
},
"evidence": "const fn = new Function(`return (async () => { ${src.includes(\"return\") ? src : \"return (\" + src + \")\"} })(",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-001",
"file": "dist/driver.js",
"line": 275,
"nonRuntime": false
}
},
{
"ruleId": "MTC-SRC-002",
"title": "Shell/command execution in server code (extension/background.js)",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "In the server's implementation (`extension/background.js:54`): 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": "extension/background.js"
},
"evidence": "origin). async function exec(tabId, code) { try { const res = await browser.tabs.executeScript(tabId, { code });",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-002",
"file": "extension/background.js",
"line": 54,
"nonRuntime": false
}
},
{
"ruleId": "MTC-FLOW-005",
"title": "Untrusted input can drive an external action",
"category": "exfiltration",
"severity": "medium",
"confidence": "strong",
"description": "Untrusted-input tools ([ff_fetch, ff_download]) co-exist with external-action tools ([eval_js, ff_eval]). 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": "ff_fetch → eval_js"
},
"evidence": "untrusted [ff_fetch, ff_download] → sinks [eval_js, ff_eval]",
"owasp": "LLM06:2025 Excessive Agency",
"references": [],
"data": {
"untrusted": [
"ff_fetch",
"ff_download"
],
"sinks": [
"eval_js",
"ff_eval"
]
}
},
{
"ruleId": "MTC-CAP-005",
"title": "Mutating tool \"eval_js\" declares no destructiveHint",
"category": "hygiene",
"severity": "low",
"confidence": "heuristic",
"description": "Tool \"eval_js\" 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": "eval_js"
},
"data": {
"tags": [
"code-exec"
]
}
},
{
"ruleId": "MTC-CAP-005",
"title": "Mutating tool \"ff_eval\" declares no destructiveHint",
"category": "hygiene",
"severity": "low",
"confidence": "heuristic",
"description": "Tool \"ff_eval\" 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": "ff_eval"
},
"data": {
"tags": [
"code-exec"
]
}
}
],
"toxicFlows": [
{
"id": "flow-1",
"severity": "medium",
"confidence": "strong",
"untrustedInput": [
"ff_fetch",
"ff_download"
],
"sensitiveSource": [],
"externalSink": [
"eval_js",
"ff_eval"
],
"selfContained": false,
"description": "Untrusted input can drive an external action even though no sensitive source is exposed."
}
],
"capabilities": [
{
"tool": "list_profiles",
"tags": [],
"reasons": {}
},
{
"tool": "get_cookies",
"tags": [],
"reasons": {}
},
{
"tool": "get_history",
"tags": [],
"reasons": {}
},
{
"tool": "get_bookmarks",
"tags": [],
"reasons": {}
},
{
"tool": "get_sessions",
"tags": [],
"reasons": {}
},
{
"tool": "get_local_storage",
"tags": [],
"reasons": {}
},
{
"tool": "get_cache_info",
"tags": [],
"reasons": {}
},
{
"tool": "clear_disk_cache",
"tags": [],
"reasons": {}
},
{
"tool": "browser_start",
"tags": [],
"reasons": {}
},
{
"tool": "list_tabs",
"tags": [],
"reasons": {}
},
{
"tool": "open_tab",
"tags": [],
"reasons": {}
},
{
"tool": "switch_tab",
"tags": [],
"reasons": {}
},
{
"tool": "close_tab",
"tags": [],
"reasons": {}
},
{
"tool": "navigate",
"tags": [],
"reasons": {}
},
{
"tool": "reload",
"tags": [],
"reasons": {}
},
{
"tool": "go_back",
"tags": [],
"reasons": {}
},
{
"tool": "go_forward",
"tags": [],
"reasons": {}
},
{
"tool": "click",
"tags": [],
"reasons": {}
},
{
"tool": "type_text",
"tags": [],
"reasons": {}
},
{
"tool": "press_key",
"tags": [],
"reasons": {}
},
{
"tool": "select_option",
"tags": [],
"reasons": {}
},
{
"tool": "hover",
"tags": [],
"reasons": {}
},
{
"tool": "scroll",
"tags": [],
"reasons": {}
},
{
"tool": "wait_for",
"tags": [],
"reasons": {}
},
{
"tool": "read_page",
"tags": [],
"reasons": {}
},
{
"tool": "eval_js",
"tags": [
"code-exec"
],
"reasons": {
"code-exec": [
"keyword \"eval\" in tool name"
]
}
},
{
"tool": "screenshot",
"tags": [],
"reasons": {}
},
{
"tool": "get_live_cookies",
"tags": [],
"reasons": {}
},
{
"tool": "set_cookie",
"tags": [],
"reasons": {}
},
{
"tool": "clear_cookies",
"tags": [],
"reasons": {}
},
{
"tool": "clear_web_storage",
"tags": [],
"reasons": {}
},
{
"tool": "close_browser",
"tags": [],
"reasons": {}
},
{
"tool": "ff_status",
"tags": [],
"reasons": {}
},
{
"tool": "ff_list_tabs",
"tags": [],
"reasons": {}
},
{
"tool": "ff_open_tab",
"tags": [],
"reasons": {}
},
{
"tool": "ff_activate_tab",
"tags": [],
"reasons": {}
},
{
"tool": "ff_close_tab",
"tags": [],
"reasons": {}
},
{
"tool": "ff_navigate",
"tags": [],
"reasons": {}
},
{
"tool": "ff_reload",
"tags": [],
"reasons": {}
},
{
"tool": "ff_read_page",
"tags": [],
"reasons": {}
},
{
"tool": "ff_click",
"tags": [],
"reasons": {}
},
{
"tool": "ff_type",
"tags": [],
"reasons": {}
},
{
"tool": "ff_scroll",
"tags": [],
"reasons": {}
},
{
"tool": "ff_wait_for",
"tags": [],
"reasons": {}
},
{
"tool": "ff_eval",
"tags": [
"code-exec"
],
"reasons": {
"code-exec": [
"keyword \"eval\" in tool name"
]
}
},
{
"tool": "ff_fetch",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "ff_download",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"download\""
]
}
},
{
"tool": "ff_list_downloads",
"tags": [],
"reasons": {}
},
{
"tool": "ff_network",
"tags": [],
"reasons": {}
},
{
"tool": "ff_clear_network",
"tags": [],
"reasons": {}
},
{
"tool": "ff_get_cookies",
"tags": [],
"reasons": {}
},
{
"tool": "ff_screenshot",
"tags": [],
"reasons": {}
}
],
"surfaceDigest": "a3f69e1a9e0a35b8f6125fced547e15ed2efbbe134e9e59511992f1af9078915",
"stats": {
"tools": 52,
"prompts": 0,
"resources": 0,
"findingsBySeverity": {
"critical": 0,
"high": 4,
"medium": 1,
"low": 2,
"info": 0
}
}
}