Cmux Agent — 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": "cmux-agent-mcp",
"source": {
"kind": "package",
"origin": "cmux-agent-mcp"
},
"server": {
"name": "cmux-agent-mcp"
}
},
"grade": "B",
"score": {
"score": 86,
"threatScore": 93,
"grade": "B",
"band": "B",
"categorySubtotals": {
"injection": 6.3,
"exfiltration": 0,
"permissions": 0,
"supply-chain": 1.2,
"network": 0,
"hygiene": 0
},
"vector": [
{
"kind": "threat",
"ruleId": "MTC-SRC-009",
"category": "injection",
"severity": "medium",
"confidence": "strong",
"rawWeight": 9,
"confidenceMult": 0.7,
"diminishingFactor": 1,
"appliedPenalty": 6.3
},
{
"kind": "threat",
"ruleId": "MTC-SUP-010",
"category": "supply-chain",
"severity": "low",
"confidence": "heuristic",
"rawWeight": 3,
"confidenceMult": 0.4,
"diminishingFactor": 1,
"appliedPenalty": 1.2
},
{
"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": [
"can execute shell commands or code"
],
"tags": [
"code-exec"
]
},
"coverage": {
"level": "source",
"inputs": {
"toolSurface": true,
"implementationSource": true,
"packageMetadata": true,
"liveTransport": false
},
"caveats": [
"Tools were statically extracted from the published source (63 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 \"cmux_browser_eval\" exposes command/code execution",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "Tool \"cmux_browser_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": "cmux_browser_eval"
},
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"tags": [
"code-exec"
]
}
},
{
"ruleId": "MTC-SRC-002",
"title": "Shell/command execution in server code (build/cmux-mcp.js)",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "In the server's implementation (`build/cmux-mcp.js:9`): 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": "build/cmux-mcp.js"
},
"evidence": ", execSync } from 'node:child_process'; import { existsSync, mkdirSync, readFileSync, readdirSync, renameSync, statSync,",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-002",
"file": "build/cmux-mcp.js",
"line": 9,
"nonRuntime": false
}
},
{
"ruleId": "MTC-SRC-002",
"title": "Shell/command execution in server code (build/init.js)",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "In the server's implementation (`build/init.js:1`): 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": "build/init.js"
},
"evidence": "{ execSync } from 'node:child_process'; import { existsSync, mkdirSync, readFileSync, writeFileSync } from 'node:fs'; im",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-002",
"file": "build/init.js",
"line": 1,
"nonRuntime": false
}
},
{
"ruleId": "MTC-SRC-009",
"title": "Untrusted input concatenated into a command sink (build/init.js)",
"category": "injection",
"severity": "medium",
"confidence": "strong",
"description": "In the server's implementation (`build/init.js:45`): A shell/process command assembled from concatenated or interpolated values is command injection when any part is attacker-influenced — the OWASP canonical RCE flow. Verify what reaches the interpolated value. 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": "build/init.js"
},
"evidence": "ry { return execSync(`eval echo ~${sudoUser}`, { encoding: 'utf8', timeout: 3000 }).trim(); }",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-009",
"file": "build/init.js",
"line": 45,
"nonRuntime": false
}
},
{
"ruleId": "MTC-CAP-005",
"title": "Mutating tool \"cmux_browser_eval\" declares no destructiveHint",
"category": "hygiene",
"severity": "low",
"confidence": "heuristic",
"description": "Tool \"cmux_browser_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": "cmux_browser_eval"
},
"data": {
"tags": [
"code-exec"
]
}
},
{
"ruleId": "MTC-SUP-010",
"title": "Package runs install-time scripts (postinstall)",
"category": "supply-chain",
"severity": "low",
"confidence": "heuristic",
"description": "\"cmux-agent-mcp\" executes postinstall script(s) at install time. An install hook runs at install time; most are routine build/setup, but review what it does before trusting it.",
"remediation": "Review the scripts; install with --ignore-scripts where possible and vet what they do.",
"location": {
"kind": "package",
"name": "cmux-agent-mcp"
},
"evidence": "node build/postinstall.js",
"owasp": "LLM03:2025 Supply Chain",
"references": [
"https://github.com/ossf/package-analysis",
"https://owasp.org/www-project-top-10-ci-cd-security-risks/"
],
"data": {
"scripts": [
"postinstall"
]
}
}
],
"toxicFlows": [],
"capabilities": [
{
"tool": "cmux_status",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_tree",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_identify",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_find",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_current_workspace",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_new_workspace",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_select_workspace",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_close_workspace",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_list_windows",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_current_window",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_new_window",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_focus_window",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_close_window",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_new_surface",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_close_surface",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_move_surface",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_reorder_surface",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_reorder_workspace",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_move_workspace_to_window",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_drag_surface_to_split",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_list_panes",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_list_panels",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_new_split",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_new_pane",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_focus_pane",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_resize_pane",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_swap_pane",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_break_pane",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_join_pane",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_respawn_pane",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_send",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_send_submit",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_send_key",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_send_panel",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_read_screen",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_capture_pane",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_list_status",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_sidebar_state",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_list_notifications",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_clear_notifications",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_open",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_navigate",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_snapshot",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_screenshot",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_eval",
"tags": [
"code-exec"
],
"reasons": {
"code-exec": [
"keyword \"eval\" in tool name"
]
}
},
{
"tool": "cmux_browser_click",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_fill",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_type",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_wait",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_get",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_tab",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_browser_console",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_workspace_snapshot",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_send_submit_some",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_send_key_all",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_read_all_deep",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_start",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_close_all",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_screenshot",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_batch",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_session_save",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_session_recover",
"tags": [],
"reasons": {}
},
{
"tool": "cmux_session_reconcile",
"tags": [],
"reasons": {}
}
],
"surfaceDigest": "5aea6e04a2edf7890b274367a80409010f2b196feca6d40e9400a54218949b70",
"stats": {
"tools": 63,
"prompts": 0,
"resources": 0,
"findingsBySeverity": {
"critical": 0,
"high": 3,
"medium": 1,
"low": 2,
"info": 0
}
}
}