Cmux Agent MCP Server
cmux-agent-mcp
npm
v0.1.2
Published by multiagentcognition — no publish provenance, so origin is unverified, but the source is public: the repository link below is self-declared yet readable, so you can inspect the code before adopting it.
CMUX MCP Server — programmable terminal control plane for multi-agent AI workflows
The grade answers one question — how safe is this server for you to adopt — so it is computed in two auditable stages. Nothing below is an opinion or an LLM's guess; every line is a real term the deterministic engine applied, and the same input always yields the same number.
1. Threat score — 100 − 7.5 = 93. What the published surface and source actually contain:
| Points | What was found | Category |
|---|---|---|
| −6.3 | Untrusted input concatenated into a command sink MTC-SRC-009 | injection |
| −1.2 | Package runs install-time scripts MTC-SUP-010 | supply-chain |
2. Client adoption risk — 93 − 7 = 86. Three small, subtract-only factors that reflect your risk in adopting it — a clean scan proves less on a powerful, unverified or barely-inspectable package, so the grade says so plainly:
| Points | Adoption-risk factor |
|---|---|
| −6 | capability blast radius (high) — client exposure if the model is manipulated |
| −1 | publisher verification (public source) — no provenance, but the source is public and inspectable |
Capability observations and info notes are shown under Findings but never scored.
Open any row's finding below for the file, line and evidence behind a deduction.
Findings 6
high Tool "cmux_browser_eval" exposes command/code executionMTC-CAP-001
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.
Fix: Sandbox execution, allowlist commands/arguments, and never pass model output to a shell unescaped.
Location: tool cmux_browser_eval
high Shell/command execution in server code (build/cmux-mcp.js)MTC-SRC-002
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.
Evidence: , execSync } from 'node:child_process'; import { existsSync, mkdirSync, readFileSync, readdirSync, renameSync, statSync,
Fix: 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: server build/cmux-mcp.js
high Shell/command execution in server code (build/init.js)MTC-SRC-002
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.
Evidence: { execSync } from 'node:child_process'; import { existsSync, mkdirSync, readFileSync, writeFileSync } from 'node:fs'; im
Fix: 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: server build/init.js
medium Untrusted input concatenated into a command sink (build/init.js)MTC-SRC-009
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.
Evidence: ry { return execSync(`eval echo ~${sudoUser}`, { encoding: 'utf8', timeout: 3000 }).trim(); }
Fix: 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: server build/init.js
low Mutating tool "cmux_browser_eval" declares no destructiveHintMTC-CAP-005
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.
Fix: Declare accurate annotations, and gate destructive tools on user confirmation regardless.
Location: tool cmux_browser_eval
low Package runs install-time scripts (postinstall)MTC-SUP-010
"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.
Evidence: node build/postinstall.js
Fix: Review the scripts; install with --ignore-scripts where possible and vet what they do.
Location: package cmux-agent-mcp
Tools 63
Each tool and what it can reach — statically extracted from the published source.
cmux_browser_evalruns code / shellcmux_batchno sensitive capabilitycmux_break_paneno sensitive capabilitycmux_browser_clickno sensitive capabilitycmux_browser_consoleno sensitive capabilitycmux_browser_fillno sensitive capabilitycmux_browser_getno sensitive capabilitycmux_browser_navigateno sensitive capabilitycmux_browser_openno sensitive capabilitycmux_browser_screenshotno sensitive capability
Show 53 more tools ↓
cmux_browser_snapshotno sensitive capabilitycmux_browser_tabno sensitive capabilitycmux_browser_typeno sensitive capabilitycmux_browser_waitno sensitive capabilitycmux_capture_paneno sensitive capabilitycmux_clear_notificationsno sensitive capabilitycmux_close_allno sensitive capabilitycmux_close_surfaceno sensitive capabilitycmux_close_windowno sensitive capabilitycmux_close_workspaceno sensitive capabilitycmux_current_windowno sensitive capabilitycmux_current_workspaceno sensitive capabilitycmux_drag_surface_to_splitno sensitive capabilitycmux_findno sensitive capabilitycmux_focus_paneno sensitive capabilitycmux_focus_windowno sensitive capabilitycmux_identifyno sensitive capabilitycmux_join_paneno sensitive capabilitycmux_list_notificationsno sensitive capabilitycmux_list_panelsno sensitive capabilitycmux_list_panesno sensitive capabilitycmux_list_statusno sensitive capabilitycmux_list_windowsno sensitive capabilitycmux_move_surfaceno sensitive capabilitycmux_move_workspace_to_windowno sensitive capabilitycmux_new_paneno sensitive capabilitycmux_new_splitno sensitive capabilitycmux_new_surfaceno sensitive capabilitycmux_new_windowno sensitive capabilitycmux_new_workspaceno sensitive capabilitycmux_read_all_deepno sensitive capabilitycmux_read_screenno sensitive capabilitycmux_reorder_surfaceno sensitive capabilitycmux_reorder_workspaceno sensitive capabilitycmux_resize_paneno sensitive capabilitycmux_respawn_paneno sensitive capabilitycmux_screenshotno sensitive capabilitycmux_select_workspaceno sensitive capabilitycmux_sendno sensitive capabilitycmux_send_keyno sensitive capabilitycmux_send_key_allno sensitive capabilitycmux_send_panelno sensitive capabilitycmux_send_submitno sensitive capabilitycmux_send_submit_someno sensitive capabilitycmux_session_reconcileno sensitive capabilitycmux_session_recoverno sensitive capabilitycmux_session_saveno sensitive capabilitycmux_sidebar_stateno sensitive capabilitycmux_startno sensitive capabilitycmux_statusno sensitive capabilitycmux_swap_paneno sensitive capabilitycmux_treeno sensitive capabilitycmux_workspace_snapshotno sensitive capability
What this scan could not see
- 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>".
Versions 1
Scan history per published version. The engine is deterministic — the same version always yields the same score, so a changed score means the package itself changed.
| Version | Score | Findings | Engine | Scanned |
|---|---|---|---|---|
v0.1.2 latest |
B 86/100 | 6 | 1.13.0 | 2026-09-07 |
Embed this score
Show this server's live Trust Score in your README, docs or website. The badge is served straight from the registry and updates automatically after every rescan — no API key needed. It links back to this page, so anyone who sees the grade can also read the findings behind it instead of taking a number on faith.
Verify this score yourself
The score above is reproducible: the same package version always yields the same result. Run it locally or over the free API — no account, no LLM, fully deterministic.
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