Cmux MCP Server
cmux-mcp
npm
v1.3.1
Published by daegweon — 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.
A Model Context Protocol server that provides access to the currently active tab of cmux
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 − 0 = 100. What the published surface and source actually contain:
The deterministic scan raised no scored threat in the surface it inspected — the threat score stayed at 100. Capability observations and advisory notes are recorded but never lower it.
2. Client adoption risk — 100 − 7 = 93. 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 21
high Tool "write_to_terminal" exposes command/code executionMTC-CAP-001
Tool "write_to_terminal" appears to run shell commands or evaluate code (parameter "command"). 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 write_to_terminal
high Tool "new_workspace" exposes command/code executionMTC-CAP-001
Tool "new_workspace" appears to run shell commands or evaluate code (parameter "command"). 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 new_workspace
high Tool "respawn_pane" exposes command/code executionMTC-CAP-001
Tool "respawn_pane" appears to run shell commands or evaluate code (parameter "command"). 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 respawn_pane
high Tool "pipe_pane" exposes command/code executionMTC-CAP-001
Tool "pipe_pane" appears to run shell commands or evaluate code (parameter "command"). 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 pipe_pane
high Tool "set_hook" exposes command/code executionMTC-CAP-001
Tool "set_hook" appears to run shell commands or evaluate code (parameter "command"). 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 set_hook
high Shell/command execution in server code (build/CommandExecutor.js)MTC-SRC-002
In the server's implementation (`build/CommandExecutor.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: ort { exec } from 'node:child_process'; import { promisify } from 'node:util'; import { openSync, closeSync } from 'node
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/CommandExecutor.js
high Shell/command execution in server code (build/ProcessTracker.js)MTC-SRC-002
In the server's implementation (`build/ProcessTracker.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: import { exec } from 'child_process'; import { promisify } from 'util'; import { existsSync } from 'fs'; import { base
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/ProcessTracker.js
high Shell/command execution in server code (build/SendControlCharacter.js)MTC-SRC-002
In the server's implementation (`build/SendControlCharacter.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: ort { exec } from 'node:child_process'; import { promisify } from 'node:util'; import { CMUX_BIN } from './cmux-path.js'
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/SendControlCharacter.js
high Shell/command execution in server code (build/TtyOutputReader.js)MTC-SRC-002
In the server's implementation (`build/TtyOutputReader.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: ort { exec } from 'node:child_process'; import { promisify } from 'node:util'; import { CMUX_BIN } from './cmux-path.js'
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/TtyOutputReader.js
high Shell/command execution in server code (build/cmux-path.js)MTC-SRC-002
In the server's implementation (`build/cmux-path.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: ecFileSync } from 'node:child_process'; import { existsSync } from 'node:fs'; function resolveCmuxBin() { // 1. Envi
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-path.js
high Shell/command execution in server code (build/index.js)MTC-SRC-002
In the server's implementation (`build/index.js:5`): 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: ort { exec } from 'node:child_process'; import { promisify } from 'node:util'; import CommandExecutor from "./CommandExe
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/index.js
medium Unconstrained command parameter "command" on "write_to_terminal"MTC-CAP-006
Tool "write_to_terminal" takes a command-shaped parameter "command" with no enum/pattern constraint. Free-form, model- or attacker-controlled arguments reaching a shell is the command-injection precondition.
Fix: Constrain the parameter (enum/pattern), or build the command from a fixed template with escaped args.
Location: tool write_to_terminal · inputSchema.properties.command
medium Unconstrained command parameter "command" on "new_workspace"MTC-CAP-006
Tool "new_workspace" takes a command-shaped parameter "command" with no enum/pattern constraint. Free-form, model- or attacker-controlled arguments reaching a shell is the command-injection precondition.
Fix: Constrain the parameter (enum/pattern), or build the command from a fixed template with escaped args.
Location: tool new_workspace · inputSchema.properties.command
medium Unconstrained command parameter "command" on "respawn_pane"MTC-CAP-006
Tool "respawn_pane" takes a command-shaped parameter "command" with no enum/pattern constraint. Free-form, model- or attacker-controlled arguments reaching a shell is the command-injection precondition.
Fix: Constrain the parameter (enum/pattern), or build the command from a fixed template with escaped args.
Location: tool respawn_pane · inputSchema.properties.command
medium Unconstrained command parameter "command" on "pipe_pane"MTC-CAP-006
Tool "pipe_pane" takes a command-shaped parameter "command" with no enum/pattern constraint. Free-form, model- or attacker-controlled arguments reaching a shell is the command-injection precondition.
Fix: Constrain the parameter (enum/pattern), or build the command from a fixed template with escaped args.
Location: tool pipe_pane · inputSchema.properties.command
medium Unconstrained command parameter "command" on "set_hook"MTC-CAP-006
Tool "set_hook" takes a command-shaped parameter "command" with no enum/pattern constraint. Free-form, model- or attacker-controlled arguments reaching a shell is the command-injection precondition.
Fix: Constrain the parameter (enum/pattern), or build the command from a fixed template with escaped args.
Location: tool set_hook · inputSchema.properties.command
low Mutating tool "write_to_terminal" declares no destructiveHintMTC-CAP-005
Tool "write_to_terminal" 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 write_to_terminal
low Mutating tool "new_workspace" declares no destructiveHintMTC-CAP-005
Tool "new_workspace" 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 new_workspace
low Mutating tool "respawn_pane" declares no destructiveHintMTC-CAP-005
Tool "respawn_pane" 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 respawn_pane
low Mutating tool "pipe_pane" declares no destructiveHintMTC-CAP-005
Tool "pipe_pane" 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 pipe_pane
low Mutating tool "set_hook" declares no destructiveHintMTC-CAP-005
Tool "set_hook" 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 set_hook
Tools 72
Each tool and what it can reach — statically extracted from the published source.
new_workspaceruns code / shellpipe_paneruns code / shellrespawn_paneruns code / shellset_hookruns code / shellwrite_to_terminalruns code / shellbreak_paneno sensitive capabilitybrowserno sensitive capabilitycapture_paneno sensitive capabilityclear_historyno sensitive capabilityclear_logno sensitive capability
Show 62 more tools ↓
clear_notificationsno sensitive capabilityclear_progressno sensitive capabilityclear_statusno sensitive capabilityclose_surfaceno sensitive capabilityclose_windowno sensitive capabilityclose_workspaceno sensitive capabilitycurrent_windowno sensitive capabilitycurrent_workspaceno sensitive capabilitydisplay_messageno sensitive capabilitydrag_surface_to_splitno sensitive capabilityfind_windowno sensitive capabilityfocus_paneno sensitive capabilityfocus_panelno sensitive capabilityfocus_surfaceno sensitive capabilityfocus_windowno sensitive capabilityidentifyno sensitive capabilityjoin_paneno sensitive capabilitylast_paneno sensitive capabilitylast_windowno sensitive capabilitylist_buffersno sensitive capabilitylist_logno sensitive capabilitylist_notificationsno sensitive capabilitylist_panelsno sensitive capabilitylist_panesno sensitive capabilitylist_statusno sensitive capabilitylist_surfacesno sensitive capabilitylist_windowsno sensitive capabilitylist_workspacesno sensitive capabilitylogno sensitive capabilitymarkdown_openno sensitive capabilitymove_surfaceno sensitive capabilitymove_workspace_to_windowno sensitive capabilitynew_paneno sensitive capabilitynew_splitno sensitive capabilitynew_surfaceno sensitive capabilitynew_windowno sensitive capabilitynext_windowno sensitive capabilitynotifyno sensitive capabilitypaste_bufferno sensitive capabilitypingno sensitive capabilityprevious_windowno sensitive capabilityread_terminal_outputno sensitive capabilityrefresh_surfacesno sensitive capabilityrename_tabno sensitive capabilityrename_windowno sensitive capabilityrename_workspaceno sensitive capabilityreorder_surfaceno sensitive capabilityreorder_workspaceno sensitive capabilityresize_paneno sensitive capabilityselect_workspaceno sensitive capabilitysend_control_characterno sensitive capabilityset_app_focusno sensitive capabilityset_bufferno sensitive capabilityset_progressno sensitive capabilityset_statusno sensitive capabilitysidebar_stateno sensitive capabilitysurface_healthno sensitive capabilityswap_paneno sensitive capabilitytreeno sensitive capabilitytrigger_flashno sensitive capabilityversionno sensitive capabilitywait_forno sensitive capability
What this scan could not see
- Tools were statically extracted from the published source (72 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 |
|---|---|---|---|---|
v1.3.1 latest |
A 93/100 | 21 | 1.13.0 | 2026-09-09 |
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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