Skills/PyPI/refract-mcp

refract-mcp@0.7.0

VERIFIED· not started

Publisher claims: "MCP proxy that compresses tool schemas — up to -98% tokens, 100% signal preserved" Observed in sandbox: no network, touches nothing outside the project, writes no memory.

Registry PyPI (MCP server)Publisher pypi · publishing for 724 daysInstalls 73Last detonated 1 h ago
$claude mcp add refract-mcp -- uvx refract-mcp
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Coverage

Not started: dependency install failed; the server itself was not observed.
Tested
the dependency install step · every file read, file written and host contacted by what ran
Not tested
server startup · the tool list · tool behavior

What this means for the label: Verified here covers what ran. The server's tools were not exercised with a real credential, so nothing about their behavior is asserted; the credential summary below says what to do with that.

Before you give it your token

It will ask for
no credential variables read in the code
Where it talks to
no vendor host named in the codeAlso my-mcp-server.com, my-server.com — not the publisher's domain; check what for before connecting.
What the honeypot saw
no credential files read · no network
What we could not test
server startup · the tool list · tool behavior

Connect it under the guard. Not started: dependency install failed; the server itself was not observed. The code names no credential variable; the guard pins the network to what the honeypot saw and logs every call.

$vet-skills run --net declared -- uvx refract-mcp

Never paste a credential into a chat, a ticket or a report, including ours. How the guard holds it.

Is [email protected] safe to install?

KillerSkills ran it in the KillerSkills honeypot sandbox (2 scenarios; not started: dependency install failed; the server itself was not observed) on 2026-11-15 and scored it 87/100 (Verified). In what ran, nothing we could detect went wrong: no undeclared network egress, no credential reads, no persistent instruction writes. What it does with a real credential was not observed; the static findings and the publisher carry the rest of the score. Summary: no network, touches nothing outside the project, writes no memory.

Behavior trace

Honeypot run · 0 s · 2 scenarios · 0 deviations
t+CategoryObserved action
0.0sprocessno install scripts in bundle
0.2sprocessdependency install exit 1 ·
0.2sclaimednot started: dependency install failed (exit 1); the server itself was not observed
0.2sprocessscript backend runs setup only
0.2sprocessno install scripts to re-run

Static findings

MEDIUM
npx invocation of non-well-known packagetests/test_cli.py:70 · npx invocation of non-well-known package — may execute untrusted code"--stdio-cmd", "npx @mcp/server /tmp",Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagetests/test_http_transport.py:142 · npx invocation of non-well-known package — may execute untrusted codeclient = _TargetClient("npx mcp-server", transport="stdio")Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagetests/test_sse_transport.py:67 · npx invocation of non-well-known package — may execute untrusted codeparser.parse_args(["--url", "https://x.com", "--stdio-cmd", "npx server"])Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
MCP server using network transport (SSE/HTTP)src/refract_cli.py:11 · MCP server using network transport (SSE/HTTP) — data sent over networkrefract-proxy --target https://my-mcp-server.com/sse --transport sseFix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
MCP server using network transport (SSE/HTTP)src/refract_cli.py:10 · MCP server using network transport (SSE/HTTP) — data sent over networkrefract-proxy --url https://my-mcp-server.com/sse --mode stdioFix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
npx invocation of non-well-known packagetests/test_install.py:113 · npx invocation of non-well-known package — may execute untrusted codeassert entry["args"] == ["--stdio-cmd", "npx my-server --flag"]Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Destructive file system command detectedtests/test_security_surface.py:129 · Destructive file system command detected"import os\n\n\ndef wipe():\n os.system('rm -rf /')\n",Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Destructive command against a filesystem root or devicetests/test_security_surface.py:129 · Destructive command against a filesystem root or device"import os\n\n\ndef wipe():\n os.system('rm -rf /')\n",Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
npx invocation of non-well-known packagetests/test_http_transport.py:114 · npx invocation of non-well-known package — may execute untrusted codeargs = parser.parse_args(["--stdio-cmd", "npx mcp-server", "--transport", "stdio"])Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Python subprocess execution detectedtests/test_extractor.py:79 · Python subprocess execution detectedresult = subprocess.run(Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
Python subprocess execution detectedtests/test_refract_status.py:307 · Python subprocess execution detectedsrc = "import subprocess\n\ndef run(cmd):\n subprocess.run(cmd)\n"Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
npx invocation of non-well-known packagetests/test_cli.py:81 · npx invocation of non-well-known package — may execute untrusted codeparser.parse_args(["--target", "https://x.com", "--stdio-cmd", "npx x"])Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Python subprocess execution detectedtests/test_extractor.py:158 · Python subprocess execution detectedresult = subprocess.run(Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
npx invocation of non-well-known packagetests/test_http_transport.py:119 · npx invocation of non-well-known package — may execute untrusted codeargs = parser.parse_args(["--stdio-cmd", "npx mcp-server"])Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
MCP server using network transport (SSE/HTTP)tests/test_http_transport.py:428 · MCP server using network transport (SSE/HTTP) — data sent over networkmain(["--stdio-cmd", "npx mcp-server", "--transport", "http"])Fix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
OS command execution function call detectedtests/test_security_surface.py:129 · OS command execution function call detected"import os\n\n\ndef wipe():\n os.system('rm -rf /')\n",Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
npx invocation of non-well-known packagesrc/refract_cli.py:55 · npx invocation of non-well-known package — may execute untrusted code"or stdio command (\"npx @mcp/server /path\"). "Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
MCP server using network transport (SSE/HTTP)src/refract_cli.py:74 · MCP server using network transport (SSE/HTTP) — data sent over network"Ex: https://my-mcp-server.com/sse"Fix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
npx invocation of non-well-known packagetests/test_cli.py:73 · npx invocation of non-well-known package — may execute untrusted codeassert args.target == "npx @mcp/server /tmp"Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagetests/test_http_transport.py:103 · npx invocation of non-well-known package — may execute untrusted codeargs = parser.parse_args(["--stdio-cmd", "npx mcp-server", "--transport", "sse"])Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagetests/test_proxy.py:243 · npx invocation of non-well-known package — may execute untrusted codeproxy = RefractProxy("npx @mcp/server /tmp")Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagesrc/refract_proxy.py:193 · npx invocation of non-well-known package — may execute untrusted code# Known stdio executables (e.g. "npx @mcp/server-fs /tmp")Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagetests/test_http_transport.py:428 · npx invocation of non-well-known package — may execute untrusted codemain(["--stdio-cmd", "npx mcp-server", "--transport", "http"])Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
MCP server using network transport (SSE/HTTP)src/refract_cli.py:14 · MCP server using network transport (SSE/HTTP) — data sent over networkrefract-proxy --target "https://my-mcp-server.com/mcp" --transport httpFix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
MCP server using network transport (SSE/HTTP)tests/test_http_transport.py:103 · MCP server using network transport (SSE/HTTP) — data sent over networkargs = parser.parse_args(["--stdio-cmd", "npx mcp-server", "--transport", "sse"])Fix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
Python subprocess execution detectedtests/test_security_surface.py:37 · Python subprocess execution detectedreturn subprocess.run(cmd, shell=True)Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
npx invocation of non-well-known packagetests/test_install.py:105 · npx invocation of non-well-known package — may execute untrusted codeanswers = iter(["3", "npx my-server --flag"])Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Python subprocess execution detectedtests/test_refract_status.py:174 · Python subprocess execution detectedsubprocess.run(cmd)Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
MCP server using network transport (SSE/HTTP)src/refract_cli.py:17 · MCP server using network transport (SSE/HTTP) — data sent over networkrefract-proxy --target "https://my-mcp-server.com/mcp" --transport http --mode http --port 8080Fix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
npx invocation of non-well-known packagetests/test_sse_transport.py:203 · npx invocation of non-well-known package — may execute untrusted codec = _TargetClient("npx @mcp/server /tmp", transport="sse")Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Python subprocess execution detectedtests/test_refract_status.py:139 · Python subprocess execution detectedreturn subprocess.run(cmd, shell=True)Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
npx invocation of non-well-known packagetests/test_sse_transport.py:268 · npx invocation of non-well-known package — may execute untrusted codec = _TargetClient("npx @mcp/server", transport="sse")Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagetests/test_sse_transport.py:219 · npx invocation of non-well-known package — may execute untrusted codec = _TargetClient("npx @mcp/server /tmp")Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagetests/test_sse_transport.py:248 · npx invocation of non-well-known package — may execute untrusted codec = _TargetClient("npx @mcp/server", transport="sse")Fix: Pin versions and sources; vendor anything fetched at install time.
AST06

Cost to the agent

Instructions loaded
≈56 tok
1 file · 37 in bundle
Tool list per prompt
≈0 tok
0 tools · 0 per tool
Handshake
no reply
launch to tools/list, stdio
Undocumented tools
0
description under 20 chars · avg 0

Tokens estimated at four characters each. The tool list is re-read by the agent on every turn, so it is the number to compare between servers that do the same job: ranked across the index.

Known vulnerabilities

Not checked against OSV yet; the weekly check has not reached this version.