Skills/PyPI/openconstraint-mcp

openconstraint-mcp@0.3.1

CAUTION· not started

Publisher claims: "Local-first MCP server for constraint solving with MiniZinc and OR-Tools CP-SAT" Observed in sandbox: no network, touches nothing outside the project, writes no memory.

Registry PyPI (MCP server)Publisher openconstraint · publishing for 93 daysInstalls 200Last detonated 17 h ago
What would fix thisWatchDispute verdict

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: Caution 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 code
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 openconstraint-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 2026-11-13 and scored it 78/100 (Caution). It is not known to be malicious, but it has behaviour or code a security policy should decide on before install. Notable findings: README directs the reader to a committed installer. 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
Process kill commandsrc/openconstraint_mcp/pyexec/core.py:6 · Process kill command — agent can terminate processesSecurity posture: timeout + output cap + process-tree kill is a **robustness**Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/protocol_text/descriptions.py:1076 · Process kill command — agent can terminate processes"a conservative per-child timeout/kill overhead — exceeds a fixed cap; "Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/pyexec/core.py:702 · Process kill command — agent can terminate processesrejected up front rather than spawning a child only to kill it immediately.Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
CRITICAL
README directs the reader to a committed installerREADME.md:497`setup-win64.exe` run silently (`setup.exe /S /D=<runtime>`) into the managedFix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Process kill commandsrc/openconstraint_mcp/pyexec/core.py:676 · Process kill command — agent can terminate processes# intermediate result block survive a timeout kill (see the partialFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/protocol_text/descriptions.py:815 · Process kill command — agent can terminate processes"execution contract, output cap, timeout, and tree-kill as "Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Python subprocess execution detectedsrc/openconstraint_mcp/minizinc/core.py:153 · Python subprocess execution detectedcompleted = subprocess.run(Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/shared/childproc.py:48 · Process kill command — agent can terminate processes"""Track ``proc`` until it finishes; if teardown already ran, kill it now.Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/shared/childrun.py:3 · Process kill command — agent can terminate processesThe shared timeout / output-cap / process-tree-kill run loop, used by everyFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/schemas/minizinc.py:378 · Process kill command — agent can terminate processesan output-cap tree-kill with no MUS in the capped transcript (the kill'sFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Python subprocess execution detectedsrc/openconstraint_mcp/runtime_install/archive.py:176 · Python subprocess execution detectedresult = subprocess.run(cmd, capture_output=True, text=True, check=False)Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/shared/proc.py:1 · Process kill command — agent can terminate processes"""Shared process-group launch and tree-kill primitives.Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Python subprocess execution detectedsrc/openconstraint_mcp/runtime_install/archive.py:195 · Python subprocess execution detectedresult = subprocess.run(cmd, capture_output=True, text=True, check=False)Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/schemas/minizinc.py:244 · Process kill command — agent can terminate processes# while a cap tree-kill surfaces as `error` (deliberate fail-closed: theFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/shared/childrun.py:266 · Process kill command — agent can terminate processes# (a second kill here would double the teardown grace for anFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/shared/childproc.py:55 · Process kill command — agent can terminate processes``cancel_requested``. The kill runs outside the lock so a slow tree-killFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Python subprocess execution detectedsrc/openconstraint_mcp/runtime_install/archive.py:127 · Python subprocess execution detectedproc = subprocess.Popen(command, stdout=sink, stderr=subprocess.STDOUT, text=True)Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
Python subprocess execution detectedsrc/openconstraint_mcp/shared/proc.py:65 · Python subprocess execution detectedreturn subprocess.Popen(Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/shared/childproc.py:96 · Process kill command — agent can terminate processesterminates outside the lock so a slow tree-kill cannot block a worker threadFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/shared/childrun.py:237 · Process kill command — agent can terminate processes# transient tree-kill error, and the job registry's cancel hook canFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/shared/proc.py:173 · Process kill command — agent can terminate processes# orphaned solver children — so the tree kill must run FIRST, not as a post-waitFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/pyexec/core.py:980 · Process kill command — agent can terminate processes``(script_timeout_ms + tree-kill grace) + (checker_timeout_ms + tree-kill grace)``,Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Python subprocess execution detectedsrc/openconstraint_mcp/runtime_install/archive.py:249 · 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
Process kill commandsrc/openconstraint_mcp/shared/childrun.py:162 · Process kill command — agent can terminate processestree-kill run loop and returns the raw process result; protocol parsing is theFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/shared/job_registry.py:208 · Process kill command — agent can terminate processesA hard server kill bypasses this — acceptable for a local, non-persistent v1.Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Python subprocess execution detectedsrc/openconstraint_mcp/shared/proc.py:176 · Python subprocess execution detectedsubprocess.run(Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
Python subprocess execution detectedsrc/openconstraint_mcp/runtime_install/core.py:55 · Python subprocess execution detectedcompleted = subprocess.run(Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
MEDIUM
Process kill commandsrc/openconstraint_mcp/runtime_install/archive.py:76 · Process kill command — agent can terminate processes"""Best-effort kill of the installer process *tree*.Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Python subprocess execution detectedsrc/openconstraint_mcp/runtime_install/archive.py:86 · Python subprocess execution detectedsubprocess.run(Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05

Cost to the agent

Instructions loaded
≈59 tok
1 file · 73 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

No advisories in OSV for openconstraint-mcp@0.3.1 as of 17 h ago. This is the package itself, not its dependencies.

What would make this Verified

2 points to 80 · weights: behavior 45%, static 25%, prompt 15%, publisher 15%
  1. README directs the reader to a committed installer≈ +9 on the totalPin versions and sources; vendor anything fetched at install time.
  2. Unclaimed publisher≈ +8 on the totalClaim openconstraint: a verified publisher gets +50 on publisher trust. It is free and usually instant with GitHub sign-in.
  3. Process kill command≈ +2 on the totalBuild commands from fixed arguments; do not interpolate untrusted strings into a shell.
  4. Python subprocess execution detected≈ +2 on the totalBuild commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
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