Parselbox MCP server

by thesanjeetc·io.github.thesanjeetc/parselbox·v0.1.1·3 stars

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Secure Python sandbox — MCP servers, APIs, shells and host functions as native Python objects.

B80/100grade B

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Safety scan

B80/100

full report

Adoption

Growing

3 stars18 downloads/wk

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If you have run it, two minutes of your experience saves the next person an afternoon.

Parselbox tools

No tool declarations could be read from the package source. They show once the server is installed.

Public scan report

scanner v0.1.10 · 2026-10-30 · same rubric, same numbers if you re-run it

1 medium

Code scan26 source files scanned20/25
–Live reliabilityno gateway calls yet and no remote to proben/a
–Tool poisoningtools not inspected (local package is not executed); not countedn/a
Auth qualitylocal package, no credentials required12/15
Maintenancelast push 33 days ago12/15
Maintainer identityregistry namespace matches repository owner; GitHub account older than a year8/10

Findings (1)

mediumeval / new Function usedexec.eval

parselbox-0.1.1/parselbox/sandbox/setup.ts: … = Object.keys(scope); const fn = new Function( ...keys, `"use strict";…

Overall 80/100. Components that don't apply are left out of the denominator. Any critical finding is an F.Rubric Appeal a finding JSON

How Parselbox compares

Against every graded MCP server, from our own scans and uptime checks. Updated after each scan run.

Safety score: 80/100; higher than 60% of 48,255 servers
GitHub stars: 3; more than 80% of 28,688 servers
Downloads a week: 18; more than 5% of 12,191 servers with a package

Install Parselbox in Claude Code, Cursor or VS Code

claude mcp add parselbox -- uvx parselbox

Add to Cursor

What the publisher says

From the Parselbox repository's README, as published. We do not edit it. Read it on GitHub

Code. Filesystem. Context. Tools.

What if agents had one tool to rule them all?

Parselbox is an embeddable Python runtime where AI agents call tools as code — MCP servers, APIs, and shells become native Python objects. Disk-backed workspace, packages, and networking built in; a single-process execution layer powered by Deno and Pyodide.

https://github.com/user-attachments/assets/d4e43d16-3aa3-4e29-83c7-a1d3885b8045

[!TIP]

Drop the Parselbox MCP alongside existing MCP server configurations. Agents instantly get a Python runtime, MCP tools as code, support for skills and a disk-backed workspace.

Why Parselbox?

Parselbox packages programmatic tool calling as a local, open-source execution layer. Drop it into an existing MCP configuration with uvx, or embed the Python API into any agent stack.

Beyond code execution, Parselbox provides a stateful, disk-backed workspace with packages, controlled networking, background tasks and progressive discovery.

Deno + Pyodide provide a single-process runtime with explicit filesystem and network permissions — no containers or microVMs required. It also enables JavaScript/npm interoperability, WASM/WASI integration and generative UI through MCP Apps.

Why an execution layer?

Most agent stacks expose each capability as a separate tool. As integrations grow, tool schemas consume more context. The model must also carry intermediate results, transform data and route values between calls.

An execution layer moves orchestration out of the context window and into code. Capabilities are discovered on demand, then composed with full control flow. A single execution can coordinate multiple tools while variables, state and files remain inside the runtime.

The result is less context bloat, fewer model-to-tool round trips and complex workflows expressed as code rather than chains of individual calls.

Features

🔒 Secure Isolation

No containers, no VMs — just a single, lightweight Deno + Pyodide process (~160 MB). Deno permissions, memory caps, timeouts, network allowlists. Snapshot caching and crash recovery.

🛠️ Tools as Code

MCP servers, REST + OpenAPI, GraphQL, shell, functions and classes — all native Python objects. Stateful across calls. Pydantic auto-conversion. Credentials stay on the host.

🐍 Polyglot Runtime

Full CPython with js() interop — use JS packages as native Python. require() for npm, local TypeScript, and .wasm modules. Virtual bash() for shell. Auto-install packages on import.

📦 WASM Tools

require() any .wasm — library exports become Python methods, WASI programs become callable commands; drop one in bin/ to run it from bash() too. In-process, inherits the sandbox's mounts and permissions, installs nothing on the host.

⚡ Background Tasks

Append .task() to any call — parallel fan-out with asyncio.gather, check progress, tail logs, drive interactive sessions with send(), await later.

Shortened. The full README is on GitHub.

Nothing above is checked by us. What we check is on the safety report.

Grade history

2026-10-30downgradeA → Bscore 80: eval / new Function used

Parselbox: common questions

Is Parselbox MCP server safe?: Mostly: it is graded B (80/100). Read the Parselbox safety report
How do I install Parselbox?: It runs on your machine. Copy the Claude Code, Cursor, VS Code or Claude Desktop config from the install section.
Does Parselbox need an API key?: Not as far as the registry entry and our scan can tell: no credentials are declared or required.
Is Parselbox maintained?: The last commit was 37 days ago (2026-09-27). The latest release is v0.1.1.
How does Parselbox compare with other MCP servers?: safety score 80/100 (higher than 60% of 48,255 servers); github stars 3 (more than 80% of 28,688 servers); downloads a week 18 (more than 5% of 12,191 servers with a package). Full comparison.