pennyrouter@0.3.38

Install and manage PennyRouter local coding-agent integrations.

AI Security Review

scanned 11d ago · by lpm-firewall-ai

The package has no npm lifecycle hook, but its CLI can configure a first-party MCP integration and Claude statusline for agent use. This is a guarded agent integration capability, not evidence of a confirmed attack, so a warning is appropriate.

Static reason

One or more suspicious static signals were detected.; previous stored version diff introduced dangerous source

Trigger

A user invokes the CLI install flow or launches Claude through PennyRouter.

Impact

The agent gains PennyRouter's MCP capability and Claude displays the managed statusline during use.

Mechanism

The install flow registers a PennyRouter MCP command in agent configuration; Claude launch setup writes a managed statusline and launch settings.

AI rationale

Evidence

src/cli.jssrc/mcp-register.jssrc/launch.jssrc/statusline.jspackage.json

Decision evidence

public snapshot

AI called this Suspicious at 86.0% confidence as Dangerous Capability with medium false-positive risk.

Evidence for warning

package.json exposes a CLI entrypoint and declares no npm lifecycle hook.
The install flow registers an MCP server after routing setup when MCP registration is enabled and dry-run is off.
The managed MCP entry launches PennyRouter's own MCP command and passes harness and optional gateway settings.
Claude launch setup writes a managed statusline script and updates the launch settings.

Evidence against

The integration writes are tied to explicit CLI install or launch flows; no automatic npm install hook was found.
The MCP entry is package-owned and namespaced, and registration code preserves or rejects conflicting user entries.

Behavioral surface

Source

ChildProcessCryptoEnvironmentVarsFilesystemNetworkShellWebSocket

Supply chain

HighEntropyStringsUrlStrings

ManifestNo manifest risk signals triggered.

Source & flagged code

10 flagged

standalone/web-demo/server.mjsView file

Lines 1-23javascript

1import { createServer } from 'node:http';

2import { randomUUID } from 'node:crypto';

3import { mkdtemp, readFile, rm, stat, writeFile } from 'node:fs/promises';

4import { spawn, execFile } from 'node:child_process';

5import { join, dirname, resolve } from 'node:path';

High

Child Process

Package source references child process execution.

standalone/web-demo/server.mjsView on unpkg · L3

6import { homedir, tmpdir } from 'node:os';

7import { fileURLToPath } from 'node:url';

8import { promisify } from 'node:util';

9import { WebSocketServer } from 'ws';

10import pty from 'node-pty';

11import { ClaudeMeter, CodexMeter, saveReport } from './claude-meter.mjs';

13const here = dirname(fileURLToPath(import.meta.url));

14const compareDir = dirname(here);

15const execFileAsync = promisify(execFile);

16const args = process.argv.slice(2);

17const claude = args.includes('--claude');

18const harnessArg = args.find((arg) => /^--harness=(claude|codex)$/.test(arg));

19const startupHarness = harnessArg?.slice('--harness='.length) || 'claude';

20const nodeMeter = args.includes('--compare-node') ||

21 (args.includes('--compare') && process.platform === 'win32');

22const compare = args.includes('--compare') || nodeMeter;

23const pythonCompare = compare && !nodeMeter && process.platform !== 'win32';

Lines 253-290javascript

253 session.onData((data) => send({ type: 'output', side: message.side, data }));

254 session.onExit(({ exitCode }) => {

255 sessions.delete(message.side);

256 send({ type: 'exit', side: message.side, code: exitCode });

src/launch.jsView file

Lines 338-378javascript

338 let replace = false;

339 try {

340 replace = (await lstat(link)).isSymbolicLink();

341 } catch (error) {

342

src/launch.test.jsView file

Lines 1-21javascript

1import assert from "node:assert/strict";

2import { spawnSync } from "node:child_process";

3import fs from "node:fs";

Medium

Install Persistence

Source writes installer persistence such as shell profile or service configuration.

src/launch.test.jsView on unpkg · L1

4import

src/harnesses/codegpt.jsView file

Lines 1-21javascript

1import { spawnSync } from "node:child_process";

High

Sandbox Evasion Gated Capability

Source gates dangerous network, credential, or execution behavior behind CI, host, platform, time, or geo fingerprint checks.

src/harnesses/codegpt.jsView on unpkg · L1

3export const codeGptHarness = {

4 id: "codegpt",

src/statusline.jsView file

•Runtime or CLI code links a write operation to an explicit external AI-agent control path: tatusline (all lines) |] penny segment (penny / penny (sub) // / penny (byok) / penny off). the wrapped statusline's first line gets the penny suffix; // any further lines (e.g. a context bar) pass through verbatim. // never blocks on the network: reads a per-session cache and refreshes it detached. import { readfilesync, mkdirsync, writefilesync, statsync } from "node:fs"; import { spawn, spawnsync } from "node:child_process"; import { join, basename } from "node:path"; import os from "node:os"; const statedir = join( process.env.xdg_state_home || join(os.homedir(), ".local", "state"), "pennyrouter", ); const cachedir = join(statedir, "statusline-cache"); const titlesessionfile = process.env.pe

High

External Ai Agent Control Surface Mutation

Runtime or CLI source writes behavior-bearing configuration into a user or project AI-agent control surface.

src/statusline.jsView on unpkg

standalone/claude-proxy.shView file

•path = standalone/claude-proxy.sh kind = build_helper sizeBytes = 8224 magicHex = [redacted]

Medium

Ships Build Helper

Package ships non-JavaScript build or shell helper files.

standalone/claude-proxy.shView on unpkg

src/mcp-register.js#virtual:normalized:round1View file

•stage = ast_semantic_analysis; reason = ast_parse_error; limitedFiles = 2

High

Semantic Analysis Limited

A bounded semantic-analysis stage reached its safety limit; remaining detectors completed, but this package requires AI review.

src/mcp-register.js#virtual:normalized:round1View on unpkg

src/cli.jsView file

•matchType = previous_version_dangerous_delta matchedPackage = pennyrouter@0.3.17 matchedIdentity = npm:cGVubnlyb3V0ZXI:0.3.17 similarity = 0.710 summary = stored previous version shares package body but lacks this dangerous source file

High

Previous Version Dangerous Delta

This package version adds a dangerous source file absent from the previous stored version; route for source-aware review.

src/cli.jsView on unpkg

Source & flagged code

10 flagged · loading source

standalone/web-demo/server.mjsView file

3import { mkdtemp, readFile, rm, stat, writeFile } from 'node:fs/promises'; L4: import { spawn, execFile } from 'node:child_process'; L5: import { join, dirname, resolve } from 'node:path';

High

Child Process

Package source references child process execution.

standalone/web-demo/server.mjsView on unpkg · L3

273server.listen(port, '127.0.0.1', () => { L274: const url = `http://127.0.0.1:${port}`; L275: console.log(`Penny Compare live terminal demo: ${url}`); ... L279: if (process.platform === 'win32') { L280: execFile(process.env.ComSpec || 'cmd.exe', ['/d', '/s', '/c', `start "" "${url}"`], L281: { windowsHide: true }, (error) => {

High

Same File Env Network Execution

A single source file combines environment access, network access, and code or shell execution; review context before blocking.

standalone/web-demo/server.mjsView on unpkg · L273

src/launch.jsView file

358const body = process.platform === "win32" L359: // `node` and the native harnesses are normally npm .cmd shims on Windows. cmd.exe L360: // resolves those through PATHEXT, while Node's direct spawn does not.

Findings

8 High5 Medium4 Low

HighChild Processstandalone/web-demo/server.mjs

HighShellsrc/launch.js

HighSame File Env Network Executionstandalone/web-demo/server.mjs

HighSandbox Evasion Gated Capabilitysrc/harnesses/codegpt.js

HighExternal Ai Agent Control Surface Mutationsrc/statusline.js

HighTrigger Reachable External Ai Agent Control Surface Mutationsrc/launch.js

HighSemantic Analysis Limitedsrc/mcp-register.js#virtual:normalized:round1

HighPrevious Version Dangerous Deltasrc/cli.js

MediumNetwork

MediumEnvironment Vars

MediumInstall Persistencesrc/launch.test.js

MediumShips Build Helperstandalone/claude-proxy.sh

Affected versions and remediation

This report applies to pennyrouter@0.3.38.

See all versions of pennyrouter for other recorded verdicts.

Review the evidence and your use of pennyrouter@0.3.38 before allowing it. Restrict the permissions described in this report.
Choose an independently verified alternative or release. This report does not establish that other versions are safe.

Evidence last updated: 2026-10-11 19:05:14.282Z (UTC).

Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.