registry / AI-agent control-surface risk / @chemx/create-chemx / 26.9.21-227

@chemx/create-chemx@26.9.21-227

Chemical X Protocol: Private drop-in architecture starter kit and capsule generator

AI Security Review

scanned 11d ago · by lpm-firewall-ai

Source confirms that an npm postinstall automatically writes MCP server configuration into project and user-level AI-agent control surfaces without a consent check. This is concrete install-time control-surface mutation, so the package should be blocked.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

npm postinstall in a consumer project.

Impact

AI agents using those configurations can run the registered Chemical X MCP server.

Mechanism

The lifecycle hook calls the MCP installer, which writes Cursor and VS Code project configuration and can modify existing Antigravity user configuration.

Policy narrative

The package’s postinstall hook invokes the MCP installer for the consumer directory. The installer adds a Chemical X server entry to project-level Cursor and VS Code configuration and also updates an existing global Antigravity configuration. These behavior-bearing AI-agent configuration changes occur during installation without a consent prompt, so the package qualifies as an unconsented install-time agent control-surface mutation.

AI rationale

Evidence

package.jsoncli/postinstall.jscli/mcp/installer.js

Decision evidence

public snapshot

AI identified this as a dangerous AI-agent capability at 98.0% confidence with low false-positive risk.

Evidence for policy risk

package.json runs cli/postinstall.js during postinstall.
The postinstall targets the consumer directory and calls installAllMcpConfigs without a consent check.
The installer writes MCP configuration into project-level Cursor and VS Code files, and also registers Antigravity configuration when its global config directory exists.
The configured MCP server can fall back to running npx chemx mcp.
The wizard’s AGENTS.md and .cursorrules writes occur in its explicit wizard flow; they are separate from the postinstall MCP mutation.

Evidence against

The installer merges a named Chemical X MCP server entry into existing configuration, which is consistent with registering this package’s own tool.
The installer spec checks that the Chemical X server entry is written to Cursor configuration.

Behavioral surface

Source

ChildProcessEnvironmentVarsFilesystemNetworkShell

Supply chain

HighEntropyStrings

Source & flagged code

10 flagged

package.jsonView file

Lines 29-69json

29 "docs",

30 "assets"

31 ],

32 "exports": {

33 ".": "./cli/index.js",

34 "./audit": "./cli/audit.js",

35 "./build": "./cli/build.js",

36 "./search": "./cli/search.js",

37 "./mcp": "./cli/mcp/index.js",

38 "./reader": "./cli/reader.js",

39 "./patcher": "./cli/patcher.js",

40 "./errors": "./cli/errors/index.js"

41 },

42 "scripts": {

43 "chemx": "node cli/index.js",

44 "test": "node --test cli/audit/*.spec.js cli/mcp/*.spec.js cli/build/*.spec.js cli/team/*.spec.js cli/errors/*.spec.js cli/*.spec.js",

45 "check:frameworks": "node scripts/check-framework-generation.mjs",

46 "prepublishOnly": "node scripts/check-framework-generation.mjs",

47 "typecheck": "tsc --noEmit",

48 "publish:both": "node scripts/publish-both.mjs",

49 "postinstall": "node cli/postinstall.js",

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg · L49

Medium

Ambiguous Install Lifecycle Script

Install-time lifecycle script is not statically allowlisted and needs review.

package.jsonView on unpkg · L49

50 "chemx:mcp": "chemx mcp",

51 "chemx:verify": "chemx verify",

52 "chemx:test": "chemx test",

53 "chemx:typecheck": "chemx typecheck"

54 },

55 "dependencies": {

56 "@babel/parser": "^7.29.8",

57 "@babel/traverse": "^7.29.8",

58 "@babel/types": "^7.29.8",

59 "react": "^18.3.1",

60 "react-dom": "^18.3.1"

61 },

62 "devDependencies": {

63 "@types/babel__traverse": "^7.28.0",

64 "@types/node": "^22.20.2",

65 "@types/react": "^18.3.31",

66 "@types/react-dom": "^18.3.7",

67 "chemx": "26.9.20-408",

68 "typescript": "^5.9.3"

69 }

cli/errors/errors.spec.jsView file

Lines 7-47javascript

7 maskSensitiveTokens,

8 normalizeHomePath,

9 sanitizeText,

10 sanitizeStackTrace

11} from './sanitizer.js';

12import {

13 buildIssueTitle,

14 buildIssueBody,

15 buildIssueWebUrl,

16 formatIssueContent

cli/audit-preflight-git.jsView file

Lines 1-21javascript

1import fs from 'node:fs';

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

High

Child Process

Package source references child process execution.

cli/audit-preflight-git.jsView on unpkg · L1

4const SOURCE_FILE_PATTERN = /\.

cli/build/executor.jsView file

Lines 1-31javascript

1import { spawn } from 'node:child_process';

3export const executeBuild = (command, cwd = process.cwd(), options = {})

cli/license.jsView file

Lines 1-23javascript

1import fs from 'node:fs';

2import path from 'node:path';

3import os from 'node:os';

4import { spawnSync } from 'node:child_process';

cli/mcp/installer.jsView file

Lines 1-21javascript

1import fs from 'node:fs';

2import path from 'node:path';

3import os from 'node:os';

4import { syncAntigravityMcpSchemas } from './antigravity.js';

cli/pillars-wizard.jsView file

•Manifest-trigger-reachable source links an external AI-agent control path to a behavior-bearing write operation. st pick = usegum ? gumchoose(choices, 'select architectural pillars configuration') : await promptquestion('select pillars: [1=recommended, 2=strict, 3=custom, 4=minimal, 5=none] (default: 1): '); if (pick && (pick.startswith('2.') || pick === '2')) { selectedpresetkey = 'strict'; selectedpillarids = [...pillar_presets.strict.pillars]; } else if (pick && (pick.startswith('3.') || pick === '3')) { selectedpresetkey = 'custom'; for (const pillar of pillars) { const defaultchoice = pillar_presets.recommended.pillars.includes(pillar.id) ? 'y/n' : 'y/n'; const isdefaultyes = defaultchoice === 'y/n'; const answer = a

High

Trigger Reachable External Ai Agent Control Surface Mutation

Manifest-trigger-reachable source writes behavior-bearing configuration into a user or project AI-agent control surface.

cli/pillars-wizard.jsView on unpkg

scripts/pre-commit.shView file

•path = scripts/pre-commit.sh kind = build_helper sizeBytes = 5174 magicHex = [redacted]

Medium

Ships Build Helper

Package ships non-JavaScript build or shell helper files.

scripts/pre-commit.shView on unpkg

Source & flagged code

10 flagged · loading source

package.jsonView file

•scripts.postinstall = node cli/postinstall.js

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

•scripts.postinstall = node cli/postinstall.js

Medium

Ambiguous Install Lifecycle Script

Install-time lifecycle script is not statically allowlisted and needs review.

package.jsonView on unpkg

cli/errors/errors.spec.jsView file

27patternName = github_pat severity = critical line = 27

Critical

Critical Secret

Package contains a critical-looking secret pattern.

cli/errors/errors.spec.jsView on unpkg · L27

Findings

3 Critical5 High5 Medium5 Low

CriticalCritical Secretcli/errors/errors.spec.js

CriticalAi Agent Control Hijackcli/mcp/installer.js

CriticalSecret Patterncli/errors/errors.spec.js

HighInstall Time Lifecycle Scriptspackage.json

HighChild Processcli/audit-preflight-git.js

HighShellcli/build/executor.js

HighSame File Env Network Executioncli/license.js

HighTrigger Reachable External Ai Agent Control Surface Mutationcli/pillars-wizard.js

MediumAmbiguous Install Lifecycle Scriptpackage.json

MediumNetwork

MediumEnvironment Vars

MediumShips Build Helperscripts/pre-commit.sh

Affected versions and remediation

This report applies to @chemx/create-chemx@26.9.21-227.

See all versions of @chemx/create-chemx for other recorded verdicts.

Avoid installing @chemx/create-chemx@26.9.21-227. Remove it from direct dependencies and check your lockfile for transitive copies.
Choose an independently verified alternative or release. This report does not establish that other versions are safe.
If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.

Evidence last updated: 2026-10-12 06:49:03.340Z (UTC).

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

AI Security Review

Decision evidence

Source & flagged code

Source & flagged code

Findings

Affected versions and remediation

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Behavioral surface

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Source & flagged code