registry / AI-agent control-surface risk / create-chemx / 26.9.26-253

create-chemx@26.9.26-253

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

AI Security Review

scanned 11d ago · by lpm-firewall-ai

The manifest-triggered postinstall calls an installer that writes agent MCP configuration into the consumer project without a consent guard. This is an unconsented install-time AI-agent control-surface mutation, so it warrants blocking.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

A consumer installs the package through npm and its postinstall hook runs.

Impact

Cursor, VS Code, and possibly Antigravity agents can invoke the package’s MCP server; when no local server is found, the configuration uses an npm execution fallback.

Mechanism

The hook targets the installation project and writes merged MCP server configuration to .cursor/mcp.json and .vscode/mcp.json. If Antigravity is configured, it also updates its global MCP configuration.

Policy narrative

The postinstall hook automatically modifies project agent configuration to register the package’s MCP server. This gives supported agents a newly configured command surface without an explicit setup action; an npm execution fallback is used when no local server is found.

AI rationale

Evidence

package.jsoncli/postinstall.jscli/mcp/installer.js.cursor/mcp.json.vscode/mcp.json~/.gemini/config/mcp_config.json

Decision evidence

public snapshot

AI identified this as a dangerous AI-agent capability at 95.0% confidence with low false-positive risk.

Evidence for policy risk

The package manifest runs a postinstall script that invokes the package’s installer.
The postinstall script targets the install-time project directory and calls the MCP configuration installer without a consent check.
That installer writes MCP server configuration into the project’s Cursor and VS Code configuration files, using a local package command or an npm execution fallback.
The installer also has code to append agent directives to AGENTS.md; a separate wizard writes AGENTS.md and .cursorrules when pillars are selected.
The installer test confirms that project MCP configuration and helper scripts are added to a consumer package.

Evidence against

The Antigravity global configuration is changed only when its configuration directory already exists.
The separate pillars wizard writes agent files only when pillars are selected and the operation is not a dry run.

Behavioral surface

Source

ChildProcessEnvironmentVarsFilesystemNetworkShell

Source & flagged code

11 flagged

package.jsonView file

Lines 33-73json

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 "bench": "node benchmarks/run-benchmark.mjs",

45 "ui": "node cli/index.js ui",

46 "dev:ui": "node cli/index.js ui --dev",

47 "dev:ui:watch": "node --watch --watch-path=cli cli/index.js ui --dev",

48 "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",

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

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

51 "typecheck": "tsc --noEmit",

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

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

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg · L53

Medium

Ambiguous Install Lifecycle Script

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

package.jsonView on unpkg · L53

54 "chemx:mcp": "chemx mcp",

55 "chemx:verify": "chemx verify",

56 "chemx:test": "chemx test",

57 "chemx:typecheck": "chemx typecheck"

58 },

59 "dependencies": {

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

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

62 "@babel/types": "^7.29.8"

63 },

64 "devDependencies": {

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

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

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

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

69 "chemx": "26.9.20-408",

70 "react": "^18.3.1",

71 "react-dom": "^18.3.1",

72 "typescript": "^5.9.3"

73 }

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 = 5153 magicHex = [redacted]

Medium

Ships Build Helper

Package ships non-JavaScript build or shell helper files.

scripts/pre-commit.shView on unpkg

cli/verify-lint.js#virtual:normalized:round1View file

•stage = ast_semantic_analysis; reason = ast_parse_error; limitedFiles = 1

High

Semantic Analysis Limited

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

cli/verify-lint.js#virtual:normalized:round1View on unpkg

Source & flagged code

11 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 Critical6 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

HighSemantic Analysis Limitedcli/verify-lint.js#virtual:normalized:round1

MediumAmbiguous Install Lifecycle Scriptpackage.json

MediumNetwork

Medium

Affected versions and remediation

This report applies to create-chemx@26.9.26-253.

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

Avoid installing create-chemx@26.9.26-253. 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 08:14:28.136Z (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

Related packages

Other AI-agent control-surface risk packages

Behavioral surface

Related packages

Other AI-agent control-surface risk packages

Source & flagged code