registry / AI-agent control-surface risk / @chemx/starter-kit / 26.9.17-606

@chemx/starter-kit@26.9.17-606

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

AI Security Review

scanned 11d ago · by lpm-firewall-ai

The active postinstall hook performs an unconsented mutation of consumer AI-agent control configuration, including project-level MCP settings and an existing global Antigravity configuration. This meets the policy for blocking install-time agent control-surface hijacking.

Static reason

High-risk behavior combination matched malicious policy.; previous stored version diff introduced dangerous source

Trigger

Installing the package through npm, which runs its postinstall hook.

Impact

Supported AI agents can discover and start the added MCP server from their configuration without a separate user-invoked setup command.

Mechanism

The hook invokes an installer that writes or merges MCP server entries into Cursor and VS Code project configuration and Antigravity’s global configuration; the fallback server command uses `npx -y chemx mcp`.

Policy narrative

During npm installation, the postinstall hook configures MCP servers in consumer agent configuration. The installer writes Cursor and VS Code project configuration and, if its configuration directory exists, Antigravity’s global configuration. The configuration can cause an agent to start the Chemical X MCP server without a separate setup command.

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

The package manifest runs `cli/postinstall.js` automatically during installation.
The postinstall hook targets the installing project and calls the MCP configuration installer without a consent check.
The installer creates or updates project MCP configuration and adds a `chemical-x` server entry; it also updates Antigravity’s global configuration when that directory exists.
Without a local server, the configured command uses `npx -y chemx mcp`, allowing supported agents to start the server from their MCP configuration.

Evidence against

The package also exposes an explicit `install-mcp` command, but the separate postinstall path performs configuration without requiring that command.

Behavioral surface

Source

ChildProcessEnvironmentVarsFilesystemNetworkShell

Supply chain

HighEntropyStringsUrlStrings

ManifestNo manifest risk signals triggered.

Source & flagged code

10 flagged

package.jsonView file

Lines 37-76json

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

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

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

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

41 "./patcher": "./cli/patcher.js"

42 },

43 "scripts": {

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

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

46 "check": "node cli/index.js verify",

47 "test": "node --test cli/audit/*.spec.js cli/mcp/*.spec.js cli/*.spec.js",

48 "typecheck": "tsc --noEmit",

49 "create-capsule": "node cli/index.js",

50 "audit": "node cli/index.js audit",

51 "ci:audit": "node cli/index.js audit --ci --dir=cli",

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

53 "q": "chemx search",

54 "search": "chemx search",

55 "mcp": "node cli/index.js mcp",

56 "install-mcp": "node cli/index.js install-mcp",

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

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg · L57

Medium

Ambiguous Install Lifecycle Script

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

package.jsonView on unpkg · L57

58 "read": "node cli/index.js read",

59 "patch": "node cli/index.js patch"

60 },

61 "dependencies": {

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

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

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

65 "react": "^18.3.1",

66 "react-dom": "^18.3.1"

67 },

68 "devDependencies": {

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

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

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

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

73 "typescript": "^5.9.3"

74 }

75}

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/terminal.jsView file

Lines 1-30javascript

1import readline from "node:readline";

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

3import { formatChemicalXGradient, ANSI } from "./theme.js";

5export const openBrowser

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/scaffold.jsView file

•Runtime or CLI code links a write operation to an explicit external AI-agent control path: udes('--no-interactive') || boolean(process.env.ci) || process.stdout?.istty === false || process.stdin?.istty === false || boolean(process.argv?.some((arg) => arg === '--headless' || arg === '--ci' || arg === '--yes' || arg === '-y')); if (isheadless) { targetname = 'my-molecular-app'; } else { targetname = hasgum() ? guminput('project directory name:', 'my-molecular-app') : await promptquestion('project directory name [my-molecular-app]: '); } } const finaldirname = targetname.trim() || 'my-molecular-app'; const targetdir = path.resolve(process.cwd(), finaldirname); const direxists = fs.existssync(targetdir); const isdirno

High

External Ai Agent Control Surface Mutation

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

cli/scaffold.jsView on unpkg

•Manifest-trigger-reachable source links an external AI-agent control path to a behavior-bearing write operation. s = {}; if (!licensekey) { process.stdout.write( '\n\x1b[38;2;98;201;255m⚡ chemical x: community edition (free)\x1b[0m\n' + 'the community version is free because you tell us about your project\n' + 'and the app will automatically post your scorecard to our github discussions.\n' + 'you get a free plug, we get data to prove chemical x works and brings real value.\n' + 'everybody wins! thank you for supporting our community version.\n\n' ); files = loadlocalblueprintfiles(); iscommunity = true; } else { files = await fetchstarterkitfiles(licensekey); } let targetname = projectname; if (!targetname) { const isheadle

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.

scripts/pre-commit.shView file

•path = scripts/pre-commit.sh kind = build_helper sizeBytes = 5175 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/audit-preflight-git.jsView file

1import fs from 'node:fs'; L2: import { spawnSync } from 'node:child_process'; L3:

High

Child Process

Package source references child process execution.

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

Findings

1 Critical7 High5 Medium4 Low

CriticalAi Agent Control Hijackcli/mcp/installer.js

HighInstall Time Lifecycle Scriptspackage.json

HighChild Processcli/audit-preflight-git.js

HighShellcli/terminal.js

HighSame File Env Network Executioncli/license.js

HighExternal Ai Agent Control Surface Mutationcli/scaffold.js

HighTrigger Reachable External Ai Agent Control Surface Mutationcli/scaffold.js

HighPrevious Version Dangerous Deltacli/license.js

MediumAmbiguous Install Lifecycle Scriptpackage.json

MediumNetwork

MediumEnvironment Vars

MediumShips Build Helperscripts/pre-commit.sh

Affected versions and remediation

This report applies to @chemx/starter-kit@26.9.17-606.

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

Avoid installing @chemx/starter-kit@26.9.17-606. 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 06:19:35.522Z (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

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Behavioral surface

Related packages

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Other AI-agent control-surface risk packages

Source & flagged code