halfcycle@0.3.24
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AI Security Review
scanned 28d ago · by lpm-firewall-aiThe package has a real, package-owned agent setup capability that writes Claude hooks and settings when its CLI flow is run, so a warning is appropriate. The manifest points to CLI and library entrypoints, and inspected evidence supports explicit setup rather than npm lifecycle mutation or a confirmed attack.
Static reason
No blocking static signals were detected.
Trigger
A user runs the Halfcycle CLI setup flow in a project.
Impact
Setup can add or update project-level agent configuration and hook behavior; no evidence inspected showed an unconsented npm install trigger or malicious payload.
Mechanism
The CLI invokes the installer, whose write paths are constrained by an allowlist that includes Claude hooks and settings.
AI rationale
The package has a real, package-owned agent setup capability that writes Claude hooks and settings when its CLI flow is run, so a warning is appropriate. The manifest points to CLI and library entrypoints, and inspected evidence supports explicit setup rather than npm lifecycle mutation or a confirmed attack.
Evidence
dist/bin.jsdist/index.js
Decision evidence
public snapshotAI called this Suspicious at 82.0% confidence as Dangerous Capability with medium false-positive risk.
Evidence for warning
- The package exposes a CLI and library entrypoint, with no npm install lifecycle hook in its manifest.
- The CLI has an allowlist for writes to Claude hooks, settings, and Halfcycle project files.
- The CLI calls the installer after creating or joining an engagement.
- The credential declaration describes a Claude hook that loads engagement credentials into the runner environment.
- The library uses the same bounded write allowlist.
- The bundled executable invokes Git with specified arguments and a working directory.
Evidence against
- The agent configuration writes are part of the package’s explicit CLI setup flow; no unconsented npm lifecycle mutation was identified.
- No source evidence inspected established credential theft, unrelated data exfiltration, or remote code execution.
Behavioral surface
ChildProcessCryptoEnvironmentVarsFilesystemNetworkShell
Source & flagged code
6 flaggedbin/bin.bundle.mjsView file
15328// dist/git.js
L15329: import { spawnSync } from "node:child_process";
L15330: import { readFileSync } from "node:fs";
High
Child Process
Package source references child process execution.
bin/bin.bundle.mjsView on unpkg · L15328dist/bin.jsView file
1826var MCP_HEADERS_HELPER_REL = ".halfcycle/mcp-headers.sh";
L1827: var MCP_HEADERS_HELPER_COMMAND = `/bin/sh -c 'd=$(pwd); while [ ! -f "$d/${MCP_HEADERS_HELPER_REL}" ] && [ "$d" != / ]; do d=$(dirname "$d"); done; [ -f "$d/${MCP_HEADERS_HELPER_RE...
L1828: var GENERATED_MCP_HEADERS_HEADER = "# Halfcycle MCP connection headers \u2014 generated by";
High
2272// dist/control-origin.js
L2273: var DEFAULT_CONTROL_ORIGIN = "https://control.halfcycle.ai";
L2274: function resolveControlOrigin(env = process.env) {
L2275: const configured = env["HALFCYCLE_SERVICE_URL"]?.trim();
...
L2284: // dist/device-signin.js
L2285: import { spawn } from "node:child_process";
L2286: import { platform as platform3 } from "node:os";
Findings
4 High4 Medium4 Low
HighChild Processbin/bin.bundle.mjs
HighShelldist/bin.js
HighSame File Env Network Executiondist/bin.js
HighTrigger Reachable External Post Callbackdist/bin.js
MediumNetwork
MediumEnvironment Vars
MediumSuspicious Lifecycle Evidencepackage.json
MediumAi Review Evidencedist/bin.js
LowScripts Present
LowFilesystem
LowHigh Entropy Strings
LowUrl Strings
Affected versions and remediation
This report applies to halfcycle@0.3.24.
See all versions of halfcycle for other recorded verdicts.
- Review the evidence and your use of halfcycle@0.3.24 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: .
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