registry / AI-agent control-surface risk / motion-diagram
motion-diagram
Agent-driven animated API/flow diagram renderer (MP4 + carousel) with an MCP server.
This report shows the evidence for motion-diagram@1.0.3. 1 of 2 known versions is blocked or flagged. See all versions.
AI Security Review
scanned 4mo ago · by lpm-firewall-aiSource inspection confirms unconsented npm postinstall mutation of foreign/broad AI-agent control surfaces, which meets the block policy even though the MCP functionality itself appears package-aligned. No additional exfiltration or destructive payload was found.
Static reason
High-risk behavior combination matched malicious policy.
Trigger
npm install of motion-diagram@1.0.3 on a machine with detected Cursor, Claude, or Pi config directories
Impact
AI agents may load and run the package's MCP server via npx without explicit user setup.
Mechanism
postinstall MCP server registration and skill copy
Policy narrative
On installation, package.json invokes scripts/install-skill.js with --auto. If Cursor, Claude, or Pi agent config directories exist, the script creates or edits their MCP config to add a motion-diagram server launched as npx -y motion-diagram-mcp, and may copy package skill files into agent skill directories. This occurs during npm postinstall rather than an explicit setup command.
AI rationale
Source inspection confirms unconsented npm postinstall mutation of foreign/broad AI-agent control surfaces, which meets the block policy even though the MCP functionality itself appears package-aligned. No additional exfiltration or destructive payload was found.
Evidence
package.jsonscripts/install-skill.jssrc/mcp/server.jssrc/cli/index.js~/.cursor/mcp.json~/Library/Application Support/Claude/claude_desktop_config.json%APPDATA%/Claude/claude_desktop_config.json~/.config/Claude/claude_desktop_config.json~/.pi/agent/mcp.json~/.claude/skills/motion-diagram~/.pi/agent/skills/motion-diagram
Decision evidence
public snapshotAI identified this as a dangerous AI-agent capability at 93.0% confidence with low false-positive risk.
Evidence for policy risk
- package.json runs postinstall: node scripts/install-skill.js --auto || true
- scripts/install-skill.js auto-detects Cursor, Claude, and Pi agent config directories
- scripts/install-skill.js writes mcpServers.motion-diagram into ~/.cursor/mcp.json, Claude config, or ~/.pi/agent/mcp.json
- scripts/install-skill.js configures agents to run npx -y motion-diagram-mcp
- scripts/install-skill.js copies package skill files into ~/.claude/skills/motion-diagram or ~/.pi/agent/skills/motion-diagram
Evidence against
- No credential harvesting or exfiltration found in inspected source
- No relevant network endpoints beyond registry npx command configuration
- MCP tools are package-aligned rendering/schema tools
- CLI reads user-provided scene JSON and writes requested render outputs
Behavioral surface
ChildProcessEnvironmentVarsFilesystemShell
HighEntropyStrings
Source & flagged code
3 flagged · loading sourcepackage.jsonView file
•scripts.postinstall = node scripts/install-skill.js --auto || true
High
Install Time Lifecycle Scripts
Package defines install-time lifecycle scripts.
package.jsonView on unpkg•scripts.postinstall = node scripts/install-skill.js --auto || true
Medium
Ambiguous Install Lifecycle Script
Install-time lifecycle script is not statically allowlisted and needs review.
package.jsonView on unpkgscripts/install-skill.jsView file
1Install-time AI-agent control hijack evidence:
L6: // node scripts/install-skill.js --client cursor # force a specific client
L7: import { cpSync, existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
L8: import { homedir, platform } from "node:os";
...
L65: const dir = dirname(path);
L66: if (!existsSync(dir)) mkdirSync(dir, { recursive: true });
L67:
L68: const cfg = existsSync(path) ? readJson(path) : {};
L69: if (!cfg.mcpServers || typeof cfg.mcpServers !== "object") cfg.mcpServers = {};
L70:
L71: const existing = cfg.mcpServers[SERVER_NAME];
L72: if (existing && JSON.stringify(existing) === JSON.stringify(SERVER_ENTRY)) {
...
L74: }
Payload evidence from skills/motion-diagram/SKILL.md:
L1: ---
L2: name: motion-diagram
Findings
1 Critical1 High3 Medium3 Low
CriticalAi Agent Control Hijackscripts/install-skill.js
HighInstall Time Lifecycle Scriptspackage.json
MediumAmbiguous Install Lifecycle Scriptpackage.json
MediumEnvironment Vars
MediumStructural Risk Force Deep Review
LowScripts Present
LowFilesystem
LowHigh Entropy Strings
Affected versions and remediation
This report applies to motion-diagram@1.0.3.
The versions list below shows the verdict for each recorded version.
- Avoid installing motion-diagram@1.0.3. 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: .
Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.