stepsecurity-mcp

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check_npm_package_on_dev_machines

Check all enrolled developer machines for installed versions of a malicious npm package to assess exposure on independent laptops, complementing CI checks. Optionally filter by compromised versions.

Instructions

Developer-machine 'Am I Affected?' check for an npm package. Searches across all enrolled developer laptops (Dev Machine Guard) for installs of the package. Complements check_npm_package_exposure — CI and dev machines are INDEPENDENT exposure surfaces, so when investigating a malicious-package incident you MUST check both. Uses the StepSecurity customer/tenant identifier (optional — falls back to STEP_SECURITY_CUSTOMER env var). The server's version filter is not applied — pass versions to filter results client-side to specific compromised versions, otherwise all installs are returned.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "packageName": "<packageName>"
    },
    "name": "check_npm_package_on_dev_machines"
  }
}

Input Schema

Name	Required	Description
`customer`	No	StepSecurity customer identifier. Optional — falls back to STEP_SECURITY_CUSTOMER env var.
`packageName`	Yes	npm package name
`versions`	No	Specific versions to match (exact string compare). Omit to return all installs.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.1Apr 24, 2026

TDQS

A4.5/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It discloses that the server's version filter is not applied, requiring client-side filtering. It also mentions the fallback to an environment variable. However, it does not discuss potential rate limits or performance implications, which could be relevant for an enterprise tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is well-structured, starting with a clear purpose, then relating to siblings, then detailing parameters. It is somewhat verbose but each sentence adds value. It could be slightly more concise, but overall effective.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no output schema and no annotations, the description covers the tool's purpose, usage context, parameter details, and behavior. It explains the relationship to a sibling tool and the client-side filtering requirement. Missing details like output format or error handling, but for a search/check tool, it is fairly complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already describes all three parameters with 100% coverage. The description adds value by clarifying that 'customer' is optional and falls back to an env var, and that 'versions' performs exact string match and can be omitted to return all installs. This complements the schema well.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description explicitly states the tool checks for npm package installs on developer machines. It distinguishes itself from the sibling tool 'check_npm_package_exposure' by clarifying that CI and dev machines are independent surfaces, and both must be checked during incident investigation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit guidance on when to use the tool: when investigating a malicious-package incident, you MUST check both this and 'check_npm_package_exposure'. It also explains optional parameters like customer and versions, and the fallback to environment variable.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.