AI agents call which to retrieve information from PSKit without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only queries system state to determine whether a binary exists and where it is located. It performs a simple lookup operation (analogous to the Unix `which` command) without side effects. While the sibling tools include destructive and execute capabilities, this specific tool is purely informational—it reads PATH environment variables and reports findings.
From the tool's definition Tool returns location and version of binaries on PATH; no modification, deletion, or execution of code occurs.
Attacks that exploit this kind of access
Check if a binary is on PATH — returns location and version. It is categorised as a Read tool in the PSKit MCP Server, which means it retrieves data without modifying state.
Register the PSKit MCP server in PolicyLayer and add a rule for which: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches PSKit. Nothing to install.
which is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the which rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for which. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
which is provided by the PSKit MCP server (nickalus12/pskit). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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