env_vars
Show environment variables, optionally filtered by name substring.
This record as markdown: /tools/mcp-hands/env-vars.md
What env_vars does on Mcp Hands
AI agents call env_vars to retrieve information from Mcp Hands without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why env_vars is rated Low
Even though env_vars only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs env_vars safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Mcp Hands, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For env_vars, this is the rule to start with:
env_vars is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Mcp Hands, apply this rule, and every env_vars call is checked against it from then on.
Questions about env_vars
Show environment variables, optionally filtered by name substring. It is categorised as a Read tool in the Mcp Hands MCP Server, which means it retrieves data without modifying state.
Register the Mcp Hands MCP server in PolicyLayer and add a rule for env_vars: 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 Mcp Hands. Nothing to install.
env_vars 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 env_vars 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 env_vars. 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.
env_vars is provided by the Mcp Hands MCP server (huocai250/mcp-hands). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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