env
Returns Go environment variables as structured JSON. Optionally request specific variables.
This record as markdown: /tools/io-github-dave-london-cargo/env.md
What env does on Cargo
AI agents call env to retrieve information from Cargo without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why env is rated Low
This tool queries and returns environment variables without creating, modifying, deleting, or executing any operations. It is purely informational/diagnostic in nature. The severity is low because environment variables themselves are typically non-sensitive system metadata, though in some contexts they might contain credentials—but the tool itself performs only read access.
From the tool's definition Tool description states it 'Returns Go environment variables as structured JSON.' The word 'Returns' indicates a read-only retrieval operation with no modification of state.
Attacks that exploit this kind of access
The rule that runs env safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Cargo, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For env, this is the rule to start with:
env 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 Cargo, apply this rule, and every env call is checked against it from then on.
Questions about env
Returns Go environment variables as structured JSON. Optionally request specific variables. It is categorised as a Read tool in the Cargo MCP Server, which means it retrieves data without modifying state.
Register the Cargo MCP server in PolicyLayer and add a rule for env: 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 Cargo. Nothing to install.
env 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 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. 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 is provided by the Cargo MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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