Read the .env file for an app (read-only)
AI agents call faber_get_env to retrieve information from Faber MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
While this is a read-only operation with no side effects, .env files typically contain sensitive configuration data such as database credentials, API keys, secret tokens, and other secrets critical to application security. Unauthorized access to this data could compromise the entire application and infrastructure. The high severity reflects the sensitivity of the data exposed, not the nature of the operation itself.
From the tool's definition Tool description explicitly states 'read-only' and the name 'faber_get_env' indicates retrieval of environment variables from a .env file.
Attacks that exploit this kind of access
Read the .env file for an app (read-only). It is categorised as a Read tool in the Faber MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Faber MCP Server MCP server in PolicyLayer and add a rule for faber_get_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 Faber MCP Server. Nothing to install.
faber_get_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 faber_get_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 faber_get_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.
faber_get_env is provided by the Faber MCP Server MCP server (joshtrebilco/faber-mcp). 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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