AI agents call readFile to retrieve information from SMART-E2B without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves file data from an isolated sandbox environment without any side effects. It does not create, modify, delete, or execute anything. The sandbox isolation further limits risk even if an agent reads unintended files. Severity is low because the blast radius is limited to information disclosure within a controlled, temporary environment.
From the tool's definition Tool name and description: 'Read a file from the sandbox' — directly indicates retrieval of file contents with no modification or deletion.
Attacks that exploit this kind of access
Read a file from the sandbox. It is categorised as a Read tool in the SMART-E2B MCP Server, which means it retrieves data without modifying state.
Register the SMART-E2B MCP server in PolicyLayer and add a rule for readFile: 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 SMART-E2B. Nothing to install.
readFile 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 readFile 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 readFile. 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.
readFile is provided by the SMART-E2B MCP server (leghis/smart-e2b). 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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