Read the contents of a file as text.
AI agents call read_file to retrieve information from Filesystem MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool retrieves file contents without modifying, deleting, or executing anything. It matches the Read category definition: 'retrieves or queries data; no side effects.' The severity is low because reading files cannot cause data loss or execution risks unless the AI processes sensitive information unsafely, but that is a downstream concern, not inherent to the tool itself.
From the tool's definition Tool name is 'read_file' and description states 'Read the contents of a file as text.' This is a retrieval operation with no side effects.
Attacks that exploit this kind of access
Read the contents of a file as text. It is categorised as a Read tool in the Filesystem MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Filesystem MCP Server MCP server in PolicyLayer and add a rule for read_file: 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 Filesystem MCP Server. Nothing to install.
read_file 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 read_file 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 read_file. 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.
read_file is provided by the Filesystem MCP Server MCP server (njbrake/filesystem-mcp-server). 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.
Teams ship this data inside their own products. See what a licence covers →