Update specific parts of a file using search and replace
AI agents use update_file to create or update resources in Enhanced Directory Context MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Enhanced Directory Context MCP Server environment.
This tool modifies file contents through targeted replacements, a reversible Write operation. While it changes data, updates can typically be undone (via version control or file restore), distinguishing it from Destructive operations. Severity is medium because careless regex replacements or prompt injection could corrupt critical files, but the operation itself is not irreversible like deletion.
From the tool's definition Tool description states 'Update specific parts of a file using search and replace', which modifies file content reversibly.
Attacks that exploit this kind of access
Update specific parts of a file using search and replace. It is categorised as a Write tool in the Enhanced Directory Context MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Enhanced Directory Context MCP Server MCP server in PolicyLayer and add a rule for update_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 Enhanced Directory Context MCP Server. Nothing to install.
update_file is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the update_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 update_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.
update_file is provided by the Enhanced Directory Context MCP Server MCP server (pwalagov/file-control-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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