Make line-based edits to a file. Each edit operation can: - Replace entire lines when no match criteria is specified - Replace specific text matches while preserving line formatting (using strMatch) - Replace regex matches while preserving line formatting (using regexMatch) - Handle multiple line...
AI agents use edit_file_lines to create or update resources in Edit File Lines MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Edit File Lines MCP Server environment.
This tool creates or modifies file content reversibly. While edits are permanent once approved, the dryRun preview mechanism and 1-minute stateId window provide some safeguards against accidental destructive changes. The tool is confined to "allowed directories" which further mitigates risk. It does not delete data or execute arbitrary code, making it Write rather than Destructive or Execute.
From the tool's definition Tool description states it "Make[s] line-based edits to a file" with capabilities to "Replace entire lines", "Replace specific text matches", and "Replace regex matches". The dryRun mode allows preview before applying edits via approve_edit.
Risk signalsBulk/mass operation — affects multiple targets
Documented attack patterns abuse exactly the kind of access edit_file_lines gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Edit File Lines MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for edit_file_lines:
{
"version": "1",
"default": "deny",
"tools": {
"edit_file_lines": {
"limits": [
{
"counter": "edit_file_lines_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}edit_file_lines stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Make line-based edits to a file. Each edit operation can: - Replace entire lines when no match criteria is specified - Replace specific text matches while preserving line formatting (using strMatch) - Replace regex matches while preserving line formatting (using regexMatch) - Handle multiple lines with full content replacement When dryRun is true, returns a diff and a stateId that can be used with approve_edit tool to apply the edit. The stateId is only valid for 1 minute. It is categorised as a Write tool in the Edit File Lines MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Edit File Lines MCP Server MCP server in PolicyLayer and add a rule for edit_file_lines: 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 Edit File Lines MCP Server. Nothing to install.
edit_file_lines 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 edit_file_lines 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 edit_file_lines. 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.
edit_file_lines is provided by the Edit File Lines MCP Server MCP server (oakenai/mcp-edit-file-lines). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 4 Edit File Lines MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4 Edit File Lines MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.