Replace content starting from a specific line number. Use startLine to keep lines 1-(startLine-1) and replace from startLine to EOF (or to endLine if specified). Ideal for bulk section replacement in large files without sending entire file content.
AI agents use write_from_line to create or update resources in OODA Computer Control — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your OODA Computer Control environment.
The tool modifies file content by replacing sections, which is a Write operation (reversible data modification). Severity is high because uncontrolled replacement of file sections—especially to EOF—could corrupt critical configuration files, source code, or system files, though the operation itself is theoretically reversible via version control or backups.
From the tool's definition Tool description explicitly states 'Replace content starting from a specific line number' and 'replace from startLine to EOF (or to endLine if specified)', indicating reversible modification of file contents.
Documented attack patterns abuse exactly the kind of access write_from_line gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OODA Computer Control, and nothing reaches the server without passing your rules. This is the rule we recommend for write_from_line:
{
"version": "1",
"default": "deny",
"tools": {
"write_from_line": {
"limits": [
{
"counter": "write_from_line_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}write_from_line 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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Replace content starting from a specific line number. Use startLine to keep lines 1-(startLine-1) and replace from startLine to EOF (or to endLine if specified). Ideal for bulk section replacement in large files without sending entire file content. It is categorised as a Write tool in the OODA Computer Control MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the OODA Computer Control MCP server in PolicyLayer and add a rule for write_from_line: 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 OODA Computer Control. Nothing to install.
write_from_line 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 write_from_line 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 write_from_line. 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.
write_from_line is provided by the OODA Computer Control MCP server (mnehmos/mnehmos.ooda.mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from OODA Computer Control, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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99 OODA Computer Control tools catalogued and risk-classified — across an index of 43,000+ MCP servers.