AI agents use tool_write_file to create or update resources in UltimateCoder — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your UltimateCoder environment.
Writing files is a reversible Write operation—it creates or modifies data on disk without permanent destruction. Severity is high because unrestricted file writes can corrupt application state, inject malicious code into projects, overwrite critical configurations, or compromise system integrity. Confidence is 0.92 (not higher due to empty description) but the tool name and server context are sufficiently clear.
From the tool's definition Tool name 'tool_write_file' combined with server description stating it 'Automate file handling' and context of sibling tools (tool_apply_patch, tool_create_directory, tool_delete_path) that manipulate the filesystem.
Documented attack patterns abuse exactly the kind of access tool_write_file gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and UltimateCoder, and nothing reaches the server without passing your rules. This is the rule we recommend for tool_write_file:
{
"version": "1",
"default": "deny",
"tools": {
"tool_write_file": {
"limits": [
{
"counter": "tool_write_file_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}tool_write_file 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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tool_write_file. It is categorised as a Write tool in the UltimateCoder MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the UltimateCoder MCP server in PolicyLayer and add a rule for tool_write_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 UltimateCoder. Nothing to install.
tool_write_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 tool_write_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 tool_write_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.
tool_write_file is provided by the UltimateCoder MCP server (m-ahmed-elbeskeri/ultimatecodermcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from UltimateCoder, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
23 UltimateCoder tools catalogued and risk-classified — across an index of 43,000+ MCP servers.