Searches for content in a file and replaces it with new content.
AI agents use search_replace_file to create or update resources in Vsc — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Vsc environment.
This tool modifies file contents by finding and replacing text. It is a Write operation (reversible modification) rather than Destructive since it replaces rather than deletes files outright. However, severity is high because an AI agent could use it to overwrite critical code across any file in the workspace, potentially causing widespread changes that may be difficult to track or revert without version control.
From the tool's definition Searches for content in a file and replaces it with new content.
Documented attack patterns abuse exactly the kind of access search_replace_file gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Vsc, and nothing reaches the server without passing your rules. This is the rule we recommend for search_replace_file:
{
"version": "1",
"default": "deny",
"tools": {
"search_replace_file": {
"limits": [
{
"counter": "search_replace_file_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}search_replace_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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Searches for content in a file and replaces it with new content. It is categorised as a Write tool in the Vsc MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Vsc MCP server in PolicyLayer and add a rule for search_replace_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 Vsc. Nothing to install.
search_replace_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 search_replace_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 search_replace_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.
search_replace_file is provided by the Vsc MCP server (thomasgazzoni/vsc-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 7 Vsc tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
7 Vsc tools catalogued and risk-classified — across an index of 42,500+ MCP servers.