Index files in a directory for semantic search. Without patterns, indexes the project from config and prunes deleted or now-excluded files. With patterns, refreshes or expands only matching files and leaves the rest of the index untouched.
AI agents use index_files to create or update resources in Local Rag — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Local Rag environment.
This tool creates or updates an index (a data structure stored persistently) based on files in a directory. It is a Write operation because it modifies the search index reversibly — files can be re-indexed or pruned. It also prunes deleted/excluded files from the index, but this is a side effect of a write/update operation rather than a destructive irreversible deletion of source data.
From the tool's definition Index files in a directory for semantic search... refreshes or expands only matching files and leaves the rest of the index untouched
Documented attack patterns abuse exactly the kind of access index_files gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Local Rag, and nothing reaches the server without passing your rules. This is the rule we recommend for index_files:
{
"version": "1",
"default": "deny",
"tools": {
"index_files": {
"limits": [
{
"counter": "index_files_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}index_files 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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Index files in a directory for semantic search. Without patterns, indexes the project from config and prunes deleted or now-excluded files. With patterns, refreshes or expands only matching files and leaves the rest of the index untouched. It is categorised as a Write tool in the Local Rag MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Local Rag MCP server in PolicyLayer and add a rule for index_files: 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 Local Rag. Nothing to install.
index_files 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 index_files 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 index_files. 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.
index_files is provided by the Local Rag MCP server (thewinci/mimirs). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Local Rag, 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.
29 Local Rag tools catalogued and risk-classified — across an index of 43,000+ MCP servers.