Index or re-index a single file in an existing project. The project must have been indexed with index_codebase first.
Risk signalsAccepts file system path (file_path)
Part of the Vibe Hnindex server.
Free to start. No card required.
AI agents call index_file to retrieve information from Vibe Hnindex without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though index_file only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"index_file": {}
}
}See the full Vibe Hnindex policy for all 22 tools.
These attack patterns abuse exactly the kind of access index_file gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Index or re-index a single file in an existing project. The project must have been indexed with index_codebase first.. It is categorised as a Read tool in the Vibe Hnindex MCP Server, which means it retrieves data without modifying state.
Register the Vibe Hnindex MCP server in PolicyLayer and add a rule for index_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 Vibe Hnindex. Nothing to install.
index_file is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the index_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 index_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.
index_file is provided by the Vibe Hnindex MCP server (vibe-hnindex). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 22 Vibe Hnindex tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.