reindexWithId
Requests Elasticsearch to delete and rebuild the index for FusionAuth users or entities. Be very careful when running this request as it will increase the CPU and I/O load on your database until the operation completes. Generally speaking you do not ever need to run this operation unless instruct...
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What reindexWithId does on Fusionauth
AI agents call reindexWithId to permanently remove resources in Fusionauth, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Why reindexWithId is rated Critical
The tool explicitly deletes the Elasticsearch index and rebuilds it from scratch. Deletion of the index is an irreversible action (the original index state is gone); while data is rebuilt from the database, the deletion step is destructive. The description warns heavily against casual use, noting CPU/I/O impact and that it should only be run under specific circumstances.
From the tool's definition 'Requests Elasticsearch to delete and rebuild the index' and 'Be very careful when running this request' — explicitly deletes the existing index before rebuilding it, which is irreversible mid-operation and causes significant system load.
Attacks that exploit this kind of access
The rule that runs reindexWithId safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Fusionauth, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For reindexWithId, this is the rule to start with:
reindexWithId is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect Fusionauth, apply this rule, and every reindexWithId call is checked against it from then on.
Questions about reindexWithId
Requests Elasticsearch to delete and rebuild the index for FusionAuth users or entities. Be very careful when running this request as it will increase the CPU and I/O load on your database until the operation completes. Generally speaking you do not ever need to run this operation unless instructed by FusionAuth support, or if you are migrating a database another system and you are not brining along the Elasticsearch index. You have been warned. It is categorised as a Destructive tool in the Fusionauth MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Fusionauth MCP server in PolicyLayer and add a rule for reindexWithId: 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 Fusionauth. Nothing to install.
reindexWithId is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the reindexWithId 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 reindexWithId. 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.
reindexWithId is provided by the Fusionauth MCP server (@fusionauth/mcp-api). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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