AI agents use update to create or update resources in Surreal — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Surreal environment.
The 'update' tool modifies existing data in a reversible manner, characteristic of Write operations. It is not Destructive (reversible), not Execute (not arbitrary code), and not Financial. While the tool description is empty, the context from the server purpose and sibling tools strongly indicates database write semantics.
From the tool's definition Tool name 'update' in a database context (SurrealDB) indicates data modification. Server description confirms this is for database operations: 'MCP Server for SurrealDB - Bridge AI assistants with SurrealDB databases'.
Documented attack patterns abuse exactly the kind of access update gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Surreal, and nothing reaches the server without passing your rules. This is the rule we recommend for update:
{
"version": "1",
"default": "deny",
"tools": {
"update": {
"limits": [
{
"counter": "update_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update 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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update. It is categorised as a Write tool in the Surreal MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Surreal MCP server in PolicyLayer and add a rule for update: 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 Surreal. Nothing to install.
update 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 update 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 update. 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.
update is provided by the Surreal MCP server (lfnovo/surreal-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Surreal, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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10 Surreal tools catalogued and risk-classified — across an index of 43,000+ MCP servers.