AI agents use upsert to create or update resources in SurrealDB MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your SurrealDB MCP Server environment.
Upsert is a reversible write operation that either inserts a new record or updates an existing one based on a condition. While it modifies data, it is not destructive (data can be undone with another upsert or delete), not executable code (it operates on structured data), and not financial.
From the tool's definition Tool name 'upsert' combined with description 'Upsert a record: create if it doesn' (incomplete but clearly indicates create/modify operations).
Documented attack patterns abuse exactly the kind of access upsert gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and SurrealDB MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for upsert:
{
"version": "1",
"default": "deny",
"tools": {
"upsert": {
"limits": [
{
"counter": "upsert_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}upsert 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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Upsert a record: create if it doesn. It is categorised as a Write tool in the SurrealDB MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the SurrealDB MCP Server MCP server in PolicyLayer and add a rule for upsert: 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 SurrealDB MCP Server. Nothing to install.
upsert 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 upsert 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 upsert. 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.
upsert is provided by the SurrealDB MCP Server MCP server (nsxdavid/surrealdb-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 10 SurrealDB MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
10 SurrealDB MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.