Add a new variant to an existing product (size/color/SKU permutation with its own price and inventory).
AI agents use create_variant to create or update resources in Mcp Afip — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mcp Afip environment.
This tool creates new product variants reversibly within an e-invoicing/tax system context. It modifies product catalog data (adds records) but does not delete, execute arbitrary code, or move money. The blast radius is medium because incorrect variants could disrupt inventory accuracy and pricing in the tax authority's invoicing system, but changes are theoretically reversible through deletion or correction.
From the tool's definition Tool description states 'Add a new variant to an existing product' with parameters for 'price and inventory', indicating creation of new product data (variant records) with modifiable pricing and stock levels.
Documented attack patterns abuse exactly the kind of access create_variant gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Afip, and nothing reaches the server without passing your rules. This is the rule we recommend for create_variant:
{
"version": "1",
"default": "deny",
"tools": {
"create_variant": {
"limits": [
{
"counter": "create_variant_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_variant 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.
Free to start. No card required.
Add a new variant to an existing product (size/color/SKU permutation with its own price and inventory). It is categorised as a Write tool in the Mcp Afip MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Mcp Afip MCP server in PolicyLayer and add a rule for create_variant: 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 Mcp Afip. Nothing to install.
create_variant 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 create_variant 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 create_variant. 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.
create_variant is provided by the Mcp Afip MCP server (codespar/mcp-dev-latam). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Afip, 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.
1300 Mcp Afip tools catalogued and risk-classified — across an index of 43,000+ MCP servers.