Medium Risk

update_variant

Update a product variant (price, compare_at_price, SKU, barcode, weight). For store owners / inventory managers. Provide only the fields you want to change.

How to control update_variant ↓

What update_variant does on Sapo

AI agents use update_variant to create or update resources in Sapo — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Sapo environment.

Medium Risk

Why update_variant needs a policy

This tool creates or modifies data reversibly by updating product variant attributes. While it modifies important business-critical fields (price, SKU, barcode), the changes are not permanent/irreversible and can be undone by subsequent updates.

From the tool's definition Tool description states 'Update a product variant (price, compare_at_price, SKU, barcode, weight)' - explicitly performs modification of product data fields including critical pricing and inventory identification attributes.

Documented attack patterns abuse exactly the kind of access update_variant gives an agent:

How to control update_variant

PolicyLayer is an MCP gateway — it sits between your AI agents and Sapo, and nothing reaches the server without passing your rules. This is the rule we recommend for update_variant:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "update_variant": {
      "limits": [
        {
          "counter": "update_variant_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

update_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.

  1. Create a free account and register Sapo — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

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Related tools and policies

Go deeper

Questions about update_variant

What does the update_variant tool do? +

Update a product variant (price, compare_at_price, SKU, barcode, weight). For store owners / inventory managers. Provide only the fields you want to change. It is categorised as a Write tool in the Sapo MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_variant? +

Register the Sapo MCP server in PolicyLayer and add a rule for update_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 Sapo. Nothing to install.

What risk level is update_variant? +

update_variant is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit update_variant? +

Yes. Add a rate_limit block to the update_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.

How do I block update_variant completely? +

Set action: deny in the PolicyLayer policy for update_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.

What MCP server provides update_variant? +

update_variant is provided by the Sapo MCP server (nguyennguyenit/sapo-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Sapo tool call.

Start from Sapo, 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.

93 Sapo tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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