Update an existing price rule. Side effect: modifies the price rule. Only provided fields are updated. value must remain a string if updating.
AI agents use update_price_rule 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.
The tool modifies existing data (price rules) but does not delete or destroy anything irreversibly. While price changes could have financial implications, the tool itself is a metadata/configuration update rather than a direct financial transaction. It belongs in Write category as a reversible modification.
From the tool's definition Tool description states 'Update an existing price rule. Side effect: modifies the price rule. Only provided fields are updated.' This is explicitly a modification operation affecting pricing rules.
Documented attack patterns abuse exactly the kind of access update_price_rule gives an agent:
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_price_rule:
{
"version": "1",
"default": "deny",
"tools": {
"update_price_rule": {
"limits": [
{
"counter": "update_price_rule_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_price_rule 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 an existing price rule. Side effect: modifies the price rule. Only provided fields are updated. value must remain a string if updating. 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.
Register the Sapo MCP server in PolicyLayer and add a rule for update_price_rule: 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.
update_price_rule 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_price_rule 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_price_rule. 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_price_rule 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.
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.