AI agents use set_business to create or update resources in Wave Accounting MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Wave Accounting MCP Server environment.
This tool changes application state by selecting which business context is active. While not creating or deleting data directly, it modifies the operational state in a reversible way (another business can be set), affecting which financial records subsequent operations will affect. This is a Write-class action because it reconfigures system state.
From the tool's definition Tool name is 'set_business' and description states 'Set the active business for operations' — this modifies the active context/state for subsequent operations.
Documented attack patterns abuse exactly the kind of access set_business gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Wave Accounting MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for set_business:
{
"version": "1",
"default": "deny",
"tools": {
"set_business": {
"limits": [
{
"counter": "set_business_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_business 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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Set the active business for operations. It is categorised as a Write tool in the Wave Accounting MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Wave Accounting MCP Server MCP server in PolicyLayer and add a rule for set_business: 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 Wave Accounting MCP Server. Nothing to install.
set_business 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 set_business 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 set_business. 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.
set_business is provided by the Wave Accounting MCP Server MCP server (vinnividivicci/wave_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Wave Accounting MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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9 Wave Accounting MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.