Create a new empty Excel workbook (.xlsx) in the user
AI agents use excel_create_workbook to create or update resources in Sage MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Sage MCP environment.
Creating a new workbook is reversible (can be deleted) and non-destructive. It modifies the user's filesystem by adding a new file but does not execute arbitrary code, delete data, or move money. This is a straightforward Write category action with low severity since the blast radius of creating an empty workbook is minimal—worst case is cluttered storage or unintended file creation.
From the tool's definition Tool creates a new empty Excel workbook (.xlsx), which is a write operation that creates a new file. The description explicitly states 'Create a new empty Excel workbook'.
Documented attack patterns abuse exactly the kind of access excel_create_workbook gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Sage MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for excel_create_workbook:
{
"version": "1",
"default": "deny",
"tools": {
"excel_create_workbook": {
"limits": [
{
"counter": "excel_create_workbook_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}excel_create_workbook 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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Create a new empty Excel workbook (.xlsx) in the user. It is categorised as a Write tool in the Sage MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Sage MCP server in PolicyLayer and add a rule for excel_create_workbook: 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 Sage MCP. Nothing to install.
excel_create_workbook 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 excel_create_workbook 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 excel_create_workbook. 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.
excel_create_workbook is provided by the Sage MCP server (sagemcp/sagemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 359 Sage MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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359 Sage MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.