Append rows to an existing table in a workbook. Values are a 2D array of row data.
AI agents use excel_append_rows 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.
This tool adds new rows to an existing Excel table, which is a reversible write operation (rows can be deleted). It modifies data in a workbook but does not delete or overwrite existing data, placing it firmly in the Write category. Severity is medium because an AI agent could append large amounts of incorrect or malicious data to business-critical spreadsheets.
From the tool's definition Append rows to an existing table in a workbook
Documented attack patterns abuse exactly the kind of access excel_append_rows 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_append_rows:
{
"version": "1",
"default": "deny",
"tools": {
"excel_append_rows": {
"limits": [
{
"counter": "excel_append_rows_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}excel_append_rows 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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Append rows to an existing table in a workbook. Values are a 2D array of row data. 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_append_rows: 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_append_rows 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_append_rows 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_append_rows. 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_append_rows 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.