Write a formula to a specific cell and return the computed result. The formula is written, the cell is read back to get the calculated value.
AI agents invoke excel_run_formula to trigger actions in Sage MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
While the tool performs a write operation (placing a formula in a cell), the primary and consequential action is execution of arbitrary formulas, which can have side effects depending on formula content (e.g., triggering external data pulls, macro-like behaviors, or cell reference chains with unintended consequences).
From the tool's definition Tool writes a formula to a cell ('Write a formula to a specific cell') and executes it to retrieve a computed result. The formula execution capability constitutes code execution within a spreadsheet context.
Documented attack patterns abuse exactly the kind of access excel_run_formula 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_run_formula:
{
"version": "1",
"default": "deny",
"tools": {
"excel_run_formula": {
"limits": [
{
"counter": "excel_run_formula_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}excel_run_formula stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Write a formula to a specific cell and return the computed result. The formula is written, the cell is read back to get the calculated value. It is categorised as a Execute tool in the Sage MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Sage MCP server in PolicyLayer and add a rule for excel_run_formula: 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_run_formula is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the excel_run_formula 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_run_formula. 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_run_formula 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.
Free to start. No card required.
359 Sage MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.