Set the font of a specific run (zero-based index) in a paragraph.
AI agents use set_run_font to create or update resources in Docx — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Docx environment.
This tool creates or modifies document data (font properties) in a reversible manner. Changing font formatting is a standard write operation that does not delete data, execute arbitrary code, or trigger financial transactions. The modification is easily undoable (can be reset to a previous font), making it clearly a Write category tool rather than Destructive.
From the tool's definition Tool description states 'Set the font of a specific run' which modifies document formatting. The server description confirms it enables 'editing' of Word documents with 'OOXML-level document manipulation.'
Documented attack patterns abuse exactly the kind of access set_run_font gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Docx, and nothing reaches the server without passing your rules. This is the rule we recommend for set_run_font:
{
"version": "1",
"default": "deny",
"tools": {
"set_run_font": {
"limits": [
{
"counter": "set_run_font_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_run_font 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.
Free to start. No card required.
Set the font of a specific run (zero-based index) in a paragraph. It is categorised as a Write tool in the Docx MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Docx MCP server in PolicyLayer and add a rule for set_run_font: 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 Docx. Nothing to install.
set_run_font 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_run_font 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_run_font. 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_run_font is provided by the Docx MCP server (securityronin/docx-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Docx, 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.
219 Docx tools catalogued and risk-classified — across an index of 43,000+ MCP servers.