Set accessibility alt text and title on an embedded image.
AI agents use set_image_alt_text 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 modifies document content by updating image properties (alt text and title attributes) in a reversible manner. It does not execute code, delete data, move funds, or cause irreversible changes. The modification is scoped to image metadata only, making it a straightforward Write operation with minimal risk if misused—an agent might add inappropriate alt text, but this can be easily corrected or undone.
From the tool's definition Tool name 'set_image_alt_text' and description 'Set accessibility alt text and title on an embedded image' indicate modification of image metadata within a Word document.
Documented attack patterns abuse exactly the kind of access set_image_alt_text 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_image_alt_text:
{
"version": "1",
"default": "deny",
"tools": {
"set_image_alt_text": {
"limits": [
{
"counter": "set_image_alt_text_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_image_alt_text 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 accessibility alt text and title on an embedded image. 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_image_alt_text: 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_image_alt_text 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_image_alt_text 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_image_alt_text. 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_image_alt_text 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.