Generate an image with the specified form field highlighted with a red box
AI agents call highlight_form_field to retrieve information from MCP PDF Forms without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and visualizes form field information by generating a highlighted image representation. It does not modify, delete, or execute operations on the PDF itself, nor does it create persistent changes to the document. It is purely a read operation that renders visual information about an existing form field.
From the tool's definition Tool name 'highlight_form_field' and description 'Generate an image with the specified form field highlighted with a red box' - this creates a visual output (highlighting) of existing form field data without modifying the underlying PDF or form data.
Documented attack patterns abuse exactly the kind of access highlight_form_field gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP PDF Forms, and nothing reaches the server without passing your rules. This is the rule we recommend for highlight_form_field:
{
"version": "1",
"default": "deny",
"tools": {
"highlight_form_field": {}
}
}highlight_form_field is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Generate an image with the specified form field highlighted with a red box. It is categorised as a Read tool in the MCP PDF Forms MCP Server, which means it retrieves data without modifying state.
Register the MCP PDF Forms MCP server in PolicyLayer and add a rule for highlight_form_field: 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 MCP PDF Forms. Nothing to install.
highlight_form_field is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the highlight_form_field 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 highlight_form_field. 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.
highlight_form_field is provided by the MCP PDF Forms MCP server (wildebeest/mcp_pdf_forms). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP PDF Forms, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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6 MCP PDF Forms tools catalogued and risk-classified — across an index of 43,000+ MCP servers.