Read all form fields from a PDF file and display them in an interactive viewer. Returns field names, types, and current values. Also renders the PDF visually — no need to also call display_pdf. All paths must be absolute paths on the user
AI agents call read_pdf_fields to retrieve information from PDF Tools without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only retrieves and queries form field metadata and visual content from an existing PDF file. It performs no modifications, deletions, or side effects—purely data retrieval and display. The tool requires absolute file paths and operates locally without external calls that could trigger unpredictable side effects.
From the tool's definition read_pdf_fields: 'Read all form fields from a PDF file and display them in an interactive viewer. Returns field names, types, and current values.' This is explicitly a read operation that retrieves and displays data without modification.
Documented attack patterns abuse exactly the kind of access read_pdf_fields gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and PDF Tools, and nothing reaches the server without passing your rules. This is the rule we recommend for read_pdf_fields:
{
"version": "1",
"default": "deny",
"tools": {
"read_pdf_fields": {}
}
}read_pdf_fields is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Read all form fields from a PDF file and display them in an interactive viewer. Returns field names, types, and current values. Also renders the PDF visually — no need to also call display_pdf. All paths must be absolute paths on the user. It is categorised as a Read tool in the PDF Tools MCP Server, which means it retrieves data without modifying state.
Register the PDF Tools MCP server in PolicyLayer and add a rule for read_pdf_fields: 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 PDF Tools. Nothing to install.
read_pdf_fields 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 read_pdf_fields 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 read_pdf_fields. 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.
read_pdf_fields is provided by the PDF Tools MCP server (open-document-alliance/pdf-tools). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 36 PDF Tools tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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36 PDF Tools tools catalogued and risk-classified — across an index of 42,500+ MCP servers.