Stamp a plain text string at a location on a PDF, saving the result as a new file. Use this for date zones (stamp today
AI agents use apply_text to create or update resources in PDF Tools — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your PDF Tools environment.
apply_text modifies PDF content by adding text at specified locations and saves the output as a new file. This is a reversible write operation—the original PDF is not altered, and the stamped result is a new artifact. The tool creates modified data rather than executing arbitrary code or destructively overwriting originals.
From the tool's definition Stamp a plain text string at a location on a PDF, saving the result as a new file.
Documented attack patterns abuse exactly the kind of access apply_text 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 apply_text:
{
"version": "1",
"default": "deny",
"tools": {
"apply_text": {
"limits": [
{
"counter": "apply_text_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}apply_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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Stamp a plain text string at a location on a PDF, saving the result as a new file. Use this for date zones (stamp today. It is categorised as a Write tool in the PDF Tools MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the PDF Tools MCP server in PolicyLayer and add a rule for apply_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 PDF Tools. Nothing to install.
apply_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 apply_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 apply_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.
apply_text 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.