Add approval stamps (Approved, Draft, Confidential, etc) to PDF
AI agents use add_stamps to create or update resources in MCP PDF — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP PDF environment.
This tool modifies a PDF by adding visual stamps/annotations. It is reversible (stamps can be removed or the action can be undone), so it falls under Write rather than Destructive. The severity is medium because while stamping can affect document interpretation or compliance (especially with 'Approved' or 'Confidential'), the change is non-destructive and localized to visual markup.
From the tool's definition Tool adds approval stamps to PDF documents, modifying document content. The description explicitly states it adds stamps like 'Approved, Draft, Confidential, etc' to the PDF, which constitutes adding metadata/visual elements to an existing document.
Documented attack patterns abuse exactly the kind of access add_stamps gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP PDF, and nothing reaches the server without passing your rules. This is the rule we recommend for add_stamps:
{
"version": "1",
"default": "deny",
"tools": {
"add_stamps": {
"limits": [
{
"counter": "add_stamps_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_stamps 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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Add approval stamps (Approved, Draft, Confidential, etc) to PDF. It is categorised as a Write tool in the MCP PDF MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP PDF MCP server in PolicyLayer and add a rule for add_stamps: 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. Nothing to install.
add_stamps 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 add_stamps 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 add_stamps. 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.
add_stamps is provided by the MCP PDF MCP server (rsp2k/mcp-pdf). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP PDF, 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.
46 MCP PDF tools catalogued and risk-classified — across an index of 43,000+ MCP servers.