Save a reusable signature the user can apply to PDFs. Two styles:
AI agents use create_signature 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.
This tool creates and stores a new signature artifact that will be reused across multiple PDFs. While it does not destructively delete data, modify financial records, or execute arbitrary code, it does persistently write new data to storage.
From the tool's definition The tool 'create_signature' is described as 'Save a reusable signature the user can apply to PDFs.' The verb 'save' and the action of storing a signature for reuse indicate creation and persistent storage of data.
Documented attack patterns abuse exactly the kind of access create_signature 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 create_signature:
{
"version": "1",
"default": "deny",
"tools": {
"create_signature": {
"limits": [
{
"counter": "create_signature_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_signature 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.
Free to start. No card required.
Save a reusable signature the user can apply to PDFs. Two styles:. 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 create_signature: 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.
create_signature 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 create_signature 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 create_signature. 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.
create_signature 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.
Free to start. No card required.
36 PDF Tools tools catalogued and risk-classified — across an index of 42,500+ MCP servers.