upload_attachment

Upload a base64-encoded attachment to a ServiceNow record (requires WRITE_ENABLED=true).

SERVERServiceNow MCP Server SOURCE@aartiq/servicenow-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity verified Pull the record →

This record as markdown: /tools/servicenow-mcp-server/upload-attachment.md

WHAT IT DOES

What upload_attachment does on ServiceNow MCP Server

AI agents use upload_attachment to create or update resources in ServiceNow MCP Server, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your ServiceNow MCP Server environment.

RISK

Why upload_attachment is rated Medium

This tool creates new attachment data attached to ServiceNow records. While uploads are modifications, they are reversible (attachments can be deleted), making this a Write action rather than Execute or Destructive. Severity is medium because attachment uploads could introduce malicious files, but the impact is scoped to the target record and doesn't directly execute code or cause destructive operations.

From the tool's definition Tool name is 'upload_attachment' and description states it uploads 'a base64-encoded attachment to a ServiceNow record' with requirement for 'WRITE_ENABLED=true', indicating it creates/adds data to records reversibly.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs upload_attachment safely

PolicyLayer is an MCP gateway: it sits between your AI agents and ServiceNow MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For upload_attachment, this is the rule to start with:

upload_attachment Rate-limited

upload_attachment 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "upload_attachment": {
      "limits": [
        {
          "counter": "upload_attachment_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect ServiceNow MCP Server, apply this rule, and every upload_attachment call is checked against it from then on.

FAQ

Questions about upload_attachment

What does the upload_attachment tool do? +

Upload a base64-encoded attachment to a ServiceNow record (requires WRITE_ENABLED=true). It is categorised as a Write tool in the ServiceNow MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on upload_attachment? +

Register the ServiceNow MCP Server MCP server in PolicyLayer and add a rule for upload_attachment: 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 ServiceNow MCP Server. Nothing to install.

What risk level is upload_attachment? +

upload_attachment is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit upload_attachment? +

Yes. Add a rate_limit block to the upload_attachment 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.

How do I block upload_attachment completely? +

Set action: deny in the PolicyLayer policy for upload_attachment. 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.

What MCP server provides upload_attachment? +

upload_attachment is provided by the ServiceNow MCP Server MCP server (@aartiq/servicenow-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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