generate_caption · Viraly MCP Server MCP: Risk & Policy

WHAT IT DOES

What generate_caption does on Viraly MCP Server

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

WHY IT NEEDS A POLICY

Why generate_caption needs a policy

The tool generates or transforms caption text that would typically be posted to social media. This is a Write operation because it creates or modifies content reversibly (captions can be edited or deleted later). It is not Destructive (changes are reversible), Execute (no code/commands executed), or Financial.

From the tool's definition Tool description states it can 'Generate or transform a social media caption using AI' and 'Returns the caption text.' This creates new or modified content that will be written to social media platforms.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

generate_caption Rate-limited

generate_caption 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": {
    "generate_caption": {
      "limits": [
        {
          "counter": "generate_caption_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Viraly MCP Server, so you can run agents against it safely.

FAQ

Questions about generate_caption

What does the generate_caption tool do? +

Generate or transform a social media caption using AI. Returns the caption text. Use mode=. It is categorised as a Write tool in the Viraly 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 generate_caption? +

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

What risk level is generate_caption? +

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

Can I rate-limit generate_caption? +

Yes. Add a rate_limit block to the generate_caption 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 generate_caption completely? +

Set action: deny in the PolicyLayer policy for generate_caption. 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 generate_caption? +

generate_caption is provided by the Viraly MCP Server MCP server (viraly-io/viraly-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.