substack_update_draft · Substack MCP Server MCP

WHAT IT DOES

What substack_update_draft does on Substack MCP Server

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

WHY IT NEEDS A POLICY

Why substack_update_draft needs a policy

This tool modifies existing draft content reversibly—updates can be undone by making further edits or discarding the draft before publication. It does not publish content (which would be Execute) or delete it (which would be Destructive). The medium severity reflects that an AI agent could maliciously modify a user's unpublished work, but the impact is limited to draft state and reversible before publication.

From the tool's definition Tool name 'substack_update_draft' and description 'Update an existing draft' indicate modification of existing data. Server description confirms 'creating drafts, publishing posts' as core capabilities.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

substack_update_draft Rate-limited

substack_update_draft 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": {
    "substack_update_draft": {
      "limits": [
        {
          "counter": "substack_update_draft_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 Substack MCP Server, so you can run agents against it safely.

FAQ

Questions about substack_update_draft

What does the substack_update_draft tool do? +

Update an existing draft. It is categorised as a Write tool in the Substack 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 substack_update_draft? +

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

What risk level is substack_update_draft? +

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

Can I rate-limit substack_update_draft? +

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

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

substack_update_draft is provided by the Substack MCP Server MCP server (jessicaruthabbott/my-substack-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.