account_block · Mastodon MCP: Risk & Policy

WHAT IT DOES

What account_block does on Mastodon

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

WHY IT NEEDS A POLICY

Why account_block needs a policy

Blocking an account is a reversible social action (it can be undone with account_unblock, which exists as a sibling tool). It modifies account relationship state but does not delete or irreversibly destroy data, placing it in the Write category. Misuse could harm user relationships but is recoverable.

From the tool's definition Block an account.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

account_block Rate-limited

account_block 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": {
    "account_block": {
      "limits": [
        {
          "counter": "account_block_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 Mastodon, so you can run agents against it safely.

FAQ

Questions about account_block

What does the account_block tool do? +

Block an account. It is categorised as a Write tool in the Mastodon MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on account_block? +

Register the Mastodon MCP server in PolicyLayer and add a rule for account_block: 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 Mastodon. Nothing to install.

What risk level is account_block? +

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

Can I rate-limit account_block? +

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

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

account_block is provided by the Mastodon MCP server (vitexsoftware/mastodon-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.