add_spell · DM20 Protocol MCP: Risk & Policy

WHAT IT DOES

What add_spell does on DM20 Protocol

AI agents use add_spell to create or update resources in DM20 Protocol — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your DM20 Protocol environment.

WHY IT NEEDS A POLICY

Why add_spell needs a policy

This tool creates or modifies character spell lists, which is reversible game state manipulation. It fits the Write category (creates or modifies data reversibly). Severity is medium because misuse could disrupt campaign balance or give unfair character advantages, but effects are confined to a game session and can be corrected by a DM.

From the tool's definition Tool name 'add_spell' and context of D&D campaign management system with character sheet modifications ('add_item_to_character', 'approve_sheet_change' as sibling tools). The 'add_' prefix indicates creation/modification of game data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_spell Rate-limited

add_spell 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": {
    "add_spell": {
      "limits": [
        {
          "counter": "add_spell_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 DM20 Protocol, so you can run agents against it safely.

FAQ

Questions about add_spell

What does the add_spell tool do? +

add_spell. It is categorised as a Write tool in the DM20 Protocol MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_spell? +

Register the DM20 Protocol MCP server in PolicyLayer and add a rule for add_spell: 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 DM20 Protocol. Nothing to install.

What risk level is add_spell? +

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

Can I rate-limit add_spell? +

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

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

add_spell is provided by the DM20 Protocol MCP server (polloinfilzato/dm20-protocol). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.