cast_spell · Habitca MCP: Risk & Policy

WHAT IT DOES

What cast_spell does on Habitca

AI agents invoke cast_spell to trigger actions in Habitca. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why cast_spell needs a policy

Casting a spell triggers an external operation in Habitica with real game effects — it consumes mana, potentially modifies stats/tasks for the caster and/or targeted party members. This is an action with side effects beyond simple data writes, affecting multiple users in a shared game environment. It falls under Execute as it triggers external operations whose effects depend on the arguments (spell type, target).

From the tool's definition Cast a class spell, optionally on a target task or party member

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

cast_spell Rate-limited

cast_spell stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "cast_spell": {
      "limits": [
        {
          "counter": "cast_spell_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about cast_spell

What does the cast_spell tool do? +

Cast a class spell, optionally on a target task or party member. It is categorised as a Execute tool in the Habitca MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on cast_spell? +

Register the Habitca MCP server in PolicyLayer and add a rule for cast_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 Habitca. Nothing to install.

What risk level is cast_spell? +

cast_spell is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit cast_spell? +

Yes. Add a rate_limit block to the cast_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 cast_spell completely? +

Set action: deny in the PolicyLayer policy for cast_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 cast_spell? +

cast_spell is provided by the Habitca MCP server (leon-jarvis1/habitca_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.