AI agents use update_character to create or update resources in D&D MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your D&D MCP Server environment.
The tool modifies character data in a D&D campaign management system. Updates are typically reversible (can be changed again), making this a Write operation rather than Destructive. The empty description lowers confidence slightly, but the name and context of related campaign management tools confirm modification capability.
From the tool's definition Tool name 'update_character' combined with sibling tools like 'add_item_to_character', 'create_character', and 'bulk_update_characters' indicates reversible modification of campaign data.
Documented attack patterns abuse exactly the kind of access update_character gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and D&D MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_character:
{
"version": "1",
"default": "deny",
"tools": {
"update_character": {
"limits": [
{
"counter": "update_character_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_character 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.
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update_character. It is categorised as a Write tool in the D&D MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the D&D MCP Server MCP server in PolicyLayer and add a rule for update_character: 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 D&D MCP Server. Nothing to install.
update_character is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the update_character 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.
Set action: deny in the PolicyLayer policy for update_character. 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.
update_character is provided by the D&D MCP Server MCP server (study-flamingo/gamemaster-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from D&D MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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30 D&D MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.