Adds a new field to an existing model.
AI agents use modelFieldAdd to create or update resources in Anki — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Anki environment.
This tool modifies the schema of an Anki note model by adding a new field. While this is a structural change that affects how notes are created and organized, it is reversible and does not delete data or execute arbitrary code. The impact is scoped to model configuration. Severity is medium because widespread addition of fields could disrupt the usability of a model or cause confusion, but the change can be undone.
From the tool's definition Tool name 'modelFieldAdd' and description 'Adds a new field to an existing model' indicate creation/modification of data structure. The action is reversible (fields can be removed or modified in subsequent operations).
Documented attack patterns abuse exactly the kind of access modelFieldAdd gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Anki, and nothing reaches the server without passing your rules. This is the rule we recommend for modelFieldAdd:
{
"version": "1",
"default": "deny",
"tools": {
"modelFieldAdd": {
"limits": [
{
"counter": "modelfieldadd_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}modelFieldAdd 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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Adds a new field to an existing model. It is categorised as a Write tool in the Anki MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Anki MCP server in PolicyLayer and add a rule for modelFieldAdd: 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 Anki. Nothing to install.
modelFieldAdd 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 modelFieldAdd 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 modelFieldAdd. 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.
modelFieldAdd is provided by the Anki MCP server (ujisati/anki-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Anki, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
40 Anki tools catalogued and risk-classified — across an index of 43,000+ MCP servers.