Update specific fields of an EXISTING Anki note. Use this ONLY when you already have the noteId of an existing card. For creating new cards, use add_card instead.
AI agents use update_note_fields to create or update resources in Anki MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Anki MCP Server environment.
This tool modifies existing flashcard data (note fields) but the changes are reversible—fields can be updated again to previous values. This is characteristic of Write operations. The severity is medium because unintended field modifications could corrupt study data or lose important information, but the impact is limited to individual notes and reversible.
From the tool's definition Tool description explicitly states 'Update specific fields of an EXISTING Anki note', and the name contains 'update' which modifies data reversibly.
Documented attack patterns abuse exactly the kind of access update_note_fields gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Anki MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_note_fields:
{
"version": "1",
"default": "deny",
"tools": {
"update_note_fields": {
"limits": [
{
"counter": "update_note_fields_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_note_fields 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.
Free to start. No card required.
Update specific fields of an EXISTING Anki note. Use this ONLY when you already have the noteId of an existing card. For creating new cards, use add_card instead. It is categorised as a Write tool in the Anki MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Anki MCP Server MCP server in PolicyLayer and add a rule for update_note_fields: 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 MCP Server. Nothing to install.
update_note_fields 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_note_fields 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_note_fields. 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_note_fields is provided by the Anki MCP Server MCP server (nietus/anki-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 22 Anki MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
22 Anki MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.