create_or_update_note

THE RISK

Medium Risk

Why create_or_update_note needs a policy

The tool creates or modifies notes through a write operation (create/update). While the changes can potentially be undone through version history or manual reversion, this is a data modification operation that falls under Write rather than Read (it modifies state) or Destructive (changes are reversible).

From the tool's definition Tool description states "Create or update a note" and "Performs upsert operation" - these are reversible write operations that modify data in the Obsidian vault without permanent deletion.

Documented attack patterns abuse exactly the kind of access create_or_update_note gives an agent:

POLICY

How to control create_or_update_note

PolicyLayer is an MCP gateway — it sits between your AI agents and Obsidian Local REST API MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_or_update_note:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_or_update_note": {
      "limits": [
        {
          "counter": "create_or_update_note_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

create_or_update_note 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.

Create a free account and register Obsidian Local REST API MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Obsidian Local REST API MCP Server tools

Destructive delete_item Delete a file or directory from the vault Write write_file Write file content with different modes: overwrite (default), append, or prepend. Handles Read find_related_notes Find notes related to a given note based on shared tags, links, or backlinks Read get_daily_note Get daily note for a specific date. Handles common daily note naming conventions and file Read get_metadata_keys Get all available frontmatter keys from notes Read get_metadata_values Get all unique values for a specific frontmatter key Read get_note Get a specific note with its content and metadata (legacy) Read get_recent_notes Get recently modified notes, ordered by modification time

All 13 Obsidian Local REST API MCP Server tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about create_or_update_note

What does the create_or_update_note tool do? +

Create or update a note with content and frontmatter. Performs upsert operation - creates if doesn. It is categorised as a Write tool in the Obsidian Local REST API MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_or_update_note? +

Register the Obsidian Local REST API MCP Server MCP server in PolicyLayer and add a rule for create_or_update_note: 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 Obsidian Local REST API MCP Server. Nothing to install.

What risk level is create_or_update_note? +

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

Can I rate-limit create_or_update_note? +

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

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

create_or_update_note is provided by the Obsidian Local REST API MCP Server MCP server (j-shelfwood/obsidian-local-rest-api-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Obsidian Local REST API MCP Server tool call.

Start from Obsidian Local REST API MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →