update_todo · Obsidian Todos MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_todo does on Obsidian Todos MCP Server

AI agents use update_todo to create or update resources in Obsidian Todos MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Obsidian Todos MCP Server environment.

WHY IT NEEDS A POLICY

Why update_todo needs a policy

update_todo modifies task data (completion status, text content) but these changes are reversible through subsequent updates or undo operations in Obsidian. This is a Write operation rather than Destructive because todos can be restored to previous states.

From the tool's definition Tool description states it can 'Update an existing todo in Obsidian (mark complete, change text, etc.)' - explicitly modifying existing data reversibly within the vault.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_todo Rate-limited

update_todo 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.

View as policy code

policy.json

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

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about update_todo

What does the update_todo tool do? +

Update an existing todo in Obsidian (mark complete, change text, etc.). It is categorised as a Write tool in the Obsidian Todos 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 update_todo? +

Register the Obsidian Todos MCP Server MCP server in PolicyLayer and add a rule for update_todo: 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 Todos MCP Server. Nothing to install.

What risk level is update_todo? +

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

Can I rate-limit update_todo? +

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

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

update_todo is provided by the Obsidian Todos MCP Server MCP server (mtuckerb/obsidian-todos-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.