update_obsidian_frontmatter · Obsidian MCP Server MCP

WHAT IT DOES

What update_obsidian_frontmatter does on Obsidian MCP Server

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

WHY IT NEEDS A POLICY

Why update_obsidian_frontmatter needs a policy

This tool modifies (updates) note frontmatter, which is metadata in Obsidian vault files. Frontmatter updates are reversible and do not destroy data, placing it in Write category rather than Destructive. The blast radius is medium because uncontrolled frontmatter changes could corrupt note metadata or break template systems, but the impact is typically recoverable.

From the tool's definition Tool name is 'update_obsidian_frontmatter'; sibling tools on the server include create, delete, append, and insert operations on Obsidian notes, establishing this as a data modification context.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_obsidian_frontmatter Rate-limited

update_obsidian_frontmatter 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_obsidian_frontmatter": {
      "limits": [
        {
          "counter": "update_obsidian_frontmatter_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 MCP Server, so you can run agents against it safely.

FAQ

Questions about update_obsidian_frontmatter

What does the update_obsidian_frontmatter tool do? +

update_obsidian_frontmatter. It is categorised as a Write tool in the Obsidian 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_obsidian_frontmatter? +

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

What risk level is update_obsidian_frontmatter? +

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

Can I rate-limit update_obsidian_frontmatter? +

Yes. Add a rate_limit block to the update_obsidian_frontmatter 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_obsidian_frontmatter completely? +

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

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