obsidian_update_frontmatter · Obsidian MCP Server MCP

WHAT IT DOES

What obsidian_update_frontmatter does on Obsidian MCP Server

AI agents use obsidian_update_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 obsidian_update_frontmatter needs a policy

Frontmatter updates are reversible modifications to note metadata (title, tags, properties, etc.) rather than irreversible deletions or code execution. The tool creates or modifies data (frontmatter fields) without permanently destroying content or executing arbitrary operations.

From the tool's definition Tool name 'obsidian_update_frontmatter' indicates modification of YAML frontmatter metadata in Obsidian notes.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

obsidian_update_frontmatter Rate-limited

obsidian_update_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": {
    "obsidian_update_frontmatter": {
      "limits": [
        {
          "counter": "obsidian_update_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 obsidian_update_frontmatter

What does the obsidian_update_frontmatter tool do? +

obsidian_update_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 obsidian_update_frontmatter? +

Register the Obsidian MCP Server MCP server in PolicyLayer and add a rule for obsidian_update_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 obsidian_update_frontmatter? +

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

Can I rate-limit obsidian_update_frontmatter? +

Yes. Add a rate_limit block to the obsidian_update_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 obsidian_update_frontmatter completely? +

Set action: deny in the PolicyLayer policy for obsidian_update_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 obsidian_update_frontmatter? +

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