replace_obsidian_frontmatter · Obsidian MCP Server MCP

WHAT IT DOES

What replace_obsidian_frontmatter does on Obsidian MCP Server

AI agents use replace_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 replace_obsidian_frontmatter needs a policy

The tool replaces frontmatter (YAML metadata) in Obsidian notes, which is a reversible write operation that modifies structured data within notes. This is categorized as Write rather than Execute because it modifies note metadata directly rather than triggering code execution.

From the tool's definition Tool name is 'replace_obsidian_frontmatter' and operates within the Obsidian MCP Server context alongside create_obsidian_note, append_to_obsidian_note, and delete_obsidian_note tools.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

replace_obsidian_frontmatter Rate-limited

replace_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": {
    "replace_obsidian_frontmatter": {
      "limits": [
        {
          "counter": "replace_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 replace_obsidian_frontmatter

What does the replace_obsidian_frontmatter tool do? +

replace_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 replace_obsidian_frontmatter? +

Register the Obsidian MCP Server MCP server in PolicyLayer and add a rule for replace_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 replace_obsidian_frontmatter? +

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

Can I rate-limit replace_obsidian_frontmatter? +

Yes. Add a rate_limit block to the replace_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 replace_obsidian_frontmatter completely? +

Set action: deny in the PolicyLayer policy for replace_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 replace_obsidian_frontmatter? +

replace_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.