set_frontmatter | PolicyLayer

WHAT IT DOES

What set_frontmatter does on Obsidian MCP (pgvector + Ollama, self-hosted)

AI agents use set_frontmatter to create or update resources in Obsidian MCP (pgvector + Ollama, self-hosted) — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Obsidian MCP (pgvector + Ollama, self-hosted) environment.

WHY IT NEEDS A POLICY

Why set_frontmatter needs a policy

The tool modifies note frontmatter (metadata), which is a reversible write operation. This fits the Write category rather than Execute because it targets data structure updates, not command execution. It is less severe than Destructive (no deletion) and aligns with the edit/create operations on this note management server.

From the tool's definition Tool name 'set_frontmatter' indicates modification of note metadata. Sibling tools include 'create_note', 'edit_note', and 'delete_note', establishing this as a note manipulation server. 'Set' is a write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_frontmatter Rate-limited

set_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": {
    "set_frontmatter": {
      "limits": [
        {
          "counter": "set_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 (pgvector + Ollama, self-hosted), so you can run agents against it safely.

FAQ

Questions about set_frontmatter

What does the set_frontmatter tool do? +

set_frontmatter. It is categorised as a Write tool in the Obsidian MCP (pgvector + Ollama, self-hosted) MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_frontmatter? +

Register the Obsidian MCP (pgvector + Ollama, self-hosted) MCP server in PolicyLayer and add a rule for set_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 (pgvector + Ollama, self-hosted). Nothing to install.

What risk level is set_frontmatter? +

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

Can I rate-limit set_frontmatter? +

Yes. Add a rate_limit block to the set_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 set_frontmatter completely? +

Set action: deny in the PolicyLayer policy for set_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 set_frontmatter? +

set_frontmatter is provided by the Obsidian MCP (pgvector + Ollama, self-hosted) MCP server (maxkuminov/obsidian-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.