append_content · Obsidian MCP Server MCP: Risk & Policy

WHAT IT DOES

What append_content does on Obsidian MCP Server

AI agents use append_content 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 append_content needs a policy

Appending content modifies a file reversibly (the original content remains; new content is added). This is a Write operation. Misuse could corrupt notes or inject unwanted content, but it does not irreversibly destroy existing data.

From the tool's definition 'Append content to an existing file' — adds data to an existing file without deleting it

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

append_content Rate-limited

append_content 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": {
    "append_content": {
      "limits": [
        {
          "counter": "append_content_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 append_content

What does the append_content tool do? +

Append content to an existing file. 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 append_content? +

Register the Obsidian MCP Server MCP server in PolicyLayer and add a rule for append_content: 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 append_content? +

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

Can I rate-limit append_content? +

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

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

append_content is provided by the Obsidian MCP Server MCP server (victors081/obsidian-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.