patch_content · Obsidian Modified MCP: Risk & Policy

WHAT IT DOES

What patch_content does on Obsidian Modified

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

WHY IT NEEDS A POLICY

Why patch_content needs a policy

This tool creates or modifies file content in a reversible manner (insertions can be undone), fitting the Write category. Severity is medium rather than high because: (1) modifications are scoped to structured locations (headings, blocks, frontmatter) rather than arbitrary positions, (2) the re-enabling with 'structural-only path validator' mitigates some risks, and (3) insertions are theoretically reversible.

From the tool's definition Tool description states 'Insert content relative to a heading, block, or frontmatter in a file.' The name 'patch_content' and verb 'insert' indicate modification of file contents.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

patch_content Rate-limited

patch_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": {
    "patch_content": {
      "limits": [
        {
          "counter": "patch_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 Modified, so you can run agents against it safely.

FAQ

Questions about patch_content

What does the patch_content tool do? +

Insert content relative to a heading, block, or frontmatter in a file. It is categorised as a Write tool in the Obsidian Modified MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on patch_content? +

Register the Obsidian Modified MCP server in PolicyLayer and add a rule for patch_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 Modified. Nothing to install.

What risk level is patch_content? +

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

Can I rate-limit patch_content? +

Yes. Add a rate_limit block to the patch_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 patch_content completely? +

Set action: deny in the PolicyLayer policy for patch_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 patch_content? +

patch_content is provided by the Obsidian Modified MCP server (@marwansaab/obsidian-modified-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.