replace_in_note

THE RISK

Medium Risk

Why replace_in_note needs a policy

This tool creates or modifies data reversibly by replacing content within a note. It does not delete notes (which would be Destructive) or irreversibly remove data, but rather updates existing content. The modification is reversible through undo or re-editing.

From the tool's definition Tool name 'replace_in_note' and description explicitly states 'Search-and-replace' functionality, which modifies note content. The mention of 'regex patterns' indicates pattern-based matching for replacements.

Documented attack patterns abuse exactly the kind of access replace_in_note gives an agent:

POLICY

How to control replace_in_note

PolicyLayer is an MCP gateway — it sits between your AI agents and Obsidian Mcp Pro, and nothing reaches the server without passing your rules. This is the rule we recommend for replace_in_note:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "replace_in_note": {
      "limits": [
        {
          "counter": "replace_in_note_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

replace_in_note 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.

Create a free account and register Obsidian Mcp Pro — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Obsidian Mcp Pro tools

Destructive delete_note Delete a note. By default the file is moved to the vault Execute index_vault Build or refresh the embedding index used by Execute query_base Run a Base file Write append_to_note Append text to the end of an existing note without altering prior content. By default, ins Write prepend_to_note Insert content at the top of an existing note Write add_canvas_edge Create a directed edge connecting two existing canvas nodes. Both fromNode and toNode must Write add_canvas_node Add a new node to an Obsidian canvas and persist the updated file. Supports four node type Write create_daily_note Create a daily note for today (or a specific date) in the vault

All 41 Obsidian Mcp Pro tools →

Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about replace_in_note

What does the replace_in_note tool do? +

Search-and-replace within a single note. Supports literal strings or regex patterns. With. It is categorised as a Write tool in the Obsidian Mcp Pro 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_in_note? +

Register the Obsidian Mcp Pro MCP server in PolicyLayer and add a rule for replace_in_note: 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 Pro. Nothing to install.

What risk level is replace_in_note? +

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

Can I rate-limit replace_in_note? +

Yes. Add a rate_limit block to the replace_in_note 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_in_note completely? +

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

replace_in_note is provided by the Obsidian Mcp Pro MCP server (rps321321/obsidian-mcp-pro). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Obsidian Mcp Pro tool call.

Start from Obsidian Mcp Pro, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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