apply_pattern · Session Buddy MCP: Risk & Policy

WHAT IT DOES

What apply_pattern does on Session Buddy

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

WHY IT NEEDS A POLICY

Why apply_pattern needs a policy

The tool writes/records pattern application data to session memory for learning and tracking purposes. This is a reversible write operation with no destructive, financial, or execution side effects. The data being recorded is metadata about pattern usage within a coding session management context, making this a straightforward Write category tool with low severity since it merely captures informational records.

From the tool's definition Tool description states 'Record a pattern application', which indicates creating or storing a record. This is a write operation that creates/stores data about pattern applications for tracking and learning purposes.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

apply_pattern Rate-limited

apply_pattern 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": {
    "apply_pattern": {
      "limits": [
        {
          "counter": "apply_pattern_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 Session Buddy, so you can run agents against it safely.

FAQ

Questions about apply_pattern

What does the apply_pattern tool do? +

Record a pattern application for tracking and learning. It is categorised as a Write tool in the Session Buddy MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on apply_pattern? +

Register the Session Buddy MCP server in PolicyLayer and add a rule for apply_pattern: 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 Session Buddy. Nothing to install.

What risk level is apply_pattern? +

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

Can I rate-limit apply_pattern? +

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

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

apply_pattern is provided by the Session Buddy MCP server (lesleslie/session-buddy). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.