Tool Filtering

The PagerDuty MCP Server exposes 55 tools across 14 domains. While comprehensive, this large number of tools can degrade AI performance — LLMs perform better with a focused, relevant set of tools.

This guide explains how to filter tools using mcp-proxy, a lightweight proxy server that sits between your MCP client and the PagerDuty MCP Server.

Background

This solution addresses the request in GitHub Issue #68: "Can we add a flag to filter MCP tools by area?" While native filtering is not yet built into the server, the mcp-proxy approach provides an effective workaround.

Local Server Only

Tool filtering via mcp-proxy is not available for the Remote MCP Server. The proxy works by wrapping a local subprocess — it cannot intercept a remotely-hosted connection.

How It Works

MCP Client → mcp-proxy (localhost:9090) → PagerDuty MCP Server
                   ↑
            Tool filter applied here

The proxy starts the PagerDuty MCP Server as a subprocess and only forwards a selected subset of tools to your client.

Installation

Install mcp-proxy:

# Using Go
go install github.com/TBXark/mcp-proxy@latest

# Or download a pre-built binary from:
# https://github.com/TBXark/mcp-proxy/releases

Configuration

Create a mcp_proxy_config.json file:

Allow List (Whitelist)

Only expose the tools you explicitly list:

{
  "mcpProxy": {
    "baseURL": "http://localhost:9090",
    "addr": ":9090",
    "type": "streamable-http"
  },
  "mcpServers": {
    "pagerduty": {
      "command": "uvx",
      "args": ["pagerduty-mcp"],
      "env": {
        "PAGERDUTY_USER_API_KEY": "your-api-token-here"
      },
      "options": {
        "toolFilter": {
          "mode": "allow",
          "list": [
            "get_user_data",
            "list_incidents",
            "get_incident",
            "list_oncalls",
            "list_schedules"
          ]
        }
      }
    }
  }
}

Deny List (Blacklist)

Expose all tools except those you list:

{
  "mcpProxy": {
    "baseURL": "http://localhost:9090",
    "addr": ":9090",
    "type": "streamable-http"
  },
  "mcpServers": {
    "pagerduty": {
      "command": "uvx",
      "args": ["pagerduty-mcp"],
      "env": {
        "PAGERDUTY_USER_API_KEY": "your-api-token-here"
      },
      "options": {
        "toolFilter": {
          "mode": "deny",
          "list": [
            "list_status_pages",
            "list_status_page_severities",
            "list_status_page_impacts",
            "list_status_page_statuses",
            "get_status_page_post",
            "list_status_page_post_updates",
            "create_status_page_post",
            "create_status_page_post_update"
          ]
        }
      }
    }
  }
}

With Write Tools

{
  "mcpProxy": {
    "baseURL": "http://localhost:9090",
    "addr": ":9090",
    "type": "streamable-http"
  },
  "mcpServers": {
    "pagerduty": {
      "command": "uvx",
      "args": ["pagerduty-mcp", "--enable-write-tools"],
      "env": {
        "PAGERDUTY_USER_API_KEY": "your-api-token-here"
      },
      "options": {
        "toolFilter": {
          "mode": "allow",
          "list": [
            "list_incidents",
            "get_incident",
            "create_incident",
            "manage_incidents",
            "add_note_to_incident"
          ]
        }
      }
    }
  }
}

Starting the Proxy

mcp-proxy --config mcp_proxy_config.json

The proxy starts on http://localhost:9090 by default.

Configuring Your MCP Client

Point your client to the proxy instead of running the server directly.

Cursor / Claude Desktop

{
  "mcpServers": {
    "pagerduty": {
      "url": "http://localhost:9090/mcp"
    }
  }
}

VS Code

{
  "mcp": {
    "servers": {
      "pagerduty": {
        "type": "http",
        "url": "http://localhost:9090/mcp"
      }
    }
  }
}

Suggested Tool Sets by Use Case

Use Case	Recommended Tools
Incident Management	list_incidents, get_incident, list_incident_notes, manage_incidents, add_note_to_incident
On-Call Overview	list_oncalls, list_schedules, get_schedule, list_schedule_users
Service Health	list_services, get_service, list_change_events, list_log_entries
Team Operations	list_teams, get_team, list_team_members, list_users
Minimal Read-Only	get_user_data, list_incidents, get_incident, list_oncalls, list_schedules