MC Prevent

What it does

When you open a dbt model or reference a table, the plugin automatically pulls Monte Carlo context into your editor: table health, active alerts, downstream blast radius, and monitor coverage. Your AI editor uses that context to shape its recommendations — not just surface it as a sidebar.

Before any edit, it assesses risk. After an edit, it generates targeted validation queries. When you add new logic, it generates and deploys the right monitor.

No commands required. It activates automatically based on what you're working on.

Core workflows

1. Table health check

Fires when you open a .sql file, dbt model, or reference a table name. Surfaces freshness, row counts, importance score, lineage, and active alerts.

2. Change impact assessment

Fires automatically before any SQL edit — not just schema changes, but filter tweaks, bugfixes, parameter changes, and reverts. Returns:

• Downstream blast radius (tables, models, BI reports)
• Active incidents on affected tables
• Column exposure in recent queries
• Monitor coverage gaps
• A risk tier: High / Medium / Low
• A plain-English recommendation tied to the specific change

If risk is High or Medium, the plugin stops and asks for confirmation before editing.

3. Monitor generation

After you add a new column, metric, filter, or business rule, the plugin suggests and generates the right monitor type — validation, metric, comparison, or custom SQL — as a YAML file ready to deploy.

4. Alert triage

When you're investigating a data quality issue: lists open alerts, checks table state, traces lineage to find the root cause or blast radius.

5. Change validation queries

After you've made a change and are ready to test, ask: "generate validation queries" or "validate this change." The plugin generates 3–5 targeted SQL queries — null checks, before/after row counts, distribution checks — based on the exact columns, filters, and business logic you modified. Saved to validation/<table_name>_<timestamp>.sql.

Compatibility

Editors

Works with any AI editor that supports MCP and the Agent Skills format: Claude Code, Cursor, VS Code.

Data stacks

Prerequisites

• Claude Code, Cursor, VS Code, or any editor with MCP support
• Monte Carlo account with Editor role or above
• MC CLI for monitor deployment: pip install montecarlodata

Installation

Recommended: Install via plugin

The plugin bundles the skill with hooks, commands, and pre-configured tool permissions for the best experience.

Step 1 — Add the Monte Carlo plugin marketplace:

/plugin marketplace add monte-carlo-data/mcd-agent-toolkit

Step 2 — Install the plugin:

/plugin install mc-prevent@mcd-agent-toolkit

Step 3 — Authenticate. In Claude Code, run /mcp, select monte-carlo-mcp, and complete the OAuth flow in your browser.

Step 4 — Verify: paste "Test my Monte Carlo connection" into Claude. It will confirm your credentials.

Note: The plugin bundles its own MCP server, so no separate MCP configuration is needed. Updates are available via claude plugin update.

Advanced: Install the skill directly

For use with non-Claude-Code agents or skill registries.

Via Vercel CLI:

npx skills add monte-carlo-data/mcd-agent-toolkit --skill prevent

Manual:

cp -r skills/prevent ~/.claude/skills/prevent

You'll also need to configure the Monte Carlo MCP server and set tool permissions manually. See the full setup guide.

Deploying generated monitors

When the plugin generates a monitor, it saves YAML to monitors/<table>.yml. Deploy with the MC CLI:

montecarlo monitors apply --dry-run    # preview changes
montecarlo monitors apply --auto-yes   # apply

Your project needs a montecarlo.yml in the working directory:

version: 1
namespace: <your-namespace>
default_resource: <your-warehouse-name>

What it won't activate on

The plugin only fires on dbt models. It does not activate on seed files, analysis files, config files (dbt_project.yml, etc.), or one-off SQL scripts outside a dbt project. For macros and snapshots, auto-context is skipped on open, but the pre-edit gate still applies.

Troubleshooting

See TROUBLESHOOTING.md in the repository.