Rules & Templates

Audience: Customer — this page documents rule types, templates, and custom rules.

Rulecatch ships with 200+ rule templates organized into 17 categories. Rules are assigned based on the user's tech stack selection during onboarding.

Rule Sources

Source	Description	Stored In	Available To
Template	Pre-built rules from Rulecatch library	`Global.ruleTemplates`	All plans
Custom	User-created rules	`user_rules`	Enterprise only
Always-Active	Rules that apply to all users	`Global.ruleTemplates` (alwaysActive: true)	All plans

Rule Structure

Every rule (template or custom) has:

Field	Type	Description
`name`	string	Human-readable name
`description`	string	What the rule detects
`category`	string	Grouping category
`severity`	`error` \| `warning` \| `info`	Impact level
`conditions`	array	Match conditions (see Matching)
`fixTimeMinutes`	number	Estimated time to fix
`difficulty`	string	`easy`, `medium`, or `hard`

Template-Specific Fields

Field	Type	Description
`pattern`	string	Match pattern (text or regex)
`isRegex`	boolean	Whether pattern is a regular expression
`isTemplate`	boolean	Always `true` for templates
`enabled`	boolean	Whether template is active globally
`alwaysActive`	boolean	If true, applies regardless of stack

Categories

Templates are organized into 17 categories:

Category	Examples	Triggered By
`security`	Hardcoded secrets, SQL injection, XSS	All stacks (universal)
`ai-specific`	AI Errors, prompt injection	All stacks (universal)
`typescript`	Type safety, strict mode	TypeScript in stack
`react`	Hook rules, key props, state management	React/Next.js in stack
`nextjs`	App Router patterns, server components	Next.js in stack
`mongodb`	Aggregation patterns, injection prevention	MongoDB in stack
`sql`	Query safety, injection prevention	PostgreSQL/MySQL/Supabase
`nodejs`	Error handling, async patterns	JavaScript/Node.js in stack
`python`	Pythonic patterns, security	Python in stack
`css`	Accessibility, performance	CSS in stack
`html`	Semantic HTML, accessibility	HTML in stack
`docker`	Dockerfile best practices, security	Docker/AWS/GCP/Azure in stack
`git`	Commit patterns, branch management	GitHub/GitLab/Bitbucket in stack
`vue`	Vue-specific patterns	Vue in stack
`performance`	Performance anti-patterns	CSS in stack

Stack-to-Category Mapping

When a user selects their tech stack during onboarding, Rulecatch maps each selection to rule categories:

Database Selections

Selection	Categories Added
MongoDB	`mongodb`
PostgreSQL	`sql`
MySQL	`sql`
Redis	`nodejs`
Supabase	`sql`, `security`
Firebase	`security`

Language Selections

Selection	Categories Added
HTML	`html`, `security`
CSS	`css`, `performance`
JavaScript	`nodejs`, `ai-specific`
TypeScript	`typescript`, `ai-specific`
Python	`python`

Framework Selections

Selection	Categories Added
React	`react`, `ai-specific`
Vue	`vue`
Next.js	`nextjs`, `react`

Git Provider Selections

Selection	Categories Added
GitHub	`git`
GitLab	`git`
Bitbucket	`git`

Deploy Platform Selections

Selection	Categories Added
Docker	`docker`, `security`
AWS	`security`, `docker`
Vercel	`nextjs`, `security`
GCP	`security`, `docker`
Azure	`security`, `docker`
Dokploy	`docker`, `security`
Netlify	`security`
Heroku	`docker`, `nodejs`

Universal Categories

These categories are always included regardless of stack selection:

security — Security rules apply to every project
ai-specific — AI-related rules apply to all AI-assisted development

Always-Active Rules

Some rules bypass the stack/category system entirely and apply to all users. These are marked with alwaysActive: true in the template.

Currently, the AI Errors category contains always-active rules that detect common AI coding mistakes.

Always-active rules:

Cannot be disabled by users
Are not affected by stack selection
Are deduplicated if they overlap with a user's stack categories

Template Sync

Rule templates are stored in the Global database on each MongoDB cluster. The rule-sync-watcher service ensures templates are synchronized between the source of truth and both regional clusters (US and EU).

Disabling Templates

Users can disable specific templates without removing them:

The disabled template ID is added to the user's disabledTemplates array
During rule resolution, disabled template IDs are excluded
Templates can be re-enabled from the Rules page

Custom Rules (Enterprise)

Enterprise users can create custom rules with:

Custom conditions (field + operator + value)
Any severity level
Any category label
Custom fix time estimate

Custom rules are stored in the user_rules collection and loaded alongside template rules during event processing.

Pattern to Conditions Conversion

Templates can define rules using a pattern field (simpler syntax) or conditions array (full control). The Tasks service converts patterns to conditions at cache-load time:

Plain text pattern → { field: 'toolInput', operator: 'contains', value: pattern }
Regex pattern → { field: 'toolInput', operator: 'regex', value: pattern }
No pattern → { field: 'toolInput', operator: 'contains', value: name.toLowerCase() }