add info to project root

AGENTS.md

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+# AGENTS.md
+
+This file provides guidance to AI coding agents (Claude Code, Cursor, Copilot, etc.) when working with code in this repository.
+
+## Repository Overview
+
+A collection of PostgreSQL best practices skills for Claude.ai and Claude Code, maintained by Supabase. Skills are packaged instructions that extend agent capabilities for database optimization.
+
+## Creating a New Rule
+
+### Directory Structure
+
+```
+skills/
+  postgresql-best-practices/
+    SKILL.md              # Required: skill definition
+    AGENTS.md             # Generated: compiled rules
+    metadata.json         # Required: version and metadata
+    rules/
+      _template.md        # Template for new rules
+      _sections.md        # Section definitions
+      _contributing.md    # Writing guidelines
+      {prefix}-{name}.md  # Individual rule files
+
+packages/
+  postgresql-best-practices-build/
+    src/                  # Build system source
+    package.json          # NPM scripts
+```
+
+### Naming Conventions
+
+- **Rule files**: `{prefix}-{kebab-case-name}.md` (e.g., `query-missing-indexes.md`)
+- **Prefixes determine section**: `query-`, `conn-`, `schema-`, `lock-`, `security-`, `data-`, `monitor-`, `advanced-`
+- **Special files**: Prefixed with `_` (e.g., `_template.md`, `_sections.md`)
+
+### Rule File Format
+
+```markdown
+---
+title: Clear, Action-Oriented Title
+impact: CRITICAL|HIGH|MEDIUM-HIGH|MEDIUM|LOW-MEDIUM|LOW
+impactDescription: Quantified benefit (e.g., "10-100x faster")
+tags: relevant, keywords
+---
+
+## [Title]
+
+[1-2 sentence explanation]
+
+**Incorrect (description):**
+
+```sql
+-- Comment explaining what's wrong
+[Bad SQL example]
+```
+
+**Correct (description):**
+
+```sql
+-- Comment explaining why this is better
+[Good SQL example]
+```
+
+**Supabase Note:** [Optional platform-specific guidance]
+
+Reference: [Link](url)
+```
+
+### Best Practices for Context Efficiency
+
+Skills are loaded on-demand. To minimize context usage:
+
+- **Keep rules focused** - One optimization pattern per rule
+- **Write specific titles** - Helps the agent know exactly when to apply
+- **Use progressive disclosure** - Reference supporting files when needed
+- **Self-contained examples** - Complete, runnable SQL
+- **Quantify impact** - Include specific metrics (10x faster, 50% smaller)
+
+### Build System
+
+After creating or updating rules:
+
+```bash
+cd packages/postgresql-best-practices-build
+npm install
+npm run validate  # Check rule format
+npm run build     # Generate AGENTS.md
+```
+
+### Impact Levels
+
+| Level | Improvement | Examples |
+|-------|-------------|----------|
+| CRITICAL | 10-100x | Missing indexes, connection exhaustion |
+| HIGH | 5-20x | Wrong index types, poor partitioning |
+| MEDIUM-HIGH | 2-5x | N+1 queries, RLS optimization |
+| MEDIUM | 1.5-3x | Redundant indexes, stale statistics |
+| LOW-MEDIUM | 1.2-2x | VACUUM tuning, config tweaks |
+| LOW | Incremental | Advanced patterns, edge cases |
+
+### File Prefix to Section Mapping
+
+| Prefix | Section | Priority |
+|--------|---------|----------|
+| `query-` | Query Performance | 1 (CRITICAL) |
+| `conn-` | Connection Management | 2 (CRITICAL) |
+| `schema-` | Schema Design | 3 (HIGH) |
+| `lock-` | Concurrency & Locking | 4 (MEDIUM-HIGH) |
+| `security-` | Security & RLS | 5 (MEDIUM-HIGH) |
+| `data-` | Data Access Patterns | 6 (MEDIUM) |
+| `monitor-` | Monitoring & Diagnostics | 7 (LOW-MEDIUM) |
+| `advanced-` | Advanced Features | 8 (LOW) |
+
+### End-User Installation
+
+**Claude Code:**
+```bash
+npx add-skill supabase/postgres-best-practices
+```
+
+**claude.ai:**
+Add the skill to project knowledge or paste SKILL.md contents into the conversation.

CLAUDE.md

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+AGENTS.md

README.md

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+# Agent Skills
+
+A collection of skills for AI coding agents. Skills are packaged instructions and scripts that extend agent capabilities.
+
+Skills follow the [Agent Skills](https://agentskills.io/) format.
+
+## Available Skills
+
+### postgresql-best-practices
+
+PostgreSQL performance optimization guidelines from Supabase. Contains rules across 8 categories, prioritized by impact.
+
+**Use when:**
+- Writing SQL queries or designing schemas
+- Implementing indexes or query optimization
+- Reviewing database performance issues
+- Configuring connection pooling or scaling
+- Working with Row-Level Security (RLS)
+
+**Categories covered:**
+- Query Performance (Critical)
+- Connection Management (Critical)
+- Schema Design (High)
+- Concurrency & Locking (Medium-High)
+- Security & RLS (Medium-High)
+- Data Access Patterns (Medium)
+- Monitoring & Diagnostics (Low-Medium)
+- Advanced Features (Low)
+
+## Installation
+
+```bash
+npx add-skill supabase/postgres-best-practices
+```
+
+## Usage
+
+Skills are automatically available once installed. The agent will use them when relevant tasks are detected.
+
+**Examples:**
+```
+Optimize this PostgreSQL query
+```
+```
+Review my schema for performance issues
+```
+```
+Help me add proper indexes to this table
+```
+
+## Skill Structure
+
+Each skill contains:
+- `SKILL.md` - Instructions for the agent
+- `AGENTS.md` - Compiled rules document (generated)
+- `rules/` - Individual rule files
+- `metadata.json` - Version and metadata
+
+## License
+
+MIT