feat: add 3 new skills, JS syntax validation in hooks CI, and edge case tests

- New skills: api-design, database-migrations, deployment-patterns
- validate-hooks.js: validate inline JS syntax in node -e hook commands
- utils.test.js: edge case tests for findFiles with null/undefined inputs
- README: update skill count to 35, add new skills to directory tree

README.md

@@ -143,7 +143,7 @@ For manual install instructions see the README in the `rules/` folder.
 /plugin list everything-claude-code@everything-claude-code
 ```
 
-✨ **That's it!** You now have access to 13 agents, 34 skills, and 31 commands.
+✨ **That's it!** You now have access to 13 agents, 35 skills, and 31 commands.
 
 ---
 
@@ -239,6 +239,9 @@ everything-claude-code/
 |   |-- postgres-patterns/         # PostgreSQL optimization patterns (NEW)
 |   |-- nutrient-document-processing/ # Document processing with Nutrient API (NEW)
 |   |-- project-guidelines-example/   # Template for project-specific skills
+|   |-- database-migrations/         # Migration patterns (Prisma, Drizzle, Django, Go) (NEW)
+|   |-- api-design/                  # REST API design, pagination, error responses (NEW)
+|   |-- deployment-patterns/         # CI/CD, Docker, health checks, rollbacks (NEW)
 |
 |-- commands/         # Slash commands for quick execution
 |   |-- tdd.md              # /tdd - Test-driven development
@@ -794,7 +797,7 @@ The configuration is automatically detected from `.opencode/opencode.json`.
 |---------|-------------|----------|--------|
 | Agents | ✅ 13 agents | ✅ 12 agents | **Claude Code leads** |
 | Commands | ✅ 31 commands | ✅ 24 commands | **Claude Code leads** |
-| Skills | ✅ 34 skills | ✅ 16 skills | **Claude Code leads** |
+| Skills | ✅ 35 skills | ✅ 16 skills | **Claude Code leads** |
 | Hooks | ✅ 3 phases | ✅ 20+ events | **OpenCode has more!** |
 | Rules | ✅ 8 rules | ✅ 8 rules | **Full parity** |
 | MCP Servers | ✅ Full | ✅ Full | **Full parity** |

scripts/ci/validate-hooks.js

@@ -5,6 +5,7 @@
 
 const fs = require('fs');
 const path = require('path');
+const vm = require('vm');
 
 const HOOKS_FILE = path.join(__dirname, '../../hooks/hooks.json');
 const VALID_EVENTS = ['PreToolUse', 'PostToolUse', 'PreCompact', 'SessionStart', 'SessionEnd', 'Stop', 'Notification', 'SubagentStop'];
@@ -68,6 +69,17 @@ function validateHooks() {
             if (!hook.command || (typeof hook.command !== 'string' && !Array.isArray(hook.command))) {
               console.error(`ERROR: ${eventType}[${i}].hooks[${j}] missing or invalid 'command' field`);
               hasErrors = true;
+            } else if (typeof hook.command === 'string') {
+              // Validate inline JS syntax in node -e commands
+              const nodeEMatch = hook.command.match(/^node -e "(.*)"$/s);
+              if (nodeEMatch) {
+                try {
+                  new vm.Script(nodeEMatch[1].replace(/\\"/g, '"').replace(/\\n/g, '\n'));
+                } catch (syntaxErr) {
+                  console.error(`ERROR: ${eventType}[${i}].hooks[${j}] has invalid inline JS: ${syntaxErr.message}`);
+                  hasErrors = true;
+                }
+              }
             }
           }
         }
@@ -96,6 +108,17 @@ function validateHooks() {
           if (!h.command || (typeof h.command !== 'string' && !Array.isArray(h.command))) {
             console.error(`ERROR: Hook ${i}.hooks[${j}] missing or invalid 'command' field`);
             hasErrors = true;
+          } else if (typeof h.command === 'string') {
+            // Validate inline JS syntax in node -e commands
+            const nodeEMatch = h.command.match(/^node -e "(.*)"$/s);
+            if (nodeEMatch) {
+              try {
+                new vm.Script(nodeEMatch[1].replace(/\\"/g, '"').replace(/\\n/g, '\n'));
+              } catch (syntaxErr) {
+                console.error(`ERROR: Hook ${i}.hooks[${j}] has invalid inline JS: ${syntaxErr.message}`);
+                hasErrors = true;
+              }
+            }
           }
         }
       }

skills/api-design/SKILL.md

@@ -0,0 +1,522 @@
+---
+name: api-design
+description: REST API design patterns including resource naming, status codes, pagination, filtering, error responses, versioning, and rate limiting for production APIs.
+---
+
+# API Design Patterns
+
+Conventions and best practices for designing consistent, developer-friendly REST APIs.
+
+## When to Activate
+
+- Designing new API endpoints
+- Reviewing existing API contracts
+- Adding pagination, filtering, or sorting
+- Implementing error handling for APIs
+- Planning API versioning strategy
+- Building public or partner-facing APIs
+
+## Resource Design
+
+### URL Structure
+
+```
+# Resources are nouns, plural, lowercase, kebab-case
+GET    /api/v1/users
+GET    /api/v1/users/:id
+POST   /api/v1/users
+PUT    /api/v1/users/:id
+PATCH  /api/v1/users/:id
+DELETE /api/v1/users/:id
+
+# Sub-resources for relationships
+GET    /api/v1/users/:id/orders
+POST   /api/v1/users/:id/orders
+
+# Actions that don't map to CRUD (use verbs sparingly)
+POST   /api/v1/orders/:id/cancel
+POST   /api/v1/auth/login
+POST   /api/v1/auth/refresh
+```
+
+### Naming Rules
+
+```
+# GOOD
+/api/v1/team-members          # kebab-case for multi-word resources
+/api/v1/orders?status=active  # query params for filtering
+/api/v1/users/123/orders      # nested resources for ownership
+
+# BAD
+/api/v1/getUsers              # verb in URL
+/api/v1/user                  # singular (use plural)
+/api/v1/team_members          # snake_case in URLs
+/api/v1/users/123/getOrders   # verb in nested resource
+```
+
+## HTTP Methods and Status Codes
+
+### Method Semantics
+
+| Method | Idempotent | Safe | Use For |
+|--------|-----------|------|---------|
+| GET | Yes | Yes | Retrieve resources |
+| POST | No | No | Create resources, trigger actions |
+| PUT | Yes | No | Full replacement of a resource |
+| PATCH | No* | No | Partial update of a resource |
+| DELETE | Yes | No | Remove a resource |
+
+*PATCH can be made idempotent with proper implementation
+
+### Status Code Reference
+
+```
+# Success
+200 OK                    — GET, PUT, PATCH (with response body)
+201 Created               — POST (include Location header)
+204 No Content            — DELETE, PUT (no response body)
+
+# Client Errors
+400 Bad Request           — Validation failure, malformed JSON
+401 Unauthorized          — Missing or invalid authentication
+403 Forbidden             — Authenticated but not authorized
+404 Not Found             — Resource doesn't exist
+409 Conflict              — Duplicate entry, state conflict
+422 Unprocessable Entity  — Semantically invalid (valid JSON, bad data)
+429 Too Many Requests     — Rate limit exceeded
+
+# Server Errors
+500 Internal Server Error — Unexpected failure (never expose details)
+502 Bad Gateway           — Upstream service failed
+503 Service Unavailable   — Temporary overload, include Retry-After
+```
+
+### Common Mistakes
+
+```
+# BAD: 200 for everything
+{ "status": 200, "success": false, "error": "Not found" }
+
+# GOOD: Use HTTP status codes semantically
+HTTP/1.1 404 Not Found
+{ "error": { "code": "not_found", "message": "User not found" } }
+
+# BAD: 500 for validation errors
+# GOOD: 400 or 422 with field-level details
+
+# BAD: 200 for created resources
+# GOOD: 201 with Location header
+HTTP/1.1 201 Created
+Location: /api/v1/users/abc-123
+```
+
+## Response Format
+
+### Success Response
+
+```json
+{
+  "data": {
+    "id": "abc-123",
+    "email": "alice@example.com",
+    "name": "Alice",
+    "created_at": "2025-01-15T10:30:00Z"
+  }
+}
+```
+
+### Collection Response (with Pagination)
+
+```json
+{
+  "data": [
+    { "id": "abc-123", "name": "Alice" },
+    { "id": "def-456", "name": "Bob" }
+  ],
+  "meta": {
+    "total": 142,
+    "page": 1,
+    "per_page": 20,
+    "total_pages": 8
+  },
+  "links": {
+    "self": "/api/v1/users?page=1&per_page=20",
+    "next": "/api/v1/users?page=2&per_page=20",
+    "last": "/api/v1/users?page=8&per_page=20"
+  }
+}
+```
+
+### Error Response
+
+```json
+{
+  "error": {
+    "code": "validation_error",
+    "message": "Request validation failed",
+    "details": [
+      {
+        "field": "email",
+        "message": "Must be a valid email address",
+        "code": "invalid_format"
+      },
+      {
+        "field": "age",
+        "message": "Must be between 0 and 150",
+        "code": "out_of_range"
+      }
+    ]
+  }
+}
+```
+
+### Response Envelope Variants
+
+```typescript
+// Option A: Envelope with data wrapper (recommended for public APIs)
+interface ApiResponse<T> {
+  data: T;
+  meta?: PaginationMeta;
+  links?: PaginationLinks;
+}
+
+interface ApiError {
+  error: {
+    code: string;
+    message: string;
+    details?: FieldError[];
+  };
+}
+
+// Option B: Flat response (simpler, common for internal APIs)
+// Success: just return the resource directly
+// Error: return error object
+// Distinguish by HTTP status code
+```
+
+## Pagination
+
+### Offset-Based (Simple)
+
+```
+GET /api/v1/users?page=2&per_page=20
+
+# Implementation
+SELECT * FROM users
+ORDER BY created_at DESC
+LIMIT 20 OFFSET 20;
+```
+
+**Pros:** Easy to implement, supports "jump to page N"
+**Cons:** Slow on large offsets (OFFSET 100000), inconsistent with concurrent inserts
+
+### Cursor-Based (Scalable)
+
+```
+GET /api/v1/users?cursor=eyJpZCI6MTIzfQ&limit=20
+
+# Implementation
+SELECT * FROM users
+WHERE id > :cursor_id
+ORDER BY id ASC
+LIMIT 21;  -- fetch one extra to determine has_next
+```
+
+```json
+{
+  "data": [...],
+  "meta": {
+    "has_next": true,
+    "next_cursor": "eyJpZCI6MTQzfQ"
+  }
+}
+```
+
+**Pros:** Consistent performance regardless of position, stable with concurrent inserts
+**Cons:** Cannot jump to arbitrary page, cursor is opaque
+
+### When to Use Which
+
+| Use Case | Pagination Type |
+|----------|----------------|
+| Admin dashboards, small datasets (<10K) | Offset |
+| Infinite scroll, feeds, large datasets | Cursor |
+| Public APIs | Cursor (default) with offset (optional) |
+| Search results | Offset (users expect page numbers) |
+
+## Filtering, Sorting, and Search
+
+### Filtering
+
+```
+# Simple equality
+GET /api/v1/orders?status=active&customer_id=abc-123
+
+# Comparison operators (use bracket notation)
+GET /api/v1/products?price[gte]=10&price[lte]=100
+GET /api/v1/orders?created_at[after]=2025-01-01
+
+# Multiple values (comma-separated)
+GET /api/v1/products?category=electronics,clothing
+
+# Nested fields (dot notation)
+GET /api/v1/orders?customer.country=US
+```
+
+### Sorting
+
+```
+# Single field (prefix - for descending)
+GET /api/v1/products?sort=-created_at
+
+# Multiple fields (comma-separated)
+GET /api/v1/products?sort=-featured,price,-created_at
+```
+
+### Full-Text Search
+
+```
+# Search query parameter
+GET /api/v1/products?q=wireless+headphones
+
+# Field-specific search
+GET /api/v1/users?email=alice
+```
+
+### Sparse Fieldsets
+
+```
+# Return only specified fields (reduces payload)
+GET /api/v1/users?fields=id,name,email
+GET /api/v1/orders?fields=id,total,status&include=customer.name
+```
+
+## Authentication and Authorization
+
+### Token-Based Auth
+
+```
+# Bearer token in Authorization header
+GET /api/v1/users
+Authorization: Bearer eyJhbGciOiJIUzI1NiIs...
+
+# API key (for server-to-server)
+GET /api/v1/data
+X-API-Key: sk_live_abc123
+```
+
+### Authorization Patterns
+
+```typescript
+// Resource-level: check ownership
+app.get("/api/v1/orders/:id", async (req, res) => {
+  const order = await Order.findById(req.params.id);
+  if (!order) return res.status(404).json({ error: { code: "not_found" } });
+  if (order.userId !== req.user.id) return res.status(403).json({ error: { code: "forbidden" } });
+  return res.json({ data: order });
+});
+
+// Role-based: check permissions
+app.delete("/api/v1/users/:id", requireRole("admin"), async (req, res) => {
+  await User.delete(req.params.id);
+  return res.status(204).send();
+});
+```
+
+## Rate Limiting
+
+### Headers
+
+```
+HTTP/1.1 200 OK
+X-RateLimit-Limit: 100
+X-RateLimit-Remaining: 95
+X-RateLimit-Reset: 1640000000
+
+# When exceeded
+HTTP/1.1 429 Too Many Requests
+Retry-After: 60
+{
+  "error": {
+    "code": "rate_limit_exceeded",
+    "message": "Rate limit exceeded. Try again in 60 seconds."
+  }
+}
+```
+
+### Rate Limit Tiers
+
+| Tier | Limit | Window | Use Case |
+|------|-------|--------|----------|
+| Anonymous | 30/min | Per IP | Public endpoints |
+| Authenticated | 100/min | Per user | Standard API access |
+| Premium | 1000/min | Per API key | Paid API plans |
+| Internal | 10000/min | Per service | Service-to-service |
+
+## Versioning
+
+### URL Path Versioning (Recommended)
+
+```
+/api/v1/users
+/api/v2/users
+```
+
+**Pros:** Explicit, easy to route, cacheable
+**Cons:** URL changes between versions
+
+### Header Versioning
+
+```
+GET /api/users
+Accept: application/vnd.myapp.v2+json
+```
+
+**Pros:** Clean URLs
+**Cons:** Harder to test, easy to forget
+
+### Versioning Strategy
+
+```
+1. Start with /api/v1/ — don't version until you need to
+2. Maintain at most 2 active versions (current + previous)
+3. Deprecation timeline:
+   - Announce deprecation (6 months notice for public APIs)
+   - Add Sunset header: Sunset: Sat, 01 Jan 2026 00:00:00 GMT
+   - Return 410 Gone after sunset date
+4. Non-breaking changes don't need a new version:
+   - Adding new fields to responses
+   - Adding new optional query parameters
+   - Adding new endpoints
+5. Breaking changes require a new version:
+   - Removing or renaming fields
+   - Changing field types
+   - Changing URL structure
+   - Changing authentication method
+```
+
+## Implementation Patterns
+
+### TypeScript (Next.js API Route)
+
+```typescript
+import { z } from "zod";
+import { NextRequest, NextResponse } from "next/server";
+
+const createUserSchema = z.object({
+  email: z.string().email(),
+  name: z.string().min(1).max(100),
+});
+
+export async function POST(req: NextRequest) {
+  const body = await req.json();
+  const parsed = createUserSchema.safeParse(body);
+
+  if (!parsed.success) {
+    return NextResponse.json({
+      error: {
+        code: "validation_error",
+        message: "Request validation failed",
+        details: parsed.error.issues.map(i => ({
+          field: i.path.join("."),
+          message: i.message,
+          code: i.code,
+        })),
+      },
+    }, { status: 422 });
+  }
+
+  const user = await createUser(parsed.data);
+
+  return NextResponse.json(
+    { data: user },
+    {
+      status: 201,
+      headers: { Location: `/api/v1/users/${user.id}` },
+    },
+  );
+}
+```
+
+### Python (Django REST Framework)
+
+```python
+from rest_framework import serializers, viewsets, status
+from rest_framework.response import Response
+
+class CreateUserSerializer(serializers.Serializer):
+    email = serializers.EmailField()
+    name = serializers.CharField(max_length=100)
+
+class UserSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = User
+        fields = ["id", "email", "name", "created_at"]
+
+class UserViewSet(viewsets.ModelViewSet):
+    serializer_class = UserSerializer
+    permission_classes = [IsAuthenticated]
+
+    def get_serializer_class(self):
+        if self.action == "create":
+            return CreateUserSerializer
+        return UserSerializer
+
+    def create(self, request):
+        serializer = CreateUserSerializer(data=request.data)
+        serializer.is_valid(raise_exception=True)
+        user = UserService.create(**serializer.validated_data)
+        return Response(
+            {"data": UserSerializer(user).data},
+            status=status.HTTP_201_CREATED,
+            headers={"Location": f"/api/v1/users/{user.id}"},
+        )
+```
+
+### Go (net/http)
+
+```go
+func (h *UserHandler) CreateUser(w http.ResponseWriter, r *http.Request) {
+    var req CreateUserRequest
+    if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+        writeError(w, http.StatusBadRequest, "invalid_json", "Invalid request body")
+        return
+    }
+
+    if err := req.Validate(); err != nil {
+        writeError(w, http.StatusUnprocessableEntity, "validation_error", err.Error())
+        return
+    }
+
+    user, err := h.service.Create(r.Context(), req)
+    if err != nil {
+        switch {
+        case errors.Is(err, domain.ErrEmailTaken):
+            writeError(w, http.StatusConflict, "email_taken", "Email already registered")
+        default:
+            writeError(w, http.StatusInternalServerError, "internal_error", "Internal error")
+        }
+        return
+    }
+
+    w.Header().Set("Location", fmt.Sprintf("/api/v1/users/%s", user.ID))
+    writeJSON(w, http.StatusCreated, map[string]any{"data": user})
+}
+```
+
+## API Design Checklist
+
+Before shipping a new endpoint:
+
+- [ ] Resource URL follows naming conventions (plural, kebab-case, no verbs)
+- [ ] Correct HTTP method used (GET for reads, POST for creates, etc.)
+- [ ] Appropriate status codes returned (not 200 for everything)
+- [ ] Input validated with schema (Zod, Pydantic, Bean Validation)
+- [ ] Error responses follow standard format with codes and messages
+- [ ] Pagination implemented for list endpoints (cursor or offset)
+- [ ] Authentication required (or explicitly marked as public)
+- [ ] Authorization checked (user can only access their own resources)
+- [ ] Rate limiting configured
+- [ ] Response does not leak internal details (stack traces, SQL errors)
+- [ ] Consistent naming with existing endpoints (camelCase vs snake_case)
+- [ ] Documented (OpenAPI/Swagger spec updated)

skills/database-migrations/SKILL.md

@@ -0,0 +1,334 @@
+---
+name: database-migrations
+description: Database migration best practices for schema changes, data migrations, rollbacks, and zero-downtime deployments across PostgreSQL, MySQL, and common ORMs (Prisma, Drizzle, Django, TypeORM, golang-migrate).
+---
+
+# Database Migration Patterns
+
+Safe, reversible database schema changes for production systems.
+
+## When to Activate
+
+- Creating or altering database tables
+- Adding/removing columns or indexes
+- Running data migrations (backfill, transform)
+- Planning zero-downtime schema changes
+- Setting up migration tooling for a new project
+
+## Core Principles
+
+1. **Every change is a migration** — never alter production databases manually
+2. **Migrations are forward-only in production** — rollbacks use new forward migrations
+3. **Schema and data migrations are separate** — never mix DDL and DML in one migration
+4. **Test migrations against production-sized data** — a migration that works on 100 rows may lock on 10M
+5. **Migrations are immutable once deployed** — never edit a migration that has run in production
+
+## Migration Safety Checklist
+
+Before applying any migration:
+
+- [ ] Migration has both UP and DOWN (or is explicitly marked irreversible)
+- [ ] No full table locks on large tables (use concurrent operations)
+- [ ] New columns have defaults or are nullable (never add NOT NULL without default)
+- [ ] Indexes created concurrently (not inline with CREATE TABLE for existing tables)
+- [ ] Data backfill is a separate migration from schema change
+- [ ] Tested against a copy of production data
+- [ ] Rollback plan documented
+
+## PostgreSQL Patterns
+
+### Adding a Column Safely
+
+```sql
+-- GOOD: Nullable column, no lock
+ALTER TABLE users ADD COLUMN avatar_url TEXT;
+
+-- GOOD: Column with default (Postgres 11+ is instant, no rewrite)
+ALTER TABLE users ADD COLUMN is_active BOOLEAN NOT NULL DEFAULT true;
+
+-- BAD: NOT NULL without default on existing table (requires full rewrite)
+ALTER TABLE users ADD COLUMN role TEXT NOT NULL;
+-- This locks the table and rewrites every row
+```
+
+### Adding an Index Without Downtime
+
+```sql
+-- BAD: Blocks writes on large tables
+CREATE INDEX idx_users_email ON users (email);
+
+-- GOOD: Non-blocking, allows concurrent writes
+CREATE INDEX CONCURRENTLY idx_users_email ON users (email);
+
+-- Note: CONCURRENTLY cannot run inside a transaction block
+-- Most migration tools need special handling for this
+```
+
+### Renaming a Column (Zero-Downtime)
+
+Never rename directly in production. Use the expand-contract pattern:
+
+```sql
+-- Step 1: Add new column (migration 001)
+ALTER TABLE users ADD COLUMN display_name TEXT;
+
+-- Step 2: Backfill data (migration 002, data migration)
+UPDATE users SET display_name = username WHERE display_name IS NULL;
+
+-- Step 3: Update application code to read/write both columns
+-- Deploy application changes
+
+-- Step 4: Stop writing to old column, drop it (migration 003)
+ALTER TABLE users DROP COLUMN username;
+```
+
+### Removing a Column Safely
+
+```sql
+-- Step 1: Remove all application references to the column
+-- Step 2: Deploy application without the column reference
+-- Step 3: Drop column in next migration
+ALTER TABLE orders DROP COLUMN legacy_status;
+
+-- For Django: use SeparateDatabaseAndState to remove from model
+-- without generating DROP COLUMN (then drop in next migration)
+```
+
+### Large Data Migrations
+
+```sql
+-- BAD: Updates all rows in one transaction (locks table)
+UPDATE users SET normalized_email = LOWER(email);
+
+-- GOOD: Batch update with progress
+DO $$
+DECLARE
+  batch_size INT := 10000;
+  rows_updated INT;
+BEGIN
+  LOOP
+    UPDATE users
+    SET normalized_email = LOWER(email)
+    WHERE id IN (
+      SELECT id FROM users
+      WHERE normalized_email IS NULL
+      LIMIT batch_size
+      FOR UPDATE SKIP LOCKED
+    );
+    GET DIAGNOSTICS rows_updated = ROW_COUNT;
+    RAISE NOTICE 'Updated % rows', rows_updated;
+    EXIT WHEN rows_updated = 0;
+    COMMIT;
+  END LOOP;
+END $$;
+```
+
+## Prisma (TypeScript/Node.js)
+
+### Workflow
+
+```bash
+# Create migration from schema changes
+npx prisma migrate dev --name add_user_avatar
+
+# Apply pending migrations in production
+npx prisma migrate deploy
+
+# Reset database (dev only)
+npx prisma migrate reset
+
+# Generate client after schema changes
+npx prisma generate
+```
+
+### Schema Example
+
+```prisma
+model User {
+  id        String   @id @default(cuid())
+  email     String   @unique
+  name      String?
+  avatarUrl String?  @map("avatar_url")
+  createdAt DateTime @default(now()) @map("created_at")
+  updatedAt DateTime @updatedAt @map("updated_at")
+  orders    Order[]
+
+  @@map("users")
+  @@index([email])
+}
+```
+
+### Custom SQL Migration
+
+For operations Prisma cannot express (concurrent indexes, data backfills):
+
+```bash
+# Create empty migration, then edit the SQL manually
+npx prisma migrate dev --create-only --name add_email_index
+```
+
+```sql
+-- migrations/20240115_add_email_index/migration.sql
+-- Prisma cannot generate CONCURRENTLY, so we write it manually
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_users_email ON users (email);
+```
+
+## Drizzle (TypeScript/Node.js)
+
+### Workflow
+
+```bash
+# Generate migration from schema changes
+npx drizzle-kit generate
+
+# Apply migrations
+npx drizzle-kit migrate
+
+# Push schema directly (dev only, no migration file)
+npx drizzle-kit push
+```
+
+### Schema Example
+
+```typescript
+import { pgTable, text, timestamp, uuid, boolean } from "drizzle-orm/pg-core";
+
+export const users = pgTable("users", {
+  id: uuid("id").primaryKey().defaultRandom(),
+  email: text("email").notNull().unique(),
+  name: text("name"),
+  isActive: boolean("is_active").notNull().default(true),
+  createdAt: timestamp("created_at").notNull().defaultNow(),
+  updatedAt: timestamp("updated_at").notNull().defaultNow(),
+});
+```
+
+## Django (Python)
+
+### Workflow
+
+```bash
+# Generate migration from model changes
+python manage.py makemigrations
+
+# Apply migrations
+python manage.py migrate
+
+# Show migration status
+python manage.py showmigrations
+
+# Generate empty migration for custom SQL
+python manage.py makemigrations --empty app_name -n description
+```
+
+### Data Migration
+
+```python
+from django.db import migrations
+
+def backfill_display_names(apps, schema_editor):
+    User = apps.get_model("accounts", "User")
+    batch_size = 5000
+    users = User.objects.filter(display_name="")
+    while users.exists():
+        batch = list(users[:batch_size])
+        for user in batch:
+            user.display_name = user.username
+        User.objects.bulk_update(batch, ["display_name"], batch_size=batch_size)
+
+def reverse_backfill(apps, schema_editor):
+    pass  # Data migration, no reverse needed
+
+class Migration(migrations.Migration):
+    dependencies = [("accounts", "0015_add_display_name")]
+
+    operations = [
+        migrations.RunPython(backfill_display_names, reverse_backfill),
+    ]
+```
+
+### SeparateDatabaseAndState
+
+Remove a column from the Django model without dropping it from the database immediately:
+
+```python
+class Migration(migrations.Migration):
+    operations = [
+        migrations.SeparateDatabaseAndState(
+            state_operations=[
+                migrations.RemoveField(model_name="user", name="legacy_field"),
+            ],
+            database_operations=[],  # Don't touch the DB yet
+        ),
+    ]
+```
+
+## golang-migrate (Go)
+
+### Workflow
+
+```bash
+# Create migration pair
+migrate create -ext sql -dir migrations -seq add_user_avatar
+
+# Apply all pending migrations
+migrate -path migrations -database "$DATABASE_URL" up
+
+# Rollback last migration
+migrate -path migrations -database "$DATABASE_URL" down 1
+
+# Force version (fix dirty state)
+migrate -path migrations -database "$DATABASE_URL" force VERSION
+```
+
+### Migration Files
+
+```sql
+-- migrations/000003_add_user_avatar.up.sql
+ALTER TABLE users ADD COLUMN avatar_url TEXT;
+CREATE INDEX CONCURRENTLY idx_users_avatar ON users (avatar_url) WHERE avatar_url IS NOT NULL;
+
+-- migrations/000003_add_user_avatar.down.sql
+DROP INDEX IF EXISTS idx_users_avatar;
+ALTER TABLE users DROP COLUMN IF EXISTS avatar_url;
+```
+
+## Zero-Downtime Migration Strategy
+
+For critical production changes, follow the expand-contract pattern:
+
+```
+Phase 1: EXPAND
+  - Add new column/table (nullable or with default)
+  - Deploy: app writes to BOTH old and new
+  - Backfill existing data
+
+Phase 2: MIGRATE
+  - Deploy: app reads from NEW, writes to BOTH
+  - Verify data consistency
+
+Phase 3: CONTRACT
+  - Deploy: app only uses NEW
+  - Drop old column/table in separate migration
+```
+
+### Timeline Example
+
+```
+Day 1: Migration adds new_status column (nullable)
+Day 1: Deploy app v2 — writes to both status and new_status
+Day 2: Run backfill migration for existing rows
+Day 3: Deploy app v3 — reads from new_status only
+Day 7: Migration drops old status column
+```
+
+## Anti-Patterns
+
+| Anti-Pattern | Why It Fails | Better Approach |
+|-------------|-------------|-----------------|
+| Manual SQL in production | No audit trail, unrepeatable | Always use migration files |
+| Editing deployed migrations | Causes drift between environments | Create new migration instead |
+| NOT NULL without default | Locks table, rewrites all rows | Add nullable, backfill, then add constraint |
+| Inline index on large table | Blocks writes during build | CREATE INDEX CONCURRENTLY |
+| Schema + data in one migration | Hard to rollback, long transactions | Separate migrations |
+| Dropping column before removing code | Application errors on missing column | Remove code first, drop column next deploy |

skills/deployment-patterns/SKILL.md

@@ -0,0 +1,426 @@
+---
+name: deployment-patterns
+description: Deployment workflows, CI/CD pipeline patterns, Docker containerization, health checks, rollback strategies, and production readiness checklists for web applications.
+---
+
+# Deployment Patterns
+
+Production deployment workflows and CI/CD best practices.
+
+## When to Activate
+
+- Setting up CI/CD pipelines
+- Dockerizing an application
+- Planning deployment strategy (blue-green, canary, rolling)
+- Implementing health checks and readiness probes
+- Preparing for a production release
+- Configuring environment-specific settings
+
+## Deployment Strategies
+
+### Rolling Deployment (Default)
+
+Replace instances gradually — old and new versions run simultaneously during rollout.
+
+```
+Instance 1: v1 → v2  (update first)
+Instance 2: v1        (still running v1)
+Instance 3: v1        (still running v1)
+
+Instance 1: v2
+Instance 2: v1 → v2  (update second)
+Instance 3: v1
+
+Instance 1: v2
+Instance 2: v2
+Instance 3: v1 → v2  (update last)
+```
+
+**Pros:** Zero downtime, gradual rollout
+**Cons:** Two versions run simultaneously — requires backward-compatible changes
+**Use when:** Standard deployments, backward-compatible changes
+
+### Blue-Green Deployment
+
+Run two identical environments. Switch traffic atomically.
+
+```
+Blue  (v1) ← traffic
+Green (v2)   idle, running new version
+
+# After verification:
+Blue  (v1)   idle (becomes standby)
+Green (v2) ← traffic
+```
+
+**Pros:** Instant rollback (switch back to blue), clean cutover
+**Cons:** Requires 2x infrastructure during deployment
+**Use when:** Critical services, zero-tolerance for issues
+
+### Canary Deployment
+
+Route a small percentage of traffic to the new version first.
+
+```
+v1: 95% of traffic
+v2:  5% of traffic  (canary)
+
+# If metrics look good:
+v1: 50% of traffic
+v2: 50% of traffic
+
+# Final:
+v2: 100% of traffic
+```
+
+**Pros:** Catches issues with real traffic before full rollout
+**Cons:** Requires traffic splitting infrastructure, monitoring
+**Use when:** High-traffic services, risky changes, feature flags
+
+## Docker
+
+### Multi-Stage Dockerfile (Node.js)
+
+```dockerfile
+# Stage 1: Install dependencies
+FROM node:22-alpine AS deps
+WORKDIR /app
+COPY package.json package-lock.json ./
+RUN npm ci --production=false
+
+# Stage 2: Build
+FROM node:22-alpine AS builder
+WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+RUN npm run build
+RUN npm prune --production
+
+# Stage 3: Production image
+FROM node:22-alpine AS runner
+WORKDIR /app
+
+RUN addgroup -g 1001 -S appgroup && adduser -S appuser -u 1001
+USER appuser
+
+COPY --from=builder --chown=appuser:appgroup /app/node_modules ./node_modules
+COPY --from=builder --chown=appuser:appgroup /app/dist ./dist
+COPY --from=builder --chown=appuser:appgroup /app/package.json ./
+
+ENV NODE_ENV=production
+EXPOSE 3000
+
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+  CMD wget --no-verbose --tries=1 --spider http://localhost:3000/health || exit 1
+
+CMD ["node", "dist/server.js"]
+```
+
+### Multi-Stage Dockerfile (Go)
+
+```dockerfile
+FROM golang:1.22-alpine AS builder
+WORKDIR /app
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o /server ./cmd/server
+
+FROM alpine:3.19 AS runner
+RUN apk --no-cache add ca-certificates
+RUN adduser -D -u 1001 appuser
+USER appuser
+
+COPY --from=builder /server /server
+
+EXPOSE 8080
+HEALTHCHECK --interval=30s --timeout=3s CMD wget -qO- http://localhost:8080/health || exit 1
+CMD ["/server"]
+```
+
+### Multi-Stage Dockerfile (Python/Django)
+
+```dockerfile
+FROM python:3.12-slim AS builder
+WORKDIR /app
+RUN pip install --no-cache-dir uv
+COPY requirements.txt .
+RUN uv pip install --system --no-cache -r requirements.txt
+
+FROM python:3.12-slim AS runner
+WORKDIR /app
+
+RUN useradd -r -u 1001 appuser
+USER appuser
+
+COPY --from=builder /usr/local/lib/python3.12/site-packages /usr/local/lib/python3.12/site-packages
+COPY --from=builder /usr/local/bin /usr/local/bin
+COPY . .
+
+ENV PYTHONUNBUFFERED=1
+EXPOSE 8000
+
+HEALTHCHECK --interval=30s --timeout=3s CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/health/')" || exit 1
+CMD ["gunicorn", "config.wsgi:application", "--bind", "0.0.0.0:8000", "--workers", "4"]
+```
+
+### Docker Best Practices
+
+```
+# GOOD practices
+- Use specific version tags (node:22-alpine, not node:latest)
+- Multi-stage builds to minimize image size
+- Run as non-root user
+- Copy dependency files first (layer caching)
+- Use .dockerignore to exclude node_modules, .git, tests
+- Add HEALTHCHECK instruction
+- Set resource limits in docker-compose or k8s
+
+# BAD practices
+- Running as root
+- Using :latest tags
+- Copying entire repo in one COPY layer
+- Installing dev dependencies in production image
+- Storing secrets in image (use env vars or secrets manager)
+```
+
+## CI/CD Pipeline
+
+### GitHub Actions (Standard Pipeline)
+
+```yaml
+name: CI/CD
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+      - run: npm ci
+      - run: npm run lint
+      - run: npm run typecheck
+      - run: npm test -- --coverage
+      - uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: coverage
+          path: coverage/
+
+  build:
+    needs: test
+    runs-on: ubuntu-latest
+    if: github.ref == 'refs/heads/main'
+    steps:
+      - uses: actions/checkout@v4
+      - uses: docker/setup-buildx-action@v3
+      - uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - uses: docker/build-push-action@v5
+        with:
+          push: true
+          tags: ghcr.io/${{ github.repository }}:${{ github.sha }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    if: github.ref == 'refs/heads/main'
+    environment: production
+    steps:
+      - name: Deploy to production
+        run: |
+          # Platform-specific deployment command
+          # Railway: railway up
+          # Vercel: vercel --prod
+          # K8s: kubectl set image deployment/app app=ghcr.io/${{ github.repository }}:${{ github.sha }}
+          echo "Deploying ${{ github.sha }}"
+```
+
+### Pipeline Stages
+
+```
+PR opened:
+  lint → typecheck → unit tests → integration tests → preview deploy
+
+Merged to main:
+  lint → typecheck → unit tests → integration tests → build image → deploy staging → smoke tests → deploy production
+```
+
+## Health Checks
+
+### Health Check Endpoint
+
+```typescript
+// Simple health check
+app.get("/health", (req, res) => {
+  res.status(200).json({ status: "ok" });
+});
+
+// Detailed health check (for internal monitoring)
+app.get("/health/detailed", async (req, res) => {
+  const checks = {
+    database: await checkDatabase(),
+    redis: await checkRedis(),
+    externalApi: await checkExternalApi(),
+  };
+
+  const allHealthy = Object.values(checks).every(c => c.status === "ok");
+
+  res.status(allHealthy ? 200 : 503).json({
+    status: allHealthy ? "ok" : "degraded",
+    timestamp: new Date().toISOString(),
+    version: process.env.APP_VERSION || "unknown",
+    uptime: process.uptime(),
+    checks,
+  });
+});
+
+async function checkDatabase(): Promise<HealthCheck> {
+  try {
+    await db.query("SELECT 1");
+    return { status: "ok", latency_ms: 2 };
+  } catch (err) {
+    return { status: "error", message: "Database unreachable" };
+  }
+}
+```
+
+### Kubernetes Probes
+
+```yaml
+livenessProbe:
+  httpGet:
+    path: /health
+    port: 3000
+  initialDelaySeconds: 10
+  periodSeconds: 30
+  failureThreshold: 3
+
+readinessProbe:
+  httpGet:
+    path: /health
+    port: 3000
+  initialDelaySeconds: 5
+  periodSeconds: 10
+  failureThreshold: 2
+
+startupProbe:
+  httpGet:
+    path: /health
+    port: 3000
+  initialDelaySeconds: 0
+  periodSeconds: 5
+  failureThreshold: 30    # 30 * 5s = 150s max startup time
+```
+
+## Environment Configuration
+
+### Twelve-Factor App Pattern
+
+```bash
+# All config via environment variables — never in code
+DATABASE_URL=postgres://user:pass@host:5432/db
+REDIS_URL=redis://host:6379/0
+API_KEY=${API_KEY}           # injected by secrets manager
+LOG_LEVEL=info
+PORT=3000
+
+# Environment-specific behavior
+NODE_ENV=production          # or staging, development
+APP_ENV=production           # explicit app environment
+```
+
+### Configuration Validation
+
+```typescript
+import { z } from "zod";
+
+const envSchema = z.object({
+  NODE_ENV: z.enum(["development", "staging", "production"]),
+  PORT: z.coerce.number().default(3000),
+  DATABASE_URL: z.string().url(),
+  REDIS_URL: z.string().url(),
+  JWT_SECRET: z.string().min(32),
+  LOG_LEVEL: z.enum(["debug", "info", "warn", "error"]).default("info"),
+});
+
+// Validate at startup — fail fast if config is wrong
+export const env = envSchema.parse(process.env);
+```
+
+## Rollback Strategy
+
+### Instant Rollback
+
+```bash
+# Docker/Kubernetes: point to previous image
+kubectl rollout undo deployment/app
+
+# Vercel: promote previous deployment
+vercel rollback
+
+# Railway: redeploy previous commit
+railway up --commit <previous-sha>
+
+# Database: rollback migration (if reversible)
+npx prisma migrate resolve --rolled-back <migration-name>
+```
+
+### Rollback Checklist
+
+- [ ] Previous image/artifact is available and tagged
+- [ ] Database migrations are backward-compatible (no destructive changes)
+- [ ] Feature flags can disable new features without deploy
+- [ ] Monitoring alerts configured for error rate spikes
+- [ ] Rollback tested in staging before production release
+
+## Production Readiness Checklist
+
+Before any production deployment:
+
+### Application
+- [ ] All tests pass (unit, integration, E2E)
+- [ ] No hardcoded secrets in code or config files
+- [ ] Error handling covers all edge cases
+- [ ] Logging is structured (JSON) and does not contain PII
+- [ ] Health check endpoint returns meaningful status
+
+### Infrastructure
+- [ ] Docker image builds reproducibly (pinned versions)
+- [ ] Environment variables documented and validated at startup
+- [ ] Resource limits set (CPU, memory)
+- [ ] Horizontal scaling configured (min/max instances)
+- [ ] SSL/TLS enabled on all endpoints
+
+### Monitoring
+- [ ] Application metrics exported (request rate, latency, errors)
+- [ ] Alerts configured for error rate > threshold
+- [ ] Log aggregation set up (structured logs, searchable)
+- [ ] Uptime monitoring on health endpoint
+
+### Security
+- [ ] Dependencies scanned for CVEs
+- [ ] CORS configured for allowed origins only
+- [ ] Rate limiting enabled on public endpoints
+- [ ] Authentication and authorization verified
+- [ ] Security headers set (CSP, HSTS, X-Frame-Options)
+
+### Operations
+- [ ] Rollback plan documented and tested
+- [ ] Database migration tested against production-sized data
+- [ ] Runbook for common failure scenarios
+- [ ] On-call rotation and escalation path defined

tests/lib/utils.test.js

@@ -248,6 +248,131 @@ function runTests() {
     }
   })) passed++; else failed++;
 
+  // Edge case tests for defensive code
+  console.log('\nEdge Cases:');
+
+  if (test('findFiles returns empty for null/undefined dir', () => {
+    assert.deepStrictEqual(utils.findFiles(null, '*.txt'), []);
+    assert.deepStrictEqual(utils.findFiles(undefined, '*.txt'), []);
+    assert.deepStrictEqual(utils.findFiles('', '*.txt'), []);
+  })) passed++; else failed++;
+
+  if (test('findFiles returns empty for null/undefined pattern', () => {
+    assert.deepStrictEqual(utils.findFiles('/tmp', null), []);
+    assert.deepStrictEqual(utils.findFiles('/tmp', undefined), []);
+    assert.deepStrictEqual(utils.findFiles('/tmp', ''), []);
+  })) passed++; else failed++;
+
+  if (test('findFiles supports maxAge filter', () => {
+    const testDir = path.join(utils.getTempDir(), `utils-test-maxage-${Date.now()}`);
+    try {
+      fs.mkdirSync(testDir);
+      fs.writeFileSync(path.join(testDir, 'recent.txt'), 'content');
+      const results = utils.findFiles(testDir, '*.txt', { maxAge: 1 });
+      assert.strictEqual(results.length, 1);
+      assert.ok(results[0].path.endsWith('recent.txt'));
+    } finally {
+      fs.rmSync(testDir, { recursive: true, force: true });
+    }
+  })) passed++; else failed++;
+
+  if (test('findFiles supports recursive option', () => {
+    const testDir = path.join(utils.getTempDir(), `utils-test-recursive-${Date.now()}`);
+    const subDir = path.join(testDir, 'sub');
+    try {
+      fs.mkdirSync(subDir, { recursive: true });
+      fs.writeFileSync(path.join(testDir, 'top.txt'), 'content');
+      fs.writeFileSync(path.join(subDir, 'nested.txt'), 'content');
+      // Without recursive: only top level
+      const shallow = utils.findFiles(testDir, '*.txt', { recursive: false });
+      assert.strictEqual(shallow.length, 1);
+      // With recursive: finds nested too
+      const deep = utils.findFiles(testDir, '*.txt', { recursive: true });
+      assert.strictEqual(deep.length, 2);
+    } finally {
+      fs.rmSync(testDir, { recursive: true, force: true });
+    }
+  })) passed++; else failed++;
+
+  if (test('countInFile handles invalid regex pattern', () => {
+    const testFile = path.join(utils.getTempDir(), `utils-test-${Date.now()}.txt`);
+    try {
+      utils.writeFile(testFile, 'test content');
+      const count = utils.countInFile(testFile, '(unclosed');
+      assert.strictEqual(count, 0);
+    } finally {
+      fs.unlinkSync(testFile);
+    }
+  })) passed++; else failed++;
+
+  if (test('countInFile handles non-string non-regex pattern', () => {
+    const testFile = path.join(utils.getTempDir(), `utils-test-${Date.now()}.txt`);
+    try {
+      utils.writeFile(testFile, 'test content');
+      const count = utils.countInFile(testFile, 42);
+      assert.strictEqual(count, 0);
+    } finally {
+      fs.unlinkSync(testFile);
+    }
+  })) passed++; else failed++;
+
+  if (test('countInFile enforces global flag on RegExp', () => {
+    const testFile = path.join(utils.getTempDir(), `utils-test-${Date.now()}.txt`);
+    try {
+      utils.writeFile(testFile, 'foo bar foo baz foo');
+      // RegExp without global flag — countInFile should still count all
+      const count = utils.countInFile(testFile, /foo/);
+      assert.strictEqual(count, 3);
+    } finally {
+      fs.unlinkSync(testFile);
+    }
+  })) passed++; else failed++;
+
+  if (test('grepFile handles invalid regex pattern', () => {
+    const testFile = path.join(utils.getTempDir(), `utils-test-${Date.now()}.txt`);
+    try {
+      utils.writeFile(testFile, 'test content');
+      const matches = utils.grepFile(testFile, '[invalid');
+      assert.deepStrictEqual(matches, []);
+    } finally {
+      fs.unlinkSync(testFile);
+    }
+  })) passed++; else failed++;
+
+  if (test('replaceInFile returns false for non-existent file', () => {
+    const result = utils.replaceInFile('/non/existent/file.txt', 'foo', 'bar');
+    assert.strictEqual(result, false);
+  })) passed++; else failed++;
+
+  if (test('countInFile returns 0 for non-existent file', () => {
+    const count = utils.countInFile('/non/existent/file.txt', /foo/g);
+    assert.strictEqual(count, 0);
+  })) passed++; else failed++;
+
+  if (test('grepFile returns empty for non-existent file', () => {
+    const matches = utils.grepFile('/non/existent/file.txt', /foo/);
+    assert.deepStrictEqual(matches, []);
+  })) passed++; else failed++;
+
+  if (test('commandExists rejects unsafe command names', () => {
+    assert.strictEqual(utils.commandExists('cmd; rm -rf'), false);
+    assert.strictEqual(utils.commandExists('$(whoami)'), false);
+    assert.strictEqual(utils.commandExists('cmd && echo hi'), false);
+  })) passed++; else failed++;
+
+  if (test('ensureDir is idempotent', () => {
+    const testDir = path.join(utils.getTempDir(), `utils-test-idem-${Date.now()}`);
+    try {
+      const result1 = utils.ensureDir(testDir);
+      const result2 = utils.ensureDir(testDir);
+      assert.strictEqual(result1, testDir);
+      assert.strictEqual(result2, testDir);
+      assert.ok(fs.existsSync(testDir));
+    } finally {
+      fs.rmSync(testDir, { recursive: true, force: true });
+    }
+  })) passed++; else failed++;
+
   // System functions tests
   console.log('\nSystem Functions:');