add-migration

name	add-migration
description	Create an EF Core migration for a specific microservice. Use after adding or modifying entities, DbSets, or entity configurations — migration creation is mandatory for any schema change.
allowed-tools	Bash, Read, Glob, Grep
user-invocable	true

Add EF Core Migration

Create a new EF Core migration for a microservice's database context.

Arguments

• {Name} — Migration name in PascalCase (e.g., AddDeviceTagsTable)
• {Service} — Target microservice (ask if ambiguous)

Service DbContext Mapping

Service	Infrastructure Project	DbContext
DeviceManager	src/DeviceManager/SignalBeam.DeviceManager.Infrastructure	DeviceManagerDbContext
BundleOrchestrator	src/BundleOrchestrator/BundleOrchestrator.Infrastructure	BundleOrchestratorDbContext
TelemetryProcessor	src/TelemetryProcessor/TelemetryProcessor.Infrastructure	TelemetryProcessorDbContext
IdentityManager	src/IdentityManager/SignalBeam.IdentityManager.Infrastructure	IdentityDbContext

Process

Step 1: Verify Changes

Before creating a migration, check that entity configurations are in place:

# Find the entity configuration
grep -rn "IEntityTypeConfiguration" src/{Service}/

Step 2: Create Migration

Run from the Infrastructure project directory:

dotnet ef migrations add {Name} \
  --project src/{Service}/{Service}.Infrastructure \
  --startup-project src/{Service}/{Service}.Host \
  --output-dir Persistence/Migrations

If the startup project differs from the convention, search for the .Host project:

find src/{Service} -name "*.Host.csproj" -o -name "*.Host" -type d

Step 3: Review Migration

Read the generated migration file and verify:

• Only expected changes are included
• No data loss operations (dropping columns/tables) without user confirmation
• Index names follow conventions
• Foreign keys are correct

# Find the latest migration
ls -t src/{Service}/**/Migrations/*.cs | head -2

Step 4: Apply Migration (Optional)

Only apply if the user explicitly asks:

dotnet ef database update \
  --project src/{Service}/{Service}.Infrastructure \
  --startup-project src/{Service}/{Service}.Host

After Creating

• Report the migration file path
• Show a summary of schema changes (tables created/altered, columns added/removed)
• Warn about any potentially destructive changes

Error Handling

• EF Core tools not installed: Run dotnet tool install --global dotnet-ef and retry.
• No pending model changes: The migration will be empty — warn the user and skip creation.
• Startup project can't build: Run dotnet build on the Host project first to surface errors.
• Migration includes unexpected changes: Warn about potential schema drift. Suggest verifying entity configurations match the intended changes.

Related Skills

• /add-entity to create the entity and EF Core configuration first
• /run-tests to verify tests still pass after migration