diff --git a/internal/application/application.go b/internal/application/application.go
new file mode 100644
index 0000000..3276ea7
--- /dev/null
+++ b/internal/application/application.go
@@ -0,0 +1,61 @@
+package application
+
+import (
+	"context"
+	"spellbook/internal/models"
+)
+
+type SpellCaster interface {
+	Cast(ctx context.Context, cast models.SpellCast) (models.CastResult, error)
+}
+
+type SpellCommand interface {
+	Add(ctx context.Context, spell models.Spell) error
+	Delete(ctx context.Context, spellName string) error
+}
+
+type SpellQuery interface {
+	Get(ctx context.Context, spellName string) (models.Spell, error)
+	GetMany(ctx context.Context, query models.SearchQuery) ([]models.Spell, error)
+}
+
+type Application struct {
+	caster     SpellCaster
+	spellCmd   SpellCommand
+	spellQuery SpellQuery
+}
+
+func (a *Application) AddSpell(
+	ctx context.Context,
+	spell models.Spell,
+) error {
+	return a.spellCmd.Add(ctx, spell)
+}
+
+func (a *Application) GetSpell(
+	ctx context.Context,
+	spellName string,
+) (models.Spell, error) {
+	return a.spellQuery.Get(ctx, spellName)
+}
+
+func (a *Application) GetSpells(
+	ctx context.Context,
+	query models.SearchQuery,
+) ([]models.Spell, error) {
+	return a.spellQuery.GetMany(ctx, query)
+}
+
+func (a *Application) DeleteSpell(
+	ctx context.Context,
+	spellName string,
+) error {
+	return a.spellCmd.Delete(ctx, spellName)
+}
+
+func (a *Application) CastSpell(
+	ctx context.Context,
+	spellCast models.SpellCast,
+) (models.CastResult, error) {
+	return a.caster.Cast(ctx, spellCast)
+}
diff --git a/internal/handlers/handlers.go b/internal/handlers/handlers.go
new file mode 100644
index 0000000..1ec4eb5
--- /dev/null
+++ b/internal/handlers/handlers.go
@@ -0,0 +1,14 @@
+package handlers
+
+import (
+	"context"
+	"spellbook/internal/models"
+)
+
+type Application interface {
+	AddSpell(ctx context.Context, spell models.Spell) error
+	GetSpell(ctx context.Context, spellName string) (models.Spell, error)
+	GetSpells(ctx context.Context, query models.SearchQuery) ([]models.Spell, error)
+	DeleteSpell(ctx context.Context, spellName string) error
+	CastSpell(ctx context.Context, spellCast models.SpellCast) (models.CastResult, error)
+}
diff --git a/internal/models/models.go b/internal/models/models.go
new file mode 100644
index 0000000..6eafe88
--- /dev/null
+++ b/internal/models/models.go
@@ -0,0 +1,31 @@
+package models
+
+import (
+	"io"
+	"time"
+)
+
+type Spell struct {
+	Name  string
+	Spell string
+	Tags  []string
+}
+
+type SpellCast struct {
+	Spell  Spell
+	Args   map[string]string
+	Stdout io.Writer
+	Stderr io.Writer
+}
+
+type CastResult struct {
+	ExitCode int
+	Duration time.Duration
+	Meta     map[string]any
+}
+
+type SearchQuery struct {
+	Cursor int
+	Limit  int
+	Tags   []string
+}