fix

- check CHANGELOG.md ver 0.2.1-alpha

internal/adapters/caster/caster.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	errors2 "github.com/abelith/spellbook/internal/errors"
 	"github.com/abelith/spellbook/internal/models"
 	"github.com/google/shlex"
 	"os/exec"
@@ -40,7 +41,7 @@ func (sc *SpellCaster) Cast(ctx context.Context, cast models.SpellCast) (models.
 			res.Err = err
 			return res, nil
 		}
-		return res, fmt.Errorf("failed to cast spell: %w", err)
+		return res, fmt.Errorf("%w: %w", errors2.ErrFailedToCast, err)
 	}
 
 	res.ExitCode = 0