diff --git a/pttodo/root.go b/pttodo/root.go
index ff7baee..13946d5 100644
--- a/pttodo/root.go
+++ b/pttodo/root.go
@@ -2,6 +2,7 @@ package pttodo
 
 import (
 	"bytes"
+	"fmt"
 	"os"
 
 	yaml "gopkg.in/yaml.v2"
@@ -44,7 +45,7 @@ func NewRootFromFile(p string) (Root, error) {
 	if err := yaml.NewDecoder(f).Decode(&result); err != nil {
 		todos, err2 := NewTodosFromFile(p)
 		if err2 != nil {
-			return Root{}, err
+			return Root{}, fmt.Errorf("failed to parse yaml from %s: %w", p, err)
 		}
 		result.Todo = todos
 	}
diff --git a/pttodo/schedule.go b/pttodo/schedule.go
index 207626d..ca3237c 100644
--- a/pttodo/schedule.go
+++ b/pttodo/schedule.go
@@ -2,6 +2,7 @@ package pttodo
 
 import (
 	"encoding/json"
+	"fmt"
 	"math"
 	"regexp"
 	"strconv"
@@ -17,7 +18,10 @@ func (schedule Schedule) MarshalJSON() ([]byte, error) {
 }
 
 func (schedule *Schedule) UnmarshalJSON(b []byte) error {
-	return json.Unmarshal(b, (*string)(schedule))
+	if err := json.Unmarshal(b, (*string)(schedule)); err != nil {
+		return fmt.Errorf("failed to parse json from %q: %w", b, err)
+	}
+	return nil
 }
 
 func (schedule Schedule) Next(t time.Time) (time.Time, error) {
diff --git a/pttodo/todo.go b/pttodo/todo.go
index bbe4805..969627b 100644
--- a/pttodo/todo.go
+++ b/pttodo/todo.go
@@ -32,7 +32,7 @@ func NewTodosFromFile(p string) ([]Todo, error) {
 
 	var result []Todo
 	if err := yaml.NewDecoder(f).Decode(&result); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to parse yaml from %s: %w", p, err)
 	}
 
 	return result, nil
diff --git a/pttodo/ts.go b/pttodo/ts.go
index e6c0d21..dc9a788 100644
--- a/pttodo/ts.go
+++ b/pttodo/ts.go
@@ -3,6 +3,7 @@ package pttodo
 import (
 	"encoding/json"
 	"errors"
+	"fmt"
 	"time"
 
 	yaml "gopkg.in/yaml.v2"
@@ -33,7 +34,10 @@ func (ts TS) MarshalYAML() (interface{}, error) {
 }
 
 func (ts *TS) UnmarshalJSON(b []byte) error {
-	return yaml.Unmarshal(b, ts)
+	if err := yaml.Unmarshal(b, ts); err != nil {
+		return fmt.Errorf("faild to unmarshal TS from %q: %w", b, err)
+	}
+	return nil
 }
 
 func (ts *TS) UnmarshalYAML(unmarshaller func(interface{}) error) error {