diff --git a/shortcuts/sheets/backward/lark_sheets_float_images.go b/shortcuts/sheets/backward/lark_sheets_float_images.go
index 689b8ff6..b822a473 100644
--- a/shortcuts/sheets/backward/lark_sheets_float_images.go
+++ b/shortcuts/sheets/backward/lark_sheets_float_images.go
@@ -5,6 +5,7 @@ package backward
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"path/filepath"
 	"strings"
@@ -145,7 +146,8 @@ func validateSheetMediaUploadFile(runtime *common.RuntimeContext, filePath strin
 	stat, err := runtime.FileIO().Stat(filePath)
 	if err != nil {
 		wrapped := common.WrapInputStatErrorTyped(err, "file not found")
-		if v, ok := wrapped.(*errs.ValidationError); ok {
+		var v *errs.ValidationError
+		if errors.As(wrapped, &v) {
 			return "", nil, v.WithParam("--file")
 		}
 		return "", nil, wrapped
diff --git a/shortcuts/sheets/flag_schema.go b/shortcuts/sheets/flag_schema.go
index ccdbc7b0..b8b90de0 100644
--- a/shortcuts/sheets/flag_schema.go
+++ b/shortcuts/sheets/flag_schema.go
@@ -6,7 +6,6 @@ package sheets
 import (
 	_ "embed"
 	"encoding/json"
-	"fmt"
 	"sort"
 	"sync"
 
@@ -54,7 +53,7 @@ func loadFlagSchemas() (*flagSchemaIndex, error) {
 	flagSchemasOnce.Do(func() {
 		var idx flagSchemaIndex
 		if err := json.Unmarshal(flagSchemasJSON, &idx); err != nil {
-			parseFlagErr = fmt.Errorf("flag-schemas.json: %w", err)
+			parseFlagErr = errs.NewInternalError(errs.SubtypeUnknown, "flag-schemas.json: %v", err).WithCause(err)
 			return
 		}
 		if idx.Flags == nil {
diff --git a/shortcuts/sheets/flag_schema_validate.go b/shortcuts/sheets/flag_schema_validate.go
index 6e9af668..af433b57 100644
--- a/shortcuts/sheets/flag_schema_validate.go
+++ b/shortcuts/sheets/flag_schema_validate.go
@@ -243,7 +243,7 @@ func validateAgainstSchema(value interface{}, schema *schemaProperty, path strin
 
 	if schema.Type != "" {
 		if !matchesJSONType(value, schema.Type) {
-			return fmt.Errorf("%sexpected type %q, got %q", pathPrefix(path), schema.Type, jsType(value))
+			return fmt.Errorf("%sexpected type %q, got %q", pathPrefix(path), schema.Type, jsType(value)) //nolint:forbidigo // intermediate error; validateFlagAgainstSchema wraps it into a typed flag validation error with a --print-schema hint
 		}
 	}
 
@@ -251,20 +251,20 @@ func validateAgainstSchema(value interface{}, schema *schemaProperty, path strin
 	// already reported above). Apply to both `number` and `integer` types.
 	if num, ok := value.(float64); ok {
 		if schema.Minimum != nil && num < *schema.Minimum {
-			return fmt.Errorf("%svalue %v is below minimum %v", pathPrefix(path), num, *schema.Minimum)
+			return fmt.Errorf("%svalue %v is below minimum %v", pathPrefix(path), num, *schema.Minimum) //nolint:forbidigo // intermediate error; validateFlagAgainstSchema wraps it into a typed flag validation error with a --print-schema hint
 		}
 		if schema.Maximum != nil && num > *schema.Maximum {
-			return fmt.Errorf("%svalue %v is above maximum %v", pathPrefix(path), num, *schema.Maximum)
+			return fmt.Errorf("%svalue %v is above maximum %v", pathPrefix(path), num, *schema.Maximum) //nolint:forbidigo // intermediate error; validateFlagAgainstSchema wraps it into a typed flag validation error with a --print-schema hint
 		}
 	}
 
 	// Array length bounds — only checked when value is an array.
 	if arr, ok := value.([]interface{}); ok {
 		if schema.MinItems != nil && len(arr) < *schema.MinItems {
-			return fmt.Errorf("%sarray has %d items, minimum is %d", pathPrefix(path), len(arr), *schema.MinItems)
+			return fmt.Errorf("%sarray has %d items, minimum is %d", pathPrefix(path), len(arr), *schema.MinItems) //nolint:forbidigo // intermediate error; validateFlagAgainstSchema wraps it into a typed flag validation error with a --print-schema hint
 		}
 		if schema.MaxItems != nil && len(arr) > *schema.MaxItems {
-			return fmt.Errorf("%sarray has %d items, maximum is %d", pathPrefix(path), len(arr), *schema.MaxItems)
+			return fmt.Errorf("%sarray has %d items, maximum is %d", pathPrefix(path), len(arr), *schema.MaxItems) //nolint:forbidigo // intermediate error; validateFlagAgainstSchema wraps it into a typed flag validation error with a --print-schema hint
 		}
 	}
 
@@ -282,7 +282,7 @@ func validateAgainstSchema(value interface{}, schema *schemaProperty, path strin
 			if hint := suggestEnumMatch(value, schema.Enum); hint != "" {
 				msg += fmt.Sprintf(` (did you mean %q?)`, hint)
 			}
-			return fmt.Errorf("%s", msg)
+			return fmt.Errorf("%s", msg) //nolint:forbidigo // intermediate error; validateFlagAgainstSchema wraps it into a typed flag validation error with a --print-schema hint
 		}
 	}
 
@@ -295,7 +295,7 @@ func validateAgainstSchema(value interface{}, schema *schemaProperty, path strin
 			}
 		}
 		if !matched {
-			return fmt.Errorf("%svalue does not match any of oneOf alternatives", pathPrefix(path))
+			return fmt.Errorf("%svalue does not match any of oneOf alternatives", pathPrefix(path)) //nolint:forbidigo // intermediate error; validateFlagAgainstSchema wraps it into a typed flag validation error with a --print-schema hint
 		}
 	}
 
@@ -305,7 +305,7 @@ func validateAgainstSchema(value interface{}, schema *schemaProperty, path strin
 	if obj, ok := value.(map[string]interface{}); ok {
 		for _, key := range schema.Required {
 			if _, present := obj[key]; !present {
-				return fmt.Errorf("required property %q is missing at %s", key, pathOrRoot(path))
+				return fmt.Errorf("required property %q is missing at %s", key, pathOrRoot(path)) //nolint:forbidigo // intermediate error; validateFlagAgainstSchema wraps it into a typed flag validation error with a --print-schema hint
 			}
 		}
 		if schema.Properties != nil {
@@ -357,7 +357,7 @@ func validateAgainstSchema(value interface{}, schema *schemaProperty, path strin
 			sort.Strings(extras)
 			for _, key := range extras {
 				if schema.AdditionalProperties.Strict {
-					return fmt.Errorf("%sunexpected property %q (not declared in schema)", pathPrefix(path), key)
+					return fmt.Errorf("%sunexpected property %q (not declared in schema)", pathPrefix(path), key) //nolint:forbidigo // intermediate error; validateFlagAgainstSchema wraps it into a typed flag validation error with a --print-schema hint
 				}
 				if schema.AdditionalProperties.Schema != nil {
 					child := key
diff --git a/shortcuts/sheets/flag_view.go b/shortcuts/sheets/flag_view.go
index b31ed7b3..b3caf826 100644
--- a/shortcuts/sheets/flag_view.go
+++ b/shortcuts/sheets/flag_view.go
@@ -281,18 +281,18 @@ func (m mapFlagView) validateRawTypes() error {
 			// parse time; reject here too to keep batch/standalone parity.
 			f, isNum := val.(float64)
 			if !isNum {
-				return fmt.Errorf("--%s must be a number, got %s", name, jsonTypeName(val))
+				return fmt.Errorf("--%s must be a number, got %s", name, jsonTypeName(val)) //nolint:forbidigo // intermediate error; the batch dispatcher wraps it into a typed operations validation error
 			}
 			if math.Trunc(f) != f {
-				return fmt.Errorf("--%s must be an integer, got %s", name, strconv.FormatFloat(f, 'g', -1, 64))
+				return fmt.Errorf("--%s must be an integer, got %s", name, strconv.FormatFloat(f, 'g', -1, 64)) //nolint:forbidigo // intermediate error; the batch dispatcher wraps it into a typed operations validation error
 			}
 		case "float64":
 			if _, isNum := val.(float64); !isNum {
-				return fmt.Errorf("--%s must be a number, got %s", name, jsonTypeName(val))
+				return fmt.Errorf("--%s must be a number, got %s", name, jsonTypeName(val)) //nolint:forbidigo // intermediate error; the batch dispatcher wraps it into a typed operations validation error
 			}
 		case "bool":
 			if _, isBool := val.(bool); !isBool {
-				return fmt.Errorf("--%s must be a boolean, got %s", name, jsonTypeName(val))
+				return fmt.Errorf("--%s must be a boolean, got %s", name, jsonTypeName(val)) //nolint:forbidigo // intermediate error; the batch dispatcher wraps it into a typed operations validation error
 			}
 		}
 	}
diff --git a/shortcuts/sheets/helpers.go b/shortcuts/sheets/helpers.go
index 38a0bd9e..6d6a32d7 100644
--- a/shortcuts/sheets/helpers.go
+++ b/shortcuts/sheets/helpers.go
@@ -10,6 +10,7 @@ package sheets
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	neturl "net/url"
 	"strings"
@@ -44,7 +45,8 @@ func sheetsValidationCauseForFlag(name string, cause error) *errs.ValidationErro
 // classification and only adds the domain's flag param.
 func sheetsInputStatError(flag string, err error) error {
 	wrapped := common.WrapInputStatErrorTyped(err)
-	if v, ok := wrapped.(*errs.ValidationError); ok {
+	var v *errs.ValidationError
+	if errors.As(wrapped, &v) {
 		return v.WithParam(sheetsFlagParam(flag))
 	}
 	return wrapped
diff --git a/shortcuts/sheets/lark_sheet_sheet_structure.go b/shortcuts/sheets/lark_sheet_sheet_structure.go
index d80355f8..e5c83e81 100644
--- a/shortcuts/sheets/lark_sheet_sheet_structure.go
+++ b/shortcuts/sheets/lark_sheet_sheet_structure.go
@@ -483,11 +483,11 @@ func dimGroupInput(runtime flagView, token, sheetID, sheetName, op string) (map[
 func parseA1Range(s string) (dimension string, startIdx, endIdx int, err error) {
 	s = strings.TrimSpace(s)
 	if s == "" {
-		return "", 0, 0, fmt.Errorf("range is empty")
+		return "", 0, 0, fmt.Errorf("range is empty") //nolint:forbidigo // intermediate error; callers wrap it into a typed flag validation error
 	}
 	parts := strings.Split(s, ":")
 	if len(parts) > 2 {
-		return "", 0, 0, fmt.Errorf("expected \"start:end\" or single element")
+		return "", 0, 0, fmt.Errorf("expected \"start:end\" or single element") //nolint:forbidigo // intermediate error; callers wrap it into a typed flag validation error
 	}
 	dim1, idx1, err := parseA1Position(parts[0])
 	if err != nil {
@@ -501,10 +501,10 @@ func parseA1Range(s string) (dimension string, startIdx, endIdx int, err error)
 		return "", 0, 0, err
 	}
 	if dim1 != dim2 {
-		return "", 0, 0, fmt.Errorf("cannot mix row (digits) and column (letters) in one range")
+		return "", 0, 0, fmt.Errorf("cannot mix row (digits) and column (letters) in one range") //nolint:forbidigo // intermediate error; callers wrap it into a typed flag validation error
 	}
 	if idx2 < idx1 {
-		return "", 0, 0, fmt.Errorf("end position is before start")
+		return "", 0, 0, fmt.Errorf("end position is before start") //nolint:forbidigo // intermediate error; callers wrap it into a typed flag validation error
 	}
 	return dim1, idx1, idx2, nil
 }
@@ -515,7 +515,7 @@ func parseA1Range(s string) (dimension string, startIdx, endIdx int, err error)
 func parseA1Position(s string) (dimension string, idx int, err error) {
 	s = strings.TrimSpace(s)
 	if s == "" {
-		return "", 0, fmt.Errorf("position is empty")
+		return "", 0, fmt.Errorf("position is empty") //nolint:forbidigo // intermediate error; callers wrap it into a typed flag validation error
 	}
 	isDigits := true
 	isLetters := true
@@ -530,14 +530,14 @@ func parseA1Position(s string) (dimension string, idx int, err error) {
 	if isDigits {
 		n, _ := strconv.Atoi(s)
 		if n <= 0 {
-			return "", 0, fmt.Errorf("row number must be >= 1 (got %q)", s)
+			return "", 0, fmt.Errorf("row number must be >= 1 (got %q)", s) //nolint:forbidigo // intermediate error; callers wrap it into a typed flag validation error
 		}
 		return "row", n - 1, nil
 	}
 	if isLetters {
 		return "column", letterToColumnIndex(s), nil
 	}
-	return "", 0, fmt.Errorf("expected pure digits (row number) or letters (column letter), got %q", s)
+	return "", 0, fmt.Errorf("expected pure digits (row number) or letters (column letter), got %q", s) //nolint:forbidigo // intermediate error; callers wrap it into a typed flag validation error
 }
 
 // columnIndexToLetter converts a 0-based column index to the spreadsheet
diff --git a/shortcuts/sheets/lark_sheet_write_cells.go b/shortcuts/sheets/lark_sheet_write_cells.go
index e6ff1e6d..be58e18b 100644
--- a/shortcuts/sheets/lark_sheet_write_cells.go
+++ b/shortcuts/sheets/lark_sheet_write_cells.go
@@ -631,23 +631,23 @@ func rangeDimensions(rangeStr string) (rows, cols int, err error) {
 	}
 	rangeStr = strings.TrimSpace(rangeStr)
 	if rangeStr == "" {
-		return 0, 0, fmt.Errorf("empty range")
+		return 0, 0, fmt.Errorf("empty range") //nolint:forbidigo // intermediate error; callers wrap it into a typed --range/--source-range validation error
 	}
 	parts := strings.SplitN(rangeStr, ":", 2)
 	if len(parts) == 1 {
 		// single cell, e.g. "A1"
 		if _, _, ok := splitCellRef(parts[0]); !ok {
-			return 0, 0, fmt.Errorf("invalid cell ref %q", parts[0])
+			return 0, 0, fmt.Errorf("invalid cell ref %q", parts[0]) //nolint:forbidigo // intermediate error; callers wrap it into a typed --range/--source-range validation error
 		}
 		return 1, 1, nil
 	}
 	startCol, startRow, ok1 := splitCellRef(parts[0])
 	endCol, endRow, ok2 := splitCellRef(parts[1])
 	if !ok1 || !ok2 {
-		return 0, 0, fmt.Errorf("unsupported range form %q (need rectangular A1:B2)", rangeStr)
+		return 0, 0, fmt.Errorf("unsupported range form %q (need rectangular A1:B2)", rangeStr) //nolint:forbidigo // intermediate error; callers wrap it into a typed --range/--source-range validation error
 	}
 	if endRow < startRow || endCol < startCol {
-		return 0, 0, fmt.Errorf("end %q must be at or after start %q", parts[1], parts[0])
+		return 0, 0, fmt.Errorf("end %q must be at or after start %q", parts[1], parts[0]) //nolint:forbidigo // intermediate error; callers wrap it into a typed --range/--source-range validation error
 	}
 	return endRow - startRow + 1, endCol - startCol + 1, nil
 }