diff --git a/internal/pkg/dsl/ast_build.go b/internal/pkg/dsl/ast_build.go
index 3a1a14edc..512a47942 100644
--- a/internal/pkg/dsl/ast_build.go
+++ b/internal/pkg/dsl/ast_build.go
@@ -6,7 +6,6 @@
 package dsl
 
 import (
-	"errors"
 	"fmt"
 
 	"github.com/johnkerl/miller/internal/pkg/lib"
@@ -255,12 +254,7 @@ func (node *ASTNode) CheckArity(
 	arity int,
 ) error {
 	if len(node.Children) != arity {
-		return errors.New(
-			fmt.Sprintf(
-				"AST node arity %d, expected %d",
-				len(node.Children), arity,
-			),
-		)
+		return fmt.Errorf("expected AST node arity %d, got %d", arity, len(node.Children))
 	} else {
 		return nil
 	}
diff --git a/internal/pkg/dsl/cst/emit_emitp.go b/internal/pkg/dsl/cst/emit_emitp.go
index 9433ca51b..9af7a63f7 100644
--- a/internal/pkg/dsl/cst/emit_emitp.go
+++ b/internal/pkg/dsl/cst/emit_emitp.go
@@ -39,7 +39,6 @@
 package cst
 
 import (
-	"errors"
 	"fmt"
 
 	"github.com/johnkerl/miller/internal/pkg/cli"
@@ -171,11 +170,9 @@ func (root *RootNode) buildEmitXStatementNode(
 			retval.topLevelEvaluableMap = evaluable
 
 		} else {
-			return nil, errors.New(
-				fmt.Sprintf(
-					"mlr: unlashe-demit node types must be local variables, field names, oosvars, or maps; got %s.",
-					childNode.Type,
-				),
+			return nil, fmt.Errorf(
+				"mlr: unlashed-emit node types must be local variables, field names, oosvars, or maps; got %s.",
+				childNode.Type,
 			)
 		}
 
@@ -183,11 +180,9 @@ func (root *RootNode) buildEmitXStatementNode(
 		retval.isLashed = true
 		for _, childNode := range emittablesNode.Children {
 			if !EMITX_NAMED_NODE_TYPES[childNode.Type] {
-				return nil, errors.New(
-					fmt.Sprintf(
-						"mlr: lashed-emit node types must be local variables, field names, or oosvars; got %s.",
-						childNode.Type,
-					),
+				return nil, fmt.Errorf(
+					"mlr: lashed-emit node types must be local variables, field names, or oosvars; got %s.",
+					childNode.Type,
 				)
 			}
 		}
@@ -276,12 +271,7 @@ func (root *RootNode) buildEmitXStatementNode(
 			} else if redirectorNode.Type == dsl.NodeTypeRedirectPipe {
 				retval.outputHandlerManager = output.NewPipeWriteHandlerManager(root.recordWriterOptions)
 			} else {
-				return nil, errors.New(
-					fmt.Sprintf(
-						"%s: unhandled redirector node type %s.",
-						"mlr", string(redirectorNode.Type),
-					),
-				)
+				return nil, fmt.Errorf("mlr: unhandled redirector node type %s.", string(redirectorNode.Type))
 			}
 		}
 	}
@@ -999,12 +989,7 @@ func (node *EmitXStatementNode) emitRecordToFileOrPipe(
 ) error {
 	redirectorTarget := node.redirectorTargetEvaluable.Evaluate(state)
 	if !redirectorTarget.IsString() {
-		return errors.New(
-			fmt.Sprintf(
-				"%s: output redirection yielded %s, not string.",
-				"mlr", redirectorTarget.GetTypeName(),
-			),
-		)
+		return fmt.Errorf("mlr: output redirection yielded %s, not string.", redirectorTarget.GetTypeName())
 	}
 	outputFileName := redirectorTarget.String()
 
diff --git a/internal/pkg/dsl/cst/tee.go b/internal/pkg/dsl/cst/tee.go
index c433bce02..893597d0e 100644
--- a/internal/pkg/dsl/cst/tee.go
+++ b/internal/pkg/dsl/cst/tee.go
@@ -122,12 +122,7 @@ func (root *RootNode) BuildTeeStatementNode(astNode *dsl.ASTNode) (IExecutable,
 		} else if redirectorNode.Type == dsl.NodeTypeRedirectPipe {
 			retval.outputHandlerManager = output.NewPipeWriteHandlerManager(root.recordWriterOptions)
 		} else {
-			return nil, errors.New(
-				fmt.Sprintf(
-					"%s: unhandled redirector node type %s.",
-					"mlr", string(redirectorNode.Type),
-				),
-			)
+			return nil, fmt.Errorf("mlr: unhandled redirector node type %s.", string(redirectorNode.Type))
 		}
 	}
 
diff --git a/internal/pkg/input/pseudo_reader_gen.go b/internal/pkg/input/pseudo_reader_gen.go
index 21172583d..003c75b40 100644
--- a/internal/pkg/input/pseudo_reader_gen.go
+++ b/internal/pkg/input/pseudo_reader_gen.go
@@ -2,7 +2,6 @@ package input
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 
 	"github.com/johnkerl/miller/internal/pkg/bifs"
@@ -124,9 +123,7 @@ func (reader *PseudoReaderGen) tryParse(
 ) (*mlrval.Mlrval, error) {
 	mvalue := mlrval.FromDeferredType(svalue)
 	if mvalue == nil || !mvalue.IsNumeric() {
-		return nil, errors.New(
-			fmt.Sprintf("mlr: gen: %s \"%s\" is not parseable as number", name, svalue),
-		)
+		return nil, fmt.Errorf("mlr: gen: %s \"%s\" is not parseable as number", name, svalue)
 	}
 	return mvalue, nil
 }
diff --git a/internal/pkg/input/record_reader_csv.go b/internal/pkg/input/record_reader_csv.go
index 1aef46b8d..b1e93cefa 100644
--- a/internal/pkg/input/record_reader_csv.go
+++ b/internal/pkg/input/record_reader_csv.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"container/list"
 	"encoding/csv"
-	"errors"
 	"fmt"
 	"io"
 	"strconv"
@@ -33,10 +32,10 @@ func NewRecordReaderCSV(
 	recordsPerBatch int,
 ) (*RecordReaderCSV, error) {
 	if readerOptions.IRS != "\n" && readerOptions.IRS != "\r\n" {
-		return nil, errors.New("CSV IRS cannot be altered; LF vs CR/LF is autodetected")
+		return nil, fmt.Errorf("for CSV, IRS cannot be altered; LF vs CR/LF is autodetected")
 	}
 	if len(readerOptions.IFS) != 1 {
-		return nil, errors.New("CSV IFS can only be a single character")
+		return nil, fmt.Errorf("for CSV, IFS can only be a single character")
 	}
 	return &RecordReaderCSV{
 		readerOptions:   readerOptions,
@@ -236,12 +235,10 @@ func (reader *RecordReaderCSV) getRecordBatch(
 
 		} else {
 			if !reader.readerOptions.AllowRaggedCSVInput {
-				err := errors.New(
-					fmt.Sprintf(
-						"mlr: CSV header/data length mismatch %d != %d "+
-							"at filename %s row %d.\n",
-						nh, nd, reader.filename, reader.rowNumber,
-					),
+				err := fmt.Errorf(
+					"mlr: CSV header/data length mismatch %d != %d "+
+						"at filename %s row %d.\n",
+					nh, nd, reader.filename, reader.rowNumber,
 				)
 				errorChannel <- err
 				return
diff --git a/internal/pkg/input/record_reader_csvlite.go b/internal/pkg/input/record_reader_csvlite.go
index aaca53239..e42fc25bb 100644
--- a/internal/pkg/input/record_reader_csvlite.go
+++ b/internal/pkg/input/record_reader_csvlite.go
@@ -20,7 +20,6 @@ package input
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 	"io"
 	"strconv"
@@ -228,12 +227,10 @@ func getRecordBatchExplicitCSVHeader(
 			// Get data lines on subsequent loop iterations
 		} else {
 			if !reader.readerOptions.AllowRaggedCSVInput && len(reader.headerStrings) != len(fields) {
-				err := errors.New(
-					fmt.Sprintf(
-						"mlr: CSV header/data length mismatch %d != %d "+
-							"at filename %s line  %d.\n",
-						len(reader.headerStrings), len(fields), filename, reader.inputLineNumber,
-					),
+				err := fmt.Errorf(
+					"mlr: CSV header/data length mismatch %d != %d "+
+						"at filename %s line  %d.\n",
+					len(reader.headerStrings), len(fields), filename, reader.inputLineNumber,
 				)
 				errorChannel <- err
 				return
@@ -348,12 +345,10 @@ func getRecordBatchImplicitCSVHeader(
 			}
 		} else {
 			if !reader.readerOptions.AllowRaggedCSVInput && len(reader.headerStrings) != len(fields) {
-				err := errors.New(
-					fmt.Sprintf(
-						"mlr: CSV header/data length mismatch %d != %d "+
-							"at filename %s line  %d.\n",
-						len(reader.headerStrings), len(fields), filename, reader.inputLineNumber,
-					),
+				err := fmt.Errorf(
+					"mlr: CSV header/data length mismatch %d != %d "+
+						"at filename %s line  %d.\n",
+					len(reader.headerStrings), len(fields), filename, reader.inputLineNumber,
 				)
 				errorChannel <- err
 				return
diff --git a/internal/pkg/input/record_reader_json.go b/internal/pkg/input/record_reader_json.go
index 7084e95c8..eeb87f1ab 100644
--- a/internal/pkg/input/record_reader_json.go
+++ b/internal/pkg/input/record_reader_json.go
@@ -3,7 +3,6 @@ package input
 import (
 	"bufio"
 	"container/list"
-	"errors"
 	"fmt"
 	"io"
 	"strings"
@@ -126,7 +125,7 @@ func (reader *RecordReaderJSON) processHandle(
 			// TODO: make a helper method
 			record := mlrval.GetMap()
 			if record == nil {
-				errorChannel <- errors.New("Internal coding error detected in JSON record-reader")
+				errorChannel <- fmt.Errorf("internal coding error detected in JSON record-reader")
 				return
 			}
 			context.UpdateForInputRecord()
@@ -140,24 +139,22 @@ func (reader *RecordReaderJSON) processHandle(
 		} else if mlrval.IsArray() {
 			records := mlrval.GetArray()
 			if records == nil {
-				errorChannel <- errors.New("Internal coding error detected in JSON record-reader")
+				errorChannel <- fmt.Errorf("internal coding error detected in JSON record-reader")
 				return
 			}
 
 			for _, mlrval := range records {
 				if !mlrval.IsMap() {
 					// TODO: more context
-					errorChannel <- errors.New(
-						fmt.Sprintf(
-							"Valid but unmillerable JSON. Expected map (JSON object); got %s.",
-							mlrval.GetTypeName(),
-						),
+					errorChannel <- fmt.Errorf(
+						"valid but unmillerable JSON. Expected map (JSON object); got %s.",
+						mlrval.GetTypeName(),
 					)
 					return
 				}
 				record := mlrval.GetMap()
 				if record == nil {
-					errorChannel <- errors.New("Internal coding error detected in JSON record-reader")
+					errorChannel <- fmt.Errorf("internal coding error detected in JSON record-reader")
 					return
 				}
 				context.UpdateForInputRecord()
@@ -170,11 +167,9 @@ func (reader *RecordReaderJSON) processHandle(
 			}
 
 		} else {
-			errorChannel <- errors.New(
-				fmt.Sprintf(
-					"Valid but unmillerable JSON. Expected map (JSON object); got %s.",
-					mlrval.GetTypeName(),
-				),
+			errorChannel <- fmt.Errorf(
+				"valid but unmillerable JSON. Expected map (JSON object); got %s.",
+				mlrval.GetTypeName(),
 			)
 			return
 		}
diff --git a/internal/pkg/input/record_reader_xtab.go b/internal/pkg/input/record_reader_xtab.go
index c2ddc7e68..c8c78e0d2 100644
--- a/internal/pkg/input/record_reader_xtab.go
+++ b/internal/pkg/input/record_reader_xtab.go
@@ -3,7 +3,7 @@ package input
 import (
 	"bufio"
 	"container/list"
-	"errors"
+	"fmt"
 	"io"
 	"regexp"
 	"strings"
@@ -311,7 +311,7 @@ func (s *tXTABIPSSplitter) Split(input string) (key, value string, err error) {
 	// Empty string is a length-0 return value.
 	n := len(input)
 	if n == 0 {
-		return "", "", errors.New("mlr: internal coding error in XTAB reader")
+		return "", "", fmt.Errorf("internal coding error in XTAB reader")
 	}
 
 	// '   abc 123' splits as key '', value 'abc 123'.
@@ -360,12 +360,12 @@ type tXTABIPSRegexSplitter struct {
 func (s *tXTABIPSRegexSplitter) Split(input string) (key, value string, err error) {
 	kv := lib.RegexSplitString(s.ipsRegex, input, 2)
 	if len(kv) == 0 {
-		return "", "", errors.New("mlr: internal coding error in XTAB reader")
+		return "", "", fmt.Errorf("internal coding error in XTAB reader")
 	} else if len(kv) == 1 {
 		return kv[0], "", nil
 	} else if len(kv) == 2 {
 		return kv[0], kv[1], nil
 	} else {
-		return "", "", errors.New("mlr: internal coding error in XTAB reader")
+		return "", "", fmt.Errorf("internal coding error in XTAB reader")
 	}
 }
diff --git a/internal/pkg/lib/file-readers.go b/internal/pkg/lib/file-readers.go
index f497fbdc3..ffd38762c 100644
--- a/internal/pkg/lib/file-readers.go
+++ b/internal/pkg/lib/file-readers.go
@@ -24,7 +24,7 @@ import (
 	"compress/bzip2"
 	"compress/gzip"
 	"compress/zlib"
-	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"os"
@@ -236,10 +236,10 @@ func IsUpdateableInPlace(
 	if strings.HasPrefix(filename, "http://") ||
 		strings.HasPrefix(filename, "https://") ||
 		strings.HasPrefix(filename, "file://") {
-		return errors.New("http://, https://, and file:// URLs are not updateable in place.")
+		return fmt.Errorf("http://, https://, and file:// URLs are not updateable in place.")
 	}
 	if prepipe != "" {
-		return errors.New("input with --prepipe or --prepipex is not updateable in place.")
+		return fmt.Errorf("input with --prepipe or --prepipex is not updateable in place.")
 	}
 	return nil
 }
@@ -281,7 +281,7 @@ func WrapOutputHandle(
 ) (io.WriteCloser, bool, error) {
 	switch inputFileEncoding {
 	case FileInputEncodingBzip2:
-		return fileWriteHandle, false, errors.New("bzip2 is not currently supported for in-place mode.")
+		return fileWriteHandle, false, fmt.Errorf("bzip2 is not currently supported for in-place mode.")
 	case FileInputEncodingGzip:
 		return gzip.NewWriter(fileWriteHandle), true, nil
 	case FileInputEncodingZlib:
diff --git a/internal/pkg/output/file-output-handlers.go b/internal/pkg/output/file-output-handlers.go
index d187c9985..75916dfd4 100644
--- a/internal/pkg/output/file-output-handlers.go
+++ b/internal/pkg/output/file-output-handlers.go
@@ -15,7 +15,6 @@ package output
 import (
 	"bufio"
 	"container/list"
-	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -283,13 +282,7 @@ func NewPipeWriteOutputHandler(
 ) (*FileOutputHandler, error) {
 	writePipe, err := lib.OpenOutboundHalfPipe(commandString)
 	if err != nil {
-		return nil, errors.New(
-			fmt.Sprintf(
-				"%s: could not launch command \"%s\" for pipe-to.",
-				"mlr",
-				commandString,
-			),
-		)
+		return nil, fmt.Errorf("could not launch command \"%s\" for pipe-to.", commandString)
 	}
 
 	return newOutputHandlerCommon(
diff --git a/internal/pkg/output/record_writer_csv.go b/internal/pkg/output/record_writer_csv.go
index 2ebdfd3e2..2767da864 100644
--- a/internal/pkg/output/record_writer_csv.go
+++ b/internal/pkg/output/record_writer_csv.go
@@ -3,7 +3,7 @@ package output
 import (
 	"bufio"
 	"encoding/csv"
-	"errors"
+	"fmt"
 	"strings"
 
 	"github.com/johnkerl/miller/internal/pkg/cli"
@@ -23,10 +23,10 @@ type RecordWriterCSV struct {
 
 func NewRecordWriterCSV(writerOptions *cli.TWriterOptions) (*RecordWriterCSV, error) {
 	if len(writerOptions.OFS) != 1 {
-		return nil, errors.New("CSV OFS can only be a single character")
+		return nil, fmt.Errorf("for CSV, OFS can only be a single character")
 	}
 	if writerOptions.ORS != "\n" && writerOptions.ORS != "\r\n" {
-		return nil, errors.New("CSV ORS cannot be altered")
+		return nil, fmt.Errorf("for CSV, ORS cannot be altered")
 	}
 	return &RecordWriterCSV{
 		writerOptions:      writerOptions,
diff --git a/internal/pkg/output/record_writer_factory.go b/internal/pkg/output/record_writer_factory.go
index b95324716..3649f25bb 100644
--- a/internal/pkg/output/record_writer_factory.go
+++ b/internal/pkg/output/record_writer_factory.go
@@ -1,7 +1,6 @@
 package output
 
 import (
-	"errors"
 	"fmt"
 
 	"github.com/johnkerl/miller/internal/pkg/cli"
@@ -26,6 +25,6 @@ func Create(writerOptions *cli.TWriterOptions) (IRecordWriter, error) {
 	case "xtab":
 		return NewRecordWriterXTAB(writerOptions)
 	default:
-		return nil, errors.New(fmt.Sprintf("output file format \"%s\" not found", writerOptions.OutputFileFormat))
+		return nil, fmt.Errorf("output file format \"%s\" not found", writerOptions.OutputFileFormat)
 	}
 }
diff --git a/internal/pkg/runtime/stack.go b/internal/pkg/runtime/stack.go
index d3db2b0a5..a5cf2499e 100644
--- a/internal/pkg/runtime/stack.go
+++ b/internal/pkg/runtime/stack.go
@@ -27,7 +27,6 @@ package runtime
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 
 	"github.com/johnkerl/miller/internal/pkg/lib"
@@ -407,11 +406,9 @@ func (frame *StackFrame) defineTyped(
 		frame.namesToOffsets[stackVariable.name] = offsetInFrame
 		return nil
 	} else {
-		return errors.New(
-			fmt.Sprintf(
-				"%s: variable %s has already been defined in the same scope.",
-				"mlr", stackVariable.name,
-			),
+		return fmt.Errorf(
+			"%s: variable %s has already been defined in the same scope.",
+			"mlr", stackVariable.name,
 		)
 	}
 }
@@ -431,11 +428,9 @@ func (frame *StackFrame) setIndexed(
 			newval.PutIndexed(indices, mv)
 			return frame.set(stackVariable, newval)
 		} else {
-			return errors.New(
-				fmt.Sprintf(
-					"%s: map indices must be int or string; got %s.\n",
-					"mlr", leadingIndex.GetTypeName(),
-				),
+			return fmt.Errorf(
+				"%s: map indices must be int or string; got %s.\n",
+				"mlr", leadingIndex.GetTypeName(),
 			)
 		}
 	} else {
diff --git a/internal/pkg/transformers/label.go b/internal/pkg/transformers/label.go
index c4b5875f5..62439885c 100644
--- a/internal/pkg/transformers/label.go
+++ b/internal/pkg/transformers/label.go
@@ -2,7 +2,6 @@ package transformers
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -108,12 +107,7 @@ func NewTransformerLabel(
 	for _, newName := range newNames {
 		_, ok := uniquenessChecker[newName]
 		if ok {
-			return nil, errors.New(
-				fmt.Sprintf(
-					"mlr label: labels must be unique; got duplicate \"%s\"\n",
-					newName,
-				),
-			)
+			return nil, fmt.Errorf("mlr label: labels must be unique; got duplicate \"%s\"\n", newName)
 		}
 		uniquenessChecker[newName] = true
 	}
diff --git a/internal/pkg/transformers/merge-fields.go b/internal/pkg/transformers/merge-fields.go
index 84f421b32..1a9c17ad5 100644
--- a/internal/pkg/transformers/merge-fields.go
+++ b/internal/pkg/transformers/merge-fields.go
@@ -2,7 +2,6 @@ package transformers
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 	"os"
 	"regexp"
@@ -257,11 +256,9 @@ func NewTransformerMergeFields(
 
 	for _, accumulatorName := range accumulatorNameList {
 		if !utils.ValidateStats1AccumulatorName(accumulatorName) {
-			return nil, errors.New(
-				fmt.Sprintf(
-					"%s %s: accumulator \"%s\" not found.\n",
-					"mlr", verbNameMergeFields, accumulatorName,
-				),
+			return nil, fmt.Errorf(
+				"mlr %s: accumulator \"%s\" not found.\n",
+				verbNameMergeFields, accumulatorName,
 			)
 		}
 	}
diff --git a/internal/pkg/transformers/put-or-filter.go b/internal/pkg/transformers/put-or-filter.go
index c7a84901f..4b441593f 100644
--- a/internal/pkg/transformers/put-or-filter.go
+++ b/internal/pkg/transformers/put-or-filter.go
@@ -2,7 +2,6 @@ package transformers
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -447,12 +446,7 @@ func NewTransformerPut(
 		for _, preset := range presets {
 			pair := strings.SplitN(preset, "=", 2)
 			if len(pair) != 2 {
-				return nil, errors.New(
-					fmt.Sprintf(
-						"mlr: missing \"=\" in preset expression \"%s\".",
-						preset,
-					),
-				)
+				return nil, fmt.Errorf("missing \"=\" in preset expression \"%s\".", preset)
 			}
 			key := pair[0]
 			svalue := pair[1]
diff --git a/internal/pkg/transformers/rename.go b/internal/pkg/transformers/rename.go
index b422bdc61..c46363c8b 100644
--- a/internal/pkg/transformers/rename.go
+++ b/internal/pkg/transformers/rename.go
@@ -2,7 +2,6 @@ package transformers
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 	"os"
 	"regexp"
@@ -149,7 +148,7 @@ func NewTransformerRename(
 	doGsub bool,
 ) (*TransformerRename, error) {
 	if len(names)%2 != 0 {
-		return nil, errors.New("Rename: names string must have even length.")
+		return nil, fmt.Errorf("mlr rename: names string must have even length")
 	}
 
 	oldToNewNames := lib.NewOrderedMap()
diff --git a/internal/pkg/transformers/seqgen.go b/internal/pkg/transformers/seqgen.go
index 427fe1a36..4eddc659b 100644
--- a/internal/pkg/transformers/seqgen.go
+++ b/internal/pkg/transformers/seqgen.go
@@ -2,7 +2,6 @@ package transformers
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -140,32 +139,17 @@ func NewTransformerSeqgen(
 
 	fstart, startIsNumeric := start.GetNumericToFloatValue()
 	if !startIsNumeric {
-		return nil, errors.New(
-			fmt.Sprintf(
-				"mlr seqgen: start value should be number; got \"%s\"",
-				startString,
-			),
-		)
+		return nil, fmt.Errorf("mlr seqgen: start value should be number; got \"%s\"", startString)
 	}
 
 	fstop, stopIsNumeric := stop.GetNumericToFloatValue()
 	if !stopIsNumeric {
-		return nil, errors.New(
-			fmt.Sprintf(
-				"mlr seqgen: stop value should be number; got \"%s\"",
-				stopString,
-			),
-		)
+		return nil, fmt.Errorf("mlr seqgen: stop value should be number; got \"%s\"", stopString)
 	}
 
 	fstep, stepIsNumeric := step.GetNumericToFloatValue()
 	if !stepIsNumeric {
-		return nil, errors.New(
-			fmt.Sprintf(
-				"mlr seqgen: step value should be number; got \"%s\"",
-				stepString,
-			),
-		)
+		return nil, fmt.Errorf("mlr seqgen: step value should be number; got \"%s\"", stepString)
 	}
 
 	if fstep > 0 {
@@ -176,9 +160,7 @@ func NewTransformerSeqgen(
 		if fstart == fstop {
 			doneComparator = bifs.BIF_equals
 		} else {
-			return nil, errors.New(
-				"mlr seqgen: step must not be zero unless start == stop.",
-			)
+			return nil, fmt.Errorf("mlr seqgen: step must not be zero unless start == stop.")
 		}
 	}
 
diff --git a/internal/pkg/transformers/stats1.go b/internal/pkg/transformers/stats1.go
index d047c6bfb..542e23f4b 100644
--- a/internal/pkg/transformers/stats1.go
+++ b/internal/pkg/transformers/stats1.go
@@ -3,7 +3,6 @@ package transformers
 import (
 	"bytes"
 	"container/list"
-	"errors"
 	"fmt"
 	"os"
 	"regexp"
@@ -316,12 +315,7 @@ func NewTransformerStats1(
 ) (*TransformerStats1, error) {
 	for _, name := range accumulatorNameList {
 		if !utils.ValidateStats1AccumulatorName(name) {
-			return nil, errors.New(
-				fmt.Sprintf(
-					"%s stats1: accumulator \"%s\" not found.\n",
-					"mlr", name,
-				),
-			)
+			return nil, fmt.Errorf("mlr stats1: accumulator \"%s\" not found.", name)
 		}
 	}
 
diff --git a/internal/pkg/transformers/stats2.go b/internal/pkg/transformers/stats2.go
index ca7b9be1f..0e66c24c7 100644
--- a/internal/pkg/transformers/stats2.go
+++ b/internal/pkg/transformers/stats2.go
@@ -2,7 +2,6 @@ package transformers
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -210,12 +209,7 @@ func NewTransformerStats2(
 ) (*TransformerStats2, error) {
 	for _, name := range accumulatorNameList {
 		if !utils.ValidateStats2AccumulatorName(name) {
-			return nil, errors.New(
-				fmt.Sprintf(
-					"%s stats2: accumulator \"%s\" not found.\n",
-					"mlr", name,
-				),
-			)
+			return nil, fmt.Errorf("mlr stats2: accumulator \"%s\" not found.", name)
 		}
 	}
 
diff --git a/internal/pkg/transformers/step.go b/internal/pkg/transformers/step.go
index 3f763eb45..f8e4122af 100644
--- a/internal/pkg/transformers/step.go
+++ b/internal/pkg/transformers/step.go
@@ -2,7 +2,6 @@ package transformers
 
 import (
 	"container/list"
-	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -180,16 +179,12 @@ func NewTransformerStep(
 ) (*TransformerStep, error) {
 
 	if len(stepperNames) == 0 || len(valueFieldNames) == 0 {
-		return nil, errors.New(
-			// TODO: parameterize verb here somehow
-			"mlr step: -a and -f are both required arguments.",
-		)
+		return nil, fmt.Errorf("mlr %s: -a and -f are both required arguments.", verbNameStep)
 	}
 	if len(stringAlphas) != 0 && len(ewmaSuffixes) != 0 {
 		if len(ewmaSuffixes) != len(stringAlphas) {
-			return nil, errors.New(
-				// TODO: parameterize verb here somehow
-				"mlr step: If -d and -o are provided, their values must have the same length.",
+			return nil, fmt.Errorf(
+				"mlr %s: If -d and -o are provided, their values must have the same length.", verbNameStep,
 			)
 		}
 	}
diff --git a/internal/pkg/transformers/utils/stats1-accumulators.go b/internal/pkg/transformers/utils/stats1-accumulators.go
index 08f21a02e..21a6f2ced 100644
--- a/internal/pkg/transformers/utils/stats1-accumulators.go
+++ b/internal/pkg/transformers/utils/stats1-accumulators.go
@@ -219,16 +219,13 @@ func (factory *Stats1AccumulatorFactory) MakeNamedAccumulator(
 		valueFieldName,
 		doInterpolatedPercentiles,
 	)
-	// We don't return errors.New here. The nominal case is that the stats1
-	// verb has already pre-validated accumulator names, and this is just a
-	// fallback. The accumulators are instantiated for every unique combination
-	// of group-by field values in the record stream, only as those values are
-	// encountered: for example, with 'mlr stats1 -a count,sum -f x,y -g
-	// color,shape', we make a new accumulator the first time we find a record
-	// with 'color=blue,shape=square' and another the first time we find a
-	// record with 'color=red,shape=circle', and so on. The right thing is to
-	// pre-validate names once when the stats1 transformer is being
-	// instantiated.
+	// We don't return an error here -- we fatal. The nominal case is that the stats1 verb has already
+	// pre-validated accumulator names, and this is just a fallback. The accumulators are instantiated for
+	// every unique combination of group-by field values in the record stream, only as those values are
+	// encountered: for example, with 'mlr stats1 -a count,sum -f x,y -g color,shape', we make a new
+	// accumulator the first time we find a record with 'color=blue,shape=square' and another the first time
+	// we find a record with 'color=red,shape=circle', and so on. The right thing is to pre-validate names
+	// once when the stats1 transformer is being instantiated.
 	lib.InternalCodingErrorIf(accumulator == nil)
 
 	return NewStats1NamedAccumulator(
diff --git a/test/cases/verb-stats1/0018/experr b/test/cases/verb-stats1/0018/experr
index 10ea04fe2..03f44410a 100644
--- a/test/cases/verb-stats1/0018/experr
+++ b/test/cases/verb-stats1/0018/experr
@@ -1,2 +1 @@
 mlr stats1: accumulator "nonesuch" not found.
-