What causes "invalid summary mode" in grafana/k6?

Use one of the exact values: compact, full, or disabled

invalid summary mode

Error message

invalid summary mode

What it means

The summary mode type only accepts three values: 'compact', 'full', and 'disabled' (constants ModeCompact/ModeFull/ModeDisabled). Mode.MarshalText/UnmarshalText return ErrInvalidSummaryMode when asked to serialize a Mode outside 0-2 or deserialize a string that is not one of the three. It surfaces via the --summary-mode flag, the K6_SUMMARY_MODE environment variable, or JSON (de)serialization of summary options.

Solutions

Use one of the exact values: compact, full, or disabled
Check K6_SUMMARY_MODE and --summary-mode in your environment/CI for typos
If parsing arbitrary input in Go, validate first with summary.ValidateMode(val) and show a friendly error listing the allowed values
When deserializing configs, reject unknown summary modes before applying them

Example fix

# before
k6 run --summary-mode=minimal script.js
# after
k6 run --summary-mode=compact script.js

Defensive patterns

Strategy: validation

Validate before calling

// Go — validate before assigning
import "go.k6.io/k6/v2/internal/lib/summary"

mode, err := summary.ValidateMode(userInput)
if err != nil {
    return fmt.Errorf("--summary-mode must be one of compact|full|disabled, got %q", userInput)
}

// Shell
[ "$K6_SUMMARY_MODE" = compact ] || [ "$K6_SUMMARY_MODE" = full ] || [ "$K6_SUMMARY_MODE" = disabled ] || unset K6_SUMMARY_MODE

Type guard

function isSummaryMode(v) {
  return ['compact', 'full', 'disabled'].includes(v);
}

Prevention

Restrict UI/pipeline inputs to the three documented values before they reach k6
Fail fast in CI with an explicit check on K6_SUMMARY_MODE rather than letting k6 exit mid-run
Pin allowed values in shared scripts/templates so typos surface at review time

When it happens

Trigger: Running k6 with --summary-mode=verbose (typo or invented value); exporting K6_SUMMARY_MODE=fulll or K6_SUMMARY_MODE=minimal; deserializing an options JSON blob containing an unknown summary mode; constructing Mode(7) in Go and calling MarshalJSON/String on it.

Common situations: Typos in CI environment variables; scripts ported from older k6 versions or third-party tooling that emit non-standard mode names; dashboards that pass user input straight into the flag.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of grafana/k6@01ffac6f24 (2026-08-18). Data as JSON: /api/errors/722054d5beda7a2d. Report an issue: GitHub.

Appendix: source

Thrown at internal/lib/summary/summary.go:22

	"errors"
	"time"

	"go.k6.io/k6/v2/metrics"
)

// A Mode specifies the mode of the Summary,
// which defines how the end-of-test summary will be rendered.
type Mode int

// Possible values for SummaryMode.
const (
	ModeCompact  = Mode(iota) // Compact mode that only displays the total results.
	ModeFull                  // Extended mode that displays total and partial results.
	ModeDisabled              // Disabled. Can be used with --summary-mode=disabled.
)

// ErrInvalidSummaryMode indicates the serialized summary mode is invalid.
var ErrInvalidSummaryMode = errors.New("invalid summary mode")

const (
	compactString  = "compact"
	fullString     = "full"
	disabledString = "disabled"
)

// MarshalJSON serializes a Mode as a human-readable string.
func (m Mode) MarshalJSON() ([]byte, error) {
	txt, err := m.MarshalText()
	if err != nil {
		return nil, err
	}
	return []byte(`"` + string(txt) + `"`), nil
}

// MarshalText serializes a Mode as a human-readable string.
func (m Mode) MarshalText() ([]byte, error) {

View on GitHub (pinned to 01ffac6f24)