What causes "time_end must be after time_start" in vxcontrol/pentagi?

Swap the values so time_start < time_end

time_end must be after time_start

Error message

time_end must be after time_start

What it means

After parsing, the temporal_window search validates that the window is ordered: time_end must come after time_start. This error fires when the parsed end timestamp is before the parsed start timestamp, which would produce an empty or nonsensical query window for Graphiti.

Solutions

Swap the values so time_start < time_end
Compute the window as start=now-minus-duration, end=now
Re-check timezone offsets on both timestamps to ensure the intended order

Example fix

// before
{"time_start": "2026-08-31T00:00:00Z", "time_end": "2026-08-01T00:00:00Z"}
// after
{"time_start": "2026-08-01T00:00:00Z", "time_end": "2026-08-31T00:00:00Z"}

Defensive patterns

Strategy: validation

Validate before calling

if !end.After(start) {
    return errors.New("time_end must be after time_start")
}

Prevention

Compute windows as start = now - duration, end = now
Double-check argument order when constructing the payload
Normalize both timestamps to UTC before comparing

When it happens

Trigger: Passing time_start later than time_end, e.g. swapped values (start=2026-08-31, end=2026-08-01) or a negative window spanning a timezone mistake.

Common situations: Agents mixing up argument order; computing 'last 24h' with the offsets assigned to the wrong fields; timezone conversions flipping the ordering.

Related errors

AI-assisted analysis of vxcontrol/pentagi@ea665308ba (2026-09-01). Data as JSON: /api/errors/439275b81023b6f4. Report an issue: GitHub.

Appendix: source

Thrown at backend/pkg/tools/graphiti_search.go:357

	observationObject *graphiti.Observation,
) (string, error) {
	// Validate temporal parameters
	if args.TimeStart == "" || args.TimeEnd == "" {
		return "", fmt.Errorf("time_start and time_end are required for temporal_window search")
	}

	timeStart, err := parseGraphitiTime(args.TimeStart)
	if err != nil {
		return "", fmt.Errorf("invalid time_start format (use ISO 8601, e.g. 2026-01-02T15:04:05Z): %w", err)
	}

	timeEnd, err := parseGraphitiTime(args.TimeEnd)
	if err != nil {
		return "", fmt.Errorf("invalid time_end format (use ISO 8601, e.g. 2026-01-02T15:04:05Z): %w", err)
	}

	if timeEnd.Before(timeStart) {
		return "", fmt.Errorf("time_end must be after time_start")
	}

	maxResults := args.MaxResults.Int()
	if maxResults <= 0 {
		maxResults = DefaultTemporalMaxResults
	}

	req := graphiti.TemporalSearchRequest{
		Query:       args.Query,
		GroupID:     &groupID,
		TimeStart:   timeStart,
		TimeEnd:     timeEnd,
		MaxResults:  maxResults,
		Observation: observationObject,
	}

	resp, err := t.graphitiClient.TemporalWindowSearch(ctx, req)
	if err != nil {

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