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.

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 {

View on GitHub (pinned to ea665308ba)

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.