{"Kiwi+_", "Kiwi", "_"},

// CallTypeNone is a sentinel value used in --species Species+_ to match
// only labels with an empty calltype.
const CallTypeNone = "_"

		if callType != "" && label.CallType != callType {

		if callType == CallTypeNone {
			if label.CallType != "" {
				continue
			}
		} else if callType != "" && label.CallType != callType {

// Use "_" as the calltype to match only labels with no calltype (e.g., "Kiwi+_").

}
func TestCallTypeNoneFiltering(t *testing.T) {
	// Create test data: Kiwi with calltype, Kiwi without, Tomtit without
	df := &utils.DataFile{
		FilePath: "/test/file1.data",
		Segments: []*utils.Segment{
			{
				StartTime: 0,
				EndTime:   10,
				Labels: []*utils.Label{
					{Species: "Kiwi", Filter: "model-1.0", CallType: "Male"},
				},
			},
			{
				StartTime: 10,
				EndTime:   20,
				Labels: []*utils.Label{
					{Species: "Kiwi", Filter: "model-1.0"}, // no calltype
				},
			},
			{
				StartTime: 20,
				EndTime:   30,
				Labels: []*utils.Label{
					{Species: "Tomtit", Filter: "model-1.0"}, // no calltype, wrong species
				},
			},
		},
	}
	// Test 1: --species Kiwi+_ should match only Kiwi with no calltype (1 segment)
	state1 := NewClassifyState(ClassifyConfig{Species: "Kiwi", CallType: utils.CallTypeNone, Certainty: -1}, []*utils.DataFile{df})
	if got := state1.TotalSegments(); got != 1 {
		t.Errorf("Species=Kiwi+_: expected 1 segment, got %d", got)
	}
	// Test 2: --species Kiwi should still match all Kiwi (2 segments)
	state2 := NewClassifyState(ClassifyConfig{Species: "Kiwi", Certainty: -1}, []*utils.DataFile{df})
	if got := state2.TotalSegments(); got != 2 {
		t.Errorf("Species=Kiwi: expected 2 segments, got %d", got)
	}
	// Test 3: --species Kiwi+Male should still work as before (1 segment)
	state3 := NewClassifyState(ClassifyConfig{Species: "Kiwi", CallType: "Male", Certainty: -1}, []*utils.DataFile{df})
	if got := state3.TotalSegments(); got != 1 {
		t.Errorf("Species=Kiwi+Male: expected 1 segment, got %d", got)
	}

+_ species (ie no calltype)

npm install -g @mariozechner/pi-coding-agent

	fmt.Fprintf(os.Stderr, "  --species <name>      Scope to species, optionally with calltype (e.g. Kiwi, Kiwi+Duet)\n")

	fmt.Fprintf(os.Stderr, "  --species <name>      Scope to species, optionally with calltype (e.g. Kiwi, Kiwi+Duet, Kiwi+_)\n")
	fmt.Fprintf(os.Stderr, "                        Use +_ to match only calls with no calltype\n")

## [2026-05-02] Add --species Species+_ to filter for no calltype
Added support for `_` as a sentinel calltype in `--species` to match only
labels with an empty calltype. For example, `--species Kiwi+_` returns only
Kiwi calls that have no calltype assigned, while `--species Kiwi` continues
to return all Kiwi calls regardless of calltype.

**Changes:**
- `utils/data_file.go`: Added `CallTypeNone` sentinel constant; updated
  `SegmentMatchesFilters` to check for empty calltype when `CallTypeNone`
  is used; updated `ParseSpeciesCallType` doc comment
- `utils/data_file_test.go`: Added test case for `Kiwi+_` parsing
- `tools/calls_classify_filter_test.go`: Added `TestCallTypeNoneFiltering`
- `cmd/calls_classify.go`: Updated help text to document `+_` syntax