diff --git a/cli/session/pipeline_phase.go b/cli/session/pipeline_phase.go
new file mode 100644
index 0000000..d5bef41
--- /dev/null
+++ b/cli/session/pipeline_phase.go
@@ -0,0 +1,36 @@
+package session
+
+// PipelinePhase identifies the step of the Agentless-style pipeline
+// (localize → repair → validate) that a session turn belongs to.
+//
+// These string constants mirror hawk-core-contracts/sessions.Phase so that
+// cost records emitted by trace can be correlated with hawk's tok.Tracker
+// AggregateByPhase output without importing the contracts package
+// (trace is a standalone CLI, not part of the hawk Go module graph).
+type PipelinePhase string
+
+const (
+	// PipelinePhaseLocalize is the file/symbol identification phase.
+	PipelinePhaseLocalize PipelinePhase = "localize"
+	// PipelinePhaseRepair is the patch generation phase.
+	PipelinePhaseRepair PipelinePhase = "repair"
+	// PipelinePhaseValidate is the test/lint verification phase.
+	PipelinePhaseValidate PipelinePhase = "validate"
+	// PipelinePhaseReview is code review; the most token-intensive phase
+	// at 59.4% of total spend (Tokenomics paper, arXiv 2601.14470).
+	PipelinePhaseReview PipelinePhase = "review"
+	// PipelinePhaseUnknown is the zero value for unattributed turns.
+	PipelinePhaseUnknown PipelinePhase = ""
+)
+
+// ParsePipelinePhase returns the PipelinePhase matching s, or
+// PipelinePhaseUnknown if unrecognised. Matching is case-sensitive to
+// stay consistent with the contracts package and JSON encoding.
+func ParsePipelinePhase(s string) PipelinePhase {
+	switch PipelinePhase(s) {
+	case PipelinePhaseLocalize, PipelinePhaseRepair,
+		PipelinePhaseValidate, PipelinePhaseReview:
+		return PipelinePhase(s)
+	}
+	return PipelinePhaseUnknown
+}
diff --git a/cli/session/pipeline_phase_test.go b/cli/session/pipeline_phase_test.go
new file mode 100644
index 0000000..5a6958f
--- /dev/null
+++ b/cli/session/pipeline_phase_test.go
@@ -0,0 +1,39 @@
+package session_test
+
+import (
+	"testing"
+
+	"github.com/GrayCodeAI/trace/cli/session"
+)
+
+func TestParsePipelinePhase_Known(t *testing.T) {
+	cases := []struct {
+		input string
+		want  session.PipelinePhase
+	}{
+		{"localize", session.PipelinePhaseLocalize},
+		{"repair", session.PipelinePhaseRepair},
+		{"validate", session.PipelinePhaseValidate},
+		{"review", session.PipelinePhaseReview},
+	}
+	for _, tc := range cases {
+		got := session.ParsePipelinePhase(tc.input)
+		if got != tc.want {
+			t.Errorf("ParsePipelinePhase(%q) = %q, want %q", tc.input, got, tc.want)
+		}
+	}
+}
+
+func TestParsePipelinePhase_Unknown(t *testing.T) {
+	for _, s := range []string{"", "unknown", "LOCALIZE", "Repair"} {
+		if got := session.ParsePipelinePhase(s); got != session.PipelinePhaseUnknown {
+			t.Errorf("ParsePipelinePhase(%q) = %q, want PipelinePhaseUnknown", s, got)
+		}
+	}
+}
+
+func TestPipelinePhaseString(t *testing.T) {
+	if string(session.PipelinePhaseReview) != "review" {
+		t.Errorf("PipelinePhaseReview string = %q, want %q", session.PipelinePhaseReview, "review")
+	}
+}