diff --git a/internal/artifacts/previous_requirements.go b/internal/artifacts/previous_requirements.go
new file mode 100644
index 0000000..9db6496
--- /dev/null
+++ b/internal/artifacts/previous_requirements.go
@@ -0,0 +1,112 @@
+package artifacts
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/narratio/internal/config"
+)
+
+// PreviousArtifactRequirement describes one previous-session artifact dependency.
+type PreviousArtifactRequirement struct {
+	Name     string
+	Required bool
+	Sources  []string
+}
+
+// CollectPreviousArtifactRequirements scans enabled Scriptorium artifacts and returns
+// deduplicated previous-session artifact requirements in deterministic order.
+func CollectPreviousArtifactRequirements(
+	artifactsCfg map[string]config.ScriptoriumArtifactConfig,
+) []PreviousArtifactRequirement {
+	if len(artifactsCfg) == 0 {
+		return nil
+	}
+
+	artifactNames := sortedScriptoriumArtifactNames(artifactsCfg)
+	byName := map[string]PreviousArtifactRequirement{}
+
+	for _, artifactName := range artifactNames {
+		artifactCfg := artifactsCfg[artifactName]
+		if !artifactCfg.Enabled {
+			continue
+		}
+
+		inputNames := sortedScriptoriumInputKeys(artifactCfg.Inputs)
+		for _, inputName := range inputNames {
+			inputCfg := artifactCfg.Inputs[inputName]
+			previousName, ok := PreviousSessionArtifactName(inputCfg.Source)
+			if !ok {
+				continue
+			}
+
+			location := fmt.Sprintf(
+				"pipeline.scriptorium.artifacts.%s.inputs.%s.source",
+				artifactName,
+				inputName,
+			)
+			requirement := byName[previousName]
+			requirement.Name = previousName
+			requirement.Required = requirement.Required || inputCfg.Required
+			requirement.Sources = append(requirement.Sources, location)
+			byName[previousName] = requirement
+		}
+	}
+
+	if len(byName) == 0 {
+		return nil
+	}
+
+	requirements := make([]PreviousArtifactRequirement, 0, len(byName))
+	for _, requirement := range byName {
+		requirement.Sources = dedupeAndSortStrings(requirement.Sources)
+		requirements = append(requirements, requirement)
+	}
+	sort.Slice(requirements, func(i, j int) bool {
+		return requirements[i].Name < requirements[j].Name
+	})
+	return requirements
+}
+
+func sortedScriptoriumArtifactNames(artifactsCfg map[string]config.ScriptoriumArtifactConfig) []string {
+	names := make([]string, 0, len(artifactsCfg))
+	for name := range artifactsCfg {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+func sortedScriptoriumInputKeys(inputs map[string]config.ScriptoriumInputConfig) []string {
+	if len(inputs) == 0 {
+		return nil
+	}
+	names := make([]string, 0, len(inputs))
+	for name := range inputs {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+func dedupeAndSortStrings(values []string) []string {
+	if len(values) == 0 {
+		return nil
+	}
+	seen := map[string]struct{}{}
+	out := make([]string, 0, len(values))
+	for _, value := range values {
+		trimmed := strings.TrimSpace(value)
+		if trimmed == "" {
+			continue
+		}
+		if _, ok := seen[trimmed]; ok {
+			continue
+		}
+		seen[trimmed] = struct{}{}
+		out = append(out, trimmed)
+	}
+	sort.Strings(out)
+	return out
+}
diff --git a/internal/artifacts/previous_requirements_test.go b/internal/artifacts/previous_requirements_test.go
new file mode 100644
index 0000000..d6b8acf
--- /dev/null
+++ b/internal/artifacts/previous_requirements_test.go
@@ -0,0 +1,190 @@
+package artifacts
+
+import (
+	"reflect"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/narratio/internal/config"
+)
+
+func TestCollectPreviousArtifactRequirements(t *testing.T) {
+	tests := []struct {
+		name         string
+		artifactsCfg map[string]config.ScriptoriumArtifactConfig
+		want         []PreviousArtifactRequirement
+	}{
+		{
+			name:         "no artifacts",
+			artifactsCfg: nil,
+			want:         nil,
+		},
+		{
+			name: "no previous inputs",
+			artifactsCfg: map[string]config.ScriptoriumArtifactConfig{
+				"session_recap": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"transcript": {Source: "narratio.transcript.trimmed", Required: true},
+					},
+				},
+			},
+			want: nil,
+		},
+		{
+			name: "one optional previous input",
+			artifactsCfg: map[string]config.ScriptoriumArtifactConfig{
+				"session_recap": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"previous_recap": {Source: "narratio.previous_session.artifact.session_recap", Required: false},
+					},
+				},
+			},
+			want: []PreviousArtifactRequirement{
+				{
+					Name:     "session_recap",
+					Required: false,
+					Sources:  []string{"pipeline.scriptorium.artifacts.session_recap.inputs.previous_recap.source"},
+				},
+			},
+		},
+		{
+			name: "one required previous input",
+			artifactsCfg: map[string]config.ScriptoriumArtifactConfig{
+				"quest_log": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"previous_quest_log": {Source: "narratio.previous_session.artifact.quest_log", Required: true},
+					},
+				},
+			},
+			want: []PreviousArtifactRequirement{
+				{
+					Name:     "quest_log",
+					Required: true,
+					Sources:  []string{"pipeline.scriptorium.artifacts.quest_log.inputs.previous_quest_log.source"},
+				},
+			},
+		},
+		{
+			name: "duplicate references are deduped",
+			artifactsCfg: map[string]config.ScriptoriumArtifactConfig{
+				"a": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"x": {Source: "narratio.previous_session.artifact.session_recap", Required: false},
+					},
+				},
+				"b": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"y": {Source: "narratio.previous_session.artifact.session_recap", Required: false},
+					},
+				},
+			},
+			want: []PreviousArtifactRequirement{
+				{
+					Name:     "session_recap",
+					Required: false,
+					Sources: []string{
+						"pipeline.scriptorium.artifacts.a.inputs.x.source",
+						"pipeline.scriptorium.artifacts.b.inputs.y.source",
+					},
+				},
+			},
+		},
+		{
+			name: "required plus optional reference becomes required",
+			artifactsCfg: map[string]config.ScriptoriumArtifactConfig{
+				"a": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"x": {Source: "narratio.previous_session.artifact.session_recap", Required: false},
+					},
+				},
+				"b": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"y": {Source: "narratio.previous_session.artifact.session_recap", Required: true},
+					},
+				},
+			},
+			want: []PreviousArtifactRequirement{
+				{
+					Name:     "session_recap",
+					Required: true,
+					Sources: []string{
+						"pipeline.scriptorium.artifacts.a.inputs.x.source",
+						"pipeline.scriptorium.artifacts.b.inputs.y.source",
+					},
+				},
+			},
+		},
+		{
+			name: "disabled artifact references are ignored",
+			artifactsCfg: map[string]config.ScriptoriumArtifactConfig{
+				"disabled_artifact": {
+					Enabled: false,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"x": {Source: "narratio.previous_session.artifact.session_recap", Required: true},
+					},
+				},
+				"enabled_artifact": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"y": {Source: "narratio.previous_session.artifact.quest_log", Required: false},
+					},
+				},
+			},
+			want: []PreviousArtifactRequirement{
+				{
+					Name:     "quest_log",
+					Required: false,
+					Sources:  []string{"pipeline.scriptorium.artifacts.enabled_artifact.inputs.y.source"},
+				},
+			},
+		},
+		{
+			name: "deterministic ordering",
+			artifactsCfg: map[string]config.ScriptoriumArtifactConfig{
+				"zz": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"b_input": {Source: "narratio.previous_session.artifact.quest_log", Required: false},
+						"a_input": {Source: "narratio.previous_session.artifact.session_recap", Required: false},
+					},
+				},
+				"aa": {
+					Enabled: true,
+					Inputs: map[string]config.ScriptoriumInputConfig{
+						"c_input": {Source: "narratio.previous_session.artifact.session_recap", Required: false},
+					},
+				},
+			},
+			want: []PreviousArtifactRequirement{
+				{
+					Name:     "quest_log",
+					Required: false,
+					Sources:  []string{"pipeline.scriptorium.artifacts.zz.inputs.b_input.source"},
+				},
+				{
+					Name:     "session_recap",
+					Required: false,
+					Sources: []string{
+						"pipeline.scriptorium.artifacts.aa.inputs.c_input.source",
+						"pipeline.scriptorium.artifacts.zz.inputs.a_input.source",
+					},
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := CollectPreviousArtifactRequirements(tt.artifactsCfg)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Fatalf("CollectPreviousArtifactRequirements() = %#v, want %#v", got, tt.want)
+			}
+		})
+	}
+}