diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/packages_integration_test.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/packages_integration_test.go
index 069be8be..cac7840e 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/packages_integration_test.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/packages_integration_test.go
@@ -5,6 +5,7 @@ package main
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"os"
 	"strings"
 	"testing"
@@ -15,6 +16,8 @@ import (
 
 	"git.novox.be/novox/mesh-sdk/go/buscompose"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
+
+	"mesh-delivery-indexer/internal/index"
 )
 
 // TestAMeshSDKMergeMovesOnlyTheModulesImportingAChangedPackage (ADR 0593 §2-§4; D11): the indexer whole against the
@@ -48,7 +51,7 @@ func TestAMeshSDKMergeMovesOnlyTheModulesImportingAChangedPackage(t *testing.T)
 		m1: {"go.mod": "f1", "go.sum": "f2", "stdio.go": "f3", "announce/announce.go": "f4", "buildstep/step.go": "f5"},
 		m2: {"go.mod": "f1", "go.sum": "f2", "stdio.go": "f3", "announce/announce.go": "f4", "buildstep/step.go": "f6"},
 	}
-	var packages jetstream.KeyValue
+	var packages, seatDefs jetstream.KeyValue
 	js, ctx, _, modules := startIndexer(t, func(context.Context, buildLog) {}, func(ctx context.Context, js jetstream.JetStream) {
 		var err error
 		if packages, err = js.CreateKeyValue(ctx, jetstream.KeyValueConfig{Bucket: delivery.PackagesBucket, History: delivery.PackagesHistory}); err != nil {
@@ -70,6 +73,14 @@ func TestAMeshSDKMergeMovesOnlyTheModulesImportingAChangedPackage(t *testing.T)
 			}
 		}
 		serveForge(t, js.Conn(), listing, goSumContent)
+		// The seat definitions' state and stream (DLV-I17), as the grants part makes them from the manifest.
+		if seatDefs, err = js.CreateKeyValue(ctx, jetstream.KeyValueConfig{Bucket: index.SeatDefinitionsBucket, History: 5}); err != nil {
+			t.Fatal(err)
+		}
+		if _, err := js.CreateStream(ctx, jetstream.StreamConfig{Name: "INDEXER_SEAT_DEFINITIONS",
+			Subjects: []string{"mesh.stream.mesh-delivery-indexer.event." + index.SeatDefinitionChangedEvent}}); err != nil {
+			t.Fatal(err)
+		}
 	})
 	merged := func(repo string, number int, merge string, f delivery.Forge) {
 		t.Helper()
@@ -179,8 +190,67 @@ func TestAMeshSDKMergeMovesOnlyTheModulesImportingAChangedPackage(t *testing.T)
 	if now := module("plain", func(delivery.Module) bool { return true }); now.FP2 != plain.FP2 {
 		t.Errorf("plain moved from %s to %s, though it imports nothing the merge changed", plain.FP2, now.FP2)
 	}
+
+	// DLV-I17, I18 (research 081 test 21, design 26): mesh-contracts merges a valid definition, said once; a pull
+	// request's head whose definition does not parse is kept as its entry naming why while the trunk's stays; it closes
+	// and its entry goes.
+	const contractsMerge, badHead = "5555555555555555555555555555555555555555", "6666666666666666666666666666666666666666"
+	git := `{"format":1,"seat":"git","scope":"mesh","grain":"seat-list","decision":"novox/hq ADR 0111","delivers":"git"}`
+	seatFiles[contractsMerge] = map[string]string{"seats/index.json": `{"format":1,"seats":["git"]}`, "seats/git/seat.json": git}
+	seatFiles[badHead] = map[string]string{"seats/index.json": `{"format":1,"seats":["git"]}`, "seats/git/seat.json": `{"format":1,"seat":"git"}`}
+	contracts := `{"module":"mesh-contracts","version":"1","build":{"artifacts":[{"name":"go","kind":"package","language":"go","paths":["go"],"series":"0.1","generated-from":"."}]}}`
+	merged("novox/mesh-contracts", 80, contractsMerge, delivery.Forge{Root: "dddddddddddddddddddddddddddddddddddddddd",
+		Trees: map[string]string{"": "dddddddddddddddddddddddddddddddddddddddd"}, Manifests: map[string]string{"": contracts}})
+	entry := func(key string, ok func(index.SeatDefinitionEntry) bool) index.SeatDefinitionEntry {
+		t.Helper()
+		var e index.SeatDefinitionEntry
+		for deadline := time.Now().Add(20 * time.Second); time.Now().Before(deadline); time.Sleep(50 * time.Millisecond) {
+			if v, err := seatDefs.Get(ctx, key); err == nil && json.Unmarshal(v.Value(), &e) == nil && ok(e) {
+				return e
+			}
+		}
+		t.Fatalf("%s.%s = %+v within 20 s", index.SeatDefinitionsState, key, e)
+		return e
+	}
+	trunk := entry("git.trunk", func(e index.SeatDefinitionEntry) bool { return e.Commit == contractsMerge && e.Digest != "" })
+	pull := func(action string) {
+		t.Helper()
+		data, _ := delivery.EncodeForge(delivery.Forge{Kind: delivery.ForgePull, Action: action, Repository: "novox/mesh-contracts", Branch: "feat/y",
+			Number: 81, Head: badHead, Dirs: []string{""}, DirsKnown: true, Manifests: map[string]string{"": contracts}})
+		if _, err := js.Publish(ctx, "mesh.stream.mesh-delivery-forge-bridge.event.forge.novox.mesh-contracts.pull", data); err != nil {
+			t.Fatal(err)
+		}
+	}
+	pull(delivery.PullUpdated)
+	pk := index.SeatDefinitionKey("git", index.SourcePull, "novox/mesh-contracts", 81)
+	if bad := entry(pk, func(e index.SeatDefinitionEntry) bool { return e.Unparsed != "" }); !strings.Contains(bad.Unparsed, "scope") || bad.Definition != nil {
+		t.Errorf("the pull request's entry %+v, want why it does not parse and no definition", bad)
+	}
+	if now := entry("git.trunk", func(index.SeatDefinitionEntry) bool { return true }); now.Digest != trunk.Digest {
+		t.Errorf("the trunk's entry moved to %+v on a pull request's head", now)
+	}
+	pull(delivery.PullClosed)
+	for deadline := time.Now().Add(20 * time.Second); ; time.Sleep(50 * time.Millisecond) {
+		if _, err := seatDefs.Get(ctx, pk); errors.Is(err, jetstream.ErrKeyNotFound) {
+			break
+		}
+		if time.Now().After(deadline) {
+			t.Fatalf("%s is kept 20 s after its pull request closed", pk)
+		}
+	}
+	info, err := js.Stream(ctx, "INDEXER_SEAT_DEFINITIONS")
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Said: the trunk's git, and the closed pull request's removal; the unparsed head says nothing.
+	if n := info.CachedInfo().State.Msgs; n != 2 {
+		t.Errorf("seat-definition-changed said %d times, want 2", n)
+	}
 }
 
+// seatFiles are mesh-contracts' files by commit, as gitea_get_file answers them.
+var seatFiles = map[string]map[string]string{}
+
 // serveForge answers the forge's tools on the bus as the gitea module does: gitea_commit_trees (the trees of a commit,
 // or with files the blobs under each directory of mesh-sdk's listing at that commit), gitea_get_file (every go.sum
 // holds goSum) and gitea_contains.
@@ -213,6 +283,17 @@ func serveForge(t *testing.T, nc *nats.Conn, listing map[string]map[string]strin
 		t.Fatal(err)
 	}
 	file, err := nc.Subscribe("mesh.mod.gitea.tool.gitea_get_file", func(m *nats.Msg) {
+		var a struct{ Repo, Path, Ref string }
+		_ = json.Unmarshal(m.Data, &a)
+		if a.Repo == "mesh-contracts" { // the seat definitions (DLV-I17): a path the commit does not hold is a 404
+			if v, ok := seatFiles[a.Ref][a.Path]; ok {
+				reply(m, map[string]any{"file": map[string]any{"content": v}})
+			} else {
+				raw, _ := json.Marshal(map[string]any{"error": "gitea: 404 Not Found", "node": "n0"})
+				_ = m.Respond(raw)
+			}
+			return
+		}
 		reply(m, map[string]any{"file": map[string]any{"content": goSum}})
 	})
 	if err != nil {