mesh-delivery-contracts: the gate's values in the seat's types with their rules (source, merge, ask, owed, turn, answer: encode, decode, check, same), the turns and approved keys, the merge states, and the checker's verdict key, goldens from go/delivery's output; the turns' times are time.Time (B5e ruling 3; ADR 0625 §4, ADR 0634 §2; issue 1966)

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i

contracts/go/clients/meshdeliverycheckerclient/client.go

@@ -278,3 +278,35 @@ func CheckPreview(p checker.PreviewsByRepositoryHeadTrunkValue) error {
 	}
 	return nil
 }
+
+// VerdictKey is the key, in the state verdicts, of a group's check at its heads: `<escaped group>.<heads hash>`, the
+// group escaped so a branch such as `fix/1.2` keys, the heads hash as the mesh-delivery client's HeadsHash gives it
+// (12 lowercase hex digits).
+func VerdictKey(group, headsHash string) (string, error) {
+	if group == "" {
+		return "", fmt.Errorf("meshdeliverycheckerclient: the group name is empty")
+	}
+	if !isHex12(headsHash) {
+		return "", fmt.Errorf("meshdeliverycheckerclient: %q is not a heads hash, 12 lowercase hex digits", headsHash)
+	}
+	return keys.EscapeName(group) + "." + headsHash, nil
+}
+
+// ParseVerdictKey is the inverse of VerdictKey.
+func ParseVerdictKey(key string) (group, headsHash string, err error) {
+	i := strings.LastIndex(key, ".")
+	if i < 0 {
+		return "", "", fmt.Errorf("meshdeliverycheckerclient: %q is not a verdict key, <group>.<heads hash>", key)
+	}
+	part, headsHash := key[:i], key[i+1:]
+	if !isHex12(headsHash) {
+		return "", "", fmt.Errorf("meshdeliverycheckerclient: %q is not a verdict key: %q is not a heads hash, 12 lowercase hex digits", key, headsHash)
+	}
+	if part == "" || strings.Contains(part, ".") {
+		return "", "", fmt.Errorf("meshdeliverycheckerclient: %q is not a verdict key: the group part is empty or holds a dot", key)
+	}
+	if group, err = keys.UnescapeName(part); err != nil {
+		return "", "", fmt.Errorf("meshdeliverycheckerclient: %q is not a verdict key: %w", key, err)
+	}
+	return group, headsHash, nil
+}

contracts/go/clients/meshdeliverycheckerclient/client_test.go

@@ -125,3 +125,27 @@ func previewIsRefused(t *testing.T) {
 		t.Errorf("a head in conflict is refused: %v", err)
 	}
 }
+
+// A verdict's key as go/delivery's CheckerVerdictKey wrote it (golden): the group escaped, the heads hash after the
+// last dot.
+func TestVerdictKeyAsGoDeliveryWroteIt(t *testing.T) {
+	key, err := VerdictKey("fix/1.2", "0123456789ab")
+	if err != nil || key != "fix/1=2e2.0123456789ab" {
+		t.Fatalf("%q %v", key, err)
+	}
+	group, heads, err := ParseVerdictKey(key)
+	if err != nil || group != "fix/1.2" || heads != "0123456789ab" {
+		t.Fatalf("%q %q %v", group, heads, err)
+	}
+	for _, bad := range []string{"nodot", "g.XYZ", ".0123456789ab", "a.b.0123456789ab", "g=zz.0123456789ab"} {
+		if _, _, err := ParseVerdictKey(bad); err == nil {
+			t.Errorf("%q parses", bad)
+		}
+	}
+	if _, err := VerdictKey("", "0123456789ab"); err == nil {
+		t.Error("an empty group keys")
+	}
+	if _, err := VerdictKey("g", "0123"); err == nil {
+		t.Error("a short hash keys")
+	}
+}

contracts/go/clients/meshdeliveryclient/gate.go

@@ -0,0 +1,407 @@
+package meshdeliveryclient
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+
+	seat "git.novox.be/novox/mesh-delivery/contracts/go/seats/meshdelivery"
+	"git.novox.be/novox/mesh-sdk/go/keys"
+)
+
+// The values of the seat's states `source`, `merges`, `asks`, `owed` and `turns`, in the seat's types: each is stamped
+// with Version when encoded, read strictly (an unknown field refused) and its version checked when decoded, and its rules
+// held on both sides, so the gate that writes them and the readers (the forge bridge, the teller, the assigner, the view)
+// agree. What the schema cannot say is written here once (ADR 0625 §4).
+
+// Version is the layout version of the seat's values.
+const Version = 1
+
+// MergeState is the state of a pull request in a merge.
+type MergeState string
+
+// The states a merge's pull request is in.
+const (
+	MergeMerging MergeState = "merging"
+	MergeMerged  MergeState = "merged"
+	MergeRefused MergeState = "refused"
+)
+
+// SourceMainKey is the one key of the state source.
+const SourceMainKey = "main"
+
+func encodeValue(v any, check error, stamp func()) ([]byte, error) {
+	if check != nil {
+		return nil, check
+	}
+	stamp()
+	return json.Marshal(v)
+}
+
+// ApprovedKey is the key, in a merge's approved heads, of a pull request: `<repository>@<number>`.
+func ApprovedKey(repository string, number int) string {
+	return repository + "@" + strconv.Itoa(number)
+}
+
+// TurnsKey is the key, in the state turns, of a repository: `<owner>.<name>`, lower-case and escaped.
+func TurnsKey(repository string) (string, error) {
+	repository = strings.ToLower(repository)
+	part, err := escapeRepository(repository)
+	if err != nil {
+		return "", err
+	}
+	return strings.Replace(part, "/", ".", 1), nil
+}
+
+// ParseTurnsKey is the inverse of TurnsKey; a key that does not name a lower-case <owner>/<name> is refused.
+func ParseTurnsKey(key string) (string, error) {
+	owner, name, ok := strings.Cut(key, ".")
+	if !ok || owner == "" || name == "" || strings.Contains(name, ".") {
+		return "", fmt.Errorf("meshdeliveryclient: %q is not a turns key, <owner>.<name>", key)
+	}
+	repository, err := unescapeRepository(owner + "/" + name)
+	if err != nil {
+		return "", fmt.Errorf("meshdeliveryclient: %q is not a turns key: %w", key, err)
+	}
+	if again, err := TurnsKey(repository); err != nil || again != key {
+		return "", fmt.Errorf("meshdeliveryclient: %q is not a turns key: it does not name a lowercase <owner>/<name>", key)
+	}
+	return repository, nil
+}
+
+// ----- source
+
+// CheckSource refuses a source naming no repository, a repository with no name or an empty head.
+func CheckSource(s seat.SourceByMainValue) error {
+	if len(s.Heads) == 0 {
+		return fmt.Errorf("meshdeliveryclient: a source names no repository")
+	}
+	for repository, head := range s.Heads {
+		if repository == "" {
+			return fmt.Errorf("meshdeliveryclient: a source names a repository with no name")
+		}
+		if head == "" {
+			return fmt.Errorf("meshdeliveryclient: the source's head of %s is empty", repository)
+		}
+	}
+	return nil
+}
+
+// EncodeSource is s as the value of the key main.
+func EncodeSource(s seat.SourceByMainValue) ([]byte, error) {
+	return encodeValue(&s, CheckSource(s), func() { s.V = Version })
+}
+
+// DecodeSource reads the value of the key main.
+func DecodeSource(data []byte) (seat.SourceByMainValue, error) {
+	if err := keys.CheckVersion(data); err != nil {
+		return seat.SourceByMainValue{}, err
+	}
+	s, err := seat.DecodeSourceByMainValue(data)
+	if err != nil {
+		return s, fmt.Errorf("meshdeliveryclient: a source does not fit its shape: %w", err)
+	}
+	return s, CheckSource(s)
+}
+
+// SameSource says whether two sources are the same.
+func SameSource(a, b seat.SourceByMainValue) bool { return reflect.DeepEqual(a, b) }
+
+// ----- merge
+
+// CheckMerge refuses a merge naming no group, ask or pull request, a pull request outside the approved heads or at
+// another head than the Approve was for, and a state that lacks what it needs: merged its commit, refused the forge's words.
+func CheckMerge(m seat.MergesByGroupValue) error {
+	if m.Group == "" {
+		return fmt.Errorf("meshdeliveryclient: a merge names no group")
+	}
+	if m.Ask == "" {
+		return fmt.Errorf("meshdeliveryclient: a merge names no ask")
+	}
+	if len(m.Pulls) == 0 {
+		return fmt.Errorf("meshdeliveryclient: a merge names no pull request")
+	}
+	for key, sha := range m.Approved {
+		if sha == "" {
+			return fmt.Errorf("meshdeliveryclient: the approved head of %s is empty", key)
+		}
+	}
+	for _, p := range m.Pulls {
+		who := fmt.Sprintf("%s#%d", p.Repository, p.Number)
+		if len(m.Approved) > 0 {
+			sha, ok := m.Approved[ApprovedKey(p.Repository, int(p.Number))]
+			if !ok {
+				return fmt.Errorf("meshdeliveryclient: the pull request %s is handed to the merge but is not among the approved heads", who)
+			}
+			if sha != p.Head {
+				return fmt.Errorf("meshdeliveryclient: the pull request %s is handed at head %q but the Approve was for %q", who, p.Head, sha)
+			}
+		}
+		switch MergeState(p.State) {
+		case MergeMerging:
+		case MergeMerged:
+			if p.Commit == "" {
+				return fmt.Errorf("meshdeliveryclient: the merged pull request %s has no merge commit", who)
+			}
+		case MergeRefused:
+			if p.Words == "" {
+				return fmt.Errorf("meshdeliveryclient: the refused pull request %s has no words of the forge", who)
+			}
+		default:
+			return fmt.Errorf("meshdeliveryclient: the state %q of %s is not merging, merged or refused", p.State, who)
+		}
+	}
+	return nil
+}
+
+// EncodeMerge is m as the value of a group's key.
+func EncodeMerge(m seat.MergesByGroupValue) ([]byte, error) {
+	return encodeValue(&m, CheckMerge(m), func() { m.V = Version })
+}
+
+// DecodeMerge reads the value of a group's key.
+func DecodeMerge(data []byte) (seat.MergesByGroupValue, error) {
+	if err := keys.CheckVersion(data); err != nil {
+		return seat.MergesByGroupValue{}, err
+	}
+	m, err := seat.DecodeMergesByGroupValue(data)
+	if err != nil {
+		return m, fmt.Errorf("meshdeliveryclient: a merge does not fit its shape: %w", err)
+	}
+	return m, CheckMerge(m)
+}
+
+// SameMerge says whether two merges are the same.
+func SameMerge(a, b seat.MergesByGroupValue) bool { return reflect.DeepEqual(a, b) }
+
+// ----- ask
+
+// HeadsOf are an ask's heads as Heads (for HeadsHash and MergeAskKey).
+func HeadsOf(items []seat.AsksByMergeGroupHeadsValueHeadsItem) []Head {
+	out := make([]Head, len(items))
+	for i, h := range items {
+		out[i] = Head{Repository: h.Repository, Number: int(h.Number), Head: h.Head}
+	}
+	return out
+}
+
+// CheckAsk refuses an ask with no group or heads, a negative count, or an ask that is no object.
+func CheckAsk(a seat.AsksByMergeGroupHeadsValue) error {
+	if a.Asking < 0 {
+		return fmt.Errorf("meshdeliveryclient: the ask's asking %d is negative", a.Asking)
+	}
+	if _, err := MergeAskKey(a.Group, HeadsOf(a.Heads)); err != nil {
+		return fmt.Errorf("meshdeliveryclient: an ask needs its group and at least one pull request's head: %w", err)
+	}
+	raw, err := json.Marshal(a.Ask)
+	var fields map[string]json.RawMessage
+	if err != nil || len(bytes.TrimSpace(raw)) == 0 || json.Unmarshal(raw, &fields) != nil || fields == nil {
+		return fmt.Errorf("meshdeliveryclient: the value carries no router's ask")
+	}
+	return nil
+}
+
+// EncodeAsk is a as the value of a merge ask's key; a.Ask may be a json.RawMessage.
+func EncodeAsk(a seat.AsksByMergeGroupHeadsValue) ([]byte, error) {
+	return encodeValue(&a, CheckAsk(a), func() { a.V = Version })
+}
+
+// DecodeAsk reads the value of a merge ask's key; its Ask is the router's ask as a decoded object.
+func DecodeAsk(data []byte) (seat.AsksByMergeGroupHeadsValue, error) {
+	if err := keys.CheckVersion(data); err != nil {
+		return seat.AsksByMergeGroupHeadsValue{}, err
+	}
+	a, err := seat.DecodeAsksByMergeGroupHeadsValue(data)
+	if err != nil {
+		return a, fmt.Errorf("meshdeliveryclient: an ask does not fit its shape: %w", err)
+	}
+	return a, CheckAsk(a)
+}
+
+// SameAsk says whether two asks are the same (the router's ask by its content).
+func SameAsk(a, b seat.AsksByMergeGroupHeadsValue) bool { return reflect.DeepEqual(a, b) }
+
+// ----- owed
+
+// EncodeOwed is o as the value of an owed key, after CheckOwed.
+func EncodeOwed(o seat.OwedByRepositoryNumberHeadActValue) ([]byte, error) {
+	return encodeValue(&o, CheckOwed(o), func() { o.V = Version })
+}
+
+// DecodeOwed reads the value of an owed key.
+func DecodeOwed(data []byte) (seat.OwedByRepositoryNumberHeadActValue, error) {
+	if err := keys.CheckVersion(data); err != nil {
+		return seat.OwedByRepositoryNumberHeadActValue{}, err
+	}
+	o, err := seat.DecodeOwedByRepositoryNumberHeadActValue(data)
+	if err != nil {
+		return o, fmt.Errorf("meshdeliveryclient: an owed value does not fit its shape: %w", err)
+	}
+	return o, CheckOwed(o)
+}
+
+// SameOwed says whether two owed values are the same.
+func SameOwed(a, b seat.OwedByRepositoryNumberHeadActValue) bool { return a == b }
+
+// ----- turns
+
+// CheckTurn refuses a turn whose repository is not lower-case, that names no delivery, or whose deliveries repeat a heads
+// hash, lack their times, are out of the order of the Approve, or name a wait without a verdict key.
+func CheckTurn(t seat.TurnsByRepositoryValue) error {
+	repository := strings.ToLower(t.Repository)
+	if repository != t.Repository {
+		return fmt.Errorf("meshdeliveryclient: the turn's repository %q is not lowercase", t.Repository)
+	}
+	if _, err := escapeRepository(repository); err != nil {
+		return err
+	}
+	if len(t.Waiting) == 0 {
+		return fmt.Errorf("meshdeliveryclient: the turn of %s names no delivery: its key is deleted instead", t.Repository)
+	}
+	seen := map[string]bool{}
+	for i, w := range t.Waiting {
+		if w.Group == "" {
+			return fmt.Errorf("meshdeliveryclient: a delivery in the turn of %s names no group", t.Repository)
+		}
+		if !hashOK.MatchString(w.Heads) {
+			return fmt.Errorf("meshdeliveryclient: the heads hash %q in the turn of %s is not 12 lowercase hex digits", w.Heads, t.Repository)
+		}
+		if seen[w.Heads] {
+			return fmt.Errorf("meshdeliveryclient: the turn of %s names the heads %s twice", t.Repository, w.Heads)
+		}
+		seen[w.Heads] = true
+		if w.Approved.IsZero() || w.Since.IsZero() {
+			return fmt.Errorf("meshdeliveryclient: the delivery %s in the turn of %s says no time of its Approve or of its wait", w.Group, t.Repository)
+		}
+		if i > 0 && w.Approved.Before(t.Waiting[i-1].Approved) {
+			return fmt.Errorf("meshdeliveryclient: the turn of %s is not in the order of the Approve: %s was approved before %s", t.Repository, w.Group, t.Waiting[i-1].Group)
+		}
+		if w.WaitsFor != "" {
+			if _, _, err := parseVerdictKey(w.WaitsFor); err != nil {
+				return fmt.Errorf("meshdeliveryclient: the delivery %s in the turn of %s waits for what is not a verdict key: %w", w.Group, t.Repository, err)
+			}
+		} else if (w.WaitsSince != nil && !w.WaitsSince.IsZero()) || w.Step != "" {
+			return fmt.Errorf("meshdeliveryclient: the delivery %s in the turn of %s says when and where a check runs, and names no check", w.Group, t.Repository)
+		}
+	}
+	return nil
+}
+
+// parseVerdictKey is the checker's verdict key `<group>.<heads hash>` (the checker's client has the same rule over its
+// own seat; a client uses its own seat's contract alone).
+func parseVerdictKey(key string) (group, heads string, err error) {
+	i := strings.LastIndex(key, ".")
+	if i < 0 || !hashOK.MatchString(key[i+1:]) || i == 0 || strings.Contains(key[:i], ".") {
+		return "", "", fmt.Errorf("%q is not a verdict key, <group>.<heads hash>", key)
+	}
+	if group, err = keys.UnescapeName(key[:i]); err != nil {
+		return "", "", err
+	}
+	return group, key[i+1:], nil
+}
+
+// TurnHolds says whether a delivery at these heads is not in the turn while the turn names others: the delivery's
+// check or merge holds back for the one before it.
+func TurnHolds(t seat.TurnsByRepositoryValue, heads string) bool {
+	if len(t.Waiting) == 0 {
+		return false
+	}
+	for _, w := range t.Waiting {
+		if w.Heads == heads {
+			return false
+		}
+	}
+	return true
+}
+
+// EncodeTurn is t as the value of a repository's key.
+func EncodeTurn(t seat.TurnsByRepositoryValue) ([]byte, error) {
+	if err := CheckTurn(t); err != nil {
+		return nil, err
+	}
+	t.V = Version
+	return json.Marshal(t)
+}
+
+// DecodeTurn reads the value of a repository's key.
+func DecodeTurn(data []byte) (seat.TurnsByRepositoryValue, error) {
+	if err := keys.CheckVersion(data); err != nil {
+		return seat.TurnsByRepositoryValue{}, err
+	}
+	t, err := seat.DecodeTurnsByRepositoryValue(data)
+	if err != nil {
+		return t, fmt.Errorf("meshdeliveryclient: a turn does not fit its shape: %w", err)
+	}
+	return t, CheckTurn(t)
+}
+
+// SameTurn says whether two turns are the same, a time by the instant it names.
+func SameTurn(a, b seat.TurnsByRepositoryValue) bool {
+	if len(a.Waiting) != len(b.Waiting) || a.Repository != b.Repository || a.V != b.V {
+		return false
+	}
+	for i := range a.Waiting {
+		x, y := a.Waiting[i], b.Waiting[i]
+		if !x.Approved.Equal(y.Approved) || !x.Since.Equal(y.Since) || !sameTime(x.WaitsSince, y.WaitsSince) {
+			return false
+		}
+		x.Approved, y.Approved, x.Since, y.Since, x.WaitsSince, y.WaitsSince = time.Time{}, time.Time{}, time.Time{}, time.Time{}, nil, nil
+		if !reflect.DeepEqual(x, y) {
+			return false
+		}
+	}
+	return true
+}
+
+func sameTime(a, b *time.Time) bool {
+	if a == nil || a.IsZero() {
+		return b == nil || b.IsZero()
+	}
+	return b != nil && a.Equal(*b)
+}
+
+// Answer is the operator's answer to a merge ask as the gate acts on it: the option chosen, the warrant that proves who
+// answered, and the words said. It is the teller's state `answers` under the ask's key (the teller's own record; this is
+// its layout for the gate that reads it).
+type Answer struct {
+	V       int    `json:"v"`
+	Option  string `json:"option"`
+	Warrant string `json:"warrant"`
+	Words   string `json:"words"`
+}
+
+// CheckAnswer refuses an answer lacking its option, warrant or words.
+func CheckAnswer(a Answer) error {
+	for _, f := range []struct{ name, value string }{{"option", a.Option}, {"warrant", a.Warrant}, {"words", a.Words}} {
+		if f.value == "" {
+			return fmt.Errorf("meshdeliveryclient: an answer has no %s", f.name)
+		}
+	}
+	return nil
+}
+
+// EncodeAnswer is a as the value of an answer's key.
+func EncodeAnswer(a Answer) ([]byte, error) {
+	return encodeValue(&a, CheckAnswer(a), func() { a.V = Version })
+}
+
+// DecodeAnswer reads the value of an answer's key.
+func DecodeAnswer(data []byte) (Answer, error) {
+	if err := keys.CheckVersion(data); err != nil {
+		return Answer{}, err
+	}
+	var a Answer
+	dec := json.NewDecoder(bytes.NewReader(data))
+	dec.DisallowUnknownFields()
+	if err := dec.Decode(&a); err != nil {
+		return Answer{}, fmt.Errorf("meshdeliveryclient: an answer does not fit its shape: %w", err)
+	}
+	return a, CheckAnswer(a)
+}
+
+// SameAnswer says whether two answers are the same.
+func SameAnswer(a, b Answer) bool { return a == b }

contracts/go/clients/meshdeliveryclient/gate_test.go

@@ -0,0 +1,186 @@
+package meshdeliveryclient
+
+import (
+	"encoding/json"
+	"errors"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+
+	seat "git.novox.be/novox/mesh-delivery/contracts/go/seats/meshdelivery"
+	"git.novox.be/novox/mesh-sdk/go/keys"
+)
+
+// sameJSON says whether two documents hold the same values (the generated types write their fields in alphabetical
+// order, the old package's in declaration order: the bytes differ, the documents do not).
+func sameJSON(t *testing.T, got []byte, want string) {
+	t.Helper()
+	var g, w any
+	if err := json.Unmarshal(got, &g); err != nil {
+		t.Fatalf("%s: %v", got, err)
+	}
+	if err := json.Unmarshal([]byte(want), &w); err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(g, w) {
+		t.Errorf("got  %s\nwant %s", got, want)
+	}
+}
+
+// The goldens are the output of go/delivery's Encode* before it was deleted; each value must encode to the same
+// document and decode back to what it was.
+func TestGateValuesEncodeAsGoDeliveryDid(t *testing.T) {
+	ap := time.Date(2026, 11, 5, 10, 0, 0, 0, time.UTC)
+	wait := ap.Add(2 * time.Minute)
+	for _, c := range []struct {
+		name   string
+		encode func() ([]byte, error)
+		decode func([]byte) (any, error)
+		value  any
+		golden string
+	}{
+		{"source", func() ([]byte, error) {
+			return EncodeSource(seat.SourceByMainValue{Group: "fix/1.2", Heads: map[string]string{"novox/a": "aaaa", "novox/b": "bbbb"}})
+		}, func(b []byte) (any, error) { return DecodeSource(b) },
+			seat.SourceByMainValue{V: 1, Group: "fix/1.2", Heads: map[string]string{"novox/a": "aaaa", "novox/b": "bbbb"}},
+			`{"v":1,"group":"fix/1.2","heads":{"novox/a":"aaaa","novox/b":"bbbb"}}`},
+		{"merge", func() ([]byte, error) {
+			return EncodeMerge(seat.MergesByGroupValue{Group: "g", Ask: "merge.g.0123456789ab", Approved: map[string]string{"novox/a@7": "h1"},
+				Pulls: []seat.MergesByGroupValuePullsItem{{Repository: "novox/a", Number: 7, Head: "h1", State: "merged", Commit: "c1"}}})
+		}, func(b []byte) (any, error) { return DecodeMerge(b) },
+			seat.MergesByGroupValue{V: 1, Group: "g", Ask: "merge.g.0123456789ab", Approved: map[string]string{"novox/a@7": "h1"},
+				Pulls: []seat.MergesByGroupValuePullsItem{{Repository: "novox/a", Number: 7, Head: "h1", State: "merged", Commit: "c1"}}},
+			`{"v":1,"group":"g","ask":"merge.g.0123456789ab","approved":{"novox/a@7":"h1"},"pulls":[{"repository":"novox/a","number":7,"head":"h1","state":"merged","commit":"c1"}]}`},
+		{"ask", func() ([]byte, error) {
+			return EncodeAsk(seat.AsksByMergeGroupHeadsValue{Group: "g", Asking: 2, Ask: json.RawMessage(`{"headline":"x"}`),
+				Heads: []seat.AsksByMergeGroupHeadsValueHeadsItem{{Repository: "novox/a", Number: 7, Head: "h1"}}})
+		}, func(b []byte) (any, error) { return DecodeAsk(b) },
+			seat.AsksByMergeGroupHeadsValue{V: 1, Group: "g", Asking: 2, Ask: map[string]any{"headline": "x"},
+				Heads: []seat.AsksByMergeGroupHeadsValueHeadsItem{{Repository: "novox/a", Number: 7, Head: "h1"}}},
+			`{"v":1,"group":"g","heads":[{"repository":"novox/a","number":7,"head":"h1"}],"ask":{"headline":"x"},"asking":2}`},
+		{"owed", func() ([]byte, error) {
+			return EncodeOwed(seat.OwedByRepositoryNumberHeadActValue{Act: OwedStatus, Context: StatusContextCheck, Target: "t", State: "pending"})
+		}, func(b []byte) (any, error) { return DecodeOwed(b) },
+			seat.OwedByRepositoryNumberHeadActValue{V: 1, Act: OwedStatus, Context: StatusContextCheck, Target: "t", State: "pending"},
+			`{"v":1,"act":"status","context":"mesh/check","target":"t","state":"pending"}`},
+		{"turn", func() ([]byte, error) {
+			return EncodeTurn(seat.TurnsByRepositoryValue{Repository: "novox/a", Waiting: []seat.TurnsByRepositoryValueWaitingItem{{
+				Group: "g", Heads: "0123456789ab", Ask: "k", Approved: ap, Since: ap.Add(time.Minute), WaitsFor: "g.0123456789ab", WaitsSince: &wait, Step: "s"}}})
+		}, func(b []byte) (any, error) { return DecodeTurn(b) },
+			seat.TurnsByRepositoryValue{V: 1, Repository: "novox/a", Waiting: []seat.TurnsByRepositoryValueWaitingItem{{
+				Group: "g", Heads: "0123456789ab", Ask: "k", Approved: ap, Since: ap.Add(time.Minute), WaitsFor: "g.0123456789ab", WaitsSince: &wait, Step: "s"}}},
+			`{"v":1,"repository":"novox/a","waiting":[{"group":"g","heads":"0123456789ab","ask":"k","approved":"2026-11-05T10:00:00Z","since":"2026-11-05T10:01:00Z","waits-for":"g.0123456789ab","waits-since":"2026-11-05T10:02:00Z","step":"s"}]}`},
+		{"answer", func() ([]byte, error) { return EncodeAnswer(Answer{Option: "merge", Warrant: "w", Words: "ok"}) },
+			func(b []byte) (any, error) { return DecodeAnswer(b) }, Answer{V: 1, Option: "merge", Warrant: "w", Words: "ok"},
+			`{"v":1,"option":"merge","warrant":"w","words":"ok"}`},
+	} {
+		raw, err := c.encode()
+		if err != nil {
+			t.Fatalf("%s: %v", c.name, err)
+		}
+		sameJSON(t, raw, c.golden)
+		back, err := c.decode([]byte(c.golden))
+		if err != nil || !reflect.DeepEqual(back, c.value) {
+			t.Errorf("%s decoded %+v, %v; want %+v", c.name, back, err, c.value)
+		}
+	}
+}
+
+func TestGateKeysAsGoDeliveryHadThem(t *testing.T) {
+	for in, want := range map[string]string{"novox/Mesh-sdk": "novox.mesh-sdk", "novox/mesh-sdk": "novox.mesh-sdk", "novox/mesh.x": "novox.mesh=2ex"} {
+		got, err := TurnsKey(in)
+		if err != nil || got != want {
+			t.Errorf("TurnsKey(%q) = %q, %v; want %q", in, got, err, want)
+		}
+	}
+	if r, err := ParseTurnsKey("novox.mesh=2ex"); err != nil || r != "novox/mesh.x" {
+		t.Errorf("%q %v", r, err)
+	}
+	for _, bad := range []string{"novox", "novox.Mesh", "a.b.c", ".x", "novox.mesh-sdk."} {
+		if _, err := ParseTurnsKey(bad); err == nil {
+			t.Errorf("%q parses as a turns key", bad)
+		}
+	}
+	if _, err := TurnsKey("novox"); err == nil {
+		t.Error("a repository with no slash keys")
+	}
+	if k := ApprovedKey("novox/a", 7); k != "novox/a@7" {
+		t.Error(k)
+	}
+	if SourceMainKey != seat.SourceByMainKey() {
+		t.Error("the source's key is the seat's")
+	}
+}
+
+func TestGateValuesRefuseWhatTheirRulesRefuse(t *testing.T) {
+	ap := time.Date(2026, 11, 5, 10, 0, 0, 0, time.UTC)
+	pull := seat.MergesByGroupValuePullsItem{Repository: "novox/a", Number: 7, Head: "h1", State: "merging"}
+	merge := func(edit func(*seat.MergesByGroupValue)) error {
+		m := seat.MergesByGroupValue{Group: "g", Ask: "k", Pulls: []seat.MergesByGroupValuePullsItem{pull}}
+		edit(&m)
+		_, err := EncodeMerge(m)
+		return err
+	}
+	turn := func(edit func(*seat.TurnsByRepositoryValue)) error {
+		tv := seat.TurnsByRepositoryValue{Repository: "novox/a", Waiting: []seat.TurnsByRepositoryValueWaitingItem{{Group: "g", Heads: "0123456789ab", Approved: ap, Since: ap}}}
+		edit(&tv)
+		_, err := EncodeTurn(tv)
+		return err
+	}
+	for name, c := range map[string]struct {
+		err  error
+		want string
+	}{
+		"merge: no group":         {merge(func(m *seat.MergesByGroupValue) { m.Group = "" }), "no group"},
+		"merge: no pull":          {merge(func(m *seat.MergesByGroupValue) { m.Pulls = nil }), "no pull request"},
+		"merge: not approved":     {merge(func(m *seat.MergesByGroupValue) { m.Approved = map[string]string{"novox/b@1": "x"} }), "not among the approved"},
+		"merge: other head":       {merge(func(m *seat.MergesByGroupValue) { m.Approved = map[string]string{"novox/a@7": "x"} }), "Approve was for"},
+		"merge: merged no commit": {merge(func(m *seat.MergesByGroupValue) { m.Pulls[0].State = "merged" }), "no merge commit"},
+		"merge: refused no words": {merge(func(m *seat.MergesByGroupValue) { m.Pulls[0].State = "refused" }), "no words"},
+		"merge: unknown state":    {merge(func(m *seat.MergesByGroupValue) { m.Pulls[0].State = "lost" }), "not merging, merged or refused"},
+		"turn: upper case":        {turn(func(v *seat.TurnsByRepositoryValue) { v.Repository = "Novox/a" }), "not lowercase"},
+		"turn: empty":             {turn(func(v *seat.TurnsByRepositoryValue) { v.Waiting = nil }), "names no delivery"},
+		"turn: bad hash":          {turn(func(v *seat.TurnsByRepositoryValue) { v.Waiting[0].Heads = "xyz" }), "12 lowercase hex"},
+		"turn: no time":           {turn(func(v *seat.TurnsByRepositoryValue) { v.Waiting[0].Since = time.Time{} }), "no time"},
+		"turn: step with no wait": {turn(func(v *seat.TurnsByRepositoryValue) { v.Waiting[0].Step = "s" }), "names no check"},
+		"turn: not a verdict key": {turn(func(v *seat.TurnsByRepositoryValue) { v.Waiting[0].WaitsFor = "nope" }), "not a verdict key"},
+	} {
+		if c.err == nil || !strings.Contains(c.err.Error(), c.want) {
+			t.Errorf("%s: %v, want %q", name, c.err, c.want)
+		}
+	}
+	if _, err := EncodeSource(seat.SourceByMainValue{Group: "g"}); err == nil {
+		t.Error("an empty source encodes")
+	}
+	if _, err := EncodeAsk(seat.AsksByMergeGroupHeadsValue{Group: "g", Ask: "text", Heads: []seat.AsksByMergeGroupHeadsValueHeadsItem{{Repository: "novox/a", Number: 1, Head: "h"}}}); err == nil {
+		t.Error("an ask that is no object encodes")
+	}
+	if _, err := EncodeAnswer(Answer{Option: "merge"}); err == nil {
+		t.Error("an answer with no warrant encodes")
+	}
+	if _, err := DecodeSource([]byte(`{"v":2,"group":"g","heads":{"a":"b"}}`)); !errors.Is(err, keys.ErrUnknownVersion) {
+		t.Errorf("another version: %v", err)
+	}
+	if _, err := DecodeMerge([]byte(`{"v":1,"group":"g","ask":"k","pulls":[],"extra":1}`)); err == nil {
+		t.Error("an unknown field decodes")
+	}
+}
+
+func TestTurnHoldsAndSameTurn(t *testing.T) {
+	ap := time.Date(2026, 11, 5, 10, 0, 0, 0, time.UTC)
+	tv := seat.TurnsByRepositoryValue{V: 1, Repository: "novox/a", Waiting: []seat.TurnsByRepositoryValueWaitingItem{{Group: "g", Heads: "0123456789ab", Approved: ap, Since: ap}}}
+	if TurnHolds(tv, "0123456789ab") || !TurnHolds(tv, "ba9876543210") || TurnHolds(seat.TurnsByRepositoryValue{}, "x") {
+		t.Error("a turn holds a delivery that is not in it while others wait")
+	}
+	other := tv
+	other.Waiting = []seat.TurnsByRepositoryValueWaitingItem{tv.Waiting[0]}
+	other.Waiting[0].Approved = ap.In(time.FixedZone("x", 3600))
+	if !SameTurn(tv, other) {
+		t.Error("the same instant in another zone is another turn")
+	}
+	other.Waiting[0].Since = ap.Add(time.Second)
+	if SameTurn(tv, other) {
+		t.Error("another instant is the same turn")
+	}
+}

contracts/go/seats/meshdelivery/contract.go

@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"errors"
 	"strings"
+	"time"
 )
 
 // Seat is the seat's name.
@@ -433,16 +434,16 @@ type OwedByRepositoryNumberHeadActValue struct {
 // TurnsByRepositoryValueWaitingItem is a type of the contract.
 type TurnsByRepositoryValueWaitingItem struct {
 	// when (RFC 3339 time)
-	Approved string `json:"approved"`
-	Ask      string `json:"ask,omitempty"`
-	Group    string `json:"group"`
-	Heads    string `json:"heads"`
+	Approved time.Time `json:"approved"`
+	Ask      string    `json:"ask,omitempty"`
+	Group    string    `json:"group"`
+	Heads    string    `json:"heads"`
 	// when (RFC 3339 time)
-	Since    string `json:"since"`
-	Step     string `json:"step,omitempty"`
-	WaitsFor string `json:"waits-for,omitempty"`
+	Since    time.Time `json:"since"`
+	Step     string    `json:"step,omitempty"`
+	WaitsFor string    `json:"waits-for,omitempty"`
 	// when (RFC 3339 time)
-	WaitsSince string `json:"waits-since,omitempty"`
+	WaitsSince *time.Time `json:"waits-since,omitempty"`
 }
 
 // TurnsByRepositoryValue is one value of the state turns under the key <repository>.

contracts/seats/mesh-delivery/seat.json

@@ -529,10 +529,12 @@
                     },
                     "approved": {
                       "type": "string",
+                      "format": "date-time",
                       "description": "when (RFC 3339 time)"
                     },
                     "since": {
                       "type": "string",
+                      "format": "date-time",
                       "description": "when (RFC 3339 time)"
                     },
                     "waits-for": {
@@ -540,6 +542,7 @@
                     },
                     "waits-since": {
                       "type": "string",
+                      "format": "date-time",
                       "description": "when (RFC 3339 time)"
                     },
                     "step": {