Assigner: serve the seat's seven verbs, so a person proposes, withdraws, adopts, hands back and reads placement through the seat (ADR 0567 §2, §7, §10, issue 1126)

2026-10-28 18:31:43 +01:00
parent 5d57b78fe9
commit 16b71ca685
5 changed files with 1077 additions and 1 deletions
@@ -0,0 +1,526 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+
+	stdio "git.novox.be/novox/mesh-sdk/go"
+	"git.novox.be/novox/mesh-sdk/go/catalogue"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+
+	"mesh-delivery-assigner/internal/assign"
+)
+
+// The seat mesh-placement's seven verbs (novox/hq ADR 0567 §10), served through the tool runner beside the put tools: a
+// process never serves (ADR 0436). They read every state the seat keeps and write what a person asks of it: a proposal
+// and its candidates (propose, adopt), a proposal marked to end (withdraw) or to be judged again (again), and the keys
+// deleted (hand-back). Everything that follows a proposal — composing it, judging the answers, the ask, the write at the
+// warrant and the seat's events on its stream — is the assigner's process's (seat.go), started by these writes.
+
+// seatStore is what the seat's verbs need of the states: the runtime's, or a test's.
+type seatStore interface {
+	store
+	del(state, key string) error
+	history(state, key string) ([]stdio.StateRevision, error)
+}
+
+func (runtimeStore) del(state, key string) error { return stdio.State(state).Delete(key) }
+
+func (runtimeStore) history(state, key string) ([]stdio.StateRevision, error) {
+	return stdio.State(state).History(key)
+}
+
+// The states the verbs read, as the runtime names them: the seat's own by their local names, the others'
+// `<module>.<state>`.
+const (
+	modulesState = delivery.IndexerModule + ".modules"
+	haveState    = "node-engine.have"
+)
+
+// seatTools serves the seat's verbs over a store, asking the controller through ask (stdio.Ask, or a test's).
+type seatTools struct {
+	st  seatStore
+	ask func(key string, body any) (json.RawMessage, error)
+	now func() time.Time
+}
+
+func newSeatTools(st seatStore, ask func(string, any) (json.RawMessage, error)) *seatTools {
+	return &seatTools{st: st, ask: ask, now: time.Now}
+}
+
+// keyed is one placement key as a verb answers it.
+type keyed struct {
+	Placement delivery.Placement `json:"placement"`
+	Revision  uint64             `json:"revision"`
+}
+
+// placements reads every node's placement and its key's revision.
+func (s *seatTools) placements() (map[string]delivery.Placement, map[string]uint64, error) {
+	keys, err := s.st.keys(delivery.PlacementState)
+	if err != nil {
+		return nil, nil, fmt.Errorf("placement cannot be listed: %w", err)
+	}
+	out, revs := map[string]delivery.Placement{}, map[string]uint64{}
+	for _, key := range keys {
+		node, err := delivery.ParsePlacementKey(key)
+		if err != nil {
+			continue
+		}
+		raw, rev, found, err := s.st.get(delivery.PlacementState, key)
+		if err != nil {
+			return nil, nil, fmt.Errorf("placement of %s cannot be read: %w", node, err)
+		}
+		if !found {
+			continue
+		}
+		p, err := delivery.DecodePlacement(raw)
+		if err != nil {
+			return nil, nil, fmt.Errorf("placement of %s cannot be read: %w", node, err)
+		}
+		out[node], revs[node] = p, rev
+	}
+	return out, revs, nil
+}
+
+// lays is what a proposal is checked against: the modules the indexer holds and the nodes with a record.
+func (s *seatTools) lays() (func(string) bool, func(string) bool, error) {
+	mods, err := s.st.keys(modulesState)
+	if err != nil {
+		return nil, nil, fmt.Errorf("the indexer's modules cannot be listed: %w", err)
+	}
+	held := map[string]bool{}
+	for _, k := range mods {
+		if name, err := delivery.ParseModulesKey(k); err == nil {
+			held[name] = true
+		}
+	}
+	haves, err := s.st.keys(haveState)
+	if err != nil {
+		return nil, nil, fmt.Errorf("the nodes' records cannot be listed: %w", err)
+	}
+	recorded := map[string]bool{}
+	for _, k := range haves {
+		node, _, isNode, err := delivery.ParseHaveKey(k)
+		if err != nil || !isNode {
+			continue
+		}
+		if raw, _, found, err := s.st.get(haveState, k); err == nil && found {
+			if h, err := delivery.DecodeHaveNode(raw); err == nil && h.Record != nil {
+				recorded[node] = true
+			}
+		}
+	}
+	return func(m string) bool { return held[m] }, func(n string) bool { return recorded[n] }, nil
+}
+
+// proposal reads one open proposal.
+func (s *seatTools) proposal(id string) (delivery.PlacementProposal, error) {
+	if err := delivery.CheckProposalID(id); err != nil {
+		return delivery.PlacementProposal{}, err
+	}
+	raw, _, found, err := s.st.get(delivery.PlacementProposalsState, id)
+	if err != nil {
+		return delivery.PlacementProposal{}, fmt.Errorf("the proposal %s cannot be read: %w", id, err)
+	}
+	if !found {
+		return delivery.PlacementProposal{}, fmt.Errorf("no proposal %s is open: mesh-placement.proposals lists those that are", id)
+	}
+	return delivery.DecodePlacementProposal(raw)
+}
+
+// write writes a proposal laid by assign.Propose: each candidate, then the proposal, whose write the assigner's process
+// takes as the event to compose and judge it.
+func (s *seatTools) write(p delivery.PlacementProposal, laid map[string]*delivery.Placement) error {
+	p.Written = s.now().UTC()
+	for _, node := range p.Nodes() {
+		key, err := delivery.PlacementCandidateKey(p.ID, node)
+		if err != nil {
+			return err
+		}
+		raw, err := delivery.EncodePlacementCandidate(delivery.PlacementCandidate{Proposal: p.ID, Placement: laid[node]})
+		if err != nil {
+			return err
+		}
+		if err := s.st.put(delivery.PlacementCandidatesState, key, raw); err != nil {
+			return fmt.Errorf("the candidate %s is not written: %w", key, err)
+		}
+	}
+	raw, err := delivery.EncodePlacementProposal(p)
+	if err != nil {
+		return err
+	}
+	if err := s.st.put(delivery.PlacementProposalsState, p.ID, raw); err != nil {
+		return fmt.Errorf("the proposal %s is not written: %w", p.ID, err)
+	}
+	return nil
+}
+
+// proposed is what propose and adopt answer.
+type proposed struct {
+	Proposal delivery.PlacementProposal `json:"proposal"`
+	Follow   string                     `json:"follow"`
+}
+
+func followProposal(id string) string {
+	return fmt.Sprintf("the nodes it touches answer it; mesh-placement.proposals with id %q says where it stands, and the "+
+		"operator is asked to approve it once its verdict passes", id)
+}
+
+// changesOf reads propose's changes: a JSON array, given as one or as its text.
+func changesOf(v any) ([]delivery.PlacementProposalChange, error) {
+	var raw []byte
+	switch c := v.(type) {
+	case string:
+		raw = []byte(c)
+	case nil:
+		return nil, errors.New("propose names its changes")
+	default:
+		var err error
+		if raw, err = json.Marshal(c); err != nil {
+			return nil, err
+		}
+	}
+	var out []delivery.PlacementProposalChange
+	dec := json.NewDecoder(strings.NewReader(string(raw)))
+	dec.DisallowUnknownFields()
+	if err := dec.Decode(&out); err != nil {
+		return nil, fmt.Errorf("the changes are no list of changes: %w", err)
+	}
+	return out, nil
+}
+
+// doPropose is the verb propose (§2).
+func (s *seatTools) doPropose(args map[string]any, by string) (any, error) {
+	changes, err := changesOf(args["changes"])
+	if err != nil {
+		return nil, err
+	}
+	for _, c := range changes {
+		if c.Op == delivery.OpSeed {
+			return nil, errors.New("the seed is adopt's alone: propose takes place, take-off, pin, unpin, hold, unhold, decide and config")
+		}
+	}
+	current, revs, err := s.placements()
+	if err != nil {
+		return nil, err
+	}
+	held, recorded, err := s.lays()
+	if err != nil {
+		return nil, err
+	}
+	now := s.now()
+	p, laid, findings := assign.Propose(assign.ProposeIn{ID: delivery.NewProposalID(now), By: by, Why: arg(args, "why"), At: now,
+		Changes: changes, Current: current, Revisions: revs, Held: held, Recorded: recorded})
+	if len(findings) > 0 {
+		return nil, fmt.Errorf("the proposal is refused: %s", strings.Join(findings, "; "))
+	}
+	if err := s.write(p, laid); err != nil {
+		return nil, err
+	}
+	return proposed{Proposal: p, Follow: followProposal(p.ID)}, nil
+}
+
+// doWithdraw is the verb withdraw (§2): the proposal is marked, and the assigner deletes it and its candidates and says
+// placement-withdrawn carrying it whole.
+func (s *seatTools) doWithdraw(args map[string]any, by string) (any, error) {
+	why := arg(args, "why")
+	if why == "" {
+		return nil, errors.New("withdraw says why: it is kept in the event that ends the proposal")
+	}
+	p, err := s.proposal(arg(args, "id"))
+	if err != nil {
+		return nil, err
+	}
+	p.Withdrawn = fmt.Sprintf("withdrawn by %s: %s", by, why)
+	raw, err := delivery.EncodePlacementProposal(p)
+	if err != nil {
+		return nil, err
+	}
+	if err := s.st.put(delivery.PlacementProposalsState, p.ID, raw); err != nil {
+		return nil, fmt.Errorf("the proposal %s is not withdrawn: %w", p.ID, err)
+	}
+	return map[string]any{"proposal": p.ID, "withdrawn": p.Withdrawn}, nil
+}
+
+// doAgain is the verb again (§10): the proposal is marked, and the assigner judges it now and raises its ask again
+// when its verdict passes.
+func (s *seatTools) doAgain(args map[string]any) (any, error) {
+	p, err := s.proposal(arg(args, "id"))
+	if err != nil {
+		return nil, err
+	}
+	p.Again = s.now().UTC()
+	raw, err := delivery.EncodePlacementProposal(p)
+	if err != nil {
+		return nil, err
+	}
+	if err := s.st.put(delivery.PlacementProposalsState, p.ID, raw); err != nil {
+		return nil, fmt.Errorf("the proposal %s is not asked again: %w", p.ID, err)
+	}
+	return map[string]any{"proposal": p.ID, "again": p.Again, "follow": followProposal(p.ID)}, nil
+}
+
+// exportCall is the controller's verb the seed is read from, by request and reply on its seat (§7).
+const exportCall = "seat:" + catalogue.ControllerSeatName + ".placement-export"
+
+// doAdopt is the verb adopt (§7): the controller's export proposed whole as the seed.
+func (s *seatTools) doAdopt(args map[string]any, by string) (any, error) {
+	current, _, err := s.placements()
+	if err != nil {
+		return nil, err
+	}
+	if len(current) > 0 {
+		return nil, fmt.Errorf("placement is taken over already (%d keys): propose a change instead, or hand it back first", len(current))
+	}
+	if ids, err := s.st.keys(delivery.PlacementProposalsState); err == nil {
+		for _, id := range ids {
+			if p, err := s.proposal(id); err == nil && p.Seed {
+				return nil, fmt.Errorf("the seed %s is open: withdraw it first, or answer its ask", id)
+			}
+		}
+	}
+	raw, err := s.ask(exportCall, map[string]any{})
+	if err != nil {
+		return nil, fmt.Errorf("the controller's placement-export did not answer: %w", err)
+	}
+	export, err := assign.ExportOf(raw)
+	if err != nil {
+		return nil, err
+	}
+	held, recorded, err := s.lays()
+	if err != nil {
+		return nil, err
+	}
+	now := s.now()
+	p, laid, findings := assign.Propose(assign.ProposeIn{ID: delivery.NewProposalID(now), By: by, Why: arg(args, "why"), At: now,
+		Changes: assign.SeedChanges(export), Current: map[string]delivery.Placement{}, Revisions: map[string]uint64{},
+		Held: held, Recorded: recorded, Seed: true, ExportDigest: delivery.ExportDigest(export)})
+	if len(findings) > 0 {
+		return nil, fmt.Errorf("the seed is refused: %s", strings.Join(findings, "; "))
+	}
+	if err := s.write(p, laid); err != nil {
+		return nil, err
+	}
+	return proposed{Proposal: p, Follow: followProposal(p.ID)}, nil
+}
+
+// handActCall records a hand act in the controller's hand-act log.
+const handActCall = "seat:" + catalogue.ControllerSeatName + ".hand-act"
+
+// doHandBack is the verb hand-back (§7): every placement key deleted, the history kept, recorded as the operator's hand
+// act; every node returns to the controller's compositions. The assigner says placement-changed for each key it sees go.
+func (s *seatTools) doHandBack(args map[string]any, by string) (any, error) {
+	if assign.Leased {
+		return nil, errors.New("placement is the mesh's alone since the lease write: there is no controller to hand it back to")
+	}
+	why := arg(args, "why")
+	if why == "" {
+		return nil, errors.New("hand-back says why: it is recorded with the hand act")
+	}
+	keys, err := s.st.keys(delivery.PlacementState)
+	if err != nil {
+		return nil, fmt.Errorf("placement cannot be listed: %w", err)
+	}
+	sort.Strings(keys)
+	if _, err := s.ask(handActCall, map[string]any{"what": "mesh-placement hand-back of " + strings.Join(keys, ", "),
+		"why": why, "cause": "asked by " + by}); err != nil {
+		return nil, fmt.Errorf("the hand-back is not recorded as a hand act, so nothing is deleted: %w", err)
+	}
+	var deleted []string
+	for _, key := range keys {
+		if err := s.st.del(delivery.PlacementState, key); err != nil {
+			return map[string]any{"deleted": deleted}, fmt.Errorf("%s is not deleted (%v); the others before it are: hand-back again", key, err)
+		}
+		deleted = append(deleted, key)
+	}
+	return map[string]any{"deleted": deleted, "follow": "each node returns to the controller's compositions as it hears its key go"}, nil
+}
+
+// placementAnswer is what the verb placement answers.
+type placementAnswer struct {
+	Keys    map[string]keyed `json:"keys,omitempty"`
+	Nodes   []string         `json:"nodes,omitempty"`
+	Count   int              `json:"count"`
+	History int              `json:"history-per-key"`
+	Changes []historyEntry   `json:"changes,omitempty"`
+	Older   string           `json:"older,omitempty"`
+}
+
+// historyEntry is one change of a key in the state's revisions.
+type historyEntry struct {
+	Node     string                   `json:"node"`
+	Revision uint64                   `json:"revision"`
+	At       time.Time                `json:"at"`
+	Change   delivery.PlacementChange `json:"change"`
+	Deleted  bool                     `json:"deleted,omitempty"`
+}
+
+// doPlacement is the verb placement (§10, §6): one node's key, one module's nodes, or every key; with history, the
+// changes in order from the revisions the state keeps.
+func (s *seatTools) doPlacement(args map[string]any) (any, error) {
+	all, revs, err := s.placements()
+	if err != nil {
+		return nil, err
+	}
+	node, module := arg(args, "node"), arg(args, "module")
+	out := placementAnswer{Keys: map[string]keyed{}, Count: len(all), History: delivery.PlacementHistory}
+	for n, p := range all {
+		if node != "" && n != node {
+			continue
+		}
+		if module != "" && !strings.Contains(" "+strings.Join(p.Assigned(), " ")+" ", " "+module+" ") {
+			continue
+		}
+		out.Keys[n] = keyed{Placement: p, Revision: revs[n]}
+		out.Nodes = append(out.Nodes, n)
+	}
+	sort.Strings(out.Nodes)
+	if node != "" && len(out.Keys) == 0 && arg(args, "history") != "true" {
+		return nil, fmt.Errorf("%s has no placement key", node)
+	}
+	if arg(args, "history") != "true" {
+		return out, nil
+	}
+	nodes := out.Nodes
+	if node != "" {
+		nodes = []string{node}
+	} else if module == "" {
+		nodes = nil
+		for n := range all {
+			nodes = append(nodes, n)
+		}
+		sort.Strings(nodes)
+	}
+	for _, n := range nodes {
+		key, err := delivery.PlacementKey(n)
+		if err != nil {
+			return nil, err
+		}
+		revisions, err := s.st.history(delivery.PlacementState, key)
+		if err != nil {
+			return nil, fmt.Errorf("the history of %s cannot be read: %w", key, err)
+		}
+		var before delivery.Placement
+		for _, r := range revisions {
+			e := historyEntry{Node: n, Revision: r.Revision, At: r.At}
+			after := delivery.Placement{}
+			if r.Op == "" || r.Op == "put" || r.Op == "PUT" {
+				if p, err := delivery.DecodePlacement(r.Value); err == nil {
+					after = p
+				}
+			} else {
+				e.Deleted = true
+			}
+			e.Change = delivery.ChangeOf(before, after)
+			e.Change.Before, e.Change.After = 0, r.Revision
+			before = after
+			if module != "" && !strings.Contains(" "+strings.Join(append(append(e.Change.Added, e.Change.Removed...), e.Change.Changed...), " ")+" ", " "+module+" ") {
+				continue
+			}
+			out.Changes = append(out.Changes, e)
+		}
+	}
+	out.Older = fmt.Sprintf("the state keeps %d revisions of each key; an older change is in its placement-changed event on "+
+		"the assigner's stream %s, kept %d days", delivery.PlacementHistory, delivery.PlacementStream, delivery.PlacementStreamDays)
+	return out, nil
+}
+
+// openProposal is one open proposal as the verb proposals answers it: the proposal (its changes, base revisions,
+// verdict with the differences and the answers it judged, its ask), its candidates by node with their revisions, and
+// every node's answer now.
+type openProposal struct {
+	Proposal   delivery.PlacementProposal          `json:"proposal"`
+	Candidates map[string]uint64                   `json:"candidates"`
+	Answers    map[string]delivery.CandidateAnswer `json:"answers,omitempty"`
+}
+
+// doProposals is the verb proposals (§10).
+func (s *seatTools) doProposals(args map[string]any) (any, error) {
+	ids, err := s.st.keys(delivery.PlacementProposalsState)
+	if err != nil {
+		return nil, fmt.Errorf("the proposals cannot be listed: %w", err)
+	}
+	cands, err := s.st.keys(delivery.PlacementCandidatesState)
+	if err != nil {
+		return nil, fmt.Errorf("the candidates cannot be listed: %w", err)
+	}
+	haves, err := s.st.keys(haveState)
+	if err != nil {
+		return nil, fmt.Errorf("the nodes' haves cannot be listed: %w", err)
+	}
+	answers := map[string]map[string]delivery.CandidateAnswer{} // by proposal, then node
+	for _, k := range haves {
+		node, _, isNode, err := delivery.ParseHaveKey(k)
+		if err != nil || !isNode {
+			continue
+		}
+		raw, _, found, err := s.st.get(haveState, k)
+		if err != nil || !found {
+			continue
+		}
+		h, err := delivery.DecodeHaveNode(raw)
+		if err != nil {
+			continue
+		}
+		for id, a := range h.Candidates {
+			if answers[id] == nil {
+				answers[id] = map[string]delivery.CandidateAnswer{}
+			}
+			answers[id][node] = a
+		}
+	}
+	sort.Strings(ids)
+	out := []openProposal{}
+	for _, id := range ids {
+		if want := arg(args, "id"); want != "" && want != id {
+			continue
+		}
+		p, err := s.proposal(id)
+		if err != nil {
+			return nil, err
+		}
+		o := openProposal{Proposal: p, Candidates: map[string]uint64{}, Answers: answers[id]}
+		for _, k := range cands {
+			pid, node, err := delivery.ParsePlacementCandidateKey(k)
+			if err != nil || pid != id {
+				continue
+			}
+			if _, rev, found, err := s.st.get(delivery.PlacementCandidatesState, k); err == nil && found {
+				o.Candidates[node] = rev
+			}
+		}
+		out = append(out, o)
+	}
+	if arg(args, "id") != "" && len(out) == 0 {
+		return nil, fmt.Errorf("no proposal %s is open", arg(args, "id"))
+	}
+	return map[string]any{"proposals": out}, nil
+}
+
+// tools are the seat's verbs as the runtime serves them, under the seat's verb names, with the seat's own schemas.
+func (s *seatTools) tools() []stdio.Tool {
+	seat, _ := catalogue.SeatNamed(catalogue.PlacementSeat)
+	input := map[string]map[string]any{}
+	description := map[string]string{}
+	for _, v := range seat.Serves {
+		input[v.Name], description[v.Name] = v.Input, v.Description
+	}
+	run := map[string]func(map[string]any) (any, error){
+		catalogue.PlacementVerbPlacement: s.doPlacement,
+		catalogue.PlacementVerbProposals: s.doProposals,
+		catalogue.PlacementVerbPropose:   func(a map[string]any) (any, error) { return s.doPropose(a, stdio.CallerOf(a)) },
+		catalogue.PlacementVerbWithdraw:  func(a map[string]any) (any, error) { return s.doWithdraw(a, stdio.CallerOf(a)) },
+		catalogue.PlacementVerbAgain:     s.doAgain,
+		catalogue.PlacementVerbAdopt:     func(a map[string]any) (any, error) { return s.doAdopt(a, stdio.CallerOf(a)) },
+		catalogue.PlacementVerbHandBack:  func(a map[string]any) (any, error) { return s.doHandBack(a, stdio.CallerOf(a)) },
+	}
+	var out []stdio.Tool
+	for _, v := range seat.Serves {
+		out = append(out, stdio.Tool{Name: v.Name, Description: description[v.Name], Input: input[v.Name], Run: run[v.Name]})
+	}
+	return out
+}
@@ -0,0 +1,161 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"os"
+	"slices"
+	"strings"
+	"testing"
+	"time"
+
+	stdio "git.novox.be/novox/mesh-sdk/go"
+	"git.novox.be/novox/mesh-sdk/go/catalogue"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+func (s memStore) del(state, key string) error {
+	delete(s[state].values, key)
+	return nil
+}
+
+func (s memStore) history(state, key string) ([]stdio.StateRevision, error) {
+	v, ok := s[state].values[key]
+	if !ok {
+		return nil, nil
+	}
+	return []stdio.StateRevision{{Key: key, Value: v, Revision: uint64(len(v)), Op: "put"}}, nil
+}
+
+// ADR 0567 §2, §7, §10: the seat's seven verbs over the states. propose lays a proposal and writes it with its candidates,
+// or refuses naming every finding and writes nothing; withdraw and again mark it for the holder; adopt proposes the
+// controller's export whole as the seed, once; hand-back records the hand act and deletes every key; placement and
+// proposals read every state the seat keeps, and history names the stream for what the state no longer keeps.
+func TestTheSeatsVerbs(t *testing.T) {
+	anchor := delivery.Placement{V: delivery.Version, Node: "anchor", Modules: []delivery.PlacedModule{{Module: "web"}}}
+	st := memStore{}
+	for _, state := range []string{delivery.PlacementState, delivery.PlacementProposalsState, delivery.PlacementCandidatesState, modulesState, haveState} {
+		st[state] = &memKV{values: map[string][]byte{}}
+	}
+	for _, m := range []string{"web", "shell"} {
+		st[modulesState].values[m] = []byte("{}")
+	}
+	for _, n := range []string{"anchor", "laptop"} {
+		raw, _ := delivery.EncodeHaveNode(delivery.HaveNode{Record: &delivery.NodeRecord{Node: n}})
+		st[haveState].values[n+".node"] = raw
+	}
+	export, _ := json.Marshal(map[string]any{"anchor": anchor})
+	var asked []string
+	s := newSeatTools(st, func(key string, body any) (json.RawMessage, error) {
+		asked = append(asked, key)
+		if key == exportCall {
+			out, _ := json.Marshal(map[string]any{"ok": true, "output": string(export)})
+			return out, nil
+		}
+		return json.RawMessage(`{"ok":true}`), nil
+	})
+	s.now = func() time.Time { return time.Date(2026, 10, 28, 20, 0, 0, 0, time.UTC) }
+
+	// adopt: the export proposed whole as the seed, once.
+	got, err := s.doAdopt(map[string]any{"why": "take over"}, "operator@laptop")
+	if err != nil {
+		t.Fatal(err)
+	}
+	seed := got.(proposed).Proposal
+	if !seed.Seed || seed.ExportDigest != delivery.ExportDigest(map[string]delivery.Placement{"anchor": anchor}) || !slices.Equal(asked, []string{exportCall}) ||
+		len(st[delivery.PlacementCandidatesState].values) != 1 || st[delivery.PlacementProposalsState].values[seed.ID] == nil {
+		t.Fatalf("adopt = %+v, asked %v", seed, asked)
+	}
+	if _, err := s.doAdopt(map[string]any{"why": "again"}, "op"); err == nil || !strings.Contains(err.Error(), "is open") {
+		t.Errorf("a second adopt with a seed open: %v", err)
+	}
+	// withdraw and again mark the proposal; the holder ends or judges it.
+	if _, err := s.doWithdraw(map[string]any{"id": seed.ID, "why": "not yet"}, "op"); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := s.doAgain(map[string]any{"id": seed.ID}); err != nil {
+		t.Fatal(err)
+	}
+	if p, err := s.proposal(seed.ID); err != nil || !strings.Contains(p.Withdrawn, "not yet") || p.Again.IsZero() {
+		t.Errorf("marked = %+v, %v", p, err)
+	}
+	if _, err := s.doWithdraw(map[string]any{"id": "p-none", "why": "x"}, "op"); err == nil {
+		t.Error("an unknown proposal was withdrawn")
+	}
+	delete(st[delivery.PlacementProposalsState].values, seed.ID) // the holder ended it
+	st[delivery.PlacementCandidatesState].values = map[string][]byte{}
+
+	// propose: refused whole, naming every finding; a valid move laid over the keys at their revisions.
+	raw, _ := delivery.EncodePlacement(anchor)
+	st[delivery.PlacementState].values["placement.anchor"] = raw
+	if _, err := s.doPropose(map[string]any{"why": "x", "changes": `[{"op":"place","node":"anchor","module":"ghost"},{"op":"hold","node":"anchor","module":"web","claim":"x"}]`}, "op"); err == nil ||
+		!strings.Contains(err.Error(), "ghost") || !strings.Contains(err.Error(), "lease write") || len(st[delivery.PlacementProposalsState].values) != 0 {
+		t.Errorf("a refused proposal: %v", err)
+	}
+	if _, err := s.doPropose(map[string]any{"why": "x", "changes": `[{"op":"swap","node":"anchor"}]`}, "op"); err == nil {
+		t.Error("an unknown change was taken")
+	}
+	got, err = s.doPropose(map[string]any{"why": "move web", "changes": []any{
+		map[string]any{"op": "take-off", "node": "anchor", "module": "web"}, map[string]any{"op": "place", "node": "laptop", "module": "web"}}}, "operator@laptop")
+	if err != nil {
+		t.Fatal(err)
+	}
+	move := got.(proposed).Proposal
+	if move.By != "operator@laptop" || move.Base["anchor"] != uint64(len(raw)) || move.Base["laptop"] != 0 || len(st[delivery.PlacementCandidatesState].values) != 2 {
+		t.Fatalf("propose = %+v", move)
+	}
+
+	// placement and proposals read every state the seat keeps (§10); history names the stream for what is older.
+	reads := map[string]bool{}
+	pa, err := s.doPlacement(map[string]any{"module": "web", "history": "true"})
+	if a := pa.(placementAnswer); err != nil || !slices.Equal(a.Nodes, []string{"anchor"}) || len(a.Changes) != 1 || !strings.Contains(a.Older, delivery.PlacementStream) {
+		t.Errorf("placement of web = %+v, %v", pa, err)
+	} else {
+		reads[delivery.PlacementState], reads["stream "+delivery.PlacementStream] = true, true
+	}
+	if _, err := s.doPlacement(map[string]any{"node": "laptop"}); err == nil {
+		t.Error("a node with no key was answered")
+	}
+	ps, err := s.doProposals(map[string]any{"id": move.ID})
+	if list := ps.(map[string]any)["proposals"].([]openProposal); err != nil || len(list) != 1 || len(list[0].Candidates) != 2 {
+		t.Errorf("proposals = %+v, %v", ps, err)
+	} else {
+		reads[delivery.PlacementProposalsState], reads[delivery.PlacementCandidatesState] = true, true
+	}
+	raw0, err := readManifest()
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, state := range raw0.State {
+		if slices.Contains([]string{delivery.PlacementState, delivery.PlacementProposalsState, delivery.PlacementCandidatesState}, state.Name) && !reads[state.Name] {
+			t.Errorf("no verb reads the seat's state %s", state.Name)
+		}
+	}
+	for _, stream := range raw0.Streams {
+		if !reads["stream "+stream.Name] {
+			t.Errorf("no verb reads the seat's stream %s", stream.Name)
+		}
+	}
+
+	// hand-back: recorded as the operator's hand act, then every key deleted; refused when the hand act is not recorded.
+	failing := newSeatTools(st, func(string, any) (json.RawMessage, error) { return nil, errors.New("no controller") })
+	if _, err := failing.doHandBack(map[string]any{"why": "back"}, "op"); err == nil || len(st[delivery.PlacementState].values) != 1 {
+		t.Errorf("a hand-back not recorded deleted keys: %v", err)
+	}
+	asked = nil
+	if _, err := s.doHandBack(map[string]any{"why": "back"}, "op"); err != nil || !slices.Equal(asked, []string{handActCall}) || len(st[delivery.PlacementState].values) != 0 {
+		t.Errorf("hand-back: %v, asked %v", err, asked)
+	}
+	if tools := s.tools(); len(tools) != 7 || tools[2].Name != catalogue.PlacementVerbPropose || tools[2].Run == nil || tools[2].Input == nil {
+		t.Errorf("the seat's verbs as served: %+v", tools)
+	}
+}
+
+// readManifest is the module's manifest, read as the controller reads it.
+func readManifest() (catalogue.Manifest, error) {
+	raw, err := os.ReadFile("../../module.json")
+	if err != nil {
+		return catalogue.Manifest{}, err
+	}
+	return catalogue.ParseManifest(raw)
+}
@@ -351,7 +351,7 @@ func serveTools() error {
 			time.Sleep(wait)
 		}
 	}()
-	return stdio.Serve("", s.tools())
+	return stdio.Serve("", append(s.tools(), newSeatTools(runtimeStore{}, stdio.Ask).tools()...))
 }

 // shortFP is a fingerprint's first twelve hex digits.
@@ -0,0 +1,281 @@
+package assign
+
+import (
+	"encoding/json"
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/asks"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// The seat mesh-placement (novox/hq ADR 0567), held by the assigner beside its wants: placement is its state
+// `placement`, changed only by a proposal (§2) the nodes it touches answer (§3), judged (§4) and written on the
+// operator's Approve at the revision it was laid over (§5). What here decides; the tools and the passes do.
+
+// Leased says whether the lease write of ADR 0547 has happened, after which the controller's assignments are read no
+// more (§8). Not before L3: until then the holder keeps the controller in step and refuses what its verbs cannot take.
+var Leased = false
+
+// ProposeIn is what a proposal is laid over: its id, who and why, its changes; every node's current placement and the
+// revision of its key; which modules the indexer holds and which nodes have a record; and, for the seed, the export's
+// digest.
+type ProposeIn struct {
+	ID, By, Why  string
+	At           time.Time
+	Changes      []delivery.PlacementProposalChange
+	Current      map[string]delivery.Placement
+	Revisions    map[string]uint64
+	Held         func(module string) bool
+	Recorded     func(node string) bool
+	Seed         bool
+	ExportDigest string
+}
+
+// Propose lays a proposal over the current keys (§2): the proposal (state answering, each changed node's base revision),
+// the laid placement of every node whose key it changes, and every finding, which refuses it whole: a change the
+// controller's verbs cannot take before the lease write (§8), a change that does not fit its node, and what
+// CheckPlacements refuses of the result laid over every placement (two modules on one host port, a provider not placed,
+// a seat held once held twice, two nodes with one address, two hubs, a module the indexer does not hold, a node with no
+// record). A key whose value the proposal leaves as it is changes nothing and is not laid.
+func Propose(in ProposeIn) (delivery.PlacementProposal, map[string]*delivery.Placement, []string) {
+	p := delivery.PlacementProposal{ID: in.ID, By: strings.TrimSpace(in.By), Why: strings.TrimSpace(in.Why), At: in.At.UTC(),
+		Changes: in.Changes, Seed: in.Seed, ExportDigest: in.ExportDigest, Base: map[string]uint64{}, State: delivery.ProposalAnswering}
+	var findings []string
+	if p.By == "" {
+		findings = append(findings, "the runtime names no caller: a proposal is made by someone")
+	}
+	if p.Why == "" {
+		findings = append(findings, "a proposal says why: it is shown to the operator")
+	}
+	if len(in.Changes) == 0 {
+		findings = append(findings, "a proposal changes something: it names no change")
+	}
+	for i, c := range in.Changes {
+		if (c.Op == delivery.OpSeed) != in.Seed {
+			findings = append(findings, fmt.Sprintf("change %d: the seed is adopt's alone, and never mixed with other changes", i+1))
+			continue
+		}
+		if !Leased {
+			if why := c.BeforeLease(); why != "" {
+				findings = append(findings, fmt.Sprintf("change %d: %s", i+1, why))
+			}
+		}
+	}
+	laid, lay := delivery.LayChanges(in.Current, in.Changes)
+	findings = append(findings, lay...)
+	all := map[string]delivery.Placement{}
+	for node, pl := range in.Current {
+		all[node] = pl
+	}
+	out := map[string]*delivery.Placement{}
+	for node, pl := range laid {
+		if before, ok := in.Current[node]; ok && delivery.SamePlacement(before, pl) {
+			continue
+		}
+		pl := pl
+		all[node] = pl
+		out[node] = &pl
+		p.Base[node] = in.Revisions[node]
+	}
+	if len(findings) == 0 && len(out) == 0 {
+		findings = append(findings, "the changes leave every placement as it is")
+	}
+	held, recorded := in.Held, in.Recorded
+	if held == nil {
+		held = func(string) bool { return false }
+	}
+	if recorded == nil {
+		recorded = func(string) bool { return false }
+	}
+	for _, r := range delivery.CheckPlacements(all, held, recorded) {
+		findings = append(findings, r)
+	}
+	return p, out, findings
+}
+
+// Write is one key a warrant writes (§5): the node, its key, the revision it is written at (0: it has none, so it is
+// created) and its value (nil: it is deleted).
+type Write struct {
+	Node, Key string
+	Base      uint64
+	Value     *delivery.Placement
+}
+
+// Writes is every key a proposal writes, by node order.
+func Writes(p delivery.PlacementProposal, laid map[string]*delivery.Placement) ([]Write, error) {
+	var out []Write
+	for _, node := range p.Nodes() {
+		key, err := delivery.PlacementKey(node)
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, Write{Node: node, Key: key, Base: p.Base[node], Value: laid[node]})
+	}
+	return out, nil
+}
+
+// ControllerCall is one call of the controller's seat verbs the holder makes after writing an approved proposal, until
+// the lease write (§8): assign, unassign, pin or unpin, with its arguments.
+type ControllerCall struct {
+	Verb string
+	Args map[string]any
+	// Node and Module name the pair the call keeps in step (a pin names no module).
+	Node, Module string
+}
+
+// Key names the call, as the condition of its pair says it.
+func (c ControllerCall) Key() string {
+	return fmt.Sprintf("mesh-controller.%s %s %s", c.Verb, c.Node, c.Module)
+}
+
+// ControllerCalls is every call that brings the controller's assignments and pins to the placement after: assign for a
+// module placed on a node before not, unassign for one taken off, pin for a pin set or changed, unpin for one removed,
+// each naming the proposal and its warrant in its why. In node order, unassigns before assigns, so a module moved
+// between nodes is first taken off.
+func ControllerCalls(before map[string]delivery.Placement, after map[string]*delivery.Placement, proposal, warrant string) []ControllerCall {
+	why := fmt.Sprintf("placement proposal %s, approved (%s)", proposal, warrant)
+	nodes := make([]string, 0, len(after))
+	for node := range after {
+		nodes = append(nodes, node)
+	}
+	sort.Strings(nodes)
+	var off, on, pins []ControllerCall
+	for _, node := range nodes {
+		was, now := before[node], delivery.Placement{}
+		if a := after[node]; a != nil {
+			now = *a
+		}
+		had, has := map[string]bool{}, map[string]bool{}
+		for _, m := range was.Modules {
+			had[m.Module] = true
+		}
+		for _, m := range now.Modules {
+			has[m.Module] = true
+			if !had[m.Module] {
+				on = append(on, ControllerCall{Verb: "assign", Node: node, Module: m.Module, Args: map[string]any{"node": node, "module": m.Module}})
+			}
+		}
+		for _, m := range was.Modules {
+			if !has[m.Module] {
+				off = append(off, ControllerCall{Verb: "unassign", Node: node, Module: m.Module, Args: map[string]any{"node": node, "module": m.Module}})
+			}
+		}
+		for _, provision := range sortedKeys(now.Pins) {
+			to := now.Pins[provision]
+			if old, ok := was.Pins[provision]; !ok || old != to {
+				pins = append(pins, ControllerCall{Verb: "pin", Node: node, Module: provision,
+					Args: map[string]any{"node": node, "provision": provision, "from": to.Node, "module": to.Module}})
+			}
+		}
+		for _, provision := range sortedKeys(was.Pins) {
+			if _, ok := now.Pins[provision]; !ok {
+				pins = append(pins, ControllerCall{Verb: "unpin", Node: node, Module: provision, Args: map[string]any{"node": node, "provision": provision}})
+			}
+		}
+	}
+	out := append(append(off, on...), pins...)
+	for i := range out {
+		out[i].Args["why"] = why
+	}
+	return out
+}
+
+// PlacementAct is the act an approved proposal's yes binds: writing exactly its changes at its base revisions.
+func PlacementAct(p delivery.PlacementProposal) asks.Act {
+	return asks.Act{"placement": "write", "proposal": p.ID, "changes": delivery.ChangesDigest(p)}
+}
+
+// PlacementAsking is a proposal's asking number: each judging that raises its ask again (again, a key moved) is
+// another asking, under an id of its own.
+func PlacementAsking(p delivery.PlacementProposal, at time.Time) int {
+	return int(at.Unix())
+}
+
+// PlacementAsk is the authorising ask about a proposal (§5): an Approve that binds its act, so only a channel that
+// proves who answered takes it, with the brief of the verdict by node (judge.Brief) as its explanation.
+func PlacementAsk(key string, p delivery.PlacementProposal, brief string, asking int, now time.Time) (delivery.AssignerAsk, error) {
+	binds, err := asks.ActDigest(PlacementAct(p))
+	if err != nil {
+		return delivery.AssignerAsk{}, err
+	}
+	nodes := p.Nodes()
+	headline := fmt.Sprintf("Change placement on %s?", strings.Join(nodes, ", "))
+	if p.Seed {
+		headline = "Take placement over from the controller?"
+	}
+	if n := len([]rune(headline)); n > asks.HeadlineLength {
+		headline = fmt.Sprintf("Change placement on %d machines?", len(nodes))
+	}
+	return delivery.AssignerAsk{Ask: asks.Ask{
+		ID:          delivery.AskingID(key, asking),
+		Headline:    headline,
+		Explanation: brief,
+		Options: []asks.Option{
+			{ID: OptionYes, Label: "Approve", Does: "the placement of " + strings.Join(nodes, ", ") + " is written as proposed",
+				Level: asks.Approve, Binds: binds},
+			{ID: OptionNo, Label: "Decline", Does: "nothing is written, and the proposal ends", Level: asks.Acknowledge},
+		},
+		Who:      asks.Operator,
+		Expires:  now.Add(asks.ApproveLasts),
+		OnExpiry: "nothing is written, and the proposal ends",
+		About:    key,
+	}, Asking: asking}, nil
+}
+
+// ExportOf reads the controller's answer to placement-export (§7): its verb answers what the command printed, the
+// JSON of every node's placement, in `output` (the controller's verbAnswer; `answer` when it carries it as data). A
+// refused or unreadable answer is an error naming it.
+func ExportOf(raw []byte) (map[string]delivery.Placement, error) {
+	var a struct {
+		Output string          `json:"output"`
+		OK     *bool           `json:"ok"`
+		Answer json.RawMessage `json:"answer"`
+	}
+	if err := json.Unmarshal(raw, &a); err != nil {
+		return nil, fmt.Errorf("the controller's placement-export answered no verb answer: %w", err)
+	}
+	if a.OK != nil && !*a.OK {
+		return nil, fmt.Errorf("the controller's placement-export refused: %s", strings.TrimSpace(a.Output))
+	}
+	data := []byte(a.Answer)
+	if len(data) == 0 || string(data) == "null" {
+		out := a.Output
+		start, end := strings.Index(out, "{"), strings.LastIndex(out, "}")
+		if start < 0 || end < start {
+			return nil, fmt.Errorf("the controller's placement-export printed no placements: %q", out)
+		}
+		data = []byte(out[start : end+1])
+	}
+	var byNode map[string]json.RawMessage
+	if err := json.Unmarshal(data, &byNode); err != nil {
+		return nil, fmt.Errorf("the controller's placement-export is no placement by node: %w", err)
+	}
+	out := map[string]delivery.Placement{}
+	for node, rawP := range byNode {
+		p, err := delivery.DecodePlacement(rawP)
+		if err != nil {
+			return nil, fmt.Errorf("the controller's placement-export of %s cannot be read: %w", node, err)
+		}
+		if p.Node != node {
+			return nil, fmt.Errorf("the controller's placement-export names %s under %s", p.Node, node)
+		}
+		out[node] = p
+	}
+	if len(out) == 0 {
+		return nil, fmt.Errorf("the controller's placement-export names no node")
+	}
+	return out, nil
+}
+
+// SeedChanges is the seed's changes: every node's placement of the export, whole, in node order.
+func SeedChanges(export map[string]delivery.Placement) []delivery.PlacementProposalChange {
+	var out []delivery.PlacementProposalChange
+	for _, node := range sortedKeys(export) {
+		p := export[node]
+		out = append(out, delivery.PlacementProposalChange{Op: delivery.OpSeed, Node: node, Whole: &p})
+	}
+	return out
+}
@@ -0,0 +1,108 @@
+package assign
+
+import (
+	"encoding/json"
+	"slices"
+	"strings"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/asks"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// ADR 0567 §2, §5, §7, §8: what the seat's holder decides of a proposal: every refusal named at once, a valid one laid
+// with the base revision of each key it changes, the writes at those revisions, the controller's calls that keep its
+// assignments in step, the authorising ask bound to the changes, and the export read as the controller answers it.
+func TestThePlacementSeatDecides(t *testing.T) {
+	anchor := delivery.Placement{V: delivery.Version, Node: "anchor", Decided: delivery.NodeDecided{Hub: true, Address: "10.0.0.1"},
+		Modules: []delivery.PlacedModule{{Module: "store", Ports: map[string]int{"5432": 5432}}, {Module: "web"}}}
+	laptop := delivery.Placement{V: delivery.Version, Node: "laptop", Decided: delivery.NodeDecided{Address: "10.0.0.2"}, Modules: []delivery.PlacedModule{{Module: "shell"}}}
+	in := func(changes ...delivery.PlacementProposalChange) ProposeIn {
+		return ProposeIn{ID: "p-one", By: "operator@laptop", Why: "move web", At: time.Unix(1, 0), Changes: changes,
+			Current: map[string]delivery.Placement{"anchor": anchor, "laptop": laptop}, Revisions: map[string]uint64{"anchor": 4, "laptop": 9},
+			Held:     func(m string) bool { return m != "ghost" },
+			Recorded: func(n string) bool { return n == "anchor" || n == "laptop" }}
+	}
+	move := []delivery.PlacementProposalChange{{Op: delivery.OpTakeOff, Node: "anchor", Module: "web"}, {Op: delivery.OpPlace, Node: "laptop", Module: "web"}}
+	p, laid, findings := Propose(in(move...))
+	if len(findings) != 0 || p.State != delivery.ProposalAnswering || p.Base["anchor"] != 4 || p.Base["laptop"] != 9 ||
+		!slices.Equal(laid["laptop"].Assigned(), []string{"shell", "web"}) || !slices.Equal(laid["anchor"].Assigned(), []string{"store"}) {
+		t.Fatalf("a move: %+v, %+v, %v", p, laid, findings)
+	}
+	if _, err := delivery.EncodePlacementProposal(p); err != nil {
+		t.Fatalf("the proposal cannot be written: %v", err)
+	}
+	for name, c := range map[string]struct {
+		in   ProposeIn
+		want string
+	}{
+		"a port before the lease": {in(delivery.PlacementProposalChange{Op: delivery.OpPlace, Node: "laptop", Module: "web", Ports: map[string]int{"80": 8080}}), "lease write"},
+		"a holding":               {in(delivery.PlacementProposalChange{Op: delivery.OpHold, Node: "anchor", Module: "store", Claim: "mesh-store", Scope: "mesh"}), "lease write"},
+		"a module not held":       {in(delivery.PlacementProposalChange{Op: delivery.OpPlace, Node: "laptop", Module: "ghost"}), "the indexer holds no module ghost"},
+		"a node with no record":   {in(delivery.PlacementProposalChange{Op: delivery.OpPlace, Node: "stranger", Module: "web"}), "stranger is a node with no record"},
+		"nothing changes":         {in(delivery.PlacementProposalChange{Op: delivery.OpPlace, Node: "anchor", Module: "web"}), "leave every placement as it is"},
+		"no why":                  {func() ProposeIn { i := in(move...); i.Why = " "; return i }(), "says why"},
+		"no caller":               {func() ProposeIn { i := in(move...); i.By = ""; return i }(), "names no caller"},
+		"a seed by hand":          {in(delivery.PlacementProposalChange{Op: delivery.OpSeed, Node: "laptop", Whole: &laptop}), "adopt's alone"},
+		"a pin of nobody placed":  {in(delivery.PlacementProposalChange{Op: delivery.OpPin, Node: "laptop", Provision: "db", Provider: &delivery.Provider{Node: "laptop", Module: "store"}}), "not placed there"},
+	} {
+		if _, _, f := Propose(c.in); !slices.ContainsFunc(f, func(s string) bool { return strings.Contains(s, c.want) }) {
+			t.Errorf("%s: findings %v, want one naming %q", name, f, c.want)
+		}
+	}
+
+	writes, err := Writes(p, laid)
+	if err != nil || len(writes) != 2 || writes[0].Key != "placement.anchor" || writes[0].Base != 4 || writes[1].Base != 9 {
+		t.Fatalf("writes = %+v, %v", writes, err)
+	}
+	pinned := *laid["laptop"]
+	pinned.Pins = map[string]delivery.Provider{"db": {Node: "anchor", Module: "store"}}
+	calls := ControllerCalls(map[string]delivery.Placement{"anchor": anchor, "laptop": laptop},
+		map[string]*delivery.Placement{"anchor": laid["anchor"], "laptop": &pinned}, "p-one", "w1@t")
+	var said []string
+	for _, c := range calls {
+		said = append(said, c.Key())
+		if !strings.Contains(c.Args["why"].(string), "p-one") {
+			t.Errorf("%s does not name the proposal: %v", c.Key(), c.Args)
+		}
+	}
+	if !slices.Equal(said, []string{"mesh-controller.unassign anchor web", "mesh-controller.assign laptop web", "mesh-controller.pin laptop db"}) {
+		t.Errorf("the controller's calls = %v", said)
+	}
+
+	a, err := PlacementAsk("placement.p-one", p, "move web (proposed by operator@laptop)", 7, time.Unix(100, 0))
+	if err != nil || a.Ask.Check(time.Unix(100, 0)) != nil || a.Ask.Options[0].Level != asks.Approve || a.Ask.Options[0].Performs(PlacementAct(p)) != nil {
+		t.Fatalf("the ask = %+v, %v", a, err)
+	}
+	q := p
+	q.Changes = append(slices.Clone(p.Changes), delivery.PlacementProposalChange{Op: delivery.OpUnpin, Node: "laptop", Provision: "x"})
+	if a.Ask.Options[0].Performs(PlacementAct(q)) == nil {
+		t.Error("the ask's yes binds changes it was not asked about")
+	}
+
+	export, _ := json.Marshal(map[string]any{"anchor": anchor, "laptop": laptop})
+	for name, c := range map[string]struct {
+		raw  string
+		want int
+	}{
+		"in output":  {`{"ok":true,"output":` + quote(string(export)+"\n") + `}`, 2},
+		"as answer":  {`{"ok":true,"output":"","answer":` + string(export) + `}`, 2},
+		"refused":    {`{"ok":false,"output":"no store"}`, 0},
+		"no node":    {`{"ok":true,"output":"{}"}`, 0},
+		"no version": {`{"ok":true,"output":"{\"anchor\":{\"node\":\"anchor\",\"modules\":[]}}"}`, 0},
+	} {
+		got, err := ExportOf([]byte(c.raw))
+		if len(got) != c.want || (c.want == 0) != (err != nil) {
+			t.Errorf("%s: %d nodes, %v", name, len(got), err)
+		}
+	}
+	if seed := SeedChanges(map[string]delivery.Placement{"laptop": laptop, "anchor": anchor}); len(seed) != 2 || seed[0].Node != "anchor" || seed[0].Op != delivery.OpSeed {
+		t.Errorf("the seed's changes = %+v", seed)
+	}
+}
+
+func quote(s string) string {
+	raw, _ := json.Marshal(s)
+	return string(raw)
+}