Merge pull request 'Engine reads keep the last answer and say an unanswered node; operator-channel asks and watchdogs presence declared (ADR 0668; issue 1966; group fix/1966-call-made-once)' (#3) from fix/1966-call-made-once into main

go/clients/nodeengineclient/enginereads/calls.go

@@ -0,0 +1,225 @@
+package enginereads
+
+import (
+	"context"
+	"maps"
+	"slices"
+	"strings"
+	"sync"
+	"time"
+)
+
+// CallID is the id of a part's finding about node's manifest-reads: the node the kept call waits on.
+func CallID(node string) string { return "manifest-reads." + node }
+
+// BoundPrefix starts the key of a node's bound in a part's state of bounds, a key that expires at its end.
+const BoundPrefix = "reads-call."
+
+// BoundOf is the node a bound key is of.
+func BoundOf(key string) (string, bool) { return strings.CutPrefix(key, BoundPrefix) }
+
+// UnansweredCall is a node's manifest-reads left unanswered past the bound while its machine is heard: what the part's
+// finding call-unanswered says (novox/hq ADR 0668 §3), and At, the part's clock when it is written.
+type UnansweredCall struct {
+	Node  string
+	Since time.Time
+	Words string
+	At    time.Time
+}
+
+// ReadsCalls is the wait of a part's kept manifest-reads calls through a Keeper, shared by every caller of the verb (the
+// assigner, the builder, the indexer): a node whose engine has not answered for Bound while its machine is heard is
+// Raised in the part's own findings, and Cleared once it answers (novox/hq ADR 0668 §3). Every step is an event; nothing
+// waits on a timer.
+//
+// With Arm set, a node unanswered is weighed when its bound ends (Expired, on the expiry of the key Arm keeps in the
+// part's state of bounds): Heard is asked then, once, and a node not heard has no finding; it is asked again when it
+// returns, on manifest-reads-changed (ADR 0668 §4). With no Arm, Heard is the part's own knowledge, asked at each Step.
+type ReadsCalls struct {
+	Keeper *Keeper
+	// Nodes are the counted nodes.
+	Nodes func() []string
+	// Heard says whether node's machine is heard (with Arm, the seat mesh-watchdogs' verb presence); an error is said and
+	// reads as not heard.
+	Heard func(ctx context.Context, node string) (bool, error)
+	// Bound is how long a node may stay unanswered before it is the finding.
+	Bound time.Duration
+	// Raise writes the finding of u in the part's findings; Clear removes the finding of node, none being nothing to clear.
+	Raise func(ctx context.Context, u UnansweredCall) error
+	Clear func(ctx context.Context, node string) error
+	// Held are the nodes whose finding the part's findings hold, written by this process or another; nil clears every
+	// counted node not raised.
+	Held func(ctx context.Context) ([]string, error)
+	// Arm keeps a bound for node ending at ends, whose expiry is Expired; nil weighs Heard at each Step.
+	Arm  func(ctx context.Context, node string, ends time.Time) error
+	Now  func() time.Time
+	Logf func(string, ...any)
+
+	mu   sync.Mutex
+	said map[string]time.Time // node -> the since its finding was written for
+}
+
+func (c *ReadsCalls) now() time.Time {
+	if c.Now != nil {
+		return c.Now()
+	}
+	return time.Now()
+}
+
+func (c *ReadsCalls) logf(f string, a ...any) {
+	if c.Logf != nil {
+		c.Logf(f, a...)
+	}
+}
+
+func (c *ReadsCalls) ready() bool {
+	return c != nil && c.Keeper != nil && c.Nodes != nil && c.Heard != nil && c.Raise != nil && c.Clear != nil
+}
+
+// unanswered is node's since while its statement is unanswered.
+func unanswered(statements map[string]Statement, node string) (time.Time, bool) {
+	s, ok := statements[node]
+	if !ok || s.Answered || s.UnansweredSince.IsZero() {
+		return time.Time{}, false
+	}
+	return s.UnansweredSince, true
+}
+
+func (c *ReadsCalls) heard(ctx context.Context, node string) bool {
+	ok, err := c.Heard(ctx, node)
+	if err != nil {
+		c.logf("whether %s's machine is heard cannot be read, so its unanswered %s is no finding: %v", node, Verb, err)
+		return false
+	}
+	return ok
+}
+
+func (c *ReadsCalls) isSaid(node string, since time.Time) bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	was, ok := c.said[node]
+	return ok && was.Equal(since)
+}
+
+// raise writes node's finding, unless written for this since already, and asks the node again once its last ask ended.
+func (c *ReadsCalls) raise(ctx context.Context, node string, since time.Time, words string) bool {
+	if !c.Keeper.Asking(node) {
+		c.Keeper.AskNode(node, "unanswered since "+since.UTC().Format(time.RFC3339)+", its machine heard")
+	}
+	if c.isSaid(node, since) {
+		return true
+	}
+	if err := c.Raise(ctx, UnansweredCall{Node: node, Since: since, Words: words, At: c.now().UTC()}); err != nil {
+		c.logf("the finding call-unanswered of %s's %s is not written: %v", node, Verb, err)
+		return false
+	}
+	c.logf("%s on %s is unanswered since %s and its machine is heard: the finding call-unanswered", Verb, node, since.UTC().Format(time.RFC3339))
+	c.mu.Lock()
+	if c.said == nil {
+		c.said = map[string]time.Time{}
+	}
+	c.said[node] = since
+	c.mu.Unlock()
+	return true
+}
+
+// Step weighs every counted node after a statement changed or the counted nodes changed: with no Arm a node unanswered
+// and heard is asked again, and past Bound it is the finding; with Arm, a node unanswered and not yet said has its bound
+// kept. Every finding no longer raised is cleared.
+func (c *ReadsCalls) Step(ctx context.Context) {
+	if !c.ready() {
+		return
+	}
+	nodes := c.Nodes()
+	statements := c.Keeper.Statements()
+	now := c.now()
+	raised := map[string]bool{}
+	for _, node := range nodes {
+		since, ok := unanswered(statements, node)
+		if !ok {
+			continue
+		}
+		if c.Arm != nil {
+			if c.isSaid(node, since) {
+				raised[node] = true
+				continue
+			}
+			if err := c.Arm(ctx, node, since.Add(c.Bound)); err != nil {
+				c.logf("the bound of %s's %s is not kept: %v", node, Verb, err)
+			}
+			continue
+		}
+		if !c.heard(ctx, node) {
+			continue
+		}
+		if now.Sub(since) < c.Bound {
+			if !c.Keeper.Asking(node) {
+				c.Keeper.AskNode(node, "unanswered since "+since.UTC().Format(time.RFC3339)+", its machine heard")
+			}
+			continue
+		}
+		raised[node] = c.raise(ctx, node, since, statements[node].Words)
+	}
+	c.clear(ctx, nodes, raised)
+}
+
+// Expired weighs node when its bound ended: unanswered past Bound and its machine heard, it is the finding and is asked
+// again; not yet past Bound, its bound is kept again; not heard, it has none.
+func (c *ReadsCalls) Expired(ctx context.Context, node string) {
+	if !c.ready() || !slices.Contains(c.Nodes(), node) {
+		return
+	}
+	statements := c.Keeper.Statements()
+	since, ok := unanswered(statements, node)
+	if !ok || c.isSaid(node, since) {
+		return
+	}
+	if c.now().Sub(since) < c.Bound {
+		if c.Arm != nil {
+			if err := c.Arm(ctx, node, since.Add(c.Bound)); err != nil {
+				c.logf("the bound of %s's %s is not kept: %v", node, Verb, err)
+			}
+		}
+		return
+	}
+	if !c.heard(ctx, node) {
+		c.logf("%s on %s is unanswered since %s and its machine is not heard: no finding; it is asked again when it returns", Verb, node, since.UTC().Format(time.RFC3339))
+		return
+	}
+	c.raise(ctx, node, since, statements[node].Words)
+}
+
+// clear removes the finding of every node held or said and not raised: with Held those it names, else every counted node.
+func (c *ReadsCalls) clear(ctx context.Context, nodes []string, raised map[string]bool) {
+	candidates := map[string]bool{}
+	if c.Held != nil {
+		held, err := c.Held(ctx)
+		if err != nil {
+			c.logf("the findings of %s held cannot be listed: %v", Verb, err)
+		}
+		for _, node := range held {
+			candidates[node] = true
+		}
+	} else {
+		for _, node := range nodes {
+			candidates[node] = true
+		}
+	}
+	c.mu.Lock()
+	for node := range c.said {
+		candidates[node] = true
+	}
+	c.mu.Unlock()
+	for _, node := range slices.Sorted(maps.Keys(candidates)) {
+		if raised[node] {
+			continue
+		}
+		if err := c.Clear(ctx, node); err != nil {
+			c.logf("the finding call-unanswered of %s's %s is not cleared: %v", node, Verb, err)
+			continue
+		}
+		c.mu.Lock()
+		delete(c.said, node)
+		c.mu.Unlock()
+	}
+}

go/clients/nodeengineclient/enginereads/enginereads.go

@@ -137,6 +137,9 @@ type Statement struct {
 	Answered      bool      `json:"answered"`
 	Words         string    `json:"words,omitempty"`
 	AskAgain      *Again    `json:"ask-again,omitempty"`
+	// UnansweredSince is when the engine first did not answer, of the asks since its last answer; zero once answered
+	// (ADR 0668 §3: a kept call unanswered past five minutes is a finding of its caller).
+	UnansweredSince time.Time `json:"unanswered-since,omitzero"`
 }
 
 // Again is a person's ask again of one node, written by the tool and answered by the part that keeps the state.
@@ -170,7 +173,8 @@ func Decode(raw []byte) (Statement, error) {
 	return s, nil
 }
 
-// Caller calls a seat's verb on one node: process.Conn.CallOn.
+// Caller calls a seat's verb on one node: process.Conn.CallKeptOn, a kept call asked again through a transport fault
+// within the bus's retry bound (novox/hq ADR 0668 §1; the verb is a read, safe to call again).
 type Caller func(node, key string, body any) (json.RawMessage, error)
 
 // Ask asks node's engine the verb once and says what it answered. An engine that answered the call with an error is
@@ -220,6 +224,10 @@ func NodeOf(subject string, data []byte) (string, bool, error) {
 type Keeper struct {
 	// Call asks the verb; nil asks nothing (every node then reads as the fallback or the baseline).
 	Call Caller
+	// Once asks the verb once (process.Conn.CallOn). When set, its fault keeps the fallback or the last statement at once,
+	// marked as not answering, while Call, the kept call, asks on until answered (novox/hq ADR 0668 §3): a part does not
+	// wait out busretry.Bound for a node whose engine answers nothing before it acts on what it last knew.
+	Once Caller
 	// Fallback reads a node's record `<node>.node` once where its engine did not answer the verb; nil reads none.
 	Fallback func(node string) ([]string, bool)
 	// Put writes a node's key of the part's state, Delete removes it; nil keeps the statements in memory only.
@@ -269,16 +277,47 @@ func (k *Keeper) AskNode(node, why string) {
 	go k.ask(node, why)
 }
 
+// AskAll asks every node of nodes once, each as AskNode does.
+func (k *Keeper) AskAll(nodes []string, why string) {
+	for _, n := range nodes {
+		k.AskNode(n, why)
+	}
+}
+
+// AtBind is what a part registers with its event hub's OnBound (process.EventHub.OnBound): at each bind of its consumer
+// every node nodes names is asked once, so a manifest-reads-changed said before the consumer existed, and a statement
+// taken while an engine restarted, end at the bind and not at the next event (novox/hq ADR 0668 §4; issue 1966 note 155).
+func (k *Keeper) AtBind(nodes func() []string) func(created time.Time) {
+	return func(created time.Time) {
+		k.AskAll(nodes(), "the part's consumer was bound, made "+created.UTC().Format(time.RFC3339))
+	}
+}
+
 func (k *Keeper) ask(node, why string) {
 	defer func() {
 		k.mu.Lock()
 		delete(k.asking, node)
 		k.mu.Unlock()
 	}()
+	if k.Call != nil && k.Once != nil {
+		first := Ask(k.Once, node, k.now())
+		if first.Answered {
+			k.take(first)
+			return
+		}
+		k.settle(first, why)
+		why += "; the kept call asks on after: " + first.Words
+	}
 	s := Statement{Node: node, AskedAt: k.now().UTC(), From: FromNone, Words: "nothing asks the verb"}
 	if k.Call != nil {
 		s = Ask(k.Call, node, k.now())
 	}
+	k.settle(s, why)
+}
+
+// settle takes s, read from the node's record in its place where the engine did not answer.
+func (k *Keeper) settle(s Statement, why string) {
+	node := s.Node
 	if s.From != FromVerb && k.Fallback != nil {
 		if reads, ok := k.Fallback(node); ok {
 			s.ManifestReads, s.From = slices.Clone(reads), FromRecord
@@ -292,6 +331,31 @@ func (k *Keeper) ask(node, why string) {
 	k.take(s)
 }
 
+// Unanswered is, of nodes, each whose engine the kept call has not answered for bound or longer by now while heard says
+// its machine is heard, with since when (novox/hq ADR 0668 §3); a node whose machine is away is none. With no Call, none.
+func (k *Keeper) Unanswered(nodes []string, heard func(node string) bool, bound time.Duration, now time.Time) map[string]time.Time {
+	out := map[string]time.Time{}
+	if k.Call == nil {
+		return out
+	}
+	k.mu.Lock()
+	defer k.mu.Unlock()
+	for _, node := range nodes {
+		s, ok := k.by[node]
+		if ok && !s.Answered && !s.UnansweredSince.IsZero() && now.Sub(s.UnansweredSince) >= bound && heard(node) {
+			out[node] = s.UnansweredSince
+		}
+	}
+	return out
+}
+
+// Asking says an ask of node runs now.
+func (k *Keeper) Asking(node string) bool {
+	k.mu.Lock()
+	defer k.mu.Unlock()
+	return k.asking[node]
+}
+
 // take keeps s, unless the node did not answer and an earlier statement stands: an away node keeps its last one (ADR 0624
 // §1), marked as not answering.
 func (k *Keeper) take(s Statement) {
@@ -299,8 +363,14 @@ func (k *Keeper) take(s Statement) {
 	if k.by == nil {
 		k.by = map[string]Statement{}
 	}
+	if !s.Answered {
+		s.UnansweredSince = s.AskedAt
+		if old, ok := k.by[s.Node]; ok && !old.Answered && !old.UnansweredSince.IsZero() {
+			s.UnansweredSince = old.UnansweredSince
+		}
+	}
 	if old, ok := k.by[s.Node]; ok && !s.Answered && old.From != FromNone {
-		old.Answered, old.AskedAt, old.Words, old.AskAgain = false, s.AskedAt, s.Words, nil
+		old.Answered, old.AskedAt, old.Words, old.AskAgain, old.UnansweredSince = false, s.AskedAt, s.Words, nil, s.UnansweredSince
 		s = old
 	}
 	k.by[s.Node] = s

go/clients/nodeengineclient/enginereads/enginereads_test.go

@@ -1,8 +1,12 @@
 package enginereads
 
 import (
+	"context"
+	"encoding/json"
+	"errors"
 	"strings"
 	"testing"
+	"time"
 )
 
 // The answer and the event are judged as the contract lays them out and its reader checks: the layout's version, a node
@@ -34,7 +38,132 @@ func TestTheAnswerAndTheEventAreJudged(t *testing.T) {
 			t.Errorf("event %s: %v, want %q", name, err, c.bad)
 		}
 	}
+	// Issue 1966 note 155, ADR 0668 §4: a part whose first call of a node timed out, and whose consumer was bound after
+	// the node's event was said, calls every node once at the bind, and the node is then held as it answered.
+	calls := map[string]int{}
+	k := &Keeper{Sync: true, Call: func(node, _ string, _ any) (json.RawMessage, error) {
+		calls[node]++
+		if node == "ace" && calls[node] == 1 {
+			return nil, context.DeadlineExceeded
+		}
+		return json.RawMessage(`{"v":1,"node":"` + node + `","manifest-reads":["a.b"],"stated-at":"` + at + `"}`), nil
+	}}
+	k.AskNode("ace", "the first view")
+	if k.Statements()["ace"].Answered {
+		t.Errorf("a call that timed out reads as answered")
+	}
+	k.AtBind(func() []string { return []string{"ace", "g14"} })(time.Unix(0, 0))
+	if p := k.Present([]string{"ace", "g14"}); len(p["ace"]) != 1 || len(p["g14"]) != 1 || calls["ace"] != 2 || calls["g14"] != 1 {
+		t.Errorf("after the bind: present %v, calls %v", p, calls)
+	}
+	// Review round 1 (ADR 0668 §3): a node whose engine answers nothing reads as its record at the first fault of the call
+	// made once, while the kept call asks on; what the kept call answers then stands.
+	var during Statement
+	f := &Keeper{Sync: true, Fallback: func(string) ([]string, bool) { return []string{"r.s"}, true },
+		Once: func(string, string, any) (json.RawMessage, error) {
+			return nil, errors.New("nats: no responders available for request")
+		}}
+	f.Call = func(node, _ string, _ any) (json.RawMessage, error) {
+		during = f.Statements()[node]
+		return json.RawMessage(`{"v":1,"node":"` + node + `","manifest-reads":["a.b"],"stated-at":"` + at + `"}`), nil
+	}
+	f.AskNode("g14", "the first view")
+	if during.From != FromRecord || during.Answered || f.Statements()["g14"].From != FromVerb {
+		t.Errorf("while the kept call asked g14 read %+v; after it %+v", during, f.Statements()["g14"])
+	}
+	// ADR 0668 §3: a node unanswered keeps when it first was not, across asks; past the bound it is unanswered while its
+	// machine is heard, none while away, and none once it answers.
+	clock := time.Date(2026, 11, 10, 3, 0, 0, 0, time.UTC)
+	answers := false
+	u := &Keeper{Sync: true, Now: func() time.Time { return clock }, Call: func(node, _ string, _ any) (json.RawMessage, error) {
+		if answers {
+			return json.RawMessage(`{"v":1,"node":"` + node + `","manifest-reads":["a.b"],"stated-at":"` + at + `"}`), nil
+		}
+		return nil, context.DeadlineExceeded
+	}}
+	first := clock
+	u.AskNode("ace", "the first view")
+	clock = clock.Add(6 * time.Minute)
+	u.AskNode("ace", "asked on")
+	heard := func(string) bool { return true }
+	if got := u.Unanswered([]string{"ace"}, heard, 5*time.Minute, clock); !got["ace"].Equal(first) ||
+		len(u.Unanswered([]string{"ace"}, func(string) bool { return false }, 5*time.Minute, clock)) != 0 {
+		t.Errorf("unanswered past the bound: %v", got)
+	}
+	answers = true
+	u.AskNode("ace", "answered")
+	if got := u.Unanswered([]string{"ace"}, heard, 5*time.Minute, clock); len(got) != 0 || !u.Statements()["ace"].UnansweredSince.IsZero() {
+		t.Errorf("an answered node is unanswered: %v", got)
+	}
 	if Verb != "manifest-reads" || Event != "manifest-reads-changed" || Consumes != "node-engine.manifest-reads-changed" || Invoke != "seat:node-engine.manifest-reads" {
 		t.Errorf("the names are %s %s %s %s", Verb, Event, Consumes, Invoke)
 	}
 }
+
+// ADR 0668 §3, ADR 0596 §2 (review round 3): the wait of a part's kept manifest-reads calls. With Arm, a node unanswered
+// has its bound kept, and only its expiry asks whether its machine is heard, once: heard, the finding is written at the
+// part's clock and the node asked again; away, none; answered, it is cleared. With no Arm, heard is weighed at each step.
+func TestReadsCallsSayAnUnansweredNodeHeard(t *testing.T) {
+	clock := time.Date(2026, 11, 10, 3, 0, 0, 0, time.UTC)
+	answers, calls := false, 0
+	k := &Keeper{Sync: true, Now: func() time.Time { return clock }, Call: func(node, _ string, _ any) (json.RawMessage, error) {
+		calls++
+		if answers {
+			return json.RawMessage(`{"v":1,"node":"` + node + `","manifest-reads":["a.b"],"stated-at":"2026-11-10T03:00:00Z"}`), nil
+		}
+		return nil, context.DeadlineExceeded
+	}}
+	for name, armed := range map[string]bool{"armed": true, "by its own knowledge": false} {
+		answers, calls = false, 0
+		k.Forget("ace")
+		first := clock
+		k.AskNode("ace", "the first view")
+		heard, asked := true, 0
+		raised, cleared := map[string]UnansweredCall{}, map[string]int{}
+		bounds := map[string]time.Time{}
+		c := &ReadsCalls{Keeper: k, Nodes: func() []string { return []string{"ace", "g14"} }, Bound: 5 * time.Minute,
+			Now:   func() time.Time { return clock.Add(time.Second) },
+			Heard: func(context.Context, string) (bool, error) { asked++; return heard, nil },
+			Raise: func(_ context.Context, u UnansweredCall) error { raised[u.Node] = u; return nil },
+			Clear: func(_ context.Context, node string) error { cleared[node]++; delete(raised, node); return nil }}
+		if armed {
+			c.Arm = func(_ context.Context, node string, ends time.Time) error { bounds[node] = ends; return nil }
+		}
+		c.Step(context.Background())
+		if armed && (asked != 0 || !bounds["ace"].Equal(first.Add(5*time.Minute)) || len(raised) != 0) {
+			t.Errorf("%s: a step before the bound asked heard %d times, bounds %v, raised %v", name, asked, bounds, raised)
+		}
+		clock = clock.Add(6 * time.Minute)
+		heard, asked = false, 0
+		if armed {
+			c.Expired(context.Background(), "ace")
+		} else {
+			c.Step(context.Background())
+		}
+		if len(raised) != 0 || asked != 1 {
+			t.Errorf("%s: away, raised %v, heard asked %d times", name, raised, asked)
+		}
+		heard, asked, calls = true, 0, 0
+		if armed {
+			c.Expired(context.Background(), "ace")
+		} else {
+			c.Step(context.Background())
+		}
+		if u, ok := raised["ace"]; !ok || !u.Since.Equal(first) || !u.At.Equal(clock.Add(time.Second)) || asked != 1 || calls != 1 {
+			t.Errorf("%s: heard past the bound, raised %+v, heard asked %d, called %d", name, raised, asked, calls)
+		}
+		answers = true
+		k.AskNode("ace", "answered")
+		c.Step(context.Background())
+		if _, ok := raised["ace"]; ok || cleared["ace"] == 0 {
+			t.Errorf("%s: answered, raised %v, cleared %v", name, raised, cleared)
+		}
+		clock = clock.Add(time.Hour)
+	}
+	if CallID("ace") != "manifest-reads.ace" {
+		t.Errorf("the call's id is %s", CallID("ace"))
+	}
+	if n, ok := BoundOf(BoundPrefix + "ace"); !ok || n != "ace" {
+		t.Errorf("the bound's node is %q %v", n, ok)
+	}
+}

health-and-repair/go/clients/meshconditionsclient/client_test.go

@@ -19,6 +19,11 @@ func TestAFindingsKeyAndTheOrderOfConditions(t *testing.T) {
 	if k := Key("call", "a b", ""); k != "call.a_b._" {
 		t.Errorf("an unsafe part and an empty token: %s", k)
 	}
+	// Issue 1966, ADR 0668 §3: a kept call unanswered is a finding the keeper can make a condition of, keyed by what waits.
+	o := CallUnanswered("ace", "seat:node-engine.manifest-reads", "ace", "no responders", "enginereads", time.Unix(0, 0))
+	if f := o.Finding("mesh-delivery-assigner", "r1", time.Unix(300, 0)); o.Key() != "call.ace.call-unanswered" || CheckFinding(f) != nil {
+		t.Errorf("a call unanswered: key %s, %v", o.Key(), CheckFinding(f))
+	}
 	good := seat.FindingsByKeyValue{Key: "machine.g14.silent", Kind: "silent", Severity: Warning, Summary: "x", Source: "S1",
 		Observer: "mesh-delivery-watchman", Subject: seat.Subject{Scope: ScopeMachine, ID: "g14"}}
 	for _, c := range []struct {

health-and-repair/go/clients/meshconditionsclient/observation.go

@@ -145,3 +145,24 @@ func Clear(b FindingBucket, scope, id, token string) (cleared bool, err error) {
 	}
 	return true, b.Delete(key)
 }
+
+// KindCallUnanswered is the kind of a kept call still unanswered past CallUnansweredAfter (novox/hq ADR 0668 §3, issue
+// 1966): a call whose answer the caller keeps, asked again through every transport fault, that no answer has ended. The
+// caller writes it into its own findings, keeps the wait, and clears it when the call is answered.
+const KindCallUnanswered = "call-unanswered"
+
+// CallUnansweredAfter is how long a kept call stays unanswered before it is a finding (ADR 0668 §3; ADR 0564 §2's bound).
+const CallUnansweredAfter = 5 * time.Minute
+
+// CallUnanswered is the observation of a kept call to callee (a seat verb's or a tool's key, as process.Conn.Call names
+// it) about id (what the caller waits on: a node, a merge, a key), unanswered since since, its last fault said. Its key
+// is `call.<id>.call-unanswered`, cleared by Clear(b, ScopeCall, id, KindCallUnanswered).
+func CallUnanswered(id, callee, machine, fault, source string, since time.Time) Observation {
+	return Observation{Scope: ScopeCall, ID: id, Kind: KindCallUnanswered, Machine: machine, Severity: Warning,
+		Summary:  fmt.Sprintf("the call %s about %s is unanswered since %s", callee, id, since.UTC().Format(time.RFC3339)),
+		Said:     fault,
+		Headline: "A call whose answer is kept is not answered",
+		Explanation: fmt.Sprintf("The call %s is made again on every transport fault and on the callee's event; it has "+
+			"not been answered since %s. Its last fault: %s.", callee, since.UTC().Format(time.RFC3339), fault),
+		Resolved: "the call is answered", Source: source}
+}

health-and-repair/go/seats/meshwatchdogs/contract.go

@@ -202,8 +202,31 @@ type PresenceInput struct {
 	Machine string `json:"machine,omitempty"`
 }
 
+// PresenceAnswerKeysItem is a type of the contract.
+type PresenceAnswerKeysItem struct {
+	// <node> or part.<part>.<instance>
+	Key string `json:"key"`
+	// the key's revision
+	Revision int64 `json:"revision,omitempty"`
+	// the key's value, online and its layout's version
+	Value map[string]any `json:"value"`
+}
+
 // PresenceAnswer is what presence answers.
-type PresenceAnswer = map[string]any
+type PresenceAnswer struct {
+	// without machine: how many keys the state holds
+	Holds int64 `json:"holds,omitempty"`
+	// without machine: each key of the state presence, <node> or part.<part>.<instance>, with its value
+	Keys []PresenceAnswerKeysItem `json:"keys,omitempty"`
+	// the machine asked, with machine
+	Machine string `json:"machine,omitempty"`
+	// with machine: whether the watchman hears the machine now; false for a machine it holds no word of
+	Online bool `json:"online,omitempty"`
+	// with machine: when its presence last changed, RFC 3339; empty for a machine the watchman holds no word of
+	Since string `json:"since,omitempty"`
+	// without machine: the state read, presence
+	State string `json:"state,omitempty"`
+}
 
 // DeadLettersInput is what dead-letters takes.
 type DeadLettersInput struct {

health-and-repair/seats/mesh-watchdogs/seat.json

@@ -43,7 +43,7 @@
     },
     {
       "name": "presence",
-      "description": "Every machine and tool runner the watchman sees connected, with its last word, and those it says silent; a machine that said it sleeps is shown as sleeping, not silent.",
+      "description": "Every machine and tool runner the watchman sees connected, with its last word, and those it says silent; a machine that said it sleeps is shown as sleeping, not silent. With machine, that machine's presence alone: whether the watchman hears it and since when.",
       "input": {
         "properties": {
           "machine": {
@@ -55,7 +55,54 @@
       },
       "answer": {
         "type": "object",
-        "description": "who is connected and who is silent"
+        "description": "with machine, that machine: online and since; without, every key of the state presence",
+        "properties": {
+          "machine": {
+            "type": "string",
+            "description": "the machine asked, with machine"
+          },
+          "online": {
+            "type": "boolean",
+            "description": "with machine: whether the watchman hears the machine now; false for a machine it holds no word of"
+          },
+          "since": {
+            "type": "string",
+            "description": "with machine: when its presence last changed, RFC 3339; empty for a machine the watchman holds no word of"
+          },
+          "state": {
+            "type": "string",
+            "description": "without machine: the state read, presence"
+          },
+          "holds": {
+            "type": "integer",
+            "description": "without machine: how many keys the state holds"
+          },
+          "keys": {
+            "type": "array",
+            "description": "without machine: each key of the state presence, <node> or part.<part>.<instance>, with its value",
+            "items": {
+              "type": "object",
+              "properties": {
+                "key": {
+                  "type": "string",
+                  "description": "<node> or part.<part>.<instance>"
+                },
+                "value": {
+                  "type": "object",
+                  "description": "the key's value, online and its layout's version"
+                },
+                "revision": {
+                  "type": "integer",
+                  "description": "the key's revision"
+                }
+              },
+              "required": [
+                "key",
+                "value"
+              ]
+            }
+          }
+        }
       }
     },
     {

health-and-repair/ts/seats/meshwatchdogs/src/index.ts

@@ -116,8 +116,30 @@ export interface PresenceInput {
   "machine"?: string;
 }
 
+export interface PresenceAnswerKeysItem {
+  /** <node> or part.<part>.<instance> */
+  "key": string;
+  /** the key's revision */
+  "revision"?: number;
+  /** the key's value, online and its layout's version */
+  "value": Record<string, unknown>;
+}
+
 /** is what presence answers. */
-export type PresenceAnswer = Record<string, unknown>;
+export interface PresenceAnswer {
+  /** without machine: how many keys the state holds */
+  "holds"?: number;
+  /** without machine: each key of the state presence, <node> or part.<part>.<instance>, with its value */
+  "keys"?: PresenceAnswerKeysItem[];
+  /** the machine asked, with machine */
+  "machine"?: string;
+  /** with machine: whether the watchman hears the machine now; false for a machine it holds no word of */
+  "online"?: boolean;
+  /** with machine: when its presence last changed, RFC 3339; empty for a machine the watchman holds no word of */
+  "since"?: string;
+  /** without machine: the state read, presence */
+  "state"?: string;
+}
 
 /** is what dead-letters takes. */
 export interface DeadLettersInput {

operator-and-conversation/go/seats/operatorchannel/contract.go

@@ -427,10 +427,33 @@ type TellAnswer = map[string]any
 
 // AsksInput is what asks takes.
 type AsksInput struct {
+	// the most bytes of the asks in the answer; said when it cuts the answer short
+	Bound int64 `json:"bound,omitempty"`
+	// one ask, by its key (<asker>.<id>); none for the open asks
+	Key string `json:"key,omitempty"`
+	// only the asks opened at or after this time, RFC 3339
+	Since string `json:"since,omitempty"`
+	// open (open and held), ended or all; none is open when no key or since is given, else all
+	State string `json:"state,omitempty"`
+}
+
+// AsksAnswerAsksItem is a type of the contract.
+type AsksAnswerAsksItem struct {
+	// <asker>.<id>
+	Key string `json:"key"`
+	// how the ask stands: open, held, or how it ended (answered, expired, cancelled)
+	State string `json:"state"`
 }
 
 // AsksAnswer is what asks answers.
-type AsksAnswer = map[string]any
+type AsksAnswer struct {
+	// each ask the router holds, as its state asks holds it
+	Asks []AsksAnswerAsksItem `json:"asks"`
+	// what the bound cut, and how to ask for more; empty when nothing was cut
+	Cut string `json:"cut,omitempty"`
+	// how many asks the arguments matched
+	Matched int64 `json:"matched,omitempty"`
+}
 
 // AskAccept is the body of ask.
 type AskAccept = Ask

operator-and-conversation/seats/operator-channel/seat.json

@@ -116,15 +116,65 @@
     },
     {
       "name": "asks",
-      "description": "The asks the router holds: open first, then the last month's, each with how it ended.",
+      "description": "The asks the router holds: open first, then the last month's, each with how it ended. With no argument only the open asks, within its default bound; key for one ask, state, since and bound narrow or widen it, and the answer says what it cut.",
       "input": {
         "type": "object",
-        "properties": {},
+        "properties": {
-        "description": "no arguments"
+          "key": {
+            "type": "string",
+            "description": "one ask, by its key (<asker>.<id>); none for the open asks"
+          },
+          "state": {
+            "type": "string",
+            "description": "open (open and held), ended or all; none is open when no key or since is given, else all"
+          },
+          "since": {
+            "type": "string",
+            "description": "only the asks opened at or after this time, RFC 3339"
+          },
+          "bound": {
+            "type": "integer",
+            "description": "the most bytes of the asks in the answer; said when it cuts the answer short"
+          }
+        }
       },
       "answer": {
         "type": "object",
-        "description": "the asks"
+        "description": "the asks, open first",
+        "properties": {
+          "asks": {
+            "type": "array",
+            "description": "each ask the router holds, as its state asks holds it",
+            "items": {
+              "type": "object",
+              "properties": {
+                "key": {
+                  "type": "string",
+                  "description": "<asker>.<id>"
+                },
+                "state": {
+                  "type": "string",
+                  "description": "how the ask stands: open, held, or how it ended (answered, expired, cancelled)"
+                }
+              },
+              "required": [
+                "key",
+                "state"
+              ]
+            }
+          },
+          "cut": {
+            "type": "string",
+            "description": "what the bound cut, and how to ask for more; empty when nothing was cut"
+          },
+          "matched": {
+            "type": "integer",
+            "description": "how many asks the arguments matched"
+          }
+        },
+        "required": [
+          "asks"
+        ]
       }
     }
   ],

operator-and-conversation/ts/seats/operatorchannel/src/index.ts

@@ -364,10 +364,32 @@ export type TellAnswer = Record<string, unknown>;
 
 /** is what asks takes. */
 export interface AsksInput {
+  /** the most bytes of the asks in the answer; said when it cuts the answer short */
+  "bound"?: number;
+  /** one ask, by its key (<asker>.<id>); none for the open asks */
+  "key"?: string;
+  /** only the asks opened at or after this time, RFC 3339 */
+  "since"?: string;
+  /** open (open and held), ended or all; none is open when no key or since is given, else all */
+  "state"?: string;
+}
+
+export interface AsksAnswerAsksItem {
+  /** <asker>.<id> */
+  "key": string;
+  /** how the ask stands: open, held, or how it ended (answered, expired, cancelled) */
+  "state": string;
 }
 
 /** is what asks answers. */
-export type AsksAnswer = Record<string, unknown>;
+export interface AsksAnswer {
+  /** each ask the router holds, as its state asks holds it */
+  "asks": AsksAnswerAsksItem[];
+  /** what the bound cut, and how to ask for more; empty when nothing was cut */
+  "cut"?: string;
+  /** how many asks the arguments matched */
+  "matched"?: number;
+}
 
 /** is the body of ask. */
 export type AskAccept = Ask;