CT15 (take-in bodies, none-yet): the seat mesh-catalog's bodies give take-in.taken and take-in.pending; revision answers none-yet in a field

The seat's bodies hold TakeInTaken (branch, source, entries with repository and pull) and TakeInPending (branch); revision's
answer gains none-yet and its revision is optional; meshcatalogclient reads the field, never the error's words. The holders'
and readers' uses of the answer follow (a pointer revision).

Builds: design 47 G §476, §493, §530, §454, §648

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

contracts/go/clients/meshcatalogclient/catalog.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"maps"
 	"strconv"
-	"strings"
 	"sync"
 	"time"
 
@@ -188,7 +187,7 @@ func (c *Catalog) ask(_ context.Context, after string) (views.Answer, error) {
 	}
 	c.mu.Lock()
 	if after == "" || c.paging == nil {
-		c.paging = &Half{Revision: a.Revision, Entries: map[string]seat.CatalogEntry{}}
+		c.paging = &Half{Revision: *a.Revision, Entries: map[string]seat.CatalogEntry{}}
 	} else if c.paging.Revision.Revision != a.Revision.Revision {
 		was := c.paging.Revision.Revision
 		c.paging = nil
@@ -216,26 +215,27 @@ func (c *Catalog) ask(_ context.Context, after string) (views.Answer, error) {
 	return views.Answer{V: 1, Owner: seat.Seat, State: c.Follower.State, Revision: uint64(rev), Created: catalogCreated, Values: values, Next: a.Next, At: time.Now()}, nil
 }
 
-// errNoneYet is the seat's answer `none yet`: the branch has no revision yet.
+// errNoneYet is the seat's answer `none-yet`: the branch has no revision yet (design 47 G §530).
 var errNoneYet = errors.New("none yet")
 
 func askRevision(call Call, in seat.RevisionInput) (seat.RevisionAnswer, error) {
 	raw, err := call(RevisionVerb, in)
 	if err != nil {
-		if strings.Contains(err.Error(), views.NoneYet) {
-			return seat.RevisionAnswer{}, errNoneYet
-		}
 		return seat.RevisionAnswer{}, err
 	}
 	answer, said, ok := buscalls.Unwrap(raw)
 	if !ok {
-		if strings.Contains(said, views.NoneYet) {
-			return seat.RevisionAnswer{}, errNoneYet
-		}
 		return seat.RevisionAnswer{}, fmt.Errorf("%s answered: %s", RevisionVerb, said)
 	}
 	var a seat.RevisionAnswer
-	if err := json.Unmarshal(answer, &a); err != nil || a.Revision.Revision <= 0 {
+	if err := json.Unmarshal(answer, &a); err != nil {
+		return seat.RevisionAnswer{}, fmt.Errorf("%s answered no revision: %s", RevisionVerb, clipBytes(answer))
+	}
+	// An answer is told by its fields, never by its words (§530): `none-yet` is a ready, empty view.
+	if a.NoneYet {
+		return seat.RevisionAnswer{}, errNoneYet
+	}
+	if a.Revision == nil || a.Revision.Revision <= 0 {
 		return seat.RevisionAnswer{}, fmt.Errorf("%s answered no revision: %s", RevisionVerb, clipBytes(answer))
 	}
 	return a, nil

contracts/go/clients/meshcatalogclient/catalog_test.go

@@ -1,6 +1,7 @@
 package meshcatalogclient
 
 import (
+	"encoding/json"
 	"errors"
 	"strings"
 	"testing"
@@ -165,3 +166,31 @@ func TestCandidatesKeyEscapesTheGroupAndReadsBack(t *testing.T) {
 		t.Error("an empty group keys")
 	}
 }
+
+// CT15 (design 47 G §476, §493, §648): the seat's `bodies` give the types the indexer writes and the runner reads: a
+// take-in.taken names its branch, source revision and entries (an entry of a merged message names its pull request),
+// a take-in.pending its branch, and a revision answer for a branch with no revision yet is `none-yet` alone.
+func TestTakeInBodiesAndNoneYetAreTheSeatsTypes(t *testing.T) {
+	var taken seat.TakeInTaken
+	body := `{"v":1,"kind":"taken","key":"m.00000000000000000007","what":"revision","branch":"beta","source":3590,"since":"2026-11-11T10:00:00Z",` +
+		`"merges":[{"repository":"novox/mesh-sdk","number":9,"merge":"cc"}],` +
+		`"entries":[{"module":"nats","commit":"cc","fingerprint":"src2:aa","repository":"novox/mesh-sdk","pull":9},{"module":"zsh","commit":"cc","fingerprint":"src2:bb"}]}`
+	if err := json.Unmarshal([]byte(body), &taken); err != nil {
+		t.Fatal(err)
+	}
+	if taken.Branch != "beta" || taken.Source != 3590 || len(taken.Entries) != 2 || taken.Entries[0].Pull != 9 || taken.Entries[1].Repository != "" {
+		t.Errorf("take-in.taken read as %+v", taken)
+	}
+	var pending seat.TakeInPending
+	if err := json.Unmarshal([]byte(`{"v":1,"kind":"pending","key":"m.1","what":"revision","branch":"beta","since":"2026-11-11T10:00:00Z","merges":[]}`), &pending); err != nil || pending.Branch != "beta" {
+		t.Errorf("take-in.pending read as %+v, %v", pending, err)
+	}
+	var none seat.RevisionAnswer
+	if err := json.Unmarshal([]byte(`{"none-yet":true}`), &none); err != nil || !none.NoneYet || none.Revision != nil {
+		t.Errorf("a none-yet answer read as %+v, %v", none, err)
+	}
+	raw, _ := json.Marshal(seat.RevisionAnswer{NoneYet: true})
+	if string(raw) != `{"none-yet":true}` {
+		t.Errorf("a none-yet answer is written as %s", raw)
+	}
+}

contracts/go/clients/meshcatalogclient/catalog_view_test.go

@@ -28,14 +28,14 @@ func (f *fakeRevisions) call(key string, body any) (json.RawMessage, error) {
 	defer f.mu.Unlock()
 	rev, ok := f.newest[in.Branch]
 	if ok && rev == 0 {
-		return nil, fmt.Errorf("revision of %s: none yet", in.Branch)
+		return json.Marshal(seat.RevisionAnswer{NoneYet: true})
 	}
 	if !ok {
 		return nil, fmt.Errorf("asked for the branch %q", in.Branch)
 	}
 	f.asks[in.Branch]++
 	return json.Marshal(seat.RevisionAnswer{
-		Revision: seat.CatalogRevision{Revision: rev, Kind: KindTrunk, Branch: in.Branch},
+		Revision: &seat.CatalogRevision{Revision: rev, Kind: KindTrunk, Branch: in.Branch},
 		Entries:  []seat.CatalogEntry{{Module: fmt.Sprintf("m-of-%s-%d", in.Branch, rev)}},
 	})
 }

contracts/go/seats/meshcatalog/contract.go

@@ -1060,6 +1060,108 @@ type VersionEntry struct {
 	Version string `json:"version"`
 }
 
+// TakeInEntry is one module of a taken-in revision (design 47 G section 476, section 648).
+type TakeInEntry struct {
+	Commit string `json:"commit"`
+	// the module's build-input fingerprint at the commit
+	Fingerprint string `json:"fingerprint"`
+	Module      string `json:"module"`
+	// from a merged message; absent for a pushed one (design 47 G section 648)
+	Pull int64 `json:"pull,omitempty"`
+	// from a merged message; absent for a pushed one (design 47 G section 648)
+	Repository string `json:"repository,omitempty"`
+}
+
+// TakeInMember is one pull request at one commit.
+type TakeInMember struct {
+	Head       string `json:"head"`
+	Number     int64  `json:"number"`
+	Repository string `json:"repository"`
+}
+
+// TakeInMerge is one merge a take-in event holds: the repository, its pull request and the merge commit the forge made of it.
+type TakeInMerge struct {
+	Merge      string `json:"merge"`
+	Number     int64  `json:"number"`
+	Repository string `json:"repository"`
+}
+
+// TakeInPending is the body of the indexer's take-in.pending: a wait for a revision or a group, with the watched branch (design 47 G section 493).
+type TakeInPending struct {
+	// the watched branch the revision is of (design 47 G section 476, section 493)
+	Branch string `json:"branch,omitempty"`
+	// who acted by hand, on a taken event
+	By string `json:"by,omitempty"`
+	// a hand drop: the merges are not taken in
+	Dropped bool `json:"dropped,omitempty"`
+	// the delivery group, for a group being gathered
+	Group string `json:"group,omitempty"`
+	// the wait's key: m.<sequence> of its oldest merge, or g.<group> for a group being gathered
+	Key string `json:"key"`
+	// the event's kind, pending or taken
+	Kind string `json:"kind"`
+	// the keys of merges whose message the forge bridge's stream no longer holds
+	Lost []string `json:"lost,omitempty"`
+	// every approved member of a group with its head
+	Members []TakeInMember `json:"members,omitempty"`
+	// the merges it holds, oldest first
+	Merges []TakeInMerge `json:"merges"`
+	// why the indexer holds a merge it does not take in although no indexer build is named
+	OwnBuildUnknown string `json:"own-build-unknown,omitempty"`
+	// why the manifest of the indexer the revision names was refused
+	Refused string `json:"refused,omitempty"`
+	// when the wait began
+	Since time.Time `json:"since"`
+	// the layout version
+	V int64 `json:"v"`
+	// the indexer build a revision waits for
+	WaitsFor string `json:"waits-for,omitempty"`
+	// what waits: a revision or a group
+	What string `json:"what"`
+	// why they acted by hand, on a taken event
+	Why string `json:"why,omitempty"`
+}
+
+// TakeInTaken is the body of the indexer's take-in.taken: a wait ended, with the branch, the source revision and the entries (design 47 G section 476, section 493).
+type TakeInTaken struct {
+	// the watched branch the revision is of (design 47 G section 476, section 493)
+	Branch string `json:"branch,omitempty"`
+	// who acted by hand, on a taken event
+	By string `json:"by,omitempty"`
+	// a hand drop: the merges are not taken in
+	Dropped bool `json:"dropped,omitempty"`
+	// one entry per module of that revision; none for a hand drop (design 47 G section 476, section 493)
+	Entries []TakeInEntry `json:"entries,omitempty"`
+	// the delivery group, for a group being gathered
+	Group string `json:"group,omitempty"`
+	// the wait's key: m.<sequence> of its oldest merge, or g.<group> for a group being gathered
+	Key string `json:"key"`
+	// the event's kind, pending or taken
+	Kind string `json:"kind"`
+	// the keys of merges whose message the forge bridge's stream no longer holds
+	Lost []string `json:"lost,omitempty"`
+	// every approved member of a group with its head
+	Members []TakeInMember `json:"members,omitempty"`
+	// the merges it holds, oldest first
+	Merges []TakeInMerge `json:"merges"`
+	// why the indexer holds a merge it does not take in although no indexer build is named
+	OwnBuildUnknown string `json:"own-build-unknown,omitempty"`
+	// why the manifest of the indexer the revision names was refused
+	Refused string `json:"refused,omitempty"`
+	// when the wait began
+	Since time.Time `json:"since"`
+	// the source revision taken in (design 47 G section 476)
+	Source int64 `json:"source,omitempty"`
+	// the layout version
+	V int64 `json:"v"`
+	// the indexer build a revision waits for
+	WaitsFor string `json:"waits-for,omitempty"`
+	// what waits: a revision or a group
+	What string `json:"what"`
+	// why they acted by hand, on a taken event
+	Why string `json:"why,omitempty"`
+}
+
 // ModulesInput is what modules takes.
 type ModulesInput struct {
 }
@@ -1180,10 +1282,12 @@ type RevisionInput struct {
 // RevisionAnswer is what revision answers.
 type RevisionAnswer struct {
 	// this page's entries whole, by module name
-	Entries []CatalogEntry `json:"entries"`
+	Entries []CatalogEntry `json:"entries,omitempty"`
 	// the module to ask after for the next page; absent on the last
-	Next     string          `json:"next,omitempty"`
-	Revision CatalogRevision `json:"revision"`
+	Next string `json:"next,omitempty"`
+	// true for a watched branch with no revision yet: no revision, no entries and no error follow, and a reader holds the branch's view ready and empty (design 47 G section 530)
+	NoneYet  bool             `json:"none-yet,omitempty"`
+	Revision *CatalogRevision `json:"revision,omitempty"`
 }
 
 // RegistrationsInput is what registrations takes.

contracts/go/seats/meshcatalog/contract_test.go

@@ -141,6 +141,8 @@ func TestFixtures(t *testing.T) {
 			decode: func(b []byte) (any, error) { var v RevisionAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 		{name: "revision answers its last page", subject: "", given: "{\"entries\":[{\"bases\":[\"arch\"],\"commit\":\"f469eb387a3015569d9b16c66ed418e9dd098f64\",\"fp\":\"src2:b427bdde1f100e2f52490cfa9df0c5112dd3700226b4892349f0c14a15a4af56\",\"invokes\":[\"node-files.read\"],\"manifest\":{\"module\":\"xclip\",\"version\":\"1\"},\"module\":\"xclip\",\"packages\":{\"git.novox.be/novox/mesh-sdk/go\":\"v0.0.0-20261101000000-f469eb387a30\"},\"path\":\"modules/xclip\",\"repository\":\"novox/mesh-catalog\",\"toolchains\":{\"go\":{\"module\":\"mesh-build-go\",\"recipe\":\"1\",\"version\":\"1.26.0\"}},\"v\":1,\"verdict\":\"accepted\"}],\"revision\":{\"at\":\"2026-11-09T19:00:00Z\",\"definitions\":[{\"digest\":\"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855\",\"seat\":\"node-build-go\"}],\"entries\":[{\"digest\":\"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855\",\"module\":\"mesh-build-go\"},{\"digest\":\"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855\",\"module\":\"xclip\"}],\"kind\":\"trunk\",\"revision\":12,\"source\":3589,\"trunk\":[{\"commit\":\"f469eb387a3015569d9b16c66ed418e9dd098f64\",\"repository\":\"novox/mesh-catalog\"}],\"v\":1}}", wire: "{\"entries\":[{\"bases\":[\"arch\"],\"commit\":\"f469eb387a3015569d9b16c66ed418e9dd098f64\",\"fp\":\"src2:b427bdde1f100e2f52490cfa9df0c5112dd3700226b4892349f0c14a15a4af56\",\"invokes\":[\"node-files.read\"],\"manifest\":{\"module\":\"xclip\",\"version\":\"1\"},\"module\":\"xclip\",\"packages\":{\"git.novox.be/novox/mesh-sdk/go\":\"v0.0.0-20261101000000-f469eb387a30\"},\"path\":\"modules/xclip\",\"repository\":\"novox/mesh-catalog\",\"toolchains\":{\"go\":{\"module\":\"mesh-build-go\",\"recipe\":\"1\",\"version\":\"1.26.0\"}},\"v\":1,\"verdict\":\"accepted\"}],\"revision\":{\"at\":\"2026-11-09T19:00:00Z\",\"definitions\":[{\"digest\":\"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855\",\"seat\":\"node-build-go\"}],\"entries\":[{\"digest\":\"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855\",\"module\":\"mesh-build-go\"},{\"digest\":\"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855\",\"module\":\"xclip\"}],\"kind\":\"trunk\",\"revision\":12,\"source\":3589,\"trunk\":[{\"commit\":\"f469eb387a3015569d9b16c66ed418e9dd098f64\",\"repository\":\"novox/mesh-catalog\"}],\"v\":1}}",
 			decode: func(b []byte) (any, error) { var v RevisionAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
+		{name: "revision answers none yet for a branch with no revision", subject: "", given: "{\"none-yet\":true}", wire: "{\"none-yet\":true}",
+			decode: func(b []byte) (any, error) { var v RevisionAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 		{name: "registrations of one module with its history", subject: "", given: "{\"history\":true,\"module\":\"nats\"}", wire: "{\"history\":true,\"module\":\"nats\"}",
 			decode: func(b []byte) (any, error) { var v RegistrationsInput; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 		{name: "registrations answers one with its versions", subject: "", given: "{\"history\":[{\"at\":\"2026-11-10T10:00:00Z\",\"branches\":[\"main\"],\"by\":\"operator@shanks\",\"module\":\"nats\",\"origin\":\"novox/mesh-catalog\",\"path\":\"modules/nats/module.json\",\"policy\":{\"steps\":{\"approval\":\"bypass\",\"composition\":\"required\",\"integration\":\"required\",\"lint\":\"required\",\"review\":\"optional\",\"unit\":\"required\"}},\"v\":1,\"version\":1,\"warrant\":\"ask-m2kx9a1b3c4d5e\"},{\"at\":\"2026-11-10T10:00:00Z\",\"branches\":[\"main\"],\"by\":\"operator@shanks\",\"module\":\"nats\",\"origin\":\"novox/mesh-catalog\",\"path\":\"modules/nats/module.json\",\"policy\":{\"artifacts\":{\"program\":{\"unit\":\"bypass\"}},\"steps\":{\"approval\":\"bypass\",\"composition\":\"required\",\"integration\":\"required\",\"lint\":\"required\",\"review\":\"optional\",\"unit\":\"required\"}},\"v\":1,\"version\":2,\"warrant\":\"ask-m2kx9a1b3c4d5e\"}],\"registrations\":[{\"at\":\"2026-11-10T10:00:00Z\",\"branches\":[\"main\"],\"by\":\"operator@shanks\",\"module\":\"nats\",\"origin\":\"novox/mesh-catalog\",\"path\":\"modules/nats/module.json\",\"policy\":{\"artifacts\":{\"program\":{\"unit\":\"bypass\"}},\"steps\":{\"approval\":\"bypass\",\"composition\":\"required\",\"integration\":\"required\",\"lint\":\"required\",\"review\":\"optional\",\"unit\":\"required\"}},\"v\":1,\"version\":2,\"warrant\":\"ask-m2kx9a1b3c4d5e\"}]}", wire: "{\"history\":[{\"at\":\"2026-11-10T10:00:00Z\",\"branches\":[\"main\"],\"by\":\"operator@shanks\",\"module\":\"nats\",\"origin\":\"novox/mesh-catalog\",\"path\":\"modules/nats/module.json\",\"policy\":{\"steps\":{\"approval\":\"bypass\",\"composition\":\"required\",\"integration\":\"required\",\"lint\":\"required\",\"review\":\"optional\",\"unit\":\"required\"}},\"v\":1,\"version\":1,\"warrant\":\"ask-m2kx9a1b3c4d5e\"},{\"at\":\"2026-11-10T10:00:00Z\",\"branches\":[\"main\"],\"by\":\"operator@shanks\",\"module\":\"nats\",\"origin\":\"novox/mesh-catalog\",\"path\":\"modules/nats/module.json\",\"policy\":{\"artifacts\":{\"program\":{\"unit\":\"bypass\"}},\"steps\":{\"approval\":\"bypass\",\"composition\":\"required\",\"integration\":\"required\",\"lint\":\"required\",\"review\":\"optional\",\"unit\":\"required\"}},\"v\":1,\"version\":2,\"warrant\":\"ask-m2kx9a1b3c4d5e\"}],\"registrations\":[{\"at\":\"2026-11-10T10:00:00Z\",\"branches\":[\"main\"],\"by\":\"operator@shanks\",\"module\":\"nats\",\"origin\":\"novox/mesh-catalog\",\"path\":\"modules/nats/module.json\",\"policy\":{\"artifacts\":{\"program\":{\"unit\":\"bypass\"}},\"steps\":{\"approval\":\"bypass\",\"composition\":\"required\",\"integration\":\"required\",\"lint\":\"required\",\"review\":\"optional\",\"unit\":\"required\"}},\"v\":1,\"version\":2,\"warrant\":\"ask-m2kx9a1b3c4d5e\"}]}",

contracts/seats/mesh-catalog/fixtures/verbs.json

@@ -152,6 +152,13 @@
       ]
     }
   },
+  {
+    "name": "revision answers none yet for a branch with no revision",
+    "of": "verb:revision.answer",
+    "given": {
+      "none-yet": true
+    }
+  },
   {
     "name": "registrations of one module with its history",
     "of": "verb:registrations.input",

contracts/seats/mesh-catalog/seat.json

@@ -250,7 +250,7 @@
     },
     {
       "name": "revision",
-      "description": "The catalog half of the revision view (ADR 0656 \u00a76): one catalog graph revision with its entries whole, the trunk heads, the seat definitions by digest, and each manifest's verdict and fingerprint; the trunk's newest when no revision and no candidate is named, or a candidate's for its group and heads. Answered by the holder from what it holds, in its own runtime (ADR 0663), in pages of entries. Reads only.",
+      "description": "The catalog half of the revision view (ADR 0656 \u00a76): one catalog graph revision with its entries whole, the trunk heads, the seat definitions by digest, and each manifest's verdict and fingerprint; the trunk's newest when no revision and no candidate is named, or a candidate's for its group and heads. Answered by the holder from what it holds, in its own runtime (ADR 0663), in pages of entries. Reads only. A watched branch with no revision yet answers {none-yet: true} alone (design 47 G section 530).",
       "input": {
         "type": "object",
         "properties": {
@@ -292,12 +292,12 @@
           "next": {
             "type": "string",
             "description": "the module to ask after for the next page; absent on the last"
+          },
+          "none-yet": {
+            "type": "boolean",
+            "description": "true for a watched branch with no revision yet: no revision, no entries and no error follow, and a reader holds the branch's view ready and empty (design 47 G section 530)"
           }
-        },
-        "required": [
-          "revision",
-          "entries"
-        ]
+        }
       },
       "class": "read"
     },
@@ -2735,5 +2735,263 @@
         "language"
       ]
     }
+  },
+  "bodies": {
+    "TakeInMerge": {
+      "type": "object",
+      "description": "one merge a take-in event holds: the repository, its pull request and the merge commit the forge made of it",
+      "properties": {
+        "repository": {
+          "type": "string"
+        },
+        "number": {
+          "type": "integer"
+        },
+        "merge": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "repository",
+        "number",
+        "merge"
+      ]
+    },
+    "TakeInMember": {
+      "type": "object",
+      "description": "one pull request at one commit",
+      "properties": {
+        "repository": {
+          "type": "string"
+        },
+        "number": {
+          "type": "integer"
+        },
+        "head": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "repository",
+        "number",
+        "head"
+      ]
+    },
+    "TakeInEntry": {
+      "type": "object",
+      "description": "one module of a taken-in revision (design 47 G section 476, section 648)",
+      "properties": {
+        "module": {
+          "type": "string"
+        },
+        "commit": {
+          "type": "string"
+        },
+        "fingerprint": {
+          "type": "string",
+          "description": "the module's build-input fingerprint at the commit"
+        },
+        "repository": {
+          "type": "string",
+          "description": "from a merged message; absent for a pushed one (design 47 G section 648)"
+        },
+        "pull": {
+          "type": "integer",
+          "description": "from a merged message; absent for a pushed one (design 47 G section 648)"
+        }
+      },
+      "required": [
+        "module",
+        "commit",
+        "fingerprint"
+      ]
+    },
+    "TakeInPending": {
+      "type": "object",
+      "description": "the body of the indexer's take-in.pending: a wait for a revision or a group, with the watched branch (design 47 G section 493)",
+      "properties": {
+        "v": {
+          "type": "integer",
+          "description": "the layout version"
+        },
+        "kind": {
+          "type": "string",
+          "description": "the event's kind, pending or taken"
+        },
+        "key": {
+          "type": "string",
+          "description": "the wait's key: m.<sequence> of its oldest merge, or g.<group> for a group being gathered"
+        },
+        "what": {
+          "type": "string",
+          "description": "what waits: a revision or a group"
+        },
+        "merges": {
+          "type": "array",
+          "items": {
+            "$ref": "#/bodies/TakeInMerge"
+          },
+          "description": "the merges it holds, oldest first"
+        },
+        "group": {
+          "type": "string",
+          "description": "the delivery group, for a group being gathered"
+        },
+        "members": {
+          "type": "array",
+          "items": {
+            "$ref": "#/bodies/TakeInMember"
+          },
+          "description": "every approved member of a group with its head"
+        },
+        "waits-for": {
+          "type": "string",
+          "description": "the indexer build a revision waits for"
+        },
+        "since": {
+          "type": "string",
+          "description": "when the wait began",
+          "format": "date-time"
+        },
+        "by": {
+          "type": "string",
+          "description": "who acted by hand, on a taken event"
+        },
+        "why": {
+          "type": "string",
+          "description": "why they acted by hand, on a taken event"
+        },
+        "dropped": {
+          "type": "boolean",
+          "description": "a hand drop: the merges are not taken in"
+        },
+        "lost": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "description": "the keys of merges whose message the forge bridge's stream no longer holds"
+        },
+        "refused": {
+          "type": "string",
+          "description": "why the manifest of the indexer the revision names was refused"
+        },
+        "own-build-unknown": {
+          "type": "string",
+          "description": "why the indexer holds a merge it does not take in although no indexer build is named"
+        },
+        "branch": {
+          "type": "string",
+          "description": "the watched branch the revision is of (design 47 G section 476, section 493)"
+        }
+      },
+      "required": [
+        "v",
+        "kind",
+        "key",
+        "what",
+        "merges",
+        "since"
+      ]
+    },
+    "TakeInTaken": {
+      "type": "object",
+      "description": "the body of the indexer's take-in.taken: a wait ended, with the branch, the source revision and the entries (design 47 G section 476, section 493)",
+      "properties": {
+        "v": {
+          "type": "integer",
+          "description": "the layout version"
+        },
+        "kind": {
+          "type": "string",
+          "description": "the event's kind, pending or taken"
+        },
+        "key": {
+          "type": "string",
+          "description": "the wait's key: m.<sequence> of its oldest merge, or g.<group> for a group being gathered"
+        },
+        "what": {
+          "type": "string",
+          "description": "what waits: a revision or a group"
+        },
+        "merges": {
+          "type": "array",
+          "items": {
+            "$ref": "#/bodies/TakeInMerge"
+          },
+          "description": "the merges it holds, oldest first"
+        },
+        "group": {
+          "type": "string",
+          "description": "the delivery group, for a group being gathered"
+        },
+        "members": {
+          "type": "array",
+          "items": {
+            "$ref": "#/bodies/TakeInMember"
+          },
+          "description": "every approved member of a group with its head"
+        },
+        "waits-for": {
+          "type": "string",
+          "description": "the indexer build a revision waits for"
+        },
+        "since": {
+          "type": "string",
+          "description": "when the wait began",
+          "format": "date-time"
+        },
+        "by": {
+          "type": "string",
+          "description": "who acted by hand, on a taken event"
+        },
+        "why": {
+          "type": "string",
+          "description": "why they acted by hand, on a taken event"
+        },
+        "dropped": {
+          "type": "boolean",
+          "description": "a hand drop: the merges are not taken in"
+        },
+        "lost": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "description": "the keys of merges whose message the forge bridge's stream no longer holds"
+        },
+        "refused": {
+          "type": "string",
+          "description": "why the manifest of the indexer the revision names was refused"
+        },
+        "own-build-unknown": {
+          "type": "string",
+          "description": "why the indexer holds a merge it does not take in although no indexer build is named"
+        },
+        "branch": {
+          "type": "string",
+          "description": "the watched branch the revision is of (design 47 G section 476, section 493)"
+        },
+        "source": {
+          "type": "integer",
+          "description": "the source revision taken in (design 47 G section 476)"
+        },
+        "entries": {
+          "type": "array",
+          "items": {
+            "$ref": "#/bodies/TakeInEntry"
+          },
+          "description": "one entry per module of that revision; none for a hand drop (design 47 G section 476, section 493)"
+        }
+      },
+      "required": [
+        "v",
+        "kind",
+        "key",
+        "what",
+        "merges",
+        "since"
+      ]
+    }
   }
 }

contracts/ts/seats/meshcatalog/index.d.ts

@@ -516,6 +516,108 @@ export interface VersionEntry {
   "version": string;
 }
 
+/** one module of a taken-in revision (design 47 G section 476, section 648) */
+export interface TakeInEntry {
+  "commit": string;
+  /** the module's build-input fingerprint at the commit */
+  "fingerprint": string;
+  "module": string;
+  /** from a merged message; absent for a pushed one (design 47 G section 648) */
+  "pull"?: number;
+  /** from a merged message; absent for a pushed one (design 47 G section 648) */
+  "repository"?: string;
+}
+
+/** one pull request at one commit */
+export interface TakeInMember {
+  "head": string;
+  "number": number;
+  "repository": string;
+}
+
+/** one merge a take-in event holds: the repository, its pull request and the merge commit the forge made of it */
+export interface TakeInMerge {
+  "merge": string;
+  "number": number;
+  "repository": string;
+}
+
+/** the body of the indexer's take-in.pending: a wait for a revision or a group, with the watched branch (design 47 G section 493) */
+export interface TakeInPending {
+  /** the watched branch the revision is of (design 47 G section 476, section 493) */
+  "branch"?: string;
+  /** who acted by hand, on a taken event */
+  "by"?: string;
+  /** a hand drop: the merges are not taken in */
+  "dropped"?: boolean;
+  /** the delivery group, for a group being gathered */
+  "group"?: string;
+  /** the wait's key: m.<sequence> of its oldest merge, or g.<group> for a group being gathered */
+  "key": string;
+  /** the event's kind, pending or taken */
+  "kind": string;
+  /** the keys of merges whose message the forge bridge's stream no longer holds */
+  "lost"?: string[];
+  /** every approved member of a group with its head */
+  "members"?: TakeInMember[];
+  /** the merges it holds, oldest first */
+  "merges": TakeInMerge[];
+  /** why the indexer holds a merge it does not take in although no indexer build is named */
+  "own-build-unknown"?: string;
+  /** why the manifest of the indexer the revision names was refused */
+  "refused"?: string;
+  /** when the wait began */
+  "since": string;
+  /** the layout version */
+  "v": number;
+  /** the indexer build a revision waits for */
+  "waits-for"?: string;
+  /** what waits: a revision or a group */
+  "what": string;
+  /** why they acted by hand, on a taken event */
+  "why"?: string;
+}
+
+/** the body of the indexer's take-in.taken: a wait ended, with the branch, the source revision and the entries (design 47 G section 476, section 493) */
+export interface TakeInTaken {
+  /** the watched branch the revision is of (design 47 G section 476, section 493) */
+  "branch"?: string;
+  /** who acted by hand, on a taken event */
+  "by"?: string;
+  /** a hand drop: the merges are not taken in */
+  "dropped"?: boolean;
+  /** one entry per module of that revision; none for a hand drop (design 47 G section 476, section 493) */
+  "entries"?: TakeInEntry[];
+  /** the delivery group, for a group being gathered */
+  "group"?: string;
+  /** the wait's key: m.<sequence> of its oldest merge, or g.<group> for a group being gathered */
+  "key": string;
+  /** the event's kind, pending or taken */
+  "kind": string;
+  /** the keys of merges whose message the forge bridge's stream no longer holds */
+  "lost"?: string[];
+  /** every approved member of a group with its head */
+  "members"?: TakeInMember[];
+  /** the merges it holds, oldest first */
+  "merges": TakeInMerge[];
+  /** why the indexer holds a merge it does not take in although no indexer build is named */
+  "own-build-unknown"?: string;
+  /** why the manifest of the indexer the revision names was refused */
+  "refused"?: string;
+  /** when the wait began */
+  "since": string;
+  /** the source revision taken in (design 47 G section 476) */
+  "source"?: number;
+  /** the layout version */
+  "v": number;
+  /** the indexer build a revision waits for */
+  "waits-for"?: string;
+  /** what waits: a revision or a group */
+  "what": string;
+  /** why they acted by hand, on a taken event */
+  "why"?: string;
+}
+
 /** is what modules takes. */
 export interface ModulesInput {
 }
@@ -632,10 +734,12 @@ export interface RevisionInput {
 /** is what revision answers. */
 export interface RevisionAnswer {
   /** this page's entries whole, by module name */
-  "entries": CatalogEntry[];
+  "entries"?: CatalogEntry[];
   /** the module to ask after for the next page; absent on the last */
   "next"?: string;
-  "revision": CatalogRevision;
+  /** true for a watched branch with no revision yet: no revision, no entries and no error follow, and a reader holds the branch's view ready and empty (design 47 G section 530) */
+  "none-yet"?: boolean;
+  "revision"?: CatalogRevision;
 }
 
 /** is what registrations takes. */

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/integration_test.go

@@ -1870,7 +1870,7 @@ func serveCatalog(t *testing.T, b *bed, nc *nats.Conn) {
 		b.cat.mu.Lock()
 		defer b.cat.mu.Unlock()
 		if b.cat.rev[branch] == 0 {
-			_ = m.Respond([]byte(`{"error":"` + views.NoneYet + `"}`))
+			_ = m.Respond([]byte(`{"result":{"none-yet":true},"node":"n0"}`))
 			return
 		}
 		rev := meshcatalog.CatalogRevision{Kind: "trunk", Branch: in.Branch, Revision: b.cat.rev[branch]}
@@ -1879,7 +1879,7 @@ func serveCatalog(t *testing.T, b *bed, nc *nats.Conn) {
 			entries = append(entries, b.cat.entries[branch][name])
 			rev.Entries = append(rev.Entries, meshcatalog.EntryRef{Module: name, Digest: "sha256:" + strings.Repeat("0", 64)})
 		}
-		raw, _ := json.Marshal(map[string]any{"result": meshcatalog.RevisionAnswer{Revision: rev, Entries: entries}, "node": "n0"})
+		raw, _ := json.Marshal(map[string]any{"result": meshcatalog.RevisionAnswer{Revision: &rev, Entries: entries}, "node": "n0"})
 		_ = m.Respond(raw)
 	}
 	for _, subject := range []string{"mesh.seat.mesh-catalog.tool.revision", "mesh.seat.mesh-catalog.call.revision.*", "mesh.seat.mesh-catalog.tool.revision.*"} {

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/integration_test.go

@@ -540,7 +540,7 @@ func startBed(t *testing.T) *bed {
 			for repo, commit := range trunkView.Load().(map[string]string) {
 				heads = append(heads, meshcatalog.Head{Repository: repo, Commit: commit})
 			}
-			body, _ := json.Marshal(meshcatalog.RevisionAnswer{Revision: meshcatalog.CatalogRevision{Kind: "trunk", Revision: 1, Trunk: heads}})
+			body, _ := json.Marshal(meshcatalog.RevisionAnswer{Revision: &meshcatalog.CatalogRevision{Kind: "trunk", Revision: 1, Trunk: heads}})
 			reply, _ := json.Marshal(map[string]any{"result": json.RawMessage(body), "node": "ctl"})
 			_ = m.Respond(reply)
 		}); err != nil {

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/trunk_test.go

@@ -18,7 +18,7 @@ func TestTrunkHeadsComeFromTheCatalogHalf(t *testing.T) {
 			if key != "seat:mesh-catalog.revision" {
 				t.Fatalf("asked %s", key)
 			}
-			return json.Marshal(meshcatalog.RevisionAnswer{Revision: meshcatalog.CatalogRevision{Kind: kind, Trunk: heads}})
+			return json.Marshal(meshcatalog.RevisionAnswer{Revision: &meshcatalog.CatalogRevision{Kind: kind, Trunk: heads}})
 		}
 	}
 	trunks := &check.Trunks{}

modules/mesh-delivery-checker/internal/check/trunkview.go

@@ -17,6 +17,9 @@ func TrunkHeads(raw json.RawMessage) (map[string]string, error) {
 	if err := json.Unmarshal(raw, &a); err != nil {
 		return nil, fmt.Errorf("the catalog half's revision does not read: %w", err)
 	}
+	if a.Revision == nil {
+		return nil, fmt.Errorf("the catalog half's revision answers no revision (none-yet: %v)", a.NoneYet)
+	}
 	if a.Revision.Kind != "trunk" {
 		return nil, fmt.Errorf("the catalog half's revision %d is a %q revision, not a trunk's", a.Revision.Revision, a.Revision.Kind)
 	}

modules/mesh-delivery-indexer/internal/index/revision_verb.go

@@ -72,7 +72,7 @@ func Revision(ctx context.Context, o Objects, holder, caller string, in meshcata
 		}
 	}
 	slices.SortFunc(entries, func(a, b meshcatalog.CatalogEntry) int { return strings.Compare(a.Module, b.Module) })
-	out.Revision, out.Entries = rev, []meshcatalog.CatalogEntry{}
+	out.Revision, out.Entries = &rev, []meshcatalog.CatalogEntry{}
 	size := 0
 	for _, e := range entries {
 		if e.Module <= in.After {

modules/mesh-delivery-view/cmd/mesh-delivery-view-tools/owners_test.go

@@ -187,7 +187,7 @@ func ownersAnswerTheToolsAsBefore(t *testing.T) {
 // catalogAnswer is the seat mesh-catalog's newest trunk revision: a with a fingerprint and the source revision it moved at,
 // b with none and the reason.
 var catalogAnswer = meshcatalog.RevisionAnswer{
-	Revision: meshcatalog.CatalogRevision{Revision: 4, Kind: meshcatalogclient.KindTrunk, Source: 7},
+	Revision: &meshcatalog.CatalogRevision{Revision: 4, Kind: meshcatalogclient.KindTrunk, Source: 7},
 	Entries: []meshcatalog.CatalogEntry{
 		{Module: "a", Repository: "novox/r", Commit: "c1", Path: ".", Manifest: map[string]any{"module": "a"}, Fp: fp2A, Inputs: &meshcatalog.EntryInputs{Src: 7}},
 		{Module: "b", Repository: "novox/r", Commit: "c2", Path: "modules/b", Manifest: map[string]any{"module": "b"}, None: "builder's fingerprint not yet known"},

modules/mesh-delivery-view/cmd/mesh-delivery-view/integration_test.go

@@ -77,7 +77,7 @@ func serveCatalog(t testing.TB, ctx context.Context, js jetstream.JetStream, nc
 	}
 	answer := func(m *nats.Msg) {
 		h.mu.Lock()
-		a := meshcatalog.RevisionAnswer{Revision: meshcatalog.CatalogRevision{Revision: h.rev, Kind: meshcatalogclient.KindTrunk}}
+		a := meshcatalog.RevisionAnswer{Revision: &meshcatalog.CatalogRevision{Revision: h.rev, Kind: meshcatalogclient.KindTrunk}}
 		for _, e := range h.entries {
 			a.Entries = append(a.Entries, e)
 		}