diff --git a/Dockerfile.api b/Dockerfile.api
index acd081f..213bc5c 100644
--- a/Dockerfile.api
+++ b/Dockerfile.api
@@ -1,9 +1,12 @@
 FROM golang:1.22-alpine AS build
 WORKDIR /src
+ARG BUILD_REVISION=devel
+ARG BUILD_TIME=unknown
+ARG BUILD_DIRTY=unknown
 COPY go.mod ./
 RUN go mod download
 COPY . ./
-RUN go build -trimpath -ldflags='-s -w' -o /out/orchestra ./cmd/orchestra
+RUN go build -trimpath -ldflags="-s -w -X orchestra/internal/buildinfo.Revision=${BUILD_REVISION} -X orchestra/internal/buildinfo.Time=${BUILD_TIME} -X orchestra/internal/buildinfo.Dirty=${BUILD_DIRTY}" -o /out/orchestra ./cmd/orchestra
 
 FROM alpine:3.21
 RUN adduser -D -u 10001 orchestra
diff --git a/cmd/orchestra-migrate/main.go b/cmd/orchestra-migrate/main.go
new file mode 100644
index 0000000..2067bbb
--- /dev/null
+++ b/cmd/orchestra-migrate/main.go
@@ -0,0 +1,29 @@
+// orchestra-migrate contains explicit, one-shot durable-store migrations.
+// It deliberately never starts the coordinator: run it only while all
+// coordinator processes for the target data directory are stopped.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"orchestra/internal/store"
+)
+
+func main() {
+	dir := flag.String("data", "", "Orchestra data directory")
+	confirm := flag.Bool("confirm", false, "confirm that every coordinator using -data is stopped")
+	flag.Parse()
+	if *dir == "" || !*confirm {
+		log.Fatal("usage: orchestra-migrate -data DIR -confirm (with all coordinators stopped)")
+	}
+	changed, err := store.NormalizeLegacyEventSequence(*dir)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if changed {
+		fmt.Println("normalized legacy event sequence; preserved events.jsonl.legacy-* backup")
+		return
+	}
+	fmt.Println("event sequence already canonical; no migration needed")
+}
diff --git a/deploy/DEPLOYMENT.md b/deploy/DEPLOYMENT.md
index d3a4d2d..8d72237 100644
--- a/deploy/DEPLOYMENT.md
+++ b/deploy/DEPLOYMENT.md
@@ -41,3 +41,28 @@ Verify the coordinator at `GET /v1/admin/diagnostics` with the normal admin
 credential: its `build` object is the coordinator provenance. `GET
 /v1/federation/workers` shows every worker's `build`, supported projects, and
 worker-local health without SSH.
+
+For the Docker coordinator deployment, provide the same provenance as build
+arguments (the Dockerfile intentionally cannot read `.git` from its build
+context):
+
+```sh
+revision=$(git rev-parse HEAD)
+build_time=$(date -u +%Y-%m-%dT%H:%M:%SZ)
+dirty=false; test -z "$(git status --porcelain)" || dirty=true
+docker compose build \
+  --build-arg BUILD_REVISION="$revision" \
+  --build-arg BUILD_TIME="$build_time" \
+  --build-arg BUILD_DIRTY="$dirty" \
+  orchestra-api
+docker compose up -d --no-deps orchestra-api
+```
+
+If a pre-v2 event log has the historical repeated-`seq=1` prefix, the current
+coordinator intentionally refuses to replay it. Stop every coordinator using
+the data directory and run the explicit, backup-preserving migration before
+deploying the current image:
+
+```sh
+orchestra-migrate -data /var/lib/orchestra/data -confirm
+```
diff --git a/internal/store/migration_test.go b/internal/store/migration_test.go
new file mode 100644
index 0000000..7f5339a
--- /dev/null
+++ b/internal/store/migration_test.go
@@ -0,0 +1,58 @@
+package store
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"orchestra/internal/domain"
+)
+
+func TestNormalizeLegacyEventSequence(t *testing.T) {
+	dir := t.TempDir()
+	events := []domain.Event{
+		{SchemaVersion: 2, Seq: 1, ID: "created", Type: "TaskCreated", TaskID: "t", Version: 1, At: time.Now().UTC(), Payload: json.RawMessage(`{"source":"test","external_id":"1","project":"p"}`), Surface: "system"},
+		{SchemaVersion: 2, Seq: 1, ID: "leased", Type: "TaskLeased", TaskID: "t", Version: 2, At: time.Now().UTC(), Payload: json.RawMessage(`{"harness_id":"h","ttl":60,"until_ns":2000000000000000000,"expected_version":1}`), Surface: "system"},
+		{SchemaVersion: 2, Seq: 2, ID: "recovered-lease", Type: "TaskLeased", TaskID: "t", Version: 2, At: time.Now().UTC(), Payload: json.RawMessage(`{"harness_id":"h","ttl":60,"until_ns":2000000000000000000,"expected_version":1}`), Surface: "system"},
+	}
+	var raw []byte
+	for _, e := range events {
+		b, err := json.Marshal(e)
+		if err != nil {
+			t.Fatal(err)
+		}
+		raw = append(raw, append(b, '\n')...)
+	}
+	if err := os.WriteFile(filepath.Join(dir, "events.jsonl"), raw, 0644); err != nil {
+		t.Fatal(err)
+	}
+	changed, err := NormalizeLegacyEventSequence(dir)
+	if err != nil || !changed {
+		t.Fatalf("NormalizeLegacyEventSequence = %v, %v", changed, err)
+	}
+	if backups, err := filepath.Glob(filepath.Join(dir, "events.jsonl.legacy-*")); err != nil || len(backups) != 1 {
+		t.Fatalf("backups = %v, %v", backups, err)
+	}
+	s, err := Open(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := len(s.Events(0)); got != 2 {
+		t.Fatalf("events = %d, want 2", got)
+	}
+	if got := s.Events(0)[1].ID; got != "recovered-lease" {
+		t.Fatalf("second event = %q, want recovered suffix", got)
+	}
+}
+
+func TestNormalizeLegacyEventSequenceRejectsOtherCorruption(t *testing.T) {
+	dir := t.TempDir()
+	if err := os.WriteFile(filepath.Join(dir, "events.jsonl"), []byte(`{"seq":2}`+"\n"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := NormalizeLegacyEventSequence(dir); err == nil {
+		t.Fatal("NormalizeLegacyEventSequence accepted non-legacy corruption")
+	}
+}
diff --git a/internal/store/store.go b/internal/store/store.go
index 7347fcb..9373d1a 100644
--- a/internal/store/store.go
+++ b/internal/store/store.go
@@ -2,6 +2,7 @@ package store
 
 import (
 	"bufio"
+	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -94,6 +95,125 @@ func Open(dir string) (*Store, error) {
 	}
 	return s, sc.Err()
 }
+
+// NormalizeLegacyEventSequence repairs one explicitly recognized pre-v2 log
+// shape: a prefix of two or more records all numbered seq=1, followed by a
+// contiguous suffix numbered 2, 3, ... that restarts the first task at
+// version 2. Early Orchestra releases emitted precisely that shape: records
+// after the first seq=1 were never included in the compatibility snapshot,
+// then were replayed again after restart. The migration retains the initial
+// TaskCreated plus the contiguous suffix, discarding only the provably
+// abandoned duplicate prefix. It is not a general corruption repair tool:
+// any other gap or duplicate is rejected so Open's fail-closed recovery
+// guarantee remains intact.
+//
+// The caller must stop every coordinator using dir first. The original log is
+// durably copied to events.jsonl.legacy-<unix-nano> before an fsync+rename
+// replacement is installed. The return value reports whether a migration was
+// needed.
+func NormalizeLegacyEventSequence(dir string) (bool, error) {
+	path := filepath.Join(dir, "events.jsonl")
+	raw, err := os.ReadFile(path)
+	if err != nil {
+		return false, err
+	}
+	lines := bytes.Split(bytes.TrimSpace(raw), []byte{'\n'})
+	if len(lines) == 0 || (len(lines) == 1 && len(lines[0]) == 0) {
+		return false, nil
+	}
+	events := make([]domain.Event, len(lines))
+	for i, line := range lines {
+		if err := json.Unmarshal(line, &events[i]); err != nil {
+			return false, fmt.Errorf("event %d: %w", i+1, err)
+		}
+	}
+	canonical := true
+	for i, e := range events {
+		if e.Seq != uint64(i+1) {
+			canonical = false
+			break
+		}
+	}
+	if canonical {
+		return false, nil
+	}
+	prefix := 0
+	for prefix < len(events) && events[prefix].Seq == 1 {
+		prefix++
+	}
+	if prefix < 2 {
+		return false, fmt.Errorf("refusing non-legacy event sequence")
+	}
+	if events[0].Type != "TaskCreated" || events[0].Version != 1 {
+		return false, fmt.Errorf("refusing legacy sequence without an initial task creation")
+	}
+	for i := 1; i < prefix; i++ {
+		if events[i].TaskID != events[0].TaskID || events[i].Version < 2 {
+			return false, fmt.Errorf("refusing non-legacy duplicate prefix at record %d", i+1)
+		}
+	}
+	if prefix == len(events) || events[prefix].Type != "TaskLeased" || events[prefix].TaskID != events[0].TaskID || events[prefix].Version != 2 {
+		return false, fmt.Errorf("refusing legacy sequence without a task-version-2 restart")
+	}
+	for i := prefix; i < len(events); i++ {
+		want := uint64(i - prefix + 2)
+		if events[i].Seq != want {
+			return false, fmt.Errorf("refusing non-legacy event sequence at record %d: got %d, want %d", i+1, events[i].Seq, want)
+		}
+	}
+	backup := fmt.Sprintf("%s.legacy-%d", path, time.Now().UTC().UnixNano())
+	backupFile, err := os.OpenFile(backup, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0644)
+	if err != nil {
+		return false, err
+	}
+	if _, err = backupFile.Write(raw); err == nil {
+		err = backupFile.Sync()
+	}
+	if closeErr := backupFile.Close(); err == nil {
+		err = closeErr
+	}
+	if err != nil {
+		return false, err
+	}
+	tmp := path + ".sequence-migration.tmp"
+	out, err := os.OpenFile(tmp, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
+	if err != nil {
+		return false, err
+	}
+	kept := append(events[:1:1], events[prefix:]...)
+	for i := range kept {
+		kept[i].Seq = uint64(i + 1)
+		line, marshalErr := json.Marshal(kept[i])
+		if marshalErr != nil {
+			err = marshalErr
+			break
+		}
+		if _, err = out.Write(append(line, '\n')); err != nil {
+			break
+		}
+	}
+	if err == nil {
+		err = out.Sync()
+	}
+	if closeErr := out.Close(); err == nil {
+		err = closeErr
+	}
+	if err != nil {
+		return false, err
+	}
+	if err := os.Rename(tmp, path); err != nil {
+		return false, err
+	}
+	d, err := os.Open(dir)
+	if err != nil {
+		return false, err
+	}
+	defer d.Close()
+	if err := d.Sync(); err != nil {
+		return false, err
+	}
+	return true, nil
+}
 func (s *Store) apply(e domain.Event) error {
 	var p map[string]any
 	if err := json.Unmarshal(e.Payload, &p); err != nil {