diff --git a/cmd/agent-system/dispatch_test.go b/cmd/agent-system/dispatch_test.go
new file mode 100644
index 0000000..d4f7096
--- /dev/null
+++ b/cmd/agent-system/dispatch_test.go
@@ -0,0 +1,28 @@
+package main
+
+import (
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+)
+
+func TestUnknownSubcommandExits(t *testing.T) {
+	if os.Getenv("DISPATCH_CHILD") == "1" {
+		os.Args = []string{"agent-system", "not-a-command"}
+		main()
+		return
+	}
+	cmd := exec.Command(os.Args[0], "-test.run=TestUnknownSubcommandExits")
+	cmd.Env = append(os.Environ(), "DISPATCH_CHILD=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatalf("未知子命令应非零退出：%s", out)
+	}
+	if !strings.Contains(string(out), "未知子命令") {
+		t.Fatalf("输出：%s", out)
+	}
+	if strings.Contains(string(out), "agent-system starting") || strings.Contains(string(out), "serving") {
+		t.Fatalf("未知子命令落入了服务路径：%s", out)
+	}
+}
diff --git a/cmd/agent-system/main.go b/cmd/agent-system/main.go
index 391d27a..f529c67 100644
--- a/cmd/agent-system/main.go
+++ b/cmd/agent-system/main.go
@@ -9,6 +9,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"strings"
 	"time"
 
 	"agent-system-backend/internal/app"
@@ -20,9 +21,16 @@ import (
 var version = "0.1.0-dev"
 
 func main() {
-	if len(os.Args) > 1 {
+	if len(os.Args) > 1 && !strings.HasPrefix(os.Args[1], "-") {
 		switch os.Args[1] {
 		case "version", "--version":
+			if len(os.Args) > 2 && os.Args[2] == "--json" {
+				if err := identity.WriteDocument(os.Stdout, "agent-system", version); err != nil {
+					fmt.Fprintln(os.Stderr, "version:", err)
+					os.Exit(1)
+				}
+				return
+			}
 			fmt.Println("agent-system", version)
 			return
 		case "serve":
@@ -35,6 +43,10 @@ func main() {
 			os.Exit(runUser(os.Args[2:]))
 		case "identity":
 			os.Exit(runIdentity(os.Args[2:]))
+		default:
+			fmt.Fprintf(os.Stderr, "agent-system: 未知子命令 %s\n", os.Args[1])
+			fmt.Fprintln(os.Stderr, "用法：agent-system <serve|version|identity|user|apikey|config> [参数]")
+			os.Exit(2)
 		}
 	}
 	fs := flag.NewFlagSet("serve", flag.ExitOnError)
diff --git a/internal/app/app.go b/internal/app/app.go
index 2244da4..314ad68 100644
--- a/internal/app/app.go
+++ b/internal/app/app.go
@@ -836,6 +836,16 @@ func withStore(storageDSN, dataDir string, fn func(*store.Store) error) error {
 	return withStoreMode(storageDSN, dataDir, false, fn)
 }
 
+// withIdentityStore 只打开既有库：不建文件、不建目录、不迁移。
+func withIdentityStore(storageDSN, dataDir string, fn func(*store.Store) error) error {
+	st, err := store.OpenIdentity(storageDSN, dataDir)
+	if err != nil {
+		return err
+	}
+	defer st.Close()
+	return fn(st)
+}
+
 func withStoreMode(storageDSN, dataDir string, openExisting bool, fn func(*store.Store) error) error {
 	var st *store.Store
 	var err error
@@ -912,17 +922,29 @@ func RevokeAPIKey(storageDSN, dataDir, owner, name string) (bool, error) {
 }
 
 // EnsureSystemIdentity CLI：显式建立库内服务身份（svc init / I2→I3 引导）。
+// 只打开既有库，不建库、不迁移。
 func EnsureSystemIdentity(storageDSN, dataDir, instanceID, dbref string) error {
-	return withStore(storageDSN, dataDir, func(st *store.Store) error {
+	return withIdentityStore(storageDSN, dataDir, func(st *store.Store) error {
 		return st.EnsureSystemIdentity(instanceID, dbref)
 	})
 }
 
 // VerifySystemIdentity CLI：校验库内服务身份（svc start 前；失败不插入）。
-func VerifySystemIdentity(storageDSN, dataDir, instanceID, dbref string) error {
-	return withStore(storageDSN, dataDir, func(st *store.Store) error {
-		return st.VerifySystemIdentity(instanceID, dbref)
+// 只打开既有库，不建库、不迁移。schemaVersion 取身份行上的值。
+func VerifySystemIdentity(storageDSN, dataDir, instanceID, dbref string) (int, error) {
+	var schemaVersion int
+	err := withIdentityStore(storageDSN, dataDir, func(st *store.Store) error {
+		if err := st.VerifySystemIdentity(instanceID, dbref); err != nil {
+			return err
+		}
+		row, err := st.GetSystemIdentity()
+		if err != nil {
+			return err
+		}
+		schemaVersion = row.SchemaVersion
+		return nil
 	})
+	return schemaVersion, err
 }
 
 // cachedInt 带短 TTL 的整型缓存读（限流值热读取免打库）。
diff --git a/internal/store/migrate_compat.go b/internal/store/migrate_compat.go
new file mode 100644
index 0000000..cd8e6fb
--- /dev/null
+++ b/internal/store/migrate_compat.go
@@ -0,0 +1,49 @@
+package store
+
+// migrationBreaksOldReaders 登记每个迁移版本落地后，schema.target 更低的旧制品
+// 还能不能读这个库。新增迁移漏登记时 TestMigrationCompatRegistered 失败。
+// true 会抬高 SchemaCompatFloor：候选若要把库迁过该版本，而旧制品的 target
+// 低于该下限，切换必须在停旧服务前拒绝，除非走已确认的 forward-only 迁移。
+var migrationBreaksOldReaders = map[int]bool{
+	1:  false,
+	2:  false,
+	3:  false,
+	4:  false,
+	5:  false,
+	6:  false,
+	7:  false,
+	8:  false,
+	9:  false,
+	10: false,
+	11: false,
+	12: false,
+	13: false,
+	14: false,
+	15: false,
+	16: false,
+	17: false,
+	18: false,
+	19: false,
+	20: false,
+	21: false,
+	22: false,
+	23: false,
+	24: false,
+	25: false,
+	26: false,
+	27: false,
+}
+
+// SchemaTarget 是本二进制会迁移到的 schema 版本。
+func SchemaTarget() int { return latestMigrationVersion() }
+
+// SchemaCompatFloor 是旧制品仍能读取的最高破坏性版本。0 表示当前全部迁移都不破坏旧读。
+func SchemaCompatFloor() int {
+	floor := 0
+	for version, breaks := range migrationBreaksOldReaders {
+		if breaks && version > floor {
+			floor = version
+		}
+	}
+	return floor
+}
diff --git a/internal/store/migrate_compat_test.go b/internal/store/migrate_compat_test.go
new file mode 100644
index 0000000..6c46cf7
--- /dev/null
+++ b/internal/store/migrate_compat_test.go
@@ -0,0 +1,20 @@
+package store
+
+import "testing"
+
+func TestMigrationCompatRegistered(t *testing.T) {
+	if len(migrationBreaksOldReaders) != len(migrations) {
+		t.Fatalf("兼容登记 %d 条，迁移 %d 条", len(migrationBreaksOldReaders), len(migrations))
+	}
+	for _, m := range migrations {
+		if _, ok := migrationBreaksOldReaders[m.version]; !ok {
+			t.Fatalf("迁移 v%d %s 未登记是否破坏旧制品读取", m.version, m.name)
+		}
+	}
+	if SchemaTarget() != latestMigrationVersion() {
+		t.Fatalf("target=%d latest=%d", SchemaTarget(), latestMigrationVersion())
+	}
+	if SchemaCompatFloor() < 0 || SchemaCompatFloor() > SchemaTarget() {
+		t.Fatalf("compatFloor=%d target=%d", SchemaCompatFloor(), SchemaTarget())
+	}
+}
diff --git a/internal/store/store.go b/internal/store/store.go
index ba64e01..edfff68 100644
--- a/internal/store/store.go
+++ b/internal/store/store.go
@@ -90,6 +90,87 @@ func OpenSQLite(path string) (*Store, error) {
 	return openSQLiteFile(path, true)
 }
 
+// OpenIdentity 打开既有库做身份 ensure/verify：不创建文件或目录，不执行迁移。
+// 缺少 agent_system_identity 表时返回 ErrIdentityTableMissing。
+func OpenIdentity(storageDSN, dataDir string) (*Store, error) {
+	if storageDSN != "" {
+		return openIdentityPostgres(storageDSN)
+	}
+	return openIdentitySQLite(filepath.Join(dataDir, "agent-system.db"))
+}
+
+func openIdentitySQLite(path string) (*Store, error) {
+	if _, err := os.Stat(path); err != nil {
+		if os.IsNotExist(err) {
+			return nil, fmt.Errorf("%w: %s", ErrIdentityDBMissing, path)
+		}
+		return nil, err
+	}
+	dsn := fmt.Sprintf("file:%s?_pragma=busy_timeout(30000)&_pragma=foreign_keys(1)&_txlock=immediate", path)
+	db, err := sql.Open("sqlite", dsn)
+	if err != nil {
+		return nil, err
+	}
+	db.SetMaxOpenConns(1)
+	if err := requireIdentityTable(db, "sqlite"); err != nil {
+		db.Close()
+		return nil, err
+	}
+	return &Store{db: db, dialect: sqliteDialect{}}, nil
+}
+
+func openIdentityPostgres(dsn string) (*Store, error) {
+	db, err := sql.Open("pgx", dsn)
+	if err != nil {
+		return nil, err
+	}
+	db.SetMaxOpenConns(2)
+	if err := db.Ping(); err != nil {
+		db.Close()
+		return nil, err
+	}
+	if err := requireIdentityTable(db, "postgres"); err != nil {
+		db.Close()
+		return nil, err
+	}
+	return &Store{db: db, dialect: postgresDialect{}}, nil
+}
+
+func requireIdentityTable(db *sql.DB, kind string) error {
+	var name string
+	var err error
+	switch kind {
+	case "postgres":
+		err = db.QueryRow(`SELECT COALESCE(to_regclass('public.agent_system_identity')::text, '')`).Scan(&name)
+	default:
+		err = db.QueryRow(`SELECT COALESCE((SELECT name FROM sqlite_master WHERE type='table' AND name='agent_system_identity'), '')`).Scan(&name)
+	}
+	if err != nil {
+		return err
+	}
+	if name == "" {
+		return fmt.Errorf("%w: 先执行受控迁移（服务启动或 migrate），身份命令不建库、不迁移", ErrIdentityTableMissing)
+	}
+	return nil
+}
+
+// SchemaVersion 读取 schema_migrations 的最大版本。表不存在时返回 0。
+func (s *Store) SchemaVersion() (int, error) {
+	var v sql.NullInt64
+	err := s.db.QueryRow(`SELECT MAX(version) FROM schema_migrations`).Scan(&v)
+	if err != nil {
+		msg := strings.ToLower(err.Error())
+		if strings.Contains(msg, "no such table") || strings.Contains(msg, "does not exist") {
+			return 0, nil
+		}
+		return 0, err
+	}
+	if !v.Valid {
+		return 0, nil
+	}
+	return int(v.Int64), nil
+}
+
 // OpenExistingSQLite 打开既有嵌入式库：数据文件不存在则失败，不创建空库或父目录。
 // 仍执行兼容迁移（requireCompatible）；用于账户运维，避免恢复操作顺带建库。
 func OpenExistingSQLite(path string) (*Store, error) {
diff --git a/internal/store/system_identity.go b/internal/store/system_identity.go
index 0aeaaa5..453f2ad 100644
--- a/internal/store/system_identity.go
+++ b/internal/store/system_identity.go
@@ -12,6 +12,15 @@ var ErrSystemIdentityMismatch = errors.New("system identity mismatch")
 // ErrSystemIdentityMissing 表中无身份行——须先 Ensure（svc init / 首次建立），禁止静默插入。
 var ErrSystemIdentityMissing = errors.New("system identity missing")
 
+// ErrIdentityDBMissing 身份 CLI 拒绝创建数据库文件或父目录。
+var ErrIdentityDBMissing = errors.New("identity database missing")
+
+// ErrIdentityTableMissing 库存在但没有冻结的身份表，须走受控迁移而不是身份 CLI。
+var ErrIdentityTableMissing = errors.New("identity table missing")
+
+// IdentityColumns 是 agent_system_identity 的冻结列序（v27）。新增列会破坏旧制品读取，必须先改本常量并补兼容测试。
+const IdentityColumns = "instance_id,dbref,schema_version,created_at"
+
 // SystemIdentity 是 agent_system_identity 表的一行（一库一服务身份）。
 type SystemIdentity struct {
 	InstanceID    string
@@ -43,7 +52,13 @@ func (s *Store) EnsureSystemIdentity(instanceID, dbref string) error {
 		}
 		return nil
 	}
-	ver := latestMigrationVersion()
+	ver, err := s.SchemaVersion()
+	if err != nil {
+		return err
+	}
+	if ver <= 0 {
+		ver = 27
+	}
 	_, err = s.db.Exec(s.q(`INSERT INTO agent_system_identity(instance_id, dbref, schema_version, created_at) VALUES(?,?,?,?)`),
 		instanceID, dbref, ver, nowISO())
 	if err != nil {
diff --git a/internal/store/system_identity_test.go b/internal/store/system_identity_test.go
index f0b4f6e..9edaea7 100644
--- a/internal/store/system_identity_test.go
+++ b/internal/store/system_identity_test.go
@@ -1,8 +1,11 @@
 package store
 
 import (
+	"database/sql"
 	"errors"
+	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 )
 
@@ -67,4 +70,89 @@ func TestSystemIdentityMigrationCreatesTable(t *testing.T) {
 	if err := st.DB().QueryRow(`SELECT name FROM sqlite_master WHERE type='table' AND name='agent_system_identity'`).Scan(&name); err != nil || name != "agent_system_identity" {
 		t.Fatalf("table missing: name=%q err=%v", name, err)
 	}
+	cols := identityColumnNames(t, st.DB())
+	if cols != IdentityColumns {
+		t.Fatalf("身份表列已偏离冻结契约：%s", cols)
+	}
+}
+
+func TestOpenIdentityReadsFutureSchemaWithoutMigrating(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "agent-system.db")
+	raw, err := sql.Open("sqlite", "file:"+path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	stmts := []string{
+		`CREATE TABLE schema_migrations (version INTEGER PRIMARY KEY, name TEXT NOT NULL, applied_at TEXT NOT NULL)`,
+		`INSERT INTO schema_migrations(version, name, applied_at) VALUES (99, 'future', 't')`,
+		`CREATE TABLE agent_system_identity (
+			instance_id TEXT NOT NULL PRIMARY KEY,
+			dbref TEXT NOT NULL,
+			schema_version INTEGER NOT NULL,
+			created_at TEXT NOT NULL)`,
+		`INSERT INTO agent_system_identity(instance_id, dbref, schema_version, created_at) VALUES ('svc-future-aaaa', 'sqlite', 99, 't')`,
+	}
+	for _, stmt := range stmts {
+		if _, err := raw.Exec(stmt); err != nil {
+			t.Fatal(err)
+		}
+	}
+	raw.Close()
+	st, err := OpenIdentity("", dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer st.Close()
+	if err := st.VerifySystemIdentity("svc-future-aaaa", "sqlite"); err != nil {
+		t.Fatal(err)
+	}
+	ver, err := st.SchemaVersion()
+	if err != nil || ver != 99 {
+		t.Fatalf("schema=%d err=%v，身份打开不得改写迁移版本", ver, err)
+	}
+	if cols := identityColumnNames(t, st.DB()); cols != IdentityColumns {
+		t.Fatalf("列=%s", cols)
+	}
+}
+
+func TestOpenIdentityMissingFileOrTable(t *testing.T) {
+	dir := t.TempDir()
+	if _, err := OpenIdentity("", filepath.Join(dir, "missing")); !errors.Is(err, ErrIdentityDBMissing) {
+		t.Fatalf("缺文件：%v", err)
+	}
+	if _, err := os.Stat(filepath.Join(dir, "missing")); !os.IsNotExist(err) {
+		t.Fatal("缺库时创建了目录")
+	}
+	path := filepath.Join(dir, "agent-system.db")
+	raw, err := sql.Open("sqlite", "file:"+path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := raw.Exec(`CREATE TABLE schema_migrations (version INTEGER PRIMARY KEY, name TEXT NOT NULL, applied_at TEXT NOT NULL)`); err != nil {
+		t.Fatal(err)
+	}
+	raw.Close()
+	parent := filepath.Dir(path)
+	if _, err := OpenIdentity("", parent); !errors.Is(err, ErrIdentityTableMissing) {
+		t.Fatalf("缺表：%v", err)
+	}
+}
+
+func identityColumnNames(t *testing.T, db *sql.DB) string {
+	t.Helper()
+	rows, err := db.Query(`SELECT name FROM pragma_table_info('agent_system_identity') ORDER BY cid`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rows.Close()
+	var names []string
+	for rows.Next() {
+		var name string
+		if err := rows.Scan(&name); err != nil {
+			t.Fatal(err)
+		}
+		names = append(names, name)
+	}
+	return strings.Join(names, ",")
 }
diff --git a/pkg/identity/identity.go b/pkg/identity/identity.go
index 88324a2..76a4e92 100644
--- a/pkg/identity/identity.go
+++ b/pkg/identity/identity.go
@@ -1,26 +1,91 @@
 // Package identity 提供服务实例库内身份子命令的公共 CLI（U1 I3：
 // manifest.instance_id ↔ agent_system_identity 表）。
-// 独立可导出包：下游组合仓（Agent-System-RDM 等）与基座二进制共用同一实现，
-// identity 语义跨产物一致。契约（2026-10-12 rdm1/rdmcand 事故后确立）：
-//   - 无参/未知子命令打印用法并以非零码退出，绝不落入服务启动路径——
-//     部署侧能力探测必须无副作用；
-//   - `identity capabilities` 输出版本化能力清单，供探测优先消费。
+// 独立可导出包：下游组合仓（Agent-System-RDM 等）与基座二进制共用同一实现。
+// 契约：无参/未知子命令打印用法并以非零码退出；只打开既有库，不建库、不迁移。
 package identity
 
 import (
+	"encoding/json"
 	"flag"
 	"fmt"
+	"io"
 	"os"
+	"runtime/debug"
+	"strings"
 
 	"agent-system-backend/internal/app"
+	"agent-system-backend/internal/store"
 )
 
 // Usage 无参/未知子命令时打印到 stderr 的用法行。探测契约：同时含 "identity"
-// 与 "ensure" 字样（svc.sh svc_bin_has_identity 按 usage 形态判有能力）。
-const Usage = "用法：identity <ensure|verify|capabilities> --instance-id ID [--dbref REF] [--data DIR] [--dsn DSN]"
+// 与 "ensure" 字样（旧 svc 探测仍按 usage 形态判有能力）。
+const Usage = "用法：identity <ensure|verify|capabilities> --instance-id ID [--dbref REF] [--data DIR] [--dsn-file FILE]"
 
-// Capabilities 版本化能力输出（新增子命令在此登记并递增 vN）。
-const Capabilities = "identity-capabilities: v1 ensure,verify"
+// Product 写入能力文档的产品名。组合仓在调用 Run 前改成自己的名字。
+var Product = "agent-system"
+
+// Document 是 version --json 与 identity capabilities 共用的能力文档。
+type Document struct {
+	Protocol int          `json:"protocol"`
+	Product  string       `json:"product"`
+	Version  string       `json:"version"`
+	Identity IdentityCaps `json:"identity"`
+	CLI      CLICaps      `json:"cli"`
+	Schema   *SchemaCaps  `json:"schema,omitempty"`
+}
+
+// IdentityCaps 描述身份子命令的打开方式。
+type IdentityCaps struct {
+	Ops  []string `json:"ops"`
+	Open string   `json:"open"`
+	DSN  string   `json:"dsn"`
+}
+
+// CLICaps 描述未知子命令的行为。
+type CLICaps struct {
+	UnknownSubcommand string `json:"unknownSubcommand"`
+}
+
+// SchemaCaps 由 D2 填入。零值时从 JSON 省略。
+type SchemaCaps struct {
+	Target      int `json:"target"`
+	CompatFloor int `json:"compatFloor"`
+}
+
+// NewDocument 构造当前进程的能力文档。
+func NewDocument(product, version string) Document {
+	if product == "" {
+		product = Product
+	}
+	if version == "" {
+		version = binaryVersion()
+	}
+	return Document{
+		Protocol: 1,
+		Product:  product,
+		Version:  version,
+		Identity: IdentityCaps{Ops: []string{"ensure", "verify"}, Open: "existing-no-migrate", DSN: "env"},
+		CLI:      CLICaps{UnknownSubcommand: "reject"},
+		Schema:   &SchemaCaps{Target: store.SchemaTarget(), CompatFloor: store.SchemaCompatFloor()},
+	}
+}
+
+// WriteDocument 把能力文档写成一行 JSON。
+func WriteDocument(w io.Writer, product, version string) error {
+	raw, err := json.Marshal(NewDocument(product, version))
+	if err != nil {
+		return err
+	}
+	_, err = fmt.Fprintf(w, "%s\n", raw)
+	return err
+}
+
+func binaryVersion() string {
+	if bi, ok := debug.ReadBuildInfo(); ok && bi.Main.Version != "" && bi.Main.Version != "(devel)" {
+		return bi.Main.Version
+	}
+	return "(devel)"
+}
 
 // Run 执行 identity 子命令；args 不含 "identity" 自身，返回进程退出码。
 func Run(args []string) int {
@@ -30,27 +95,36 @@ func Run(args []string) int {
 	}
 	sub := args[0]
 	if sub == "capabilities" {
-		fmt.Println(Capabilities)
+		if err := WriteDocument(os.Stdout, Product, ""); err != nil {
+			fmt.Fprintln(os.Stderr, "identity capabilities:", err)
+			return 1
+		}
 		return 0
 	}
-	fs := flag.NewFlagSet("identity "+sub, flag.ExitOnError)
+	fs := flag.NewFlagSet("identity "+sub, flag.ContinueOnError)
+	fs.SetOutput(io.Discard)
 	data := fs.String("data", "./data", "数据目录（SQLite 路径 <data>/agent-system.db）")
-	dsn := fs.String("dsn", "", "PostgreSQL 档 DSN（空 = 嵌入式 SQLite；亦可用环境 AGENT_SYSTEM_DSN 交付——凭据不进命令行）")
-	instanceID := fs.String("instance-id", "", "服务实例 ID（manifest.instance_id，形如 svc-<group>-…）")
+	dsnFlag := fs.String("dsn", "", "PostgreSQL DSN（会进入进程参数；优先用环境变量或 --dsn-file）")
+	dsnFile := fs.String("dsn-file", "", "权限恰好 0600 的 DSN 文件")
+	instanceID := fs.String("instance-id", "", "服务实例 ID（manifest.instance_id）")
 	dbref := fs.String("dbref", "", "数据库锚点（空 = sqlite 或 pg）")
-	fs.Parse(args[1:])
-	// DSN 交付纪律（G1-7 同源）：调用方（svc.sh）经 AGENT_SYSTEM_DSN 环境交付，
-	// 命令行对同机任何进程可见——显式 --dsn 仍最高优先，其次环境，最后嵌入式。
-	if *dsn == "" {
-		*dsn = os.Getenv("AGENT_SYSTEM_DSN")
+	if err := fs.Parse(args[1:]); err != nil {
+		fmt.Fprintln(os.Stderr, "identity:", err)
+		fmt.Fprintln(os.Stderr, Usage)
+		return 2
 	}
 	if *instanceID == "" {
 		fmt.Fprintln(os.Stderr, "identity: --instance-id 必填")
 		return 2
 	}
+	dsn, err := ResolveDSN(*dsnFlag, *dsnFile)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "identity:", err)
+		return 2
+	}
 	ref := *dbref
 	if ref == "" {
-		if *dsn != "" {
+		if dsn != "" {
 			ref = "pg"
 		} else {
 			ref = "sqlite"
@@ -58,18 +132,19 @@ func Run(args []string) int {
 	}
 	switch sub {
 	case "ensure":
-		if err := app.EnsureSystemIdentity(*dsn, *data, *instanceID, ref); err != nil {
+		if err := app.EnsureSystemIdentity(dsn, *data, *instanceID, ref); err != nil {
 			fmt.Fprintln(os.Stderr, "identity ensure:", err)
 			return 1
 		}
 		fmt.Printf("ensured instance_id=%s dbref=%s\n", *instanceID, ref)
 		return 0
 	case "verify":
-		if err := app.VerifySystemIdentity(*dsn, *data, *instanceID, ref); err != nil {
+		ver, err := app.VerifySystemIdentity(dsn, *data, *instanceID, ref)
+		if err != nil {
 			fmt.Fprintln(os.Stderr, "identity verify:", err)
 			return 1
 		}
-		fmt.Printf("verified instance_id=%s dbref=%s\n", *instanceID, ref)
+		fmt.Printf("verified instance_id=%s dbref=%s schema_version=%d\n", *instanceID, ref, ver)
 		return 0
 	default:
 		fmt.Fprintln(os.Stderr, "identity: 未知子命令", sub)
@@ -77,3 +152,36 @@ func Run(args []string) int {
 		return 2
 	}
 }
+
+// ResolveDSN 按 --dsn-file、环境变量、--dsn 的顺序取值。--dsn 会告警。
+// --dsn 与 --dsn-file 同时出现则拒绝。文件权限必须恰好 0600，且不能是符号链接。
+func ResolveDSN(flagDSN, flagFile string) (string, error) {
+	if flagDSN != "" && flagFile != "" {
+		return "", fmt.Errorf("--dsn 与 --dsn-file 只能选一个")
+	}
+	if flagFile != "" {
+		st, err := os.Lstat(flagFile)
+		if err != nil {
+			return "", err
+		}
+		if st.Mode()&os.ModeSymlink != 0 {
+			return "", fmt.Errorf("--dsn-file 不能是符号链接")
+		}
+		if st.Mode().Perm() != 0o600 {
+			return "", fmt.Errorf("--dsn-file 权限必须为 0600（当前 %o）", st.Mode().Perm())
+		}
+		raw, err := os.ReadFile(flagFile)
+		if err != nil {
+			return "", err
+		}
+		return strings.TrimSpace(string(raw)), nil
+	}
+	if env := strings.TrimSpace(os.Getenv("AGENT_SYSTEM_DSN")); env != "" && flagDSN == "" {
+		return env, nil
+	}
+	if flagDSN != "" {
+		fmt.Fprintln(os.Stderr, "identity: 警告：--dsn 会进入进程参数，请改用 AGENT_SYSTEM_DSN 或 --dsn-file")
+		return flagDSN, nil
+	}
+	return "", nil
+}
diff --git a/pkg/identity/identity_test.go b/pkg/identity/identity_test.go
index 2d14dd6..81a238f 100644
--- a/pkg/identity/identity_test.go
+++ b/pkg/identity/identity_test.go
@@ -1,11 +1,14 @@
 package identity
 
 import (
+	"encoding/json"
 	"io"
 	"os"
 	"path/filepath"
 	"strings"
 	"testing"
+
+	"agent-system-backend/internal/store"
 )
 
 // capture 把 stdout/stderr 重定向到管道并在 fn 返回后给出捕获文本。
@@ -51,21 +54,60 @@ func TestUsageAndUnknownExitWithoutServe(t *testing.T) {
 
 func TestCapabilities(t *testing.T) {
 	out, _ := capture(t, func() { Run([]string{"capabilities"}) })
-	if !strings.HasPrefix(out, "identity-capabilities: v1") ||
-		!strings.Contains(out, "ensure") || !strings.Contains(out, "verify") {
-		t.Fatalf("capabilities 输出异常：%q", out)
+	var doc Document
+	if err := json.Unmarshal([]byte(strings.TrimSpace(out)), &doc); err != nil {
+		t.Fatalf("capabilities 不是 JSON：%v %q", err, out)
+	}
+	if doc.Protocol != 1 || doc.Identity.Open != "existing-no-migrate" || doc.CLI.UnknownSubcommand != "reject" {
+		t.Fatalf("能力文档异常：%+v", doc)
+	}
+	if doc.Schema == nil || doc.Schema.Target != store.SchemaTarget() || doc.Schema.CompatFloor != store.SchemaCompatFloor() {
+		t.Fatalf("schema 能力异常：%+v", doc.Schema)
 	}
 }
 
-func TestEnsureVerifyRoundTripSQLite(t *testing.T) {
+func migratedData(t *testing.T) (string, int) {
+	t.Helper()
 	dir := t.TempDir()
-	args := []string{"--data", filepath.Join(dir, "d1")}
+	data := filepath.Join(dir, "data")
+	st, err := store.OpenSQLite(filepath.Join(data, "agent-system.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	ver, err := st.SchemaVersion()
+	if err != nil {
+		t.Fatal(err)
+	}
+	st.Close()
+	return data, ver
+}
+
+func TestEnsureVerifyRoundTripSQLite(t *testing.T) {
+	data, before := migratedData(t)
+	args := []string{"--data", data}
 	id := "svc-t1-abcdef123456"
 	if rc := Run(append([]string{"ensure", "--instance-id", id}, args...)); rc != 0 {
 		t.Fatalf("ensure rc=%d", rc)
 	}
-	if rc := Run(append([]string{"verify", "--instance-id", id}, args...)); rc != 0 {
-		t.Fatalf("verify rc=%d", rc)
+	out, _ := capture(t, func() {
+		if rc := Run(append([]string{"verify", "--instance-id", id}, args...)); rc != 0 {
+			t.Fatalf("verify rc=%d", rc)
+		}
+	})
+	if !strings.Contains(out, "schema_version=") {
+		t.Fatalf("verify 未带 schema_version：%q", out)
+	}
+	st, err := store.OpenIdentity("", data)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer st.Close()
+	after, err := st.SchemaVersion()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if after != before {
+		t.Fatalf("身份命令改变了 schema：%d → %d", before, after)
 	}
 	if rc := Run(append([]string{"verify", "--instance-id", "svc-t1-zzzzzz999999"}, args...)); rc != 1 {
 		t.Fatalf("错 id 须 rc=1，得 %d", rc)
@@ -75,17 +117,57 @@ func TestEnsureVerifyRoundTripSQLite(t *testing.T) {
 	}
 }
 
-// DSN 交付纪律：AGENT_SYSTEM_DSN 环境回退生效（凭据不进命令行）。
-func TestDSNEnvFallback(t *testing.T) {
-	t.Setenv("AGENT_SYSTEM_DSN", "")
-	// 环境置位时空 --dsn 生效口径由真 PG 专项验证；此处仅验证不干扰 SQLite 路径
-	//（环境为空 → 仍走嵌入式）与 flag 优先级不回归。
+func TestVerifyMissingDBCreatesNothing(t *testing.T) {
 	dir := t.TempDir()
-	id := "svc-dsnenv-abcdef123456"
-	if rc := Run([]string{"ensure", "--instance-id", id, "--data", dir}); rc != 0 {
-		t.Fatalf("ensure rc=%d", rc)
+	missing := filepath.Join(dir, "absent")
+	if rc := Run([]string{"verify", "--instance-id", "svc-missing-aaaa", "--data", missing}); rc == 0 {
+		t.Fatal("缺库不应成功")
 	}
-	if rc := Run([]string{"verify", "--instance-id", id, "--data", dir}); rc != 0 {
+	if _, err := os.Stat(missing); !os.IsNotExist(err) {
+		t.Fatalf("缺库路径被创建：%v", err)
+	}
+	if _, err := os.Stat(filepath.Join(missing, "agent-system.db")); !os.IsNotExist(err) {
+		t.Fatal("缺库时创建了数据库文件")
+	}
+}
+
+func TestDSNFileMode(t *testing.T) {
+	dir := t.TempDir()
+	good := filepath.Join(dir, "dsn")
+	if err := os.WriteFile(good, []byte("postgres://example\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	got, err := ResolveDSN("", good)
+	if err != nil || got != "postgres://example" {
+		t.Fatalf("0600 文件：%q %v", got, err)
+	}
+	loose := filepath.Join(dir, "loose")
+	if err := os.WriteFile(loose, []byte("postgres://x"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := ResolveDSN("", loose); err == nil {
+		t.Fatal("0644 的 dsn 文件必须拒绝")
+	}
+	_, errS := capture(t, func() { ResolveDSN("postgres://flag", "") })
+	if !strings.Contains(errS, "警告") {
+		t.Fatalf("--dsn 应告警：%q", errS)
+	}
+}
+
+// DSN 交付纪律：空的 AGENT_SYSTEM_DSN 不干扰已有 SQLite 库。
+func TestDSNEnvFallback(t *testing.T) {
+	t.Setenv("AGENT_SYSTEM_DSN", "")
+	data, _ := migratedData(t)
+	id := "svc-dsnenv-abcdef123456"
+	if rc := Run([]string{"ensure", "--instance-id", id, "--data", data}); rc != 0 {
+		t.Fatalf("ensure rc=%d", rc)
+	}
+	if rc := Run([]string{"verify", "--instance-id", id, "--data", data}); rc != 0 {
 		t.Fatalf("verify rc=%d", rc)
+	}
+	t.Setenv("AGENT_SYSTEM_DSN", "postgres://from-env")
+	got, err := ResolveDSN("", "")
+	if err != nil || got != "postgres://from-env" {
+		t.Fatalf("环境 DSN：%q %v", got, err)
 	}
 }