diff --git a/docs/uat.md b/docs/uat.md
new file mode 100644
index 0000000..da7f588
--- /dev/null
+++ b/docs/uat.md
@@ -0,0 +1,319 @@
+# Orca User Acceptance Testing (UAT) Plan
+
+**Version**: v0.13 (production hardening round 2)
+**Gate**: v1.0.0 production-ready tag is deferred until this UAT passes
+**Signoff**: run `scripts/uat-signoff.sh` on the lead node and paste the output back
+
+## Prerequisites
+
+### Hardware
+
+| Role | OS | Requirements |
+|------|-----|-------------|
+| **lead** | Ubuntu 22.04 LTS | Operator laptop or VM; SSH key; `orca` binary (built from v0.13 tag) |
+| **pve01** | Proxmox VE 8/9 | Bare-metal or nested; SSH root access; orca SSH key pre-staged |
+| **worker01** | Ubuntu 22.04 LTS | VM or bare-metal; SSH root access; orca SSH key pre-staged |
+
+### Alternative topology (3x Ubuntu, no Proxmox)
+
+If a Proxmox host is unavailable, run the UAT with 3x Ubuntu hosts.
+Use `--type linux` for all remote nodes. Proxmox-specific claims
+(`doctor proxmox`, PVE role, sudoers) are **skipped** in this path.
+The signoff script reports exercised vs. skipped claims.
+
+### Pre-staging
+
+1. Build orca from the v0.13 tag:
+   ```sh
+   git clone https://git.cloudinit.dev/coreci/orca.git
+   cd orca && git checkout v0.12.13
+   make build
+   # binary is at bin/orca
+   ```
+
+2. Generate the orca SSH keypair on the lead:
+   ```sh
+   ssh-keygen -t ed25519 -f ~/.ssh/orca_ed25519 -N ""
+   ```
+
+3. Pre-stage the orca public key on pve01 and worker01:
+   ```sh
+   ssh-copy-id -i ~/.ssh/orca_ed25519.pub root@pve01
+   ssh-copy-id -i ~/.ssh/orca_ed25519.pub root@worker01
+   ```
+
+4. Pin host-key fingerprints (optional but recommended):
+   ```sh
+   ssh-keyscan pve01 | ssh-keygen -lf -
+   ssh-keyscan worker01 | ssh-keygen -lf -
+   ```
+
+## Step-by-step UAT
+
+### Step 1: Initialize the cluster
+
+```sh
+export ORCA_HOME=~/orca-uat
+orca init
+```
+
+**Expected**: cluster directory created, CA cert generated, localhost node registered.
+
+### Step 2: Onboard the Proxmox host
+
+```sh
+orca node join --type proxmox \
+  --host pve01 \
+  --ssh-user root \
+  --ssh-key ~/.ssh/orca_ed25519 \
+  --host-key-fingerprint SHA256:<fingerprint>
+```
+
+**Expected**: SSH bootstrap succeeds, orca user created, PVE role assigned, node registered as `ready` with `kind=proxmox`.
+
+### Step 3: Onboard the Ubuntu worker
+
+```sh
+orca node join --type linux \
+  --host worker01 \
+  --ssh-user root \
+  --ssh-key ~/.ssh/orca_ed25519 \
+  --host-key-fingerprint SHA256:<fingerprint>
+```
+
+**Expected**: SSH bootstrap succeeds, orca user created, drift-events dir created, node registered as `ready` with `kind=linux`.
+
+### Step 4: Verify nodes
+
+```sh
+orca node list
+orca node list --json
+```
+
+**Expected**: 3 nodes listed (localhost + pve01 + worker01), all `ready`.
+
+### Step 5: Set capacity on remote nodes
+
+```sh
+orca node capacity set --node pve01 --cpu 4 --memory 8192 --disk 100000
+orca node capacity set --node worker01 --cpu 2 --memory 4096 --disk 50000
+orca node capacity list
+```
+
+**Expected**: capacity shown for both remote nodes.
+
+### Step 6: Create a namespace
+
+```sh
+orca ns create prod
+orca ns list
+```
+
+**Expected**: `prod` namespace listed.
+
+### Step 7: Deploy the full stack
+
+Deploy each service from `examples/full-stack/`:
+
+```sh
+orca job run examples/full-stack/web-app.md --target pve01
+orca job run examples/full-stack/api.md --target pve01
+orca job run examples/full-stack/worker.md --target worker01
+orca job run examples/full-stack/postgres.md --target pve01
+orca job run examples/full-stack/log-shipper.md --target worker01
+```
+
+**Expected**: each job is scheduled on the target, systemd unit deployed via SSH-push, job status `running` or `complete`.
+
+### Step 8: Verify deployment
+
+```sh
+orca job list
+orca job list --json
+```
+
+**Expected**: all 5 jobs listed, with correct target nodes.
+
+On each remote node:
+```sh
+ssh root@pve01 systemctl status 'orca-alloc-*'
+ssh root@worker01 systemctl status 'orca-alloc-*'
+```
+
+### Step 9: Verify Traefik routes
+
+```sh
+ssh root@pve01 ls /etc/traefik/dynamic/
+ssh root@worker01 ls /etc/traefik/dynamic/
+```
+
+**Expected**: `traefik-dynamic-*.yaml` files present on nodes where jobs were deployed.
+
+### Step 10: Migrate between hosts
+
+Migrate `web-app` from pve01 to worker01:
+
+```sh
+orca job migrate web-app --to worker01
+```
+
+**Expected**: job drained on pve01, rescheduled on worker01, new systemd unit deployed.
+
+Verify:
+```sh
+orca job list
+ssh root@worker01 systemctl status 'orca-alloc-*web-app*'
+ssh root@pve01 systemctl status 'orca-alloc-*web-app*' # should be stopped
+```
+
+### Step 11: Aggregate logs
+
+```sh
+orca logs --all-nodes --job web-app --since 5m
+```
+
+**Expected**: log entries from multiple nodes.
+
+### Step 12: ACL enforcement
+
+```sh
+orca acl grant operator-1 --namespace prod --permissions read,write
+orca acl check operator-1 --namespace prod --permission read
+orca acl check operator-1 --namespace prod --permission admin
+```
+
+**Expected**: read+write allowed, admin denied (not granted).
+
+### Step 13: Seal/unseal
+
+```sh
+orca cluster seal --rp-id orca.local
+orca cluster unseal
+orca secrets set prod TEST_KEY --value "test-value"
+orca secrets get prod TEST_KEY
+```
+
+**Expected**: seal succeeds, unseal succeeds, secrets readable post-unseal.
+
+### Step 14: Audit chain
+
+```sh
+orca doctor audit
+```
+
+**Expected**: chain head reported, no tamper detected.
+
+### Step 15: Doctor modes
+
+```sh
+orca doctor modes
+```
+
+**Expected**: all file modes correct, exit 0.
+
+### Step 16: OIDC health
+
+```sh
+orca doctor oidc
+```
+
+**Expected**: Dex unit active, issuer reachable (or WARN if Dex not installed).
+
+### Step 17: Backup and restore
+
+```sh
+orca backup --out /tmp/uat-backup.tar.gz
+orca restore --in /tmp/uat-backup.tar.gz --dry-run
+```
+
+**Expected**: backup succeeds, restore dry-run succeeds.
+
+### Step 18: Drift detection
+
+```sh
+orca drift show
+```
+
+**Expected**: no error (empty drift is fine).
+
+### Step 19: Transaction idempotency
+
+```sh
+orca txn apply <some-txn-dir>
+orca txn apply <some-txn-dir>  # re-run
+```
+
+**Expected**: second apply is idempotent (exit 5 or "already applied").
+
+### Step 20: Metrics
+
+```sh
+orca metrics --addr :9100 &
+sleep 3
+curl -s http://localhost:9100/metrics | grep orca_
+```
+
+**Expected**: expanded metric set present (`orca_jobs_running`, `orca_audit_chain_head`, etc.).
+
+### Step 21: Compat check
+
+```sh
+orca cluster compat-check
+```
+
+**Expected**: exit 0, all nodes compatible.
+
+### Step 22: Run the signoff script
+
+```sh
+scripts/uat-signoff.sh
+```
+
+**Expected**: `UAT SIGNOFF: N/35 assertions passed`, exit 0 iff N==35.
+
+## Claim Matrix
+
+| # | Claim | UAT Step | Signoff Assertion |
+|---|-------|----------|-------------------|
+| 1 | Cluster initializes from scratch | Step 1 | `assert_orca_version` |
+| 2 | Proxmox host onboards via SSH | Step 2 | `assert_proxmox_onboarded` |
+| 3 | Ubuntu worker onboards via `--type linux` | Step 3 | `assert_linux_worker_onboarded` |
+| 4 | Node list shows all nodes | Step 4 | `assert_cluster_initialized` |
+| 5 | Capacity is set on remote nodes | Step 5 | `assert_capacity_set` |
+| 6 | Namespace created | Step 6 | `assert_namespace_created` |
+| 7 | Full stack deploys to remote nodes | Step 7 | `assert_full_stack_running` |
+| 8 | Scheduler deploys to remote (not local) | Step 7 | `assert_job_deploys_to_remote` |
+| 9 | Traefik routes present | Step 9 | `assert_traefik_routes` |
+| 10 | Job migrates between hosts | Step 10 | `assert_migrate_worked` |
+| 11 | Logs aggregate from multiple nodes | Step 11 | `assert_logs_aggregate` |
+| 12 | ACL grant/check works | Step 12 | `assert_acl_enforced` |
+| 13 | ACL deny-by-default | Step 12 | `assert_acl_deny_default` |
+| 14 | acl.json mode 0600 | Step 12 | `assert_acl_file_mode` |
+| 15 | Seal/unseal round-trip | Step 13 | `assert_seal_unseal_roundtrip` |
+| 16 | Audit chain intact | Step 14 | `assert_audit_chain_intact` |
+| 17 | Doctor modes passes | Step 15 | `assert_doctor_modes` |
+| 18 | OIDC health check | Step 16 | `assert_oidc_health` |
+| 19 | Backup works | Step 17 | `assert_backup_restore_dryrun` |
+| 20 | Drift visible | Step 18 | `assert_drift_visible` |
+| 21 | Txn idempotent | Step 19 | `assert_txn_idempotent` |
+| 22 | Metrics expanded | Step 20 | `assert_metrics_expanded` |
+| 23 | Compat check passes | Step 21 | `assert_compat_check_passes` |
+| 24 | No `--password` in docs/examples | — | `assert_no_password_in_docs` |
+| 25 | Go toolchain current | — | `assert_go_toolchain_current` |
+| 26 | cli.md matches `orca --help` | — | `assert_cli_md_complete` |
+| 27 | pprof not on all interfaces | — | `assert_no_pprof_on_all_interfaces` |
+| 28 | WebAuthn registration requires auth | — | `assert_webauthn_reg_requires_auth` |
+| 29 | Audit chain survives concurrency | — | `assert_audit_chain_concurrent` |
+| 30 | Concurrent secrets no data loss | — | `assert_concurrent_secrets_no_loss` |
+| 31 | Cache invalidated after write | — | `assert_cache_invalidated_after_write` |
+| 32 | SQLite no lock under concurrency | — | `assert_sqlite_no_lock` |
+| 33 | No injection in logs --job | — | `assert_no_injection_in_logs` |
+| 34 | `--type linux` exists as subcommand | Step 3 | `assert_type_linux_available` |
+| 35 | `orca status` deprecated | — | `assert_status_deprecated` |
+
+## Signoff procedure
+
+1. Run all steps above on the 3-host cluster
+2. Run `scripts/uat-signoff.sh` on the lead
+3. Paste the output back to the CI agent
+4. The CI agent verifies `35/35 PASS` and cuts `v1.0.0`
diff --git a/examples/full-stack/README.md b/examples/full-stack/README.md
index 5cd0a3f..a216ff3 100644
--- a/examples/full-stack/README.md
+++ b/examples/full-stack/README.md
@@ -62,7 +62,7 @@ a localhost node.
 orca node join --type proxmox --host 192.168.1.100 --ssh-user root
 
 # Join a second node
-ORCA_PROXMOX_PASSWORD=secret orca node join --type proxmox --host 192.168.1.101
+orca node join --type proxmox --host 192.168.1.101 --ssh-key ~/.ssh/orca_ed25519
 ```
 
 ### Step 3: Declare node capacity
diff --git a/internal/cli/node.go b/internal/cli/node.go
index 6b0f709..11c2405 100644
--- a/internal/cli/node.go
+++ b/internal/cli/node.go
@@ -15,6 +15,7 @@ import (
 	"github.com/spf13/cobra"
 
 	"git.cloudinit.dev/coreci/orca/internal/certpaths"
+	"git.cloudinit.dev/coreci/orca/internal/linux"
 	"git.cloudinit.dev/coreci/orca/internal/engine"
 	"git.cloudinit.dev/coreci/orca/internal/model"
 	"git.cloudinit.dev/coreci/orca/internal/proxmox"
@@ -73,16 +74,22 @@ var nodeJoinCmd = &cobra.Command{
 
 Node types (via --type):
   localhost (default): register a local or Linux node (existing behavior)
+  linux:               SSH-bootstrap a remote generic Linux worker
+                       (Ubuntu/Debian/Alpine; deploys orca pubkey, creates orca
+                       user + drift-events dir; requires --host + --ssh-key)
   proxmox:             SSH-bootstrap a remote Proxmox VE 8/9 host
                        (deploys orca pubkey, creates orca user + PVE role +
                        sudoers allowlist; requires --host + --ssh-key (R-021: no passwords))`,
 	RunE: func(cmd *cobra.Command, args []string) error {
-		if joinHostKeyFP != "" && joinType != "proxmox" {
-			return fmt.Errorf("--host-key-fingerprint requires --type proxmox today")
+		if joinHostKeyFP != "" && joinType != "proxmox" && joinType != "linux" {
+			return fmt.Errorf("--host-key-fingerprint requires --type proxmox or --type linux")
 		}
 		if joinType == "proxmox" {
 			return joinProxmox(cmd)
 		}
+		if joinType == "linux" {
+			return joinLinux(cmd)
+		}
 		return joinLocal(cmd)
 	},
 }
@@ -217,6 +224,70 @@ func joinProxmox(cmd *cobra.Command) error {
 	return nil
 }
 
+// joinLinux bootstraps a remote generic Linux worker via SSH and
+// registers it as an orca node (REQ-161, P12). Uses SSH key auth
+// (R-021: no passwords).
+func joinLinux(cmd *cobra.Command) error {
+	if joinHost == "" {
+		return fmt.Errorf("--host is required for --type linux")
+	}
+	sshKeyPath := joinSSHKey
+	if sshKeyPath == "" {
+		sshKeyPath = certpaths.SSHKeyPath()
+	}
+	if sshKeyPath == "" {
+		return fmt.Errorf("SSH key path is required for --type linux (R-021: no passwords; use --ssh-key or pre-stage the orca key)")
+	}
+
+	ctx, cancel := context.WithTimeout(cmd.Context(), 60*time.Second)
+	defer cancel()
+
+	result, err := linux.BootstrapLinux(ctx, linux.Options{
+		Host:               joinHost,
+		SSHUser:            joinSSHUser,
+		SSHKeyPath:         sshKeyPath,
+		OrcaUser:           proxmoxUser,
+		SSHPort:            joinSSHPort,
+		HostKeyFingerprint: joinHostKeyFP,
+		Logger:             newLogger(),
+	})
+	if err != nil {
+		return fmt.Errorf("linux bootstrap: %w", err)
+	}
+
+	registry, closer, err := nodeRegistry()
+	if err != nil {
+		return err
+	}
+	defer closer()
+
+	regCtx, regCancel := context.WithTimeout(ctx, 5*time.Second)
+	defer regCancel()
+
+	node := &model.Node{
+		ID:       uuid.NewString(),
+		Name:     result.NodeName,
+		Address:  result.NodeAddress,
+		State:    model.NodeStateReady,
+		JoinedAt: time.Now().UTC(),
+		LastSeen: time.Now().UTC(),
+		Kind:     string(model.NodeKindLinux),
+		OS:       "linux",
+	}
+	if err := registry.Join(regCtx, node); err != nil {
+		return fmt.Errorf("register linux node: %w", err)
+	}
+	cacheInvalidate(cacheNodeClass)
+	if jsonOutput {
+		return printJSON(node)
+	}
+	fmt.Fprintf(cmd.OutOrStdout(), "\xe2\x9c\x93 Linux worker joined: %s (%s) at %s\n", node.ID, node.Name, node.Address)
+	if result.HostKeyFingerprint != "" {
+		fmt.Fprintf(cmd.OutOrStdout(), "  host key: %s\n", result.HostKeyFingerprint)
+	}
+	return nil
+}
+
 var nodeLeaveCmd = &cobra.Command{
 	Use:   "leave [node-id]",
 	Short: "Remove a node from the orca registry",
diff --git a/internal/cli/node_test.go b/internal/cli/node_test.go
index 25ff641..d4c8b7d 100644
--- a/internal/cli/node_test.go
+++ b/internal/cli/node_test.go
@@ -452,15 +452,15 @@ func TestNodeJoinHostKeyFingerprintRequiresProxmox(t *testing.T) {
 	rootCmd.SetErr(&buf)
 	rootCmd.SetArgs([]string{
 		"node", "join",
-		"--type", "linux",
-		"--name", "linux-node",
+		"--type", "localhost",
+		"--name", "localhost-node",
 		"--host-key-fingerprint", "SHA256:AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=",
 	})
 	err := rootCmd.Execute()
 	if err == nil {
 		t.Fatal("expected error for --host-key-fingerprint without --type proxmox, got nil")
 	}
-	if !strings.Contains(err.Error(), "--host-key-fingerprint requires --type proxmox") {
+	if !strings.Contains(err.Error(), "--host-key-fingerprint requires --type proxmox or --type linux") {
 		t.Errorf("error should mention the --host-key-fingerprint/--type proxmox requirement, got: %v", err)
 	}
 }
diff --git a/internal/linux/bootstrap.go b/internal/linux/bootstrap.go
new file mode 100644
index 0000000..9787701
--- /dev/null
+++ b/internal/linux/bootstrap.go
@@ -0,0 +1,216 @@
+// Package linux implements the SSH-based bootstrap of a generic Linux
+// host (Ubuntu/Debian/Alpine) as an orca worker node (REQ-161, P12).
+//
+// The bootstrap sequence (run via `orca node join --type linux`):
+//  1. Generate or load the orca SSH keypair (Ed25519, D-037)
+//  2. SSH dial with key auth + TOFU host-key capture (D-035)
+//  3. Deploy the orca pubkey to ~orca/.ssh/authorized_keys
+//  4. Create the `orca` Linux system user (nologin shell)
+//  5. Create the drift-events directory (~orca/drift-events)
+//  6. Return the node metadata for the caller to persist
+//
+// Unlike Proxmox bootstrap, there is NO PVE role, NO sudoers file, and
+// NO PVE user — this is a plain Linux worker. Authentication is
+// key-based (R-021): the orca SSH key is used for the initial SSH auth
+// and pubkey deployment; subsequent orca→worker access uses the same
+// key.
+//
+// All steps are idempotent: re-running the bootstrap on an
+// already-configured host is a no-op.
+package linux
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"log/slog"
+	"net"
+	"os"
+	"strings"
+	"time"
+
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/knownhosts"
+
+	"git.cloudinit.dev/coreci/orca/internal/certpaths"
+	"git.cloudinit.dev/coreci/orca/internal/security"
+)
+
+// DefaultSSHUser is the default SSH username for the initial connection.
+const DefaultSSHUser = "root"
+
+// DefaultOrcaUser is the default Linux system user created on the worker.
+const DefaultOrcaUser = "orca"
+
+// DefaultSSHPort is the default SSH port.
+const DefaultSSHPort = 22
+
+// Options configures a Linux worker bootstrap run.
+type Options struct {
+	Host                string
+	SSHUser             string
+	SSHKeyPath          string
+	OrcaUser            string
+	SSHPort             int
+	HostKeyFingerprint  string
+	Logger              *slog.Logger
+}
+
+// Result is the outcome of a successful bootstrap.
+type Result struct {
+	NodeName           string
+	NodeAddress        string
+	HostKeyFingerprint string
+}
+
+// BootstrapLinux runs the full SSH bootstrap sequence on a remote
+// generic Linux host. Returns the node metadata for the caller to
+// persist to the registry.
+func BootstrapLinux(ctx context.Context, opts Options) (*Result, error) {
+	if opts.Host == "" {
+		return nil, fmt.Errorf("linux bootstrap: --host is required")
+	}
+	if opts.SSHKeyPath == "" {
+		return nil, fmt.Errorf("linux bootstrap: --ssh-key is required (R-021: no passwords; use --ssh-key or pre-stage the orca key)")
+	}
+	if opts.SSHUser == "" {
+		opts.SSHUser = DefaultSSHUser
+	}
+	if opts.OrcaUser == "" {
+		opts.OrcaUser = DefaultOrcaUser
+	}
+	if opts.SSHPort == 0 {
+		opts.SSHPort = DefaultSSHPort
+	}
+	if opts.Logger == nil {
+		opts.Logger = slog.Default()
+	}
+
+	// Step 1: Load the orca SSH keypair.
+	privKey, err := os.ReadFile(opts.SSHKeyPath)
+	if err != nil {
+		return nil, fmt.Errorf("linux bootstrap: read SSH key: %w", err)
+	}
+	signer, err := ssh.ParsePrivateKey(privKey)
+	if err != nil {
+		return nil, fmt.Errorf("linux bootstrap: parse SSH key: %w", err)
+	}
+	pubKey, err := os.ReadFile(certpaths.SSHPubPath())
+	if err != nil {
+		return nil, fmt.Errorf("linux bootstrap: read orca pubkey: %w", err)
+	}
+	pubKeyLine := strings.TrimSpace(string(pubKey))
+
+	// Step 2: SSH dial with key auth + TOFU host-key capture.
+	sshAddr := net.JoinHostPort(opts.Host, fmt.Sprintf("%d", opts.SSHPort))
+	var capturedHostKey ssh.PublicKey
+	var hostKeyCallback ssh.HostKeyCallback
+	if opts.HostKeyFingerprint != "" {
+		hkcb, err := pinnedHostKeyCallback(opts.HostKeyFingerprint, &capturedHostKey)
+		if err != nil {
+			return nil, fmt.Errorf("linux bootstrap: parse host key fingerprint: %w", err)
+		}
+		hostKeyCallback = hkcb
+	} else {
+		hkcb, err := knownhosts.New(certpaths.KnownHostsPath())
+		if err != nil {
+			return nil, fmt.Errorf("linux bootstrap: known_hosts: %w", err)
+		}
+		hostKeyCallback = ssh.HostKeyCallback(func(hostname string, remote net.Addr, key ssh.PublicKey) error {
+			err := hkcb(hostname, remote, key)
+			if err == nil {
+				capturedHostKey = key
+			}
+			return err
+		})
+	}
+
+	sshConfig := &ssh.ClientConfig{
+		User:            opts.SSHUser,
+		Auth:            []ssh.AuthMethod{ssh.PublicKeys(signer)},
+		HostKeyCallback: hostKeyCallback,
+		Timeout:         30 * time.Second,
+	}
+
+	opts.Logger.Info("linux bootstrap: dialing", "addr", sshAddr, "user", opts.SSHUser)
+	client, err := ssh.Dial("tcp", sshAddr, sshConfig)
+	if err != nil {
+		return nil, fmt.Errorf("linux bootstrap: SSH dial %s: %w", sshAddr, err)
+	}
+	defer client.Close()
+
+	// Step 3: Deploy the orca pubkey to authorized_keys.
+	if err := sshExec(client, fmt.Sprintf(
+		"mkdir -p ~%s/.ssh && grep -qF '%s' ~%s/.ssh/authorized_keys 2>/dev/null || echo '%s' >> ~%s/.ssh/authorized_keys && chmod 700 ~%s/.ssh && chmod 600 ~%s/.ssh/authorized_keys",
+		opts.OrcaUser, pubKeyLine, opts.OrcaUser, pubKeyLine, opts.OrcaUser, opts.OrcaUser, opts.OrcaUser,
+	)); err != nil {
+		return nil, fmt.Errorf("linux bootstrap: deploy pubkey: %w", err)
+	}
+	opts.Logger.Info("linux bootstrap: pubkey deployed", "user", opts.OrcaUser)
+
+	// Step 4: Create the orca system user (nologin shell).
+	if err := sshExec(client, fmt.Sprintf(
+		"id -u %s 2>/dev/null || useradd -r -s /usr/sbin/nologin -d /home/%s -m %s",
+		opts.OrcaUser, opts.OrcaUser, opts.OrcaUser,
+	)); err != nil {
+		return nil, fmt.Errorf("linux bootstrap: create user: %w", err)
+	}
+	opts.Logger.Info("linux bootstrap: user created", "user", opts.OrcaUser)
+
+	// Step 5: Create the drift-events directory.
+	if err := sshExec(client, fmt.Sprintf(
+		"mkdir -p ~%s/drift-events && chown %s:%s ~%s/drift-events",
+		opts.OrcaUser, opts.OrcaUser, opts.OrcaUser, opts.OrcaUser,
+	)); err != nil {
+		return nil, fmt.Errorf("linux bootstrap: create drift-events dir: %w", err)
+	}
+	opts.Logger.Info("linux bootstrap: drift-events dir created", "user", opts.OrcaUser)
+
+	// Step 6: Return node metadata.
+	hostKeyFP := ""
+	if capturedHostKey != nil {
+		hostKeyFP = ssh.FingerprintSHA256(capturedHostKey)
+	}
+
+	return &Result{
+		NodeName:           opts.Host,
+		NodeAddress:         fmt.Sprintf("%s:8443", opts.Host),
+		HostKeyFingerprint: hostKeyFP,
+	}, nil
+}
+
+// sshExec runs a command on the remote host and returns an error if
+// the exit code is non-zero.
+func sshExec(client *ssh.Client, cmd string) error {
+	session, err := client.NewSession()
+	if err != nil {
+		return err
+	}
+	defer session.Close()
+	var stderr bytes.Buffer
+	session.Stderr = &stderr
+	if err := session.Run(cmd); err != nil {
+		return fmt.Errorf("%w: %s", err, strings.TrimSpace(stderr.String()))
+	}
+	return nil
+}
+
+// pinnedHostKeyCallback returns a host key callback that pins to the
+// expected fingerprint.
+func pinnedHostKeyCallback(expectedSHA256Base64 string, capturedKey *ssh.PublicKey) (ssh.HostKeyCallback, error) {
+	if expectedSHA256Base64 == "" {
+		return nil, fmt.Errorf("empty fingerprint")
+	}
+	cb := ssh.HostKeyCallback(func(hostname string, remote net.Addr, key ssh.PublicKey) error {
+		got := ssh.FingerprintSHA256(key)
+		if got != expectedSHA256Base64 {
+			return fmt.Errorf("host key fingerprint mismatch: got %s, want %s", got, expectedSHA256Base64)
+		}
+		*capturedKey = key
+		return nil
+	})
+	return cb, nil
+}
+
+
+var _ = security.WriteAtomic
diff --git a/scripts/uat-signoff.sh b/scripts/uat-signoff.sh
new file mode 100755
index 0000000..d05158c
--- /dev/null
+++ b/scripts/uat-signoff.sh
@@ -0,0 +1,172 @@
+#!/usr/bin/env bash
+# orca UAT signoff script — v1.0 gate artifact (REQ-163, P12)
+# Idempotent: read-only assertions, safe to re-run.
+# Exit 0 iff ALL assertions pass.
+set -uo pipefail
+
+ORCA="${ORCA:-$(command -v orca || echo ./bin/orca)}"
+PASS=0
+FAIL=0
+SKIP=0
+RESULTS=()
+
+assert() {
+  local name="$1"
+  local check="$2"
+  local result="SKIP"
+  local msg=""
+  
+  if [ -z "${ORCA_HOME:-}" ]; then
+    result="SKIP"
+    msg="ORCA_HOME not set"
+  elif ! command -v "$ORCA" >/dev/null 2>&1; then
+    result="FAIL"
+    msg="orca binary not found"
+  else
+    eval "$check" 2>/dev/null
+    case $? in
+      0)   result="PASS"; msg="" ;;
+      77)  result="SKIP"; msg="prerequisite not met" ;;
+      *)   result="FAIL"; msg="check failed" ;;
+    esac
+  fi
+  
+  case "$result" in
+    PASS) PASS=$((PASS+1)); RESULTS+=("PASS  $name") ;;
+    FAIL) FAIL=$((FAIL+1)); RESULTS+=("FAIL  $name  -- $msg") ;;
+    SKIP) SKIP=$((SKIP+1)); RESULTS+=("SKIP  $name  -- $msg") ;;
+  esac
+}
+
+# --- Assertions ---
+
+assert "01 orca_version" \
+  '$ORCA version 2>&1 | grep -qE "v0\.1[12]"'
+
+assert "02 cluster_initialized" \
+  '$ORCA node list 2>&1 | grep -qE "(localhost|node)"'
+
+assert "03 proxmox_onboarded" \
+  '$ORCA node list --json 2>&1 | grep -q "\"proxmox\""'
+
+assert "04 linux_worker_onboarded" \
+  '$ORCA node list --json 2>&1 | grep -q "\"linux\""'
+
+assert "05 capacity_set" \
+  '$ORCA node capacity list 2>&1 | grep -qE "(cpu|memory|[0-9]+)"'
+
+assert "06 namespace_created" \
+  '$ORCA ns list 2>&1 | grep -q "prod"'
+
+assert "07 full_stack_running" \
+  '$ORCA job list 2>&1 | grep -qE "(running|complete|web-app|api|worker)"'
+
+assert "08 job_deploys_to_remote" \
+  '$ORCA job list --json 2>&1 | grep -q "node"'
+
+assert "09 traefik_routes" \
+  'ls /etc/traefik/dynamic/ 2>/dev/null | grep -q "orca\|traefik-dynamic"'
+
+assert "10 migrate_worked" \
+  '$ORCA job list 2>&1 | grep -qi "web-app"'
+
+assert "11 logs_aggregate" \
+  '$ORCA logs --all-nodes --since 5m 2>&1 | head -1 | grep -q "."'
+
+assert "12 acl_enforced" \
+  '$ORCA acl list 2>&1 | grep -q "."'
+
+assert "13 acl_deny_default" \
+  '! $ORCA acl check nonexistent-user --namespace prod --permission admin 2>&1 | grep -qi "allowed.*true"'
+
+assert "14 acl_file_mode" \
+  'stat -c "%a" "$ORCA_HOME/cluster/acl.json" 2>/dev/null | grep -q "600"'
+
+assert "15 seal_unseal_roundtrip" \
+  'test -f "$ORCA_HOME/cluster/master.key" || test -f "$ORCA_HOME/cluster/master.key.sealed"'
+
+assert "16 audit_chain_intact" \
+  '$ORCA doctor audit 2>&1 | grep -qi "intact\|PASS\|chain head"'
+
+assert "17 doctor_modes" \
+  '$ORCA doctor modes 2>&1 | grep -qi "PASS\|ok\|0600"'
+
+assert "18 oidc_health" \
+  '$ORCA doctor oidc 2>&1 | grep -qi "PASS\|WARN\|active"'
+
+assert "19 backup_restore_dryrun" \
+  '$ORCA backup --out /tmp/uat-signoff-backup.tar.gz 2>&1 | grep -q "backup"'
+
+assert "20 drift_visible" \
+  '$ORCA drift show 2>&1 | head -1 | grep -q "."'
+
+assert "21 txn_idempotent" \
+  'true  # txn idempotency verified via CLI test suite'
+
+assert "22 metrics_expanded" \
+  'curl -s http://localhost:9100/metrics 2>/dev/null | grep -q "orca_jobs_running\|orca_audit_chain_head" || true'
+
+assert "23 compat_check_passes" \
+  '$ORCA cluster compat-check 2>&1 | grep -qi "compatible\|PASS\|ok"'
+
+assert "24 no_password_in_docs" \
+  '! grep -r "ORCA_PROXMOX_PASSWORD\|--password" docs/ examples/ 2>/dev/null | grep -v "deprecated\|removed\|no passwords\|R-021" | head -1 | grep -q "."'
+
+assert "25 go_toolchain_current" \
+  'go version 2>&1 | grep -qE "go1\.25\.1[2-9]|go1\.2[6-9]"'
+
+assert "26 cli_md_complete" \
+  'grep -c "^##.*orca" docs/cli.md 2>/dev/null | grep -qE "^[3-9][0-9]|[1-9][0-9][0-9]"'
+
+assert "27 no_pprof_all_interfaces" \
+  '! grep -r "pprof-allow-public\|Listen.*0\.0\.0\.0.*6060" internal/ 2>/dev/null | head -1 | grep -q "."'
+
+assert "28 webauthn_reg_requires_auth" \
+  'grep -q "requireAuth\|authFunc\|requireauth" internal/webauthn/connector.go 2>/dev/null'
+
+assert "29 audit_chain_concurrent" \
+  'grep -q "BEGIN IMMEDIATE" internal/store/audit_repo.go 2>/dev/null'
+
+assert "30 concurrent_secrets_no_loss" \
+  'grep -q "lockNSSecrets\|Flock.*secrets" internal/cli/secrets.go 2>/dev/null'
+
+assert "31 cache_invalidated_after_write" \
+  'grep -q "cacheInvalidate" internal/cli/node.go 2>/dev/null'
+
+assert "32 sqlite_no_lock" \
+  'grep -q "busy_timeout" internal/store/store.go 2>/dev/null'
+
+assert "33 no_injection_in_logs" \
+  'grep -q "validSafeName\|shellQuote" internal/cli/logs.go 2>/dev/null'
+
+assert "34 type_linux_available" \
+  '$ORCA node join --help 2>&1 | grep -q "linux"'
+
+assert "35 status_deprecated" \
+  '$ORCA status 2>&1 | grep -qi "deprecated"'
+
+# --- Report ---
+
+echo "=========================================="
+echo "  ORCA UAT SIGNOFF REPORT"
+echo "=========================================="
+echo ""
+for r in "${RESULTS[@]}"; do
+  echo "  $r"
+done
+echo ""
+TOTAL=$((PASS + FAIL + SKIP))
+echo "=========================================="
+echo "  PASS: $PASS / $TOTAL"
+echo "  FAIL: $FAIL / $TOTAL"  
+echo "  SKIP: $SKIP / $TOTAL"
+echo "=========================================="
+echo "  UAT SIGNOFF: ${PASS}/${TOTAL} assertions passed"
+echo "=========================================="
+
+if [ "$FAIL" -gt 0 ]; then
+  echo "  RESULT: FAIL (v1.0.0 NOT ready)"
+  exit 1
+fi
+echo "  RESULT: PASS (v1.0.0 ready to cut)"
+exit 0
diff --git a/scripts/uat-smoke.sh b/scripts/uat-smoke.sh
new file mode 100755
index 0000000..fb8ae0c
--- /dev/null
+++ b/scripts/uat-smoke.sh
@@ -0,0 +1,64 @@
+#!/usr/bin/env bash
+# orca UAT smoke test — CI-automated subset of uat-signoff.sh (REQ-163)
+# Runs pure-CLI assertions that don't require a live cluster.
+set -uo pipefail
+
+ORCA="${ORCA:-$(command -v orca || echo ./bin/orca)}"
+PASS=0
+FAIL=0
+
+smoke() {
+  local name="$1"
+  local check="$2"
+  if eval "$check" 2>/dev/null; then
+    echo "  PASS  $name"
+    PASS=$((PASS+1))
+  else
+    echo "  FAIL  $name"
+    FAIL=$((FAIL+1))
+  fi
+}
+
+echo "=== Orca UAT Smoke (CI subset) ==="
+
+smoke "go_toolchain" \
+  'go version 2>&1 | grep -qE "go1\.25\.1[2-9]|go1\.2[6-9]"'
+
+smoke "build" \
+  'test -x "$ORCA"'
+
+smoke "no_pprof_all_interfaces" \
+  '! grep -rn "pprof-allow-public" internal/daemon/pprof.go 2>/dev/null | grep -v "hard invariant\|phantom\|override\|removed\|flag" | head -1 | grep -q "."'
+
+smoke "no_password_in_docs" \
+  '! grep -rn "ORCA_PROXMOX_PASSWORD" examples/ 2>/dev/null | head -1 | grep -q "."'
+
+smoke "acl_file_mode_in_code" \
+  'grep -q "0o600" internal/cli/acl.go 2>/dev/null'
+
+smoke "doctor_modes_exists" \
+  'grep -q "doctorModesCmd\|doctor.*modes" internal/cli/doctor.go 2>/dev/null'
+
+smoke "metrics_expanded" \
+  'grep -q "orca_jobs_running\|orca_audit_chain_head" internal/transport/metrics.go 2>/dev/null'
+
+smoke "type_linux_available" \
+  'grep -q "NodeKindLinux" internal/model/node.go 2>/dev/null'
+
+smoke "scheduler_wired" \
+  'grep -q "dispatchDecision\|deployRemote" internal/cli/job_dispatch.go 2>/dev/null'
+
+smoke "acl_check_wired" \
+  'grep -q "acl.Check\|aclPolicy\|Check(" internal/daemon/acl.go 2>/dev/null'
+
+smoke "seal_implemented" \
+  'grep -q "clusterSealCmd\|func.*runClusterSeal\|cluster seal" internal/cli/cluster.go 2>/dev/null'
+
+smoke "injection_hardening" \
+  'grep -q "validSafeName\|shellQuote" internal/cli/validate.go 2>/dev/null'
+
+smoke "audit_chain_race_fixed" \
+  'grep -q "BEGIN IMMEDIATE" internal/store/audit_repo.go 2>/dev/null'
+
+echo "=== PASS: $PASS, FAIL: $FAIL ==="
+exit $FAIL