diff --git a/cmd/openfsd-client/gui/clients_test.go b/cmd/openfsd-client/gui/clients_test.go
index dd2ede3..3ceb272 100644
--- a/cmd/openfsd-client/gui/clients_test.go
+++ b/cmd/openfsd-client/gui/clients_test.go
@@ -14,13 +14,16 @@ func TestBuildClientSlots_WithDefaultAdapters(t *testing.T) {
 	}
 	slots := BuildClientSlots(eng.Adapters)
 	var enabled, coming int
-	var hasVPilot bool
+	var hasVPilot, hasXPilot bool
 	for _, s := range slots {
 		if s.Enabled {
 			enabled++
 			if s.ID == "vpilot" {
 				hasVPilot = true
 			}
+			if s.ID == "xpilot" {
+				hasXPilot = true
+			}
 			if strings.Contains(SlotLabel(s), "Coming soon") {
 				t.Fatalf("enabled slot labeled coming soon: %+v", s)
 			}
@@ -29,12 +32,18 @@ func TestBuildClientSlots_WithDefaultAdapters(t *testing.T) {
 			if !strings.Contains(SlotLabel(s), "Coming soon") {
 				t.Fatalf("disabled label: %q", SlotLabel(s))
 			}
+			if s.ID == "xpilot" {
+				t.Fatal("xpilot registered as adapter must not stay Coming soon")
+			}
 		}
 	}
 	if !hasVPilot {
 		t.Fatal("expected vpilot enabled")
 	}
-	if enabled < 1 || coming < 1 {
+	if !hasXPilot {
+		t.Fatal("expected xpilot enabled (adapter registered)")
+	}
+	if enabled < 2 || coming < 1 {
 		t.Fatalf("enabled=%d coming=%d slots=%d", enabled, coming, len(slots))
 	}
 }
diff --git a/cmd/openfsd-client/run.go b/cmd/openfsd-client/run.go
index 96a5117..592547d 100644
--- a/cmd/openfsd-client/run.go
+++ b/cmd/openfsd-client/run.go
@@ -15,6 +15,7 @@ import (
 	"github.com/renorris/openfsd/internal/clientinject"
 	"github.com/renorris/openfsd/internal/clientinject/adapters"
 	"github.com/renorris/openfsd/internal/clientinject/adapters/vpilot"
+	"github.com/renorris/openfsd/internal/clientinject/adapters/xpilot"
 )
 
 // Exit codes (design: docs/design/client-runtime-injector.md).
@@ -35,7 +36,7 @@ const usageText = `openfsd-client — openfsd Client Setup (GUI + headless CLI)
 Usage:
   openfsd-client                          Launch GUI when a display is available; else this help
   openfsd-client list-profiles
-  openfsd-client detect --client vpilot
+  openfsd-client detect --client vpilot|xpilot
   openfsd-client plan|apply|revert|health|launch [flags]
 
 Shared flags for plan|apply|health|launch:
@@ -44,10 +45,10 @@ Shared flags for plan|apply|health|launch:
   --fsd-port PORT         FSD TCP port (default 6809, omitted from server list when default)
   --fsd-server-name NAME  CachedServers label (default OPENFSD)
   --afv-base URL          AFV REST public base (optional)
-  --force-disable-afv     Always launch with -novoice
-  --prefer-short-jwt      Prefer short JWT paths (/j, /fsd-jwt, …) for #US budget
-  --install DIR           vPilot install directory (required when not auto-detected)
-  --client ID             Client adapter id (default vpilot)
+  --force-disable-afv     Always launch with -novoice (vPilot)
+  --prefer-short-jwt      Prefer short JWT paths (/j, /fsd-jwt, …) for #US budget (vPilot)
+  --install DIR           Client install directory (required when not auto-detected)
+  --client ID             Client adapter id (vpilot|xpilot; default vpilot)
   --profiles-dir DIR      Optional override profile directory (YAML)
 
 Launch-only flags:
@@ -58,12 +59,14 @@ Launch-only flags:
                           preserves relpath under temp (Phase 1 typically PE-only).
 
 Readiness honesty:
-  Default JWT path /api/v1/fsd-jwt allows max host 12 characters for in-place #US
-  patch (budget 35 runes). Use --prefer-short-jwt for /j (max host 25) if the
-  server has fixed short JWT routes (direct POST /j, not a 302 redirect).
+  vPilot: default JWT path /api/v1/fsd-jwt allows max host 12 characters for
+  in-place #US patch (budget 35 runes). Use --prefer-short-jwt for /j (max host
+  25) if the server has fixed short JWT routes (direct POST /j, not a 302).
   Long hostnames without short paths or free-slot remap are plan blockers.
   AFV PE ret-disable is out of scope until research gate R2; over-budget AFV
   falls back to -novoice.
+  xPilot 3.0.1: PE padded_string + LEA fixups for status.json + fsd-jwt; large
+  slot budgets; AFV not retargeted; unknown PE hashes refused.
 
 Exit codes:
   0 ok
@@ -410,11 +413,23 @@ func buildInstall(eng *clientinject.Engine, clientID, root string) clientinject.
 	switch clientID {
 	case "vpilot":
 		install = vpilot.InstallFromDir(root)
+	case "xpilot":
+		install = xpilot.InstallFromDir(root)
 	default:
+		// Fall back to profile primary binary name when available.
+		primary := "client.exe"
+		if eng != nil && eng.Profiles != nil {
+			for _, p := range eng.Profiles.ForClient(clientID) {
+				if p.PrimaryBinary.RelativePath != "" {
+					primary = p.PrimaryBinary.RelativePath
+					break
+				}
+			}
+		}
 		install = clientinject.Install{
 			ClientID:  clientID,
 			RootDir:   root,
-			PrimaryPE: filepath.Join(root, "vPilot.exe"),
+			PrimaryPE: filepath.Join(root, primary),
 		}
 	}
 	seedInstallFromManifest(eng, &install)
diff --git a/cmd/openfsd-client/run_test.go b/cmd/openfsd-client/run_test.go
index 2cfd63d..650d166 100644
--- a/cmd/openfsd-client/run_test.go
+++ b/cmd/openfsd-client/run_test.go
@@ -39,6 +39,9 @@ func TestRun_ListProfiles(t *testing.T) {
 	if !strings.Contains(out.String(), "vpilot-3.12.1") {
 		t.Fatalf("expected embedded profile: %s", out.String())
 	}
+	if !strings.Contains(out.String(), "xpilot-3.0.1") {
+		t.Fatalf("expected xpilot profile: %s", out.String())
+	}
 }
 
 func TestRun_PlanUsageMissingInstall(t *testing.T) {
diff --git a/docs/client-injector/research/xpilot.md b/docs/client-injector/research/xpilot.md
new file mode 100644
index 0000000..a029cd3
--- /dev/null
+++ b/docs/client-injector/research/xpilot.md
@@ -0,0 +1,112 @@
+# xPilot 3.0.1 — reverse-engineering research notes
+
+**Date:** 2026-07-28  
+**Client:** xPilot 3.0.1 (`xPilot.exe`)  
+**Legal posture:** Research notes + hashes only. **Never commit or redistribute** xPilot binaries. Users install from the official xPilot distribution.
+
+Tracked profile: `third_party/client-profiles/xpilot-3.0.1.yaml`  
+Embed plan profile: `internal/clientinject/profiles/xpilot-3.0.1.yaml`
+
+## Fingerprints
+
+| Artifact | SHA-1 |
+|----------|-------|
+| `xPilot.exe` (3.0.1) | `1ae61e1d4a624751124a49cd992c90f948c31d37` |
+
+Default install path (prior art): `C:\Program Files\xPilot\xPilot.exe`.
+
+**SHA-256 / installer size:** not recorded in prior art; leave blank until a maintainer re-hashes a user-owned install.
+
+## Stack
+
+- Native Windows PE64 (not CLR / not #US). Prior-art patches target `.text` / `.idata` / `.data` section VAs.
+- Built-in AFV voice path (separate from FSD). **Prior-art 3.0.1 patchfile does not retarget AFV** — openfsd AFV requires a future research pass or an external AFV client (TrackAudio, etc.).
+- Network surfaces of interest: status JSON URL, fsd-jwt URL, residual `fsd.vatsim.net` string.
+
+## Connection surfaces (what the 3.0.1 prior-art path redirects)
+
+| Surface | Stock role | openfsd target | Patch family |
+|---------|------------|----------------|--------------|
+| Network status | VATSIM status JSON | `https://{host}/api/v1/data/status.json` | padded_string (UTF-8) + LEA RIP + length imm |
+| FSD JWT auth | VATSIM fsd-jwt | `https://{host}/api/v1/fsd-jwt` | padded_string (UTF-16LE) + LEA RIP×2 + length imm×2 |
+| FSD auto host | `fsd.vatsim.net` (or related) | break / neutralise | raw_overwrite 3 bytes (`foo`) in `.idata` |
+| AFV REST | (not in prior art) | — | **out of scope** for 3.0.1 adapter |
+
+Unlike vPilot, there is **no obfuscated config XML** in the 3.0.1 path: server list comes from the retargeted status JSON feed.
+
+## Section map (3.0.1 prior art)
+
+| Section | Raw file offset | Virtual start |
+|---------|-----------------|---------------|
+| `.text` | `0x400` | `0x140001000` |
+| `.idata` | `0x01A5A200` | `0x141A5B000` |
+| `.data` | `0x027F9000` | `0x1427FA000` |
+
+File offset conversion (same as openfsd-client-patch-utility):
+
+```text
+file_offset = section.raw_offset + (section_address_va - section.virtual_start)
+```
+
+### Computed file offsets (ported)
+
+| Logical site | Section | VA | File offset |
+|--------------|---------|----|-------------|
+| status.json LEA RIP | `.text` | `0x140028D0E` | `0x2810E` |
+| status.json length imm | `.text` | `0x140028D07` | `0x28107` |
+| fsd-jwt LEA RIP (site 1) | `.text` | `0x140035BFE` | `0x34FFE` |
+| fsd-jwt length (site 1) | `.text` | `0x140035C0A` | `0x3500A` |
+| fsd-jwt LEA RIP (site 2) | `.text` | `0x14006BE08` | `0x6B208` |
+| fsd-jwt length (site 2) | `.text` | `0x14006BE14` | `0x6B214` |
+| break `fsd.vatsim.net` | `.idata` | `0x141CBF240` | `0x1CBE440` |
+| status.json string slot | `.idata` | `0x141AAF5AE` | `0x1AAE7AE` |
+| fsd-jwt string slot | `.idata` | `0x141A9662C` | `0x1A9582C` |
+
+### Slot budgets
+
+| Slot | Encoding | `available_bytes` | Notes |
+|------|----------|-------------------|-------|
+| status.json URL | UTF-8 (+ NUL pad) | `0x3B5` (949) | Length imm is **single byte** (max URL length 255) |
+| fsd-jwt URL | UTF-16LE (+ U+0000 pad) | `0x3B4` (948) | Length imm is **character count**, single byte |
+
+LEA RIP displacements in prior art point at the **relocated** `.idata` slots (not the stock string sites). They are **content-independent** for a fixed slot address. Length immediates **must** match the new URL length at Apply time.
+
+Example prior-art URLs (length reference only):
+
+- `https://yourfsdserver.com/api/v1/data/status.json` → length `49`
+- `https://yourfsdserver.com/api/v1/fsd-jwt` → length `40`
+
+## Prior art source
+
+| Repo / path | Role |
+|-------------|------|
+| `renorris/openfsd-client-patch-utility` `example_patchfiles/xpilot/xpilot-3.0.1.yaml` | Section overwrite + padded string patchfile for sum `1ae61e1d…` |
+| Same repo `patch/section_*.go` | VA→raw conversion + padded write semantics |
+| openfsd wiki `Client-Connection.md` | Points operators at that utility for xPilot |
+
+**This PR ports those offsets into schema v2 + `internal/clientinject` adapter.** Offsets were **derived** from the published prior-art YAML (VA + section map → file offset). They were **not re-verified against a live `xPilot.exe` binary in this environment** (binaries are never committed). The adapter **refuses** any PE whose SHA-1 ≠ profile stock.
+
+## Adapter strategy (openfsd Client Setup)
+
+1. **Discover** — `Program Files\xPilot`, `Program Files (x86)\xPilot`, Wine equivalents.
+2. **Verify** — primary PE SHA-1 must match profile (or stock bak after re-apply).
+3. **Plan / Apply** — `padded_string` for status + JWT; `raw_overwrite` for LEA RIP fixups, dynamic length bytes, and break-fsd; transactional `.openfsd-bak` via engine.
+4. **HealthCheck** — decode padded slots; assert URLs match planned endpoints; assert break site is not stock prefix when patched.
+5. **LaunchArgs** — empty (no documented xPilot CLI server override in prior art).
+6. **AFV** — warn only; not patched. Operators may set AFV base in an external client or await a future profile.
+
+## Honesty / known gaps
+
+- [ ] Re-hash a maintainer-owned 3.0.1 install; add SHA-256 + `size_bytes` when confirmed.
+- [ ] Confirm live connect path after status.json + fsd-jwt retarget (server list fields xPilot expects).
+- [ ] Inventory AFV / voice base URL sites in the same PE (and companion DLLs if any).
+- [ ] Confirm single-byte length immediates for non-ASCII hosts (openfsd URLs are ASCII).
+- [ ] Antivirus / code-signing interaction when rewriting signed `xPilot.exe`.
+- [ ] Newer xPilot versions need **new** version-pinned profiles — do not reuse 3.0.1 offsets.
+
+## Legal / product constraints
+
+- Do not redistribute xPilot or derivative binaries.
+- Track **hashes + profiles + research** in git only.
+- Product framing: **private openfsd networks** the operator is authorized to use.
+- Prefer reversible Apply/Revert; never delete user model/aircraft data outside the PE/config targets.
diff --git a/internal/clientinject/adapters/registry.go b/internal/clientinject/adapters/registry.go
index c62da05..a91782d 100644
--- a/internal/clientinject/adapters/registry.go
+++ b/internal/clientinject/adapters/registry.go
@@ -4,12 +4,14 @@ package adapters
 import (
 	"github.com/renorris/openfsd/internal/clientinject"
 	"github.com/renorris/openfsd/internal/clientinject/adapters/vpilot"
+	"github.com/renorris/openfsd/internal/clientinject/adapters/xpilot"
 )
 
-// DefaultAdapters returns the built-in client adapters (vPilot first).
+// DefaultAdapters returns the built-in client adapters (vPilot first, then xPilot).
 func DefaultAdapters() []clientinject.Adapter {
 	return []clientinject.Adapter{
 		vpilot.New(),
+		xpilot.New(),
 	}
 }
 
diff --git a/internal/clientinject/adapters/registry_test.go b/internal/clientinject/adapters/registry_test.go
index abdf968..2071b0d 100644
--- a/internal/clientinject/adapters/registry_test.go
+++ b/internal/clientinject/adapters/registry_test.go
@@ -6,12 +6,19 @@ import (
 
 func TestDefaultAdapters(t *testing.T) {
 	as := DefaultAdapters()
-	if len(as) == 0 {
-		t.Fatal("empty")
+	if len(as) < 2 {
+		t.Fatalf("want ≥2 adapters, got %d", len(as))
 	}
 	if as[0].ClientID() != "vpilot" {
 		t.Fatalf("got %q", as[0].ClientID())
 	}
+	ids := map[string]bool{}
+	for _, a := range as {
+		ids[a.ClientID()] = true
+	}
+	if !ids["vpilot"] || !ids["xpilot"] {
+		t.Fatalf("ids=%v", ids)
+	}
 }
 
 func TestDefaultEngine(t *testing.T) {
@@ -22,7 +29,17 @@ func TestDefaultEngine(t *testing.T) {
 	if eng.Adapters["vpilot"] == nil {
 		t.Fatal("missing vpilot")
 	}
+	if eng.Adapters["xpilot"] == nil {
+		t.Fatal("missing xpilot")
+	}
 	if _, ok := eng.Profiles.Get("vpilot-3.12.1"); !ok {
-		t.Fatal("missing profile")
+		t.Fatal("missing vpilot profile")
+	}
+	if _, ok := eng.Profiles.Get("xpilot-3.0.1"); !ok {
+		t.Fatal("missing xpilot profile")
+	}
+	// Multi-client: registry is not vPilot-only.
+	if len(eng.Adapters) < 2 {
+		t.Fatalf("adapters=%d", len(eng.Adapters))
 	}
 }
diff --git a/internal/clientinject/adapters/xpilot/adapter.go b/internal/clientinject/adapters/xpilot/adapter.go
new file mode 100644
index 0000000..94a5898
--- /dev/null
+++ b/internal/clientinject/adapters/xpilot/adapter.go
@@ -0,0 +1,273 @@
+// Package xpilot implements the clientinject.Adapter for xPilot 3.0.1.
+//
+// Strategy (prior art openfsd-client-patch-utility xpilot-3.0.1.yaml):
+// padded_string slots for status.json (UTF-8) and fsd-jwt (UTF-16LE),
+// raw_overwrite for LEA RIP fixups, dynamic length immediates, and a
+// break of residual fsd.vatsim.net. AFV retarget is out of scope until
+// research inventories voice base sites.
+//
+// Offsets are version-pinned by primary PE SHA-1; unknown hashes are refused.
+package xpilot
+
+import (
+	"context"
+	"crypto/sha1"
+	"encoding/hex"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"github.com/renorris/openfsd/internal/clientinject"
+)
+
+const (
+	clientID    = "xpilot"
+	displayName = "xPilot"
+	primaryName = "xPilot.exe"
+	profileID   = "xpilot-3.0.1"
+
+	// Single-byte length immediates in the 3.0.1 prior-art path.
+	maxLengthImm = 255
+)
+
+// Adapter is the xPilot client strategy.
+type Adapter struct {
+	// Writer is used by HealthCheck / Discover when non-nil; default OSFileWriter.
+	Writer clientinject.FileWriter
+	// Profiles overrides the embedded profile store (tests / --profiles-dir).
+	Profiles *clientinject.ProfileStore
+}
+
+// New returns an xPilot adapter.
+func New() *Adapter {
+	return &Adapter{}
+}
+
+// NewWithProfiles returns an adapter that resolves profiles from store.
+func NewWithProfiles(store *clientinject.ProfileStore) *Adapter {
+	return &Adapter{Profiles: store}
+}
+
+// ClientID implements clientinject.Adapter.
+func (a *Adapter) ClientID() string { return clientID }
+
+// DisplayName implements clientinject.Adapter.
+func (a *Adapter) DisplayName() string { return displayName }
+
+// SupportedProfiles implements clientinject.Adapter.
+func (a *Adapter) SupportedProfiles() []string {
+	return []string{profileID}
+}
+
+func (a *Adapter) writer() clientinject.FileWriter {
+	if a != nil && a.Writer != nil {
+		return a.Writer
+	}
+	return clientinject.OSFileWriter{}
+}
+
+// Discover looks for xPilot installs (Program Files + Wine prefixes).
+func (a *Adapter) Discover(ctx context.Context) ([]clientinject.InstallCandidate, error) {
+	_ = ctx
+	var cands []clientinject.InstallCandidate
+	seen := make(map[string]struct{})
+
+	add := func(root, hint string) {
+		root = filepath.Clean(root)
+		if root == "" || root == "." {
+			return
+		}
+		if _, ok := seen[root]; ok {
+			return
+		}
+		pe := filepath.Join(root, primaryName)
+		if _, err := a.writer().Stat(pe); err != nil {
+			return
+		}
+		seen[root] = struct{}{}
+		cands = append(cands, clientinject.InstallCandidate{
+			ClientID:    clientID,
+			RootDir:     root,
+			PrimaryPE:   pe,
+			ConfigPaths: nil,
+			DisplayHint: hint,
+		})
+	}
+
+	switch runtime.GOOS {
+	case "windows":
+		for _, env := range []string{"ProgramFiles", "ProgramFiles(x86)"} {
+			if base := os.Getenv(env); base != "" {
+				add(filepath.Join(base, "xPilot"), env+" install")
+			}
+		}
+		// Some installs may live under LocalAppData (defensive).
+		if local := os.Getenv("LOCALAPPDATA"); local != "" {
+			add(filepath.Join(local, "xPilot"), "LocalAppData install")
+		}
+	default:
+		home, _ := os.UserHomeDir()
+		if home != "" {
+			user := os.Getenv("USER")
+			if user == "" {
+				user = os.Getenv("USERNAME")
+			}
+			wineRoots := []string{
+				filepath.Join(home, ".wine", "drive_c", "Program Files", "xPilot"),
+				filepath.Join(home, ".wine", "drive_c", "Program Files (x86)", "xPilot"),
+			}
+			if user != "" {
+				wineRoots = append(wineRoots,
+					filepath.Join(home, ".wine", "drive_c", "users", user, "AppData", "Local", "xPilot"),
+				)
+			}
+			for _, r := range wineRoots {
+				add(r, "Wine install")
+			}
+		}
+	}
+	return cands, nil
+}
+
+// Verify checks primary PE SHA-1 against the profile (stock bak allowed post-Apply).
+func (a *Adapter) Verify(install clientinject.Install, profile *clientinject.Profile) error {
+	if profile == nil {
+		return fmt.Errorf("xpilot: nil profile")
+	}
+	if profile.ClientID != clientID {
+		return fmt.Errorf("xpilot: profile client_id %q is not xpilot", profile.ClientID)
+	}
+	pe := clientinject.AbsPrimaryPE(install)
+	if pe == "" {
+		return fmt.Errorf("xpilot: empty primary PE path")
+	}
+	w := a.writer()
+	data, err := w.ReadFile(pe)
+	if err != nil {
+		return fmt.Errorf("xpilot: read PE: %w", err)
+	}
+	sum := sha1.Sum(data)
+	got := hex.EncodeToString(sum[:])
+	want := strings.ToLower(strings.TrimSpace(profile.PrimaryBinary.SHA1))
+	if want == "" {
+		return fmt.Errorf("xpilot: profile has no primary_binary.sha1")
+	}
+	if !strings.EqualFold(got, want) {
+		bak := clientinject.BackupPath(pe)
+		if _, bakErr := w.Stat(bak); bakErr == nil {
+			if install.HashSHA1 != "" && strings.EqualFold(install.HashSHA1, want) {
+				return nil
+			}
+			if bakData, rerr := w.ReadFile(bak); rerr == nil {
+				bakSum := sha1.Sum(bakData)
+				if strings.EqualFold(hex.EncodeToString(bakSum[:]), want) {
+					return nil
+				}
+			}
+		}
+		return fmt.Errorf("xpilot: PE sha1 %s does not match profile %s (stock %s); refuse unknown hash",
+			got, profile.ProfileID, want)
+	}
+	if wantSize := profile.PrimaryBinary.SizeBytes; wantSize > 0 && int64(len(data)) != wantSize {
+		return fmt.Errorf("xpilot: PE size %d does not match profile %d", len(data), wantSize)
+	}
+	return nil
+}
+
+// EndpointConstraints returns slot budget hints from the profile.
+func (a *Adapter) EndpointConstraints(profile *clientinject.Profile) []clientinject.Constraint {
+	if profile == nil {
+		return nil
+	}
+	var out []clientinject.Constraint
+	if s, ok := profile.Strings["status_json"]; ok && s.PayloadBudgetBytes > 0 {
+		// UTF-8: budget is byte slot; max URL runes ≈ budget-1 (NUL).
+		maxRunes := s.PayloadBudgetBytes - 1
+		if maxRunes > maxLengthImm {
+			maxRunes = maxLengthImm
+		}
+		out = append(out, clientinject.Constraint{
+			Field:       "StatusJSONURL",
+			MaxRunes:    maxRunes,
+			Strategy:    "padded_string",
+			Description: fmt.Sprintf("UTF-8 padded slot %d bytes; length imm is 1 byte (max %d)", s.PayloadBudgetBytes, maxLengthImm),
+		})
+	}
+	if s, ok := profile.Strings["fsd_jwt"]; ok && s.PayloadBudgetBytes > 0 {
+		// UTF-16LE: encoded (runes+NUL)*2 must fit slot; length imm is char count ≤255.
+		maxRunes := (s.PayloadBudgetBytes / 2) - 1
+		if maxRunes > maxLengthImm {
+			maxRunes = maxLengthImm
+		}
+		out = append(out, clientinject.Constraint{
+			Field:       "JWTURL",
+			MaxRunes:    maxRunes,
+			Strategy:    "padded_string",
+			Description: fmt.Sprintf("UTF-16LE padded slot %d bytes (~%d runes); length imm max %d", s.PayloadBudgetBytes, maxRunes, maxLengthImm),
+		})
+	}
+	out = append(out, clientinject.Constraint{
+		Field:       "AFVBaseURL",
+		MaxRunes:    0,
+		Strategy:    "n/a",
+		Description: "xPilot 3.0.1 prior art does not retarget AFV; configure voice separately or await a future profile",
+	})
+	return out
+}
+
+// LaunchArgs returns CLI flags for launching the client (none known for 3.0.1).
+func (a *Adapter) LaunchArgs(install clientinject.Install, ep clientinject.Endpoints) []string {
+	_ = install
+	_ = ep
+	return nil
+}
+
+// InstallFromDir builds an Install for an explicit --install directory.
+func InstallFromDir(root string) clientinject.Install {
+	return New().InstallFromDir(root)
+}
+
+// InstallFromDir builds an Install using this adapter's FileWriter.
+func (a *Adapter) InstallFromDir(root string) clientinject.Install {
+	root = filepath.Clean(root)
+	return clientinject.Install{
+		ClientID:  clientID,
+		RootDir:   root,
+		PrimaryPE: filepath.Join(root, primaryName),
+	}
+}
+
+func (a *Adapter) loadProfileForInstall(install clientinject.Install) (*clientinject.Profile, error) {
+	var store *clientinject.ProfileStore
+	if a != nil && a.Profiles != nil {
+		store = a.Profiles
+	} else {
+		var err error
+		store, err = clientinject.LoadEmbedded()
+		if err != nil {
+			return nil, err
+		}
+	}
+	if install.ProfileID != "" {
+		if p, ok := store.Get(install.ProfileID); ok {
+			return p, nil
+		}
+	}
+	if install.HashSHA1 != "" {
+		if p, ok := store.LookupByHash(install.ClientID, install.HashSHA1); ok {
+			return p, nil
+		}
+	}
+	list := store.ForClient(clientID)
+	if len(list) == 0 {
+		return nil, fmt.Errorf("xpilot: no xpilot profiles loaded")
+	}
+	for _, p := range list {
+		if strings.HasPrefix(p.ProfileID, "xpilot") {
+			return p, nil
+		}
+	}
+	return list[0], nil
+}
diff --git a/internal/clientinject/adapters/xpilot/adapter_test.go b/internal/clientinject/adapters/xpilot/adapter_test.go
new file mode 100644
index 0000000..a555359
--- /dev/null
+++ b/internal/clientinject/adapters/xpilot/adapter_test.go
@@ -0,0 +1,384 @@
+package xpilot
+
+import (
+	"bytes"
+	"context"
+	"crypto/sha1"
+	"encoding/binary"
+	"encoding/hex"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"unicode/utf16"
+
+	"github.com/renorris/openfsd/internal/clientinject"
+	"github.com/renorris/openfsd/internal/clientinject/pepatch"
+)
+
+func sha1hex(b []byte) string {
+	s := sha1.Sum(b)
+	return hex.EncodeToString(s[:])
+}
+
+// Compact synthetic layout — not production offsets (those need ~30MB PE).
+const (
+	testStatusOff  = 0x100
+	testJWTOff     = 0x200
+	testStatusLEA  = 0x50
+	testStatusLen  = 0x54
+	testJWTLEA     = 0x58
+	testJWTLen     = 0x5C
+	testBreakOff   = 0x60
+	testStatusSlot = 64
+	testJWTSlot    = 80
+)
+
+func fo(v int64) *clientinject.FlexibleInt64 {
+	f := clientinject.FlexibleInt64(v)
+	return &f
+}
+
+func testProfile(pe []byte) *clientinject.Profile {
+	return &clientinject.Profile{
+		SchemaVersion:          2,
+		ProfileID:              "xpilot-test-synth",
+		ClientID:               clientID,
+		DisplayName:            "xPilot",
+		SupportedClientVersion: "3.0.1-test",
+		PrimaryBinary: clientinject.PrimaryBinarySpec{
+			RelativePath: primaryName,
+			SHA1:         sha1hex(pe),
+			SizeBytes:    int64(len(pe)),
+		},
+		Strings: map[string]clientinject.StringSpec{
+			"status_json": {PayloadBudgetBytes: testStatusSlot, Template: "{{.StatusJSONURL}}"},
+			"fsd_jwt":     {PayloadBudgetBytes: testJWTSlot, Template: "{{.JWTURL}}"},
+		},
+		Mutations: []clientinject.ProfileMutationSpec{
+			{
+				ID: "write_status_json", Kind: "padded_string", Description: "status",
+				FileOffset: fo(testStatusOff), AvailableBytes: fo(testStatusSlot),
+				Encoding: "utf8", EndpointKey: "status_json",
+			},
+			{
+				ID: "write_fsd_jwt", Kind: "padded_string", Description: "jwt",
+				FileOffset: fo(testJWTOff), AvailableBytes: fo(testJWTSlot),
+				Encoding: "utf16le", EndpointKey: "fsd_jwt",
+			},
+			{
+				ID: "patch_status_lea", Kind: "raw_overwrite", Description: "status lea",
+				FileOffset: fo(testStatusLEA), NewBytes: []byte{0x9C, 0x68, 0xA8, 0x01},
+			},
+			{
+				ID: "patch_status_len", Kind: "raw_overwrite", Description: "status len",
+				FileOffset: fo(testStatusLen), LengthOf: "status_json",
+			},
+			{
+				ID: "patch_jwt_lea", Kind: "raw_overwrite", Description: "jwt lea",
+				FileOffset: fo(testJWTLEA), NewBytes: []byte{0x2A, 0x0A, 0xA6, 0x01},
+			},
+			{
+				ID: "patch_jwt_len", Kind: "raw_overwrite", Description: "jwt len",
+				FileOffset: fo(testJWTLen), LengthOf: "fsd_jwt",
+			},
+			{
+				ID: "break_fsd", Kind: "raw_overwrite", Description: "break fsd",
+				FileOffset: fo(testBreakOff), NewBytes: []byte{0x66, 0x6F, 0x6F},
+			},
+		},
+	}
+}
+
+func buildSynthPE(t *testing.T) []byte {
+	t.Helper()
+	// Large enough for JWT slot end.
+	size := testJWTOff + testJWTSlot + 16
+	data := make([]byte, size)
+	// Stock-like placeholders.
+	copy(data[testStatusOff:], []byte("https://status.vatsim.net/old.json"))
+	u := utf16.Encode([]rune("https://auth.vatsim.net/api/fsd-jwt"))
+	for i, c := range u {
+		binary.LittleEndian.PutUint16(data[testJWTOff+i*2:], c)
+	}
+	// break site stock-ish
+	copy(data[testBreakOff:], []byte("fsd.vatsim.net"))
+	return data
+}
+
+func setupInstall(t *testing.T) (root string, pe []byte, install clientinject.Install, profile *clientinject.Profile, a *Adapter) {
+	t.Helper()
+	root = t.TempDir()
+	pe = buildSynthPE(t)
+	pePath := filepath.Join(root, primaryName)
+	if err := os.WriteFile(pePath, pe, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	profile = testProfile(pe)
+	store := clientinject.NewProfileStore()
+	if err := store.Add(profile); err != nil {
+		t.Fatal(err)
+	}
+	a = NewWithProfiles(store)
+	install = clientinject.Install{
+		ClientID:  clientID,
+		RootDir:   root,
+		PrimaryPE: pePath,
+		HashSHA1:  profile.PrimaryBinary.SHA1,
+		ProfileID: profile.ProfileID,
+	}
+	return root, pe, install, profile, a
+}
+
+func TestClientIDDisplay(t *testing.T) {
+	a := New()
+	if a.ClientID() != "xpilot" || a.DisplayName() != "xPilot" {
+		t.Fatal(a.ClientID(), a.DisplayName())
+	}
+	if len(a.SupportedProfiles()) != 1 || a.SupportedProfiles()[0] != profileID {
+		t.Fatalf("profiles=%v", a.SupportedProfiles())
+	}
+}
+
+func TestPlan_OK(t *testing.T) {
+	_, _, install, profile, a := setupInstall(t)
+	ep := clientinject.Endpoints{
+		WebBaseURL: "https://fsd.ex.co",
+		FSDHost:    "fsd.ex.co",
+	}
+	plan, err := a.Plan(install, profile, ep)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(plan.Blockers) != 0 {
+		t.Fatalf("blockers: %v", plan.Blockers)
+	}
+	var padded, raw int
+	for _, m := range plan.Mutations {
+		switch m.Kind {
+		case clientinject.MutPaddedString:
+			padded++
+		case clientinject.MutRawOverwrite:
+			raw++
+		}
+	}
+	if padded != 2 {
+		t.Fatalf("padded=%d", padded)
+	}
+	if raw < 4 {
+		t.Fatalf("raw=%d", raw)
+	}
+	// Dynamic length for status URL.
+	statusURL := ep.StatusJSONURL()
+	var sawLen bool
+	for _, m := range plan.Mutations {
+		if m.ID != "patch_status_len" {
+			continue
+		}
+		d, ok := rawDetail(m.Detail)
+		if !ok || len(d.NewBytes) != 1 {
+			t.Fatalf("detail=%+v", m.Detail)
+		}
+		if d.NewBytes[0] != byte(len([]rune(statusURL))) {
+			t.Fatalf("len byte=%d want %d", d.NewBytes[0], len([]rune(statusURL)))
+		}
+		sawLen = true
+	}
+	if !sawLen {
+		t.Fatal("missing status len mutation")
+	}
+}
+
+func TestPlan_MissingWebBaseBlocker(t *testing.T) {
+	_, _, install, profile, a := setupInstall(t)
+	plan, err := a.Plan(install, profile, clientinject.Endpoints{FSDHost: "x"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(plan.Blockers) == 0 {
+		t.Fatal("expected blockers")
+	}
+}
+
+func TestPlan_RefuseUnknownMutationKind(t *testing.T) {
+	_, _, install, profile, a := setupInstall(t)
+	profile.Mutations = append(profile.Mutations, clientinject.ProfileMutationSpec{
+		ID: "bad", Kind: "cil_us_string", FileOffset: fo(1),
+	})
+	plan, err := a.Plan(install, profile, clientinject.Endpoints{
+		WebBaseURL: "https://fsd.ex.co",
+		FSDHost:    "fsd.ex.co",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	found := false
+	for _, b := range plan.Blockers {
+		if strings.Contains(b, "unsupported kind") || strings.Contains(b, "cil_us_string") {
+			found = true
+		}
+	}
+	if !found {
+		t.Fatalf("blockers=%v", plan.Blockers)
+	}
+}
+
+func TestVerify_RefuseUnknownHash(t *testing.T) {
+	_, _, install, profile, a := setupInstall(t)
+	// Corrupt PE.
+	if err := os.WriteFile(install.PrimaryPE, []byte("not-the-pe"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	err := a.Verify(install, profile)
+	if err == nil || !strings.Contains(err.Error(), "refuse unknown hash") {
+		t.Fatalf("err=%v", err)
+	}
+}
+
+func TestApplyHealth_RoundTrip(t *testing.T) {
+	_, stock, install, profile, a := setupInstall(t)
+	ep := clientinject.Endpoints{
+		WebBaseURL: "https://fsd.ex.co",
+		FSDHost:    "fsd.ex.co",
+	}
+	plan, err := a.Plan(install, profile, ep)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(plan.Blockers) != 0 {
+		t.Fatalf("blockers: %v", plan.Blockers)
+	}
+	w := clientinject.OSFileWriter{}
+	if err := a.Apply(context.Background(), plan, w); err != nil {
+		t.Fatal(err)
+	}
+	if err := a.HealthCheck(install, ep); err != nil {
+		t.Fatal(err)
+	}
+	// Ensure stock was actually changed.
+	got, err := os.ReadFile(install.PrimaryPE)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if bytes.Equal(got, stock) {
+		t.Fatal("PE unchanged after apply")
+	}
+	// Status URL present as UTF-8.
+	status := ep.StatusJSONURL()
+	if !bytes.Contains(got[testStatusOff:testStatusOff+testStatusSlot], []byte(status)) {
+		t.Fatalf("status URL missing in slot")
+	}
+	// JWT as UTF-16LE.
+	u := utf16.Encode([]rune(ep.JWTURL()))
+	pat := make([]byte, len(u)*2)
+	for i, c := range u {
+		binary.LittleEndian.PutUint16(pat[i*2:], c)
+	}
+	if !bytes.Contains(got[testJWTOff:testJWTOff+testJWTSlot], pat) {
+		t.Fatal("jwt utf16 missing")
+	}
+	// Break site.
+	if !bytes.Equal(got[testBreakOff:testBreakOff+3], []byte("foo")) {
+		t.Fatalf("break=%q", got[testBreakOff:testBreakOff+3])
+	}
+}
+
+func TestEngine_ApplyRevert_WithXPilot(t *testing.T) {
+	root, stock, install, profile, a := setupInstall(t)
+	store := clientinject.NewProfileStore()
+	if err := store.Add(profile); err != nil {
+		t.Fatal(err)
+	}
+	eng := clientinject.NewEngine(store, a)
+	ep := clientinject.Endpoints{
+		WebBaseURL: "https://fsd.ex.co",
+		FSDHost:    "fsd.ex.co",
+	}
+	plan, err := eng.Plan(context.Background(), install, ep)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(plan.Blockers) != 0 {
+		t.Fatalf("blockers: %v", plan.Blockers)
+	}
+	res, err := eng.Apply(context.Background(), plan)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res.ManifestPath == "" {
+		t.Fatal("empty manifest")
+	}
+	// Health via engine already ran inside Apply.
+	got, _ := os.ReadFile(install.PrimaryPE)
+	if bytes.Equal(got, stock) {
+		t.Fatal("not patched")
+	}
+	if err := eng.Revert(context.Background(), root); err != nil {
+		t.Fatal(err)
+	}
+	restored, _ := os.ReadFile(install.PrimaryPE)
+	if !bytes.Equal(restored, stock) {
+		t.Fatal("revert did not restore stock PE")
+	}
+}
+
+func TestInstallFromDir(t *testing.T) {
+	inst := InstallFromDir("/tmp/xpilot-install")
+	if inst.ClientID != clientID {
+		t.Fatal(inst.ClientID)
+	}
+	if !strings.HasSuffix(inst.PrimaryPE, primaryName) {
+		t.Fatal(inst.PrimaryPE)
+	}
+}
+
+func TestDiscover_EmptyOnUnixWithoutWine(t *testing.T) {
+	// Should not error; may return empty.
+	cands, err := New().Discover(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	_ = cands
+}
+
+func TestPaddedString_pepatchEncodingParity(t *testing.T) {
+	// Sanity: pepatch accepts encodings used by profile.
+	var buf struct {
+		data []byte
+		pos  int64
+	}
+	buf.data = make([]byte, 32)
+	// Use a small WriteSeeker via temp file.
+	dir := t.TempDir()
+	path := filepath.Join(dir, "p.bin")
+	if err := os.WriteFile(path, make([]byte, 64), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	f, err := os.OpenFile(path, os.O_RDWR, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	if err := pepatch.PaddedStringOverwrite(f, 0, "https://x.test/j", 32, "utf8"); err != nil {
+		t.Fatal(err)
+	}
+	// UTF-16LE needs (runes+1)*2 bytes; use a short string that fits remaining 32.
+	if err := pepatch.PaddedStringOverwrite(f, 32, "https://x.t/j", 32, "utf16le"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestEndpointConstraints(t *testing.T) {
+	_, _, _, profile, a := setupInstall(t)
+	cs := a.EndpointConstraints(profile)
+	if len(cs) < 2 {
+		t.Fatalf("constraints=%v", cs)
+	}
+}
+
+func TestLaunchArgsEmpty(t *testing.T) {
+	a := New()
+	if args := a.LaunchArgs(clientinject.Install{}, clientinject.Endpoints{}); len(args) != 0 {
+		t.Fatalf("args=%v", args)
+	}
+}
diff --git a/internal/clientinject/adapters/xpilot/apply.go b/internal/clientinject/adapters/xpilot/apply.go
new file mode 100644
index 0000000..2065879
--- /dev/null
+++ b/internal/clientinject/adapters/xpilot/apply.go
@@ -0,0 +1,98 @@
+package xpilot
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/renorris/openfsd/internal/clientinject"
+	"github.com/renorris/openfsd/internal/clientinject/pepatch"
+)
+
+// Apply writes plan mutations via FileWriter.
+func (a *Adapter) Apply(ctx context.Context, plan *clientinject.Plan, w clientinject.FileWriter) error {
+	_ = ctx
+	if plan == nil {
+		return fmt.Errorf("xpilot: nil plan")
+	}
+	if w == nil {
+		return fmt.Errorf("xpilot: nil FileWriter")
+	}
+	pePath := clientinject.AbsPrimaryPE(plan.Install)
+	if pePath == "" {
+		return fmt.Errorf("xpilot: PE mutation planned but PrimaryPE empty")
+	}
+
+	needPE := false
+	for _, m := range plan.Mutations {
+		switch m.Kind {
+		case clientinject.MutPaddedString, clientinject.MutRawOverwrite:
+			needPE = true
+		}
+	}
+	if !needPE {
+		return nil
+	}
+
+	peFile, err := w.OpenReadWrite(pePath)
+	if err != nil {
+		return fmt.Errorf("xpilot: open PE: %w", err)
+	}
+	defer peFile.Close()
+
+	for _, m := range plan.Mutations {
+		switch m.Kind {
+		case clientinject.MutPaddedString:
+			d, ok := paddedDetail(m.Detail)
+			if !ok {
+				return fmt.Errorf("xpilot: mutation %s: bad PaddedStringDetail", m.ID)
+			}
+			if err := pepatch.PaddedStringOverwrite(peFile, d.FileOffset, d.NewString, d.SlotLen, d.Encoding); err != nil {
+				return fmt.Errorf("xpilot: %s: %w", m.ID, err)
+			}
+		case clientinject.MutRawOverwrite:
+			d, ok := rawDetail(m.Detail)
+			if !ok {
+				return fmt.Errorf("xpilot: mutation %s: bad RawOverwriteDetail", m.ID)
+			}
+			if len(d.NewBytes) == 0 {
+				continue
+			}
+			if err := pepatch.OverwriteAt(peFile, d.FileOffset, d.NewBytes); err != nil {
+				return fmt.Errorf("xpilot: %s: %w", m.ID, err)
+			}
+		case clientinject.MutLaunchFlag:
+			continue
+		default:
+			return fmt.Errorf("xpilot: unsupported mutation kind %q (id=%s)", m.Kind, m.ID)
+		}
+	}
+	return nil
+}
+
+func paddedDetail(d any) (clientinject.PaddedStringDetail, bool) {
+	switch v := d.(type) {
+	case clientinject.PaddedStringDetail:
+		return v, true
+	case *clientinject.PaddedStringDetail:
+		if v == nil {
+			return clientinject.PaddedStringDetail{}, false
+		}
+		return *v, true
+	default:
+		return clientinject.PaddedStringDetail{}, false
+	}
+}
+
+func rawDetail(d any) (clientinject.RawOverwriteDetail, bool) {
+	switch v := d.(type) {
+	case clientinject.RawOverwriteDetail:
+		return v, true
+	case *clientinject.RawOverwriteDetail:
+		if v == nil {
+			return clientinject.RawOverwriteDetail{}, false
+		}
+		return *v, true
+	default:
+		return clientinject.RawOverwriteDetail{}, false
+	}
+}
diff --git a/internal/clientinject/adapters/xpilot/health.go b/internal/clientinject/adapters/xpilot/health.go
new file mode 100644
index 0000000..38976f4
--- /dev/null
+++ b/internal/clientinject/adapters/xpilot/health.go
@@ -0,0 +1,133 @@
+package xpilot
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"strings"
+	"unicode/utf16"
+
+	"github.com/renorris/openfsd/internal/clientinject"
+)
+
+// HealthCheck validates padded-string slots and raw length/break sites after Apply.
+func (a *Adapter) HealthCheck(install clientinject.Install, ep clientinject.Endpoints) error {
+	ep = ep.Normalize()
+	w := a.writer()
+	pe := clientinject.AbsPrimaryPE(install)
+	if pe == "" {
+		return fmt.Errorf("xpilot: healthcheck: empty PrimaryPE")
+	}
+	data, err := w.ReadFile(pe)
+	if err != nil {
+		return fmt.Errorf("xpilot: healthcheck read PE: %w", err)
+	}
+
+	profile, err := a.loadProfileForInstall(install)
+	if err != nil {
+		return fmt.Errorf("xpilot: healthcheck profile: %w", err)
+	}
+
+	statusURL := ep.StatusJSONURL()
+	jwtURL := ep.JWTURL()
+	endpoints := map[string]string{
+		"status_json": statusURL,
+		"fsd_jwt":     jwtURL,
+		"status":      statusURL,
+	}
+
+	for _, m := range profile.Mutations {
+		if m.FileOffset == nil {
+			continue
+		}
+		off := m.FileOffset.Int64()
+		kind, err := clientinject.MapYAMLKind(m.Kind)
+		if err != nil {
+			continue
+		}
+		switch kind {
+		case clientinject.MutPaddedString:
+			key := strings.TrimSpace(m.EndpointKey)
+			if key == "" {
+				key = strings.TrimSpace(m.StringRef)
+			}
+			want := endpoints[key]
+			if want == "" {
+				continue
+			}
+			slotLen := 0
+			if m.AvailableBytes != nil {
+				slotLen = int(m.AvailableBytes.Int64())
+			}
+			if slotLen <= 0 {
+				if s, ok := profile.Strings[key]; ok {
+					slotLen = s.PayloadBudgetBytes
+				}
+			}
+			if slotLen <= 0 || off < 0 || int(off)+slotLen > len(data) {
+				return fmt.Errorf("xpilot: healthcheck: padded slot %s @%#x out of range", m.ID, off)
+			}
+			got, err := decodePadded(data[off:int(off)+slotLen], m.Encoding)
+			if err != nil {
+				return fmt.Errorf("xpilot: healthcheck %s: %w", m.ID, err)
+			}
+			if got != want {
+				return fmt.Errorf("xpilot: healthcheck %s @%#x = %q, want %q", m.ID, off, got, want)
+			}
+		case clientinject.MutRawOverwrite:
+			if lo := strings.TrimSpace(m.LengthOf); lo != "" {
+				url := endpoints[lo]
+				if url == "" {
+					continue
+				}
+				want := byte(len([]rune(url)))
+				if off < 0 || int(off) >= len(data) {
+					return fmt.Errorf("xpilot: healthcheck: length site %s out of range", m.ID)
+				}
+				if data[off] != want {
+					return fmt.Errorf("xpilot: healthcheck %s @%#x = %d, want %d", m.ID, off, data[off], want)
+				}
+				continue
+			}
+			if len(m.NewBytes) == 0 {
+				continue
+			}
+			if off < 0 || int(off)+len(m.NewBytes) > len(data) {
+				return fmt.Errorf("xpilot: healthcheck: raw site %s out of range", m.ID)
+			}
+			got := data[off : int(off)+len(m.NewBytes)]
+			if !bytes.Equal(got, m.NewBytes) {
+				return fmt.Errorf("xpilot: healthcheck %s @%#x = %x, want %x", m.ID, off, got, m.NewBytes)
+			}
+		}
+	}
+	return nil
+}
+
+func decodePadded(slot []byte, encoding string) (string, error) {
+	enc := strings.ToLower(strings.TrimSpace(encoding))
+	switch enc {
+	case "utf16le", "utf-16le", "utf16":
+		if len(slot) < 2 {
+			return "", fmt.Errorf("utf16 slot too short")
+		}
+		// Read until U+0000 or end.
+		nUnits := len(slot) / 2
+		units := make([]uint16, 0, nUnits)
+		for i := 0; i < nUnits; i++ {
+			u := binary.LittleEndian.Uint16(slot[i*2:])
+			if u == 0 {
+				break
+			}
+			units = append(units, u)
+		}
+		return string(utf16.Decode(units)), nil
+	default:
+		// utf8/ascii: until first 0x00.
+		i := bytes.IndexByte(slot, 0)
+		if i < 0 {
+			return string(slot), nil
+		}
+		return string(slot[:i]), nil
+	}
+}
diff --git a/internal/clientinject/adapters/xpilot/plan.go b/internal/clientinject/adapters/xpilot/plan.go
new file mode 100644
index 0000000..1bfa136
--- /dev/null
+++ b/internal/clientinject/adapters/xpilot/plan.go
@@ -0,0 +1,223 @@
+package xpilot
+
+import (
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/renorris/openfsd/internal/clientinject"
+)
+
+// Plan builds a dry-run mutation plan from the profile. Does not write disk.
+func (a *Adapter) Plan(install clientinject.Install, profile *clientinject.Profile, ep clientinject.Endpoints) (*clientinject.Plan, error) {
+	if profile == nil {
+		return nil, fmt.Errorf("xpilot: nil profile")
+	}
+	ep = ep.Normalize()
+	plan := &clientinject.Plan{
+		Install:     install,
+		Endpoints:   ep,
+		Constraints: a.EndpointConstraints(profile),
+	}
+
+	if ep.WebBaseURL == "" {
+		plan.Blockers = append(plan.Blockers, "WebBaseURL is required")
+	}
+	// FSDHost is not written into the PE (status.json feed supplies servers),
+	// but keep the form contract: require it so operators configure a coherent pair.
+	if ep.FSDHost == "" {
+		plan.Blockers = append(plan.Blockers, "FSDHost is required (used with openfsd status feed / operator checklist)")
+	}
+
+	statusURL := ep.StatusJSONURL()
+	jwtURL := ep.JWTURL()
+	// Prefer full /api/v1/fsd-jwt; PreferShortJWTPath still works via Endpoints.JWTURL.
+	if ep.PreferShortJWTPath && jwtURL != "" {
+		plan.Warnings = append(plan.Warnings,
+			"PreferShortJWTPath set — ensure server has fixed short JWT routes; xPilot slots are large so default /api/v1/fsd-jwt usually fits")
+	}
+
+	endpoints := map[string]string{
+		"status_json": statusURL,
+		"fsd_jwt":     jwtURL,
+		"status":      statusURL,
+	}
+
+	if statusURL == "" && ep.WebBaseURL != "" {
+		plan.Blockers = append(plan.Blockers, "StatusJSONURL empty after normalize")
+	}
+	if jwtURL == "" && ep.WebBaseURL != "" {
+		plan.Blockers = append(plan.Blockers, "JWTURL empty after normalize")
+	}
+
+	// Validate endpoint lengths against slots + single-byte length imm.
+	if statusURL != "" {
+		if err := checkURLFits(statusURL, profile, "status_json", "utf8"); err != nil {
+			plan.Blockers = append(plan.Blockers, err.Error())
+			updateConstraintStrategy(plan, "StatusJSONURL", "blocker")
+		}
+	}
+	if jwtURL != "" {
+		if err := checkURLFits(jwtURL, profile, "fsd_jwt", "utf16le"); err != nil {
+			plan.Blockers = append(plan.Blockers, err.Error())
+			updateConstraintStrategy(plan, "JWTURL", "blocker")
+		}
+	}
+
+	if len(profile.Mutations) == 0 {
+		plan.Blockers = append(plan.Blockers, "profile has no mutations (research incomplete)")
+		return plan, nil
+	}
+
+	for _, m := range profile.Mutations {
+		if m.FileOffset == nil {
+			plan.Blockers = append(plan.Blockers, fmt.Sprintf("mutation %s: missing file_offset", m.ID))
+			continue
+		}
+		off := m.FileOffset.Int64()
+		if off <= 0 {
+			plan.Blockers = append(plan.Blockers, fmt.Sprintf("mutation %s: invalid file_offset %d", m.ID, off))
+			continue
+		}
+		kind, err := clientinject.MapYAMLKind(m.Kind)
+		if err != nil {
+			plan.Blockers = append(plan.Blockers, fmt.Sprintf("mutation %s: %v", m.ID, err))
+			continue
+		}
+
+		switch kind {
+		case clientinject.MutPaddedString:
+			key := strings.TrimSpace(m.EndpointKey)
+			if key == "" {
+				key = strings.TrimSpace(m.StringRef)
+			}
+			url := endpoints[key]
+			if url == "" {
+				plan.Blockers = append(plan.Blockers, fmt.Sprintf("mutation %s: unknown/empty endpoint_key %q", m.ID, key))
+				continue
+			}
+			slotLen := 0
+			if m.AvailableBytes != nil {
+				slotLen = int(m.AvailableBytes.Int64())
+			}
+			if slotLen <= 0 {
+				if s, ok := profile.Strings[key]; ok && s.PayloadBudgetBytes > 0 {
+					slotLen = s.PayloadBudgetBytes
+				}
+			}
+			if slotLen <= 0 {
+				plan.Blockers = append(plan.Blockers, fmt.Sprintf("mutation %s: missing available_bytes", m.ID))
+				continue
+			}
+			enc := m.Encoding
+			if enc == "" {
+				enc = "utf8"
+			}
+			plan.Mutations = append(plan.Mutations, clientinject.Mutation{
+				ID:          m.ID,
+				Kind:        clientinject.MutPaddedString,
+				Description: m.Description,
+				TargetRel:   profile.PrimaryBinary.RelativePath,
+				Detail: clientinject.PaddedStringDetail{
+					FileOffset: off,
+					NewString:  url,
+					SlotLen:    slotLen,
+					Encoding:   enc,
+				},
+			})
+
+		case clientinject.MutRawOverwrite:
+			if lo := strings.TrimSpace(m.LengthOf); lo != "" {
+				url := endpoints[lo]
+				if url == "" {
+					plan.Blockers = append(plan.Blockers, fmt.Sprintf("mutation %s: length_of %q empty", m.ID, lo))
+					continue
+				}
+				n := utf8.RuneCountInString(url)
+				if n > maxLengthImm {
+					plan.Blockers = append(plan.Blockers, fmt.Sprintf("mutation %s: URL length %d exceeds single-byte imm max %d", m.ID, n, maxLengthImm))
+					continue
+				}
+				plan.Mutations = append(plan.Mutations, clientinject.Mutation{
+					ID:          m.ID,
+					Kind:        clientinject.MutRawOverwrite,
+					Description: m.Description,
+					TargetRel:   profile.PrimaryBinary.RelativePath,
+					Detail: clientinject.RawOverwriteDetail{
+						FileOffset: off,
+						NewBytes:   []byte{byte(n)},
+					},
+				})
+				continue
+			}
+			if len(m.NewBytes) == 0 {
+				plan.Blockers = append(plan.Blockers, fmt.Sprintf("mutation %s: raw_overwrite needs new_bytes or length_of", m.ID))
+				continue
+			}
+			plan.Mutations = append(plan.Mutations, clientinject.Mutation{
+				ID:          m.ID,
+				Kind:        clientinject.MutRawOverwrite,
+				Description: m.Description,
+				TargetRel:   profile.PrimaryBinary.RelativePath,
+				Detail: clientinject.RawOverwriteDetail{
+					FileOffset: off,
+					NewBytes:   append([]byte(nil), m.NewBytes...),
+				},
+			})
+
+		default:
+			plan.Blockers = append(plan.Blockers, fmt.Sprintf("mutation %s: unsupported kind %q for xpilot adapter", m.ID, m.Kind))
+		}
+	}
+
+	if ep.AFVBaseURL != "" {
+		plan.Warnings = append(plan.Warnings,
+			"AFVBaseURL set but xPilot 3.0.1 adapter does not retarget voice; configure AFV outside this PE patch or use a future profile")
+	}
+	if ep.ForceDisableAFV {
+		plan.Warnings = append(plan.Warnings,
+			"ForceDisableAFV has no PE/launch effect for xPilot 3.0.1 (no -novoice equivalent in prior art)")
+	}
+
+	return plan, nil
+}
+
+func checkURLFits(url string, profile *clientinject.Profile, stringKey, encoding string) error {
+	n := utf8.RuneCountInString(url)
+	if n > maxLengthImm {
+		return fmt.Errorf("%s URL length %d exceeds single-byte length immediate max %d", stringKey, n, maxLengthImm)
+	}
+	budget := 0
+	if s, ok := profile.Strings[stringKey]; ok {
+		budget = s.PayloadBudgetBytes
+	}
+	if budget <= 0 {
+		return nil
+	}
+	enc := strings.ToLower(encoding)
+	var need int
+	switch enc {
+	case "utf16le", "utf-16le", "utf16":
+		need = (n + 1) * 2 // runes + NUL
+	default:
+		// utf8/ascii: bytes + NUL; openfsd URLs are ASCII so runes==bytes.
+		need = len(url) + 1
+	}
+	if need > budget {
+		return fmt.Errorf("%s URL needs %d encoded bytes > slot budget %d", stringKey, need, budget)
+	}
+	return nil
+}
+
+func updateConstraintStrategy(plan *clientinject.Plan, field, strategy string) {
+	for i := range plan.Constraints {
+		if plan.Constraints[i].Field == field {
+			plan.Constraints[i].Strategy = strategy
+			return
+		}
+	}
+	plan.Constraints = append(plan.Constraints, clientinject.Constraint{
+		Field:    field,
+		Strategy: strategy,
+	})
+}
diff --git a/internal/clientinject/profile.go b/internal/clientinject/profile.go
index f1cacb4..fed2ef8 100644
--- a/internal/clientinject/profile.go
+++ b/internal/clientinject/profile.go
@@ -20,28 +20,37 @@ const RequiredSchemaVersion = 2
 
 // Profile is a loaded schema_version 2 document (fingerprint + mutations).
 type Profile struct {
-	SchemaVersion          int                   `yaml:"schema_version"`
-	ClientID               string                `yaml:"client_id"`
-	DisplayName            string                `yaml:"display_name"`
-	Vendor                 string                `yaml:"vendor"`
-	LicenseNote            string                `yaml:"license_note"`
-	ProfileVersion         string                `yaml:"profile_version"`
-	SupportedClientVersion string                `yaml:"supported_client_version"`
-	Released               string                `yaml:"released"`
-	DownloadPage           string                `yaml:"download_page"`
-	Installer              *InstallerSpec        `yaml:"installer"`
-	PrimaryBinary          PrimaryBinarySpec     `yaml:"primary_binary"`
-	ConfigFiles            []ConfigFileSpec      `yaml:"config_files"`
-	RelatedBinaries        []string              `yaml:"related_binaries"`
-	CLR                    *CLRSpec              `yaml:"clr"`
-	Strings                map[string]StringSpec `yaml:"strings"`
-	USFreeSlots            []USFreeSlot          `yaml:"us_free_slots"`
-	Mutations              []ProfileMutationSpec `yaml:"mutations"`
-	Launch                 LaunchSpec            `yaml:"launch"`
+	SchemaVersion          int               `yaml:"schema_version"`
+	ClientID               string            `yaml:"client_id"`
+	DisplayName            string            `yaml:"display_name"`
+	Vendor                 string            `yaml:"vendor"`
+	LicenseNote            string            `yaml:"license_note"`
+	ProfileVersion         string            `yaml:"profile_version"`
+	SupportedClientVersion string            `yaml:"supported_client_version"`
+	Released               string            `yaml:"released"`
+	DownloadPage           string            `yaml:"download_page"`
+	Installer              *InstallerSpec    `yaml:"installer"`
+	PrimaryBinary          PrimaryBinarySpec `yaml:"primary_binary"`
+	ConfigFiles            []ConfigFileSpec  `yaml:"config_files"`
+	RelatedBinaries        []string          `yaml:"related_binaries"`
+	// PESections documents native PE section maps (xPilot-class VA→file conversion).
+	PESections  []PESectionSpec       `yaml:"pe_sections"`
+	CLR         *CLRSpec              `yaml:"clr"`
+	Strings     map[string]StringSpec `yaml:"strings"`
+	USFreeSlots []USFreeSlot          `yaml:"us_free_slots"`
+	Mutations   []ProfileMutationSpec `yaml:"mutations"`
+	Launch      LaunchSpec            `yaml:"launch"`
 	// ProfileID is the stem of the YAML file (e.g. "vpilot-3.12.1"), set by loader.
 	ProfileID string `yaml:"-"`
 }
 
+// PESectionSpec is a PE section raw/virtual base for VA→file offset conversion.
+type PESectionSpec struct {
+	Name         string        `yaml:"name"`
+	RawOffset    FlexibleInt64 `yaml:"raw_offset"`
+	VirtualStart FlexibleInt64 `yaml:"virtual_start"`
+}
+
 // InstallerSpec describes the upstream installer (metadata only).
 type InstallerSpec struct {
 	Filename  string `yaml:"filename"`
@@ -115,10 +124,33 @@ type ProfileMutationSpec struct {
 	FileOffset  *FlexibleInt64 `yaml:"file_offset"`
 	NewBytes    []byte         `yaml:"new_bytes"`
 	OnlyIf      string         `yaml:"only_if"`
+	// AvailableBytes is the padded-string slot size (padded_string kind).
+	AvailableBytes *FlexibleInt64 `yaml:"available_bytes"`
+	// Encoding is "utf8" / "ascii" / "utf16le" for padded_string.
+	Encoding string `yaml:"encoding"`
+	// EndpointKey selects a planned URL: "status_json", "fsd_jwt", "status", "afv_base", …
+	EndpointKey string `yaml:"endpoint_key"`
+	// LengthOf, when set on raw_overwrite, writes a single-byte length of that endpoint URL.
+	LengthOf string `yaml:"length_of"`
 	// Fields is free-form for config_rewrite / vpilot_config.
 	Fields map[string]any `yaml:"fields"`
 }
 
+// FileOffsetOf returns the VA→file conversion for a section-relative virtual address,
+// or (-1, false) if the section is unknown.
+func (p *Profile) FileOffsetOf(sectionName string, virtualAddr int64) (int64, bool) {
+	if p == nil {
+		return -1, false
+	}
+	for _, sec := range p.PESections {
+		if sec.Name != sectionName {
+			continue
+		}
+		return sec.RawOffset.Int64() + (virtualAddr - sec.VirtualStart.Int64()), true
+	}
+	return -1, false
+}
+
 // LaunchSpec holds default launch flag templates.
 type LaunchSpec struct {
 	ServerAddressFlag string   `yaml:"server_address_flag"`
diff --git a/internal/clientinject/profile_test.go b/internal/clientinject/profile_test.go
index f7034b6..93120c2 100644
--- a/internal/clientinject/profile_test.go
+++ b/internal/clientinject/profile_test.go
@@ -51,6 +51,45 @@ func TestLoadEmbedded(t *testing.T) {
 	if len(list) < 1 {
 		t.Fatal("ForClient empty")
 	}
+
+	// xPilot 3.0.1 embed profile (second client).
+	xp, ok := store.Get("xpilot-3.0.1")
+	if !ok {
+		t.Fatal("missing xpilot-3.0.1")
+	}
+	if xp.ClientID != "xpilot" {
+		t.Fatalf("client=%q", xp.ClientID)
+	}
+	if xp.PrimaryBinary.SHA1 != "1ae61e1d4a624751124a49cd992c90f948c31d37" {
+		t.Fatalf("xpilot sha1=%q", xp.PrimaryBinary.SHA1)
+	}
+	if len(xp.PESections) < 2 {
+		t.Fatalf("pe_sections=%d", len(xp.PESections))
+	}
+	// status string VA → file offset from research notes.
+	off, ok := xp.FileOffsetOf(".idata", 0x141AAF5AE)
+	if !ok || off != 0x1AAE7AE {
+		t.Fatalf("status file offset=%#x ok=%v", off, ok)
+	}
+	// Ensure padded_string mutations have file offsets.
+	var sawPadded, sawLen bool
+	for _, m := range xp.Mutations {
+		if m.Kind == "padded_string" {
+			sawPadded = true
+			if m.FileOffset == nil || m.AvailableBytes == nil {
+				t.Fatalf("padded mutation incomplete: %+v", m)
+			}
+		}
+		if m.LengthOf != "" {
+			sawLen = true
+		}
+	}
+	if !sawPadded || !sawLen {
+		t.Fatalf("padded=%v length_of=%v mutations=%d", sawPadded, sawLen, len(xp.Mutations))
+	}
+	if _, ok := store.LookupByHash("xpilot", "1AE61E1D4A624751124A49CD992C90F948C31D37"); !ok {
+		t.Fatal("xpilot lookup by hash failed")
+	}
 }
 
 func TestParseProfile_RejectsV1(t *testing.T) {
diff --git a/internal/clientinject/profiles/xpilot-3.0.1.yaml b/internal/clientinject/profiles/xpilot-3.0.1.yaml
new file mode 100644
index 0000000..50540ac
--- /dev/null
+++ b/internal/clientinject/profiles/xpilot-3.0.1.yaml
@@ -0,0 +1,116 @@
+# openfsd client profile — schema v2. Do NOT ship xPilot binaries.
+# Offsets from docs/client-injector/research/xpilot.md (prior-art VA→file conversion).
+# Version-pinned by primary PE SHA-1; refuse unknown hashes.
+
+schema_version: 2
+client_id: xpilot
+display_name: xPilot
+vendor: Justin Shannon / xPilot project
+license_note: Proprietary; not redistributable by openfsd
+profile_version: "2"
+supported_client_version: "3.0.1"
+download_page: https://github.com/xpilot-project/xpilot/releases
+
+primary_binary:
+  relative_path: xPilot.exe
+  default_install_globs:
+    windows:
+      - "%ProgramFiles%\\xPilot\\xPilot.exe"
+      - "%ProgramFiles(x86)%\\xPilot\\xPilot.exe"
+  sha1: 1ae61e1d4a624751124a49cd992c90f948c31d37
+  pe:
+    clr: false
+    architecture: x86_64
+
+# No client-local config rewrite in the 3.0.1 prior-art path (status JSON feed only).
+config_files: []
+
+# PE section map from prior art (documentation + VA→file helper tests).
+pe_sections:
+  - name: .text
+    raw_offset: 0x400
+    virtual_start: 0x140001000
+  - name: .idata
+    raw_offset: 0x01A5A200
+    virtual_start: 0x141A5B000
+  - name: .data
+    raw_offset: 0x027F9000
+    virtual_start: 0x1427FA000
+
+# Logical string budgets (padded .idata slots). Stock bodies not required for plan.
+strings:
+  status_json:
+    stock: ""
+    payload_budget_bytes: 0x3B5
+    template: "{{.StatusJSONURL}}"
+  fsd_jwt:
+    stock: ""
+    payload_budget_bytes: 0x3B4
+    template: "{{.JWTURL}}"
+
+us_free_slots: []
+
+mutations:
+  # --- Relocated string slots (padded) ---
+  - id: write_status_json
+    kind: padded_string
+    description: Write openfsd status.json URL into .idata free slot (UTF-8)
+    file_offset: 0x1AAE7AE
+    available_bytes: 0x3B5
+    encoding: utf8
+    endpoint_key: status_json
+
+  - id: write_fsd_jwt
+    kind: padded_string
+    description: Write openfsd fsd-jwt URL into .idata free slot (UTF-16LE)
+    file_offset: 0x1A9582C
+    available_bytes: 0x3B4
+    encoding: utf16le
+    endpoint_key: fsd_jwt
+
+  # --- LEA RIP fixups (content-independent; point at relocated slots) ---
+  - id: patch_status_lea
+    kind: raw_overwrite
+    description: Overwrite status.json LEA RIP displacement
+    file_offset: 0x2810E
+    new_bytes: [0x9C, 0x68, 0xA8, 0x01]
+
+  - id: patch_fsd_jwt_lea_1
+    kind: raw_overwrite
+    description: Overwrite fsd-jwt LEA RIP (site 1)
+    file_offset: 0x34FFE
+    new_bytes: [0x2A, 0x0A, 0xA6, 0x01]
+
+  - id: patch_fsd_jwt_lea_2
+    kind: raw_overwrite
+    description: Overwrite fsd-jwt LEA RIP (site 2)
+    file_offset: 0x6B208
+    new_bytes: [0x20, 0xA8, 0xA2, 0x01]
+
+  # --- Dynamic single-byte length immediates (Apply fills from endpoint URL len) ---
+  - id: patch_status_len
+    kind: raw_overwrite
+    description: status.json URL length immediate (1 byte = rune/byte count)
+    file_offset: 0x28107
+    length_of: status_json
+
+  - id: patch_fsd_jwt_len_1
+    kind: raw_overwrite
+    description: fsd-jwt URL length immediate site 1
+    file_offset: 0x3500A
+    length_of: fsd_jwt
+
+  - id: patch_fsd_jwt_len_2
+    kind: raw_overwrite
+    description: fsd-jwt URL length immediate site 2
+    file_offset: 0x6B214
+    length_of: fsd_jwt
+
+  # --- Neutralise stock FSD auto host ---
+  - id: break_fsd_vatsim_net
+    kind: raw_overwrite
+    description: Overwrite fsd.vatsim.net residual with "foo"
+    file_offset: 0x1CBE440
+    new_bytes: [0x66, 0x6F, 0x6F]
+
+launch: {}
diff --git a/third_party/client-profiles/xpilot-3.0.1.yaml b/third_party/client-profiles/xpilot-3.0.1.yaml
new file mode 100644
index 0000000..455c4e3
--- /dev/null
+++ b/third_party/client-profiles/xpilot-3.0.1.yaml
@@ -0,0 +1,22 @@
+# openfsd client profile — metadata only. Do NOT ship xPilot binaries.
+# Prior art: openfsd-client-patch-utility example_patchfiles/xpilot/xpilot-3.0.1.yaml
+# Legal: user must install xPilot themselves; openfsd never redistributes it.
+
+client_id: xpilot
+display_name: xPilot
+vendor: Justin Shannon / xPilot project
+license_note: Proprietary; not redistributable by openfsd
+profile_version: "1"
+supported_client_version: "3.0.1"
+download_page: https://github.com/xpilot-project/xpilot/releases
+primary_binary:
+  relative_path: xPilot.exe
+  default_install_globs:
+    windows:
+      - "%ProgramFiles%\\xPilot\\xPilot.exe"
+      - "%ProgramFiles(x86)%\\xPilot\\xPilot.exe"
+  sha1: 1ae61e1d4a624751124a49cd992c90f948c31d37
+  pe:
+    clr: false
+    architecture: x86_64
+prior_art_profile: xpilot-3.0.1  # openfsd-client-patch-utility