diff --git a/CHANGELOG.en.md b/CHANGELOG.en.md
index fd0a490..be8fb54 100644
--- a/CHANGELOG.en.md
+++ b/CHANGELOG.en.md
@@ -20,7 +20,29 @@ Chinese is the primary changelog and this file is its maintained English mirror.
   explicitly unapproved for distribution without changing the XCFramework
   Release's RootFS exclusion policy.
 
-## v0.4.0-abi.6 (planned Stage1 maintenance prerelease)
+## v0.4.0-abi.7 (planned Stage1 maintenance prerelease)
+
+This is a compatibility maintenance release after `v0.4.0-abi.6`. It remains a
+prerelease and is **not stable v0.4.0**.
+
+- The pinned iSH fork adds `RENAME_NOREPLACE` syscall semantics, mapping them to
+  `renameatx_np(RENAME_EXCL)` in the Darwin fakefs backend and `renameat2` on a
+  Linux host. An existing destination is never replaced, without a racy
+  check-then-move sequence.
+- The public C API adds `ish_embed_rename_noreplace`. It executes the atomic
+  rename through the content-addressed guest supervisor selected at boot and
+  returns guest errno in a bounded decimal record; malformed protocol output or
+  helper failure fails closed.
+- The Swift API adds `IshInstance.renameNoReplace(from:to:timeout:)` and
+  `IshFilesystemError`. An existing destination maps to `.destinationExists`.
+  While source temporarily links `v0.4.0-abi.6`, a weak fallback reports
+  unsupported instead of producing a missing symbol.
+- The public C ABI version remains 1 and wire protocol remains v4; the new
+  function symbol is backward-compatible and additive. RootFS remains outside
+  the Release. This version does not implement a native Agent Loop or install
+  Codex CLI.
+
+## v0.4.0-abi.6 (published Stage1 maintenance prerelease)
 
 This is a compatibility maintenance release after `v0.4.0-abi.5`. It remains a
 prerelease and is **not stable v0.4.0**.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4e37bb0..ef6f8db 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,7 +15,24 @@
   `fs.tar.gz`，环境差异仍保留在外部证据中。CI 不上传制品，候选仍明确标记为未获分发
   批准，不改变 XCFramework Release 的 RootFS 排除策略。
 
-## v0.4.0-abi.6（计划中的 Stage1 维护预发布）
+## v0.4.0-abi.7（计划中的 Stage1 维护预发布）
+
+这是 `v0.4.0-abi.6` 之后的兼容性维护版本，仍是 prerelease，**不是稳定
+v0.4.0**。
+
+- 固定的 iSH fork 新增 `RENAME_NOREPLACE` syscall 语义，并在 Darwin fakefs 后端使用
+  `renameatx_np(RENAME_EXCL)`、Linux host 后端使用 `renameat2`，从底层保证目标存在时
+  不覆盖，不采用易竞争的“先检查、再移动”。
+- 公开 C API 新增 `ish_embed_rename_noreplace`。它通过启动时选定的内容寻址 guest
+  supervisor 执行原子重命名，以有界十进制记录返回 guest errno；协议损坏或 helper
+  异常会 fail closed。
+- Swift API 新增 `IshInstance.renameNoReplace(from:to:timeout:)` 与
+  `IshFilesystemError`。目标已存在映射为 `.destinationExists`；源码临时链接
+  `v0.4.0-abi.6` 时通过 weak fallback 明确报告 unsupported，不会产生缺失符号。
+- 公开 C ABI 版本仍为 1，wire protocol 仍为 v4；新增函数符号是向后兼容扩展。
+  RootFS 不进入 Release。本版本不实现原生 Agent Loop，也不会安装 Codex CLI。
+
+## v0.4.0-abi.6（已发布的 Stage1 维护预发布）
 
 这是 `v0.4.0-abi.5` 之后的兼容性维护版本，仍是 prerelease，**不是稳定
 v0.4.0**。
diff --git a/README.en.md b/README.en.md
index 42a7f44..d42ddea 100644
--- a/README.en.md
+++ b/README.en.md
@@ -15,17 +15,17 @@ and simulator slices are arm64.
 
 ## Current phase: native ABI transition
 
-The default branch has published `v0.4.0-abi.5` and is preparing the compatible
-maintenance prerelease `v0.4.0-abi.6`. Both belong to the Stage1 **native ABI
+The default branch has published `v0.4.0-abi.6` and is preparing the compatible
+maintenance prerelease `v0.4.0-abi.7`. Both belong to the Stage1 **native ABI
 transition**. Neither is stable `v0.4.0` or the complete v0.4 Swift API. Keep
 these four version surfaces distinct:
 
-| Surface | Current `v0.4.0-abi.5` | Planned `v0.4.0-abi.6` |
+| Surface | Current `v0.4.0-abi.6` | Planned `v0.4.0-abi.7` |
 | --- | --- | --- |
-| Public C ABI | `ISH_EMBED_ABI_VERSION == 1`; compatible symbols are published | Still ABI 1, with no new public symbols |
+| Public C ABI | `ISH_EMBED_ABI_VERSION == 1`; compatible symbols are published | Still ABI 1, with one backward-compatible atomic-rename function symbol |
 | Internal wire protocol | exact-match v4 between host and embedded supervisor | still v4; this is not the public C ABI version |
-| `Package.swift` | pins the public `v0.4.0-abi.5` URL/checksum | the release transaction creates a manifest-only release commit pinned to the maintenance binary |
-| Swift source | remains v0.3.3-ABI compatible and does not call retain/release | keeps the same Swift API and old-ABI usage |
+| `Package.swift` | pins the public `v0.4.0-abi.6` URL/checksum | the release transaction creates a manifest-only release commit pinned to the maintenance binary |
+| Swift source | remains v0.3.3-ABI compatible and does not call retain/release | adds a typed rename API with a weak fallback for old binaries |
 
 Stage1 native code adds session retain/release, a joinable kernel thread,
 soft-halt, exact wire v4, and complete session close. The existing Swift wrapper
@@ -88,15 +88,15 @@ gives those narrow differences independent PRs, CI, and an exact gitlink, making
 PocketRoot builds and releases reproducible. We do not directly rewrite somebody
 else's local upstream repository; generally useful fixes can still be contributed
 to [iSH upstream](https://github.com/ish-app/ish), while the fork carries project
-gates until upstream accepts and releases them. The current `v0.4.0-abi.6`
+gates until upstream accepts and releases them. The current `v0.4.0-abi.7`
 source change includes neither RootFS content nor any prebuilt XCFramework/guest
 binary; binaries may be produced and published only by a later release
 transaction after its gates pass.
 
 ## Installation status
 
-`v0.4.0-abi.5` is public and [`Package.swift`](Package.swift) currently pins it.
-Until `v0.4.0-abi.6` is published, the manifest keeps pointing at that verified
+`v0.4.0-abi.6` is public and [`Package.swift`](Package.swift) currently pins it.
+Until `v0.4.0-abi.7` is published, the manifest keeps pointing at that verified
 asset instead of advertising a future 404 URL. Use Xcode's
 **File → Add Package Dependencies…** with:
 
@@ -108,8 +108,9 @@ Select a version whose tag, `libIshKernel.xcframework.zip`, Corresponding Source
 and manifest URL/checksum all match. Consumer projects do not need Meson, Zig,
 or LLVM.
 
-`v0.4.0-abi.6` completes Swift-marshalling and stdin-close reuse of the original
-SPAWN deadline. It does not implement a native Agent Loop or
+`v0.4.0-abi.7` adds guest-atomic rename without a shell or check-then-rename
+race and maps an existing destination to a typed Swift error. It does not
+implement a native Agent Loop or
 install Codex CLI in the app.
 Node.js/npm remain optional choices of the RootFS/guest package-management flow,
 not runtime requirements.
@@ -131,6 +132,15 @@ let result = try instance.runOneshot(
     .init(argv: ["/bin/echo", "hello"], timeout: 10)
 )
 print(String(decoding: result.stdoutData, as: UTF8.self))
+
+do {
+    try instance.renameNoReplace(
+        from: "/workspace/draft.txt",
+        to: "/workspace/final.txt"
+    )
+} catch IshFilesystemError.destinationExists {
+    // The destination remains unchanged; ask the user for another name.
+}
 ```
 
 `IshSpawnOptions.timeout` applies to both `runOneshot` and streaming `spawn`.
diff --git a/README.md b/README.md
index 66fe827..cb4a040 100644
--- a/README.md
+++ b/README.md
@@ -13,16 +13,16 @@ RootFS 安装、产品级命令策略、Swift Concurrency 隔离和界面。项
 
 ## 当前阶段：Native ABI 过渡
 
-当前默认分支已发布 `v0.4.0-abi.5`，正在准备兼容性维护预发布
-`v0.4.0-abi.6`。它们都属于 **Stage1 native ABI 过渡**，不是稳定 `v0.4.0`，
+当前默认分支已发布 `v0.4.0-abi.6`，正在准备兼容性维护预发布
+`v0.4.0-abi.7`。它们都属于 **Stage1 native ABI 过渡**，不是稳定 `v0.4.0`，
 也不是完整 v0.4 Swift API。请同时区分下面四个版本面：
 
-| 版本面 | 当前 `v0.4.0-abi.5` | 计划中的 `v0.4.0-abi.6` |
+| 版本面 | 当前 `v0.4.0-abi.6` | 计划中的 `v0.4.0-abi.7` |
 | --- | --- | --- |
-| 公开 C ABI | `ISH_EMBED_ABI_VERSION == 1`；兼容性符号已发布 | 仍为 ABI 1，不新增公开符号 |
+| 公开 C ABI | `ISH_EMBED_ABI_VERSION == 1`；兼容性符号已发布 | 仍为 ABI 1，新增向后兼容的原子 rename 函数符号 |
 | 内部 wire protocol | host 与内嵌 supervisor 精确匹配 v4 | 仍为 v4；它不是公开 C ABI 版本 |
-| `Package.swift` | 固定已公开的 `v0.4.0-abi.5` URL/checksum | 发布事务生成只改 manifest 的 release commit，固定到维护二进制 |
-| Swift 源 | 保持 v0.3.3 ABI 兼容，不调用 retain/release | 保持相同 Swift API 与旧 ABI 用法 |
+| `Package.swift` | 固定已公开的 `v0.4.0-abi.6` URL/checksum | 发布事务生成只改 manifest 的 release commit，固定到维护二进制 |
+| Swift 源 | 保持 v0.3.3 ABI 兼容，不调用 retain/release | 新增类型化 rename API；通过 weak fallback 兼容旧 binary |
 
 Stage1 的 native runtime 已加入 session retain/release、可等待 kernel 线程、soft-halt、
 严格 v4 协议和完整 session close 等底层能力。现有 Swift wrapper 刻意不调用新增
@@ -68,13 +68,13 @@ JIT 脏页一致性必须修改模拟器核心，无法只在 outer package 或
 窄差异拥有独立 PR、CI 和精确 gitlink，PocketRoot 的构建与发布也因此可复现。我们不会在
 本地直接改写别人维护的上游仓库；适合通用化的修复仍可回馈
 [iSH upstream](https://github.com/ish-app/ish)，但在上游接受并发布前由 fork 承担项目门禁。
-当前 `v0.4.0-abi.6` 源码变更不纳入 RootFS，也不提交任何预构建
+当前 `v0.4.0-abi.7` 源码变更不纳入 RootFS，也不提交任何预构建
 XCFramework/guest binary；二进制只能在后续发布事务通过后生成和发布。
 
 ## 安装状态
 
-`v0.4.0-abi.5` 已公开且当前 [`Package.swift`](Package.swift) 固定到它。
-`v0.4.0-abi.6` 发布前，manifest 继续指向这个已验证的资产，不会提前引用 404 URL。
+`v0.4.0-abi.6` 已公开且当前 [`Package.swift`](Package.swift) 固定到它。
+`v0.4.0-abi.7` 发布前，manifest 继续指向这个已验证的资产，不会提前引用 404 URL。
 在 Xcode 的 **File → Add Package Dependencies…** 中使用：
 
 ```text
@@ -84,8 +84,8 @@ https://github.com/jacklv-coder/ish-arm64-pkg
 请选择明确包含 `libIshKernel.xcframework.zip`、对应源码归档，并且 manifest URL/checksum
 与同一标签匹配的版本。业务工程不需要安装 Meson、Zig 或 LLVM。
 
-`v0.4.0-abi.6` 补全 Swift 参数封送和 stdin close 对原始 SPAWN deadline 的复用；
-它不实现原生 Agent Loop，也不会
+`v0.4.0-abi.7` 新增无 shell、无 check-then-rename 竞争窗口的 guest 原子重命名，
+并把目标已存在映射为 Swift 类型化错误；它不实现原生 Agent Loop，也不会
 在 App 内安装 Codex CLI。Node.js/npm 如有需要仍由
 RootFS/guest 包管理流程选择，不属于 runtime 的强制依赖。
 
@@ -106,6 +106,15 @@ let result = try instance.runOneshot(
     .init(argv: ["/bin/echo", "hello"], timeout: 10)
 )
 print(String(decoding: result.stdoutData, as: UTF8.self))
+
+do {
+    try instance.renameNoReplace(
+        from: "/workspace/draft.txt",
+        to: "/workspace/final.txt"
+    )
+} catch IshFilesystemError.destinationExists {
+    // 目标保持原样；调用方可以提示用户换一个名称。
+}
 ```
 
 `IshSpawnOptions.timeout` 同时适用于 `runOneshot` 与 streaming `spawn`。有限超时从
diff --git a/Sources/CIshEmbed/CIshEmbed.c b/Sources/CIshEmbed/CIshEmbed.c
index da49e12..e5d293e 100644
--- a/Sources/CIshEmbed/CIshEmbed.c
+++ b/Sources/CIshEmbed/CIshEmbed.c
@@ -1,4 +1,36 @@
-/* Empty translation unit so the SwiftPM target produces a real
- * object file. The C ABI itself is implemented inside the prebuilt
- * libIshKernel.xcframework; this target only re-exports its header
- * to Swift via the modulemap in include/. */
+/* Source compatibility bridge for the short interval between merging a new
+ * Swift API and publishing its matching XCFramework. The weak fallback keeps
+ * Package.swift resolvable against the previous release; the bridge reports
+ * unsupported until the new binary is linked. */
+
+#include "ishembed.h"
+#include "IshEmbedSwiftShim.h"
+
+enum { ISH_SWIFT_ERR_UNSUPPORTED = -22 };
+
+/* A weak definition keeps source builds linkable while Package.swift still
+ * points at the previous XCFramework. The new archive contains the strong
+ * implementation in the same member as the established runtime API, so it is
+ * loaded normally and overrides this fallback after publication. */
+__attribute__((weak))
+int ish_embed_rename_noreplace(ish_embed_instance_t *inst,
+                               const char *source,
+                               const char *destination,
+                               uint32_t timeout_ms,
+                               int32_t *out_guest_errno) {
+    (void)inst;
+    (void)source;
+    (void)destination;
+    (void)timeout_ms;
+    if (out_guest_errno) *out_guest_errno = 0;
+    return ISH_SWIFT_ERR_UNSUPPORTED;
+}
+
+int ish_embed_swift_rename_noreplace(ish_embed_instance_t *inst,
+                                     const char *source,
+                                     const char *destination,
+                                     uint32_t timeout_ms,
+                                     int32_t *out_guest_errno) {
+    return ish_embed_rename_noreplace(
+        inst, source, destination, timeout_ms, out_guest_errno);
+}
diff --git a/Sources/CIshEmbed/include/IshEmbedSwiftShim.h b/Sources/CIshEmbed/include/IshEmbedSwiftShim.h
new file mode 100644
index 0000000..6839d20
--- /dev/null
+++ b/Sources/CIshEmbed/include/IshEmbedSwiftShim.h
@@ -0,0 +1,22 @@
+#ifndef ISH_EMBED_SWIFT_SHIM_H
+#define ISH_EMBED_SWIFT_SHIM_H
+
+#include "ishembed.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* SwiftPM source-target bridge. C embedders should call the public
+ * ish_embed_rename_noreplace symbol directly from abi.7 or newer. */
+int ish_embed_swift_rename_noreplace(ish_embed_instance_t *inst,
+                                     const char *source,
+                                     const char *destination,
+                                     uint32_t timeout_ms,
+                                     int32_t *out_guest_errno);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/Sources/CIshEmbed/include/module.modulemap b/Sources/CIshEmbed/include/module.modulemap
index 2d92fb9..b724b07 100644
--- a/Sources/CIshEmbed/include/module.modulemap
+++ b/Sources/CIshEmbed/include/module.modulemap
@@ -1,4 +1,5 @@
 module CIshEmbed {
     header "ishembed.h"
+    header "IshEmbedSwiftShim.h"
     export *
 }
diff --git a/Sources/IshEmbed/IshEmbed.swift b/Sources/IshEmbed/IshEmbed.swift
index c94102a..67c2364 100644
--- a/Sources/IshEmbed/IshEmbed.swift
+++ b/Sources/IshEmbed/IshEmbed.swift
@@ -38,6 +38,23 @@ public enum IshError: Error, CustomStringConvertible {
     }
 }
 
+public enum IshFilesystemError: Error, Equatable, CustomStringConvertible {
+    /// The destination existed at the atomic rename point. Neither path was
+    /// replaced, and the source remains unchanged.
+    case destinationExists
+    /// A positive Linux guest errno returned by the filesystem operation.
+    case guestErrno(Int32)
+
+    public var description: String {
+        switch self {
+        case .destinationExists:
+            return "The destination already exists."
+        case .guestErrno(let value):
+            return "Guest filesystem operation failed with Linux errno \(value)."
+        }
+    }
+}
+
 public struct IshSpawnOptions {
     public var argv: [String]
     public var cwd: String?
@@ -106,6 +123,7 @@ public enum IshSessionEvent {
 // The C header exposes ISH_OK / ISH_ERR_* as an unnamed enum and
 // ISH_STREAM_* as #define ints; both arrive as Int32 in Swift.
 private let ishOK: Int32                = ISH_OK.rawValue
+private let ishUnsupported: Int32       = -22
 private let ishErrNotRunning: Int32     = ISH_ERR_NOT_RUNNING.rawValue
 private let ishErrAlreadyBooted: Int32  = ISH_ERR_ALREADY_BOOTED.rawValue
 private let ishErrNoSession: Int32      = ISH_ERR_NO_SESSION.rawValue
@@ -188,6 +206,9 @@ struct IshLifecycleNativeCalls: @unchecked Sendable {
                 UnsafeMutablePointer<ish_embed_spawn_opts_t>,
                 IshSpawnTimeoutBudget) throws ->
         (result: Int32, session: OpaquePointer?)
+    let renameNoReplace: (OpaquePointer, UnsafePointer<CChar>,
+                          UnsafePointer<CChar>, UInt32,
+                          UnsafeMutablePointer<Int32>) -> Int32
     let sessionClose: (OpaquePointer) -> Void
     let freeBuffer: (UnsafeMutablePointer<UInt8>) -> Void
 
@@ -216,6 +237,12 @@ struct IshLifecycleNativeCalls: @unchecked Sendable {
             let result = ish_embed_spawn(instance, opts, &session)
             return (result, session)
         },
+        renameNoReplace: { instance, source, destination, timeoutMs,
+                           guestErrno in
+            ish_embed_swift_rename_noreplace(
+                instance, source, destination, timeoutMs, guestErrno
+            )
+        },
         sessionClose: { session in
             ish_embed_session_close(session)
         },
@@ -336,6 +363,52 @@ public final class IshInstance: @unchecked Sendable {
         }
     }
 
+    /// Atomically renames a guest file or directory without replacing an
+    /// existing destination. Both paths are absolute inside the Linux guest.
+    /// This operation does not invoke a shell and does not perform a racy
+    /// existence check before rename.
+    public func renameNoReplace(
+        from source: String,
+        to destination: String,
+        timeout: TimeInterval? = 5
+    ) throws {
+        guard source.first == "/", source.count > 1,
+              destination.first == "/", destination.count > 1,
+              !source.utf8.contains(0), !destination.utf8.contains(0) else {
+            throw IshError.from(ishErrInvalidArg)
+        }
+        let timeoutBudget = try IshSpawnTimeoutBudget(
+            timeout: timeout,
+            startedAt: ProcessInfo.processInfo.systemUptime
+        )
+        let lease = try callGate.acquireCall()
+        defer { lease.release() }
+        let timeoutMs = try timeoutBudget.remainingMilliseconds(
+            at: ProcessInfo.processInfo.systemUptime
+        )
+        var guestErrno: Int32 = 0
+        let rc = source.withCString { sourceC in
+            destination.withCString { destinationC in
+                nativeCalls.renameNoReplace(
+                    lease.raw, sourceC, destinationC, timeoutMs, &guestErrno
+                )
+            }
+        }
+        if rc == ishUnsupported {
+            throw IshError.raw(
+                rc,
+                "Atomic no-replace rename requires IshEmbed v0.4.0-abi.7 or newer."
+            )
+        }
+        if rc != ishOK { throw IshError.from(rc) }
+        if guestErrno == 17 {
+            throw IshFilesystemError.destinationExists
+        }
+        if guestErrno != 0 {
+            throw IshFilesystemError.guestErrno(guestErrno)
+        }
+    }
+
     /// Spawn a streaming session.
     public func spawn(_ opts: IshSpawnOptions) throws -> IshSession {
         let timeoutBudget = try IshSpawnTimeoutBudget(
diff --git a/Tests/IshEmbedTests/IshEmbedTests.swift b/Tests/IshEmbedTests/IshEmbedTests.swift
index 57a46f8..630dcd2 100644
--- a/Tests/IshEmbedTests/IshEmbedTests.swift
+++ b/Tests/IshEmbedTests/IshEmbedTests.swift
@@ -3,6 +3,8 @@ import XCTest
 import CIshEmbed
 @testable import IshEmbed
 
+private let ishUnsupported: Int32 = -22
+
 private final class LockedResults: @unchecked Sendable {
     private let lock = NSLock()
     private var values: [Int32]
@@ -56,6 +58,8 @@ private final class LifecycleNativeHarness: @unchecked Sendable {
         (UnsafeMutablePointer<ish_embed_oneshot_result_t>) -> Int32
     private let timeoutObservedBody: (UInt32) -> Void
     private let spawnTimeoutObservedBody: (UInt32) -> Void
+    private let renameBody:
+        (String, String, UInt32, UnsafeMutablePointer<Int32>) -> Int32
     private let sessionCloseBody: () -> Void
     private let bufferFreedBody: () -> Void
     private let lock = NSLock()
@@ -63,6 +67,7 @@ private final class LifecycleNativeHarness: @unchecked Sendable {
     private var shutdownCalls = 0
     private var oneshotCalls = 0
     private var spawnCalls = 0
+    private var renameCalls = 0
     private var sessionCloseCalls = 0
     private var freeBufferCalls = 0
     private var oneshotResultWasZeroed = true
@@ -75,6 +80,10 @@ private final class LifecycleNativeHarness: @unchecked Sendable {
             },
          timeoutObservedBody: @escaping (UInt32) -> Void = { _ in },
          spawnTimeoutObservedBody: @escaping (UInt32) -> Void = { _ in },
+         renameBody: @escaping
+            (String, String, UInt32, UnsafeMutablePointer<Int32>) -> Int32 = {
+                _, _, _, _ in ishUnsupported
+            },
          sessionCloseBody: @escaping () -> Void = {},
          bufferFreedBody: @escaping () -> Void = {}) {
         self.spawnResult = spawnResult
@@ -82,6 +91,7 @@ private final class LifecycleNativeHarness: @unchecked Sendable {
         self.oneshotBody = oneshotBody
         self.timeoutObservedBody = timeoutObservedBody
         self.spawnTimeoutObservedBody = spawnTimeoutObservedBody
+        self.renameBody = renameBody
         self.sessionCloseBody = sessionCloseBody
         self.bufferFreedBody = bufferFreedBody
     }
@@ -135,6 +145,18 @@ private final class LifecycleNativeHarness: @unchecked Sendable {
                 return (spawnResult,
                         spawnResult == 0 ? sessionRaw : nil)
             },
+            renameNoReplace: { [self] _, source, destination, timeoutMs,
+                               guestErrno in
+                lock.lock()
+                renameCalls += 1
+                lock.unlock()
+                return renameBody(
+                    String(cString: source),
+                    String(cString: destination),
+                    timeoutMs,
+                    guestErrno
+                )
+            },
             sessionClose: { [self] _ in
                 lock.lock()
                 sessionCloseCalls += 1
@@ -151,10 +173,11 @@ private final class LifecycleNativeHarness: @unchecked Sendable {
     }
 
     func counts() -> (boot: Int, shutdown: Int, oneshot: Int, spawn: Int,
+                      rename: Int,
                       close: Int, freeBuffer: Int, resultWasZeroed: Bool) {
         lock.lock()
         defer { lock.unlock() }
-        return (bootCalls, shutdownCalls, oneshotCalls, spawnCalls,
+        return (bootCalls, shutdownCalls, oneshotCalls, spawnCalls, renameCalls,
                 sessionCloseCalls, freeBufferCalls,
                 oneshotResultWasZeroed)
     }
@@ -253,6 +276,94 @@ final class IshEmbedTests: XCTestCase {
         XCTAssertEqual(native.counts().shutdown, 1)
     }
 
+    func testAtomicRenameMapsGuestResultsAndValidatesPaths() throws {
+        var observed: [(String, String, UInt32)] = []
+        let native = LifecycleNativeHarness(
+            renameBody: { source, destination, timeoutMs, guestErrno in
+                observed.append((source, destination, timeoutMs))
+                guestErrno.pointee =
+                    destination.hasSuffix("exists") ? 17 :
+                    destination.hasSuffix("denied") ? 13 : 0
+                return 0
+            })
+        let instance = IshInstance(nativeCalls: native.nativeCalls())
+        try instance.boot(.init(rootfsPath: "/unused-test-rootfs"))
+
+        try instance.renameNoReplace(
+            from: "/workspace/source",
+            to: "/workspace/renamed"
+        )
+        XCTAssertThrowsError(
+            try instance.renameNoReplace(
+                from: "/workspace/source",
+                to: "/workspace/exists"
+            )
+        ) { error in
+            XCTAssertEqual(error as? IshFilesystemError, .destinationExists)
+        }
+        XCTAssertThrowsError(
+            try instance.renameNoReplace(
+                from: "/workspace/source",
+                to: "/workspace/denied"
+            )
+        ) { error in
+            XCTAssertEqual(error as? IshFilesystemError, .guestErrno(13))
+        }
+        XCTAssertThrowsError(
+            try instance.renameNoReplace(from: "relative", to: "/valid")
+        ) { error in
+            XCTAssertEqual(ishErrorCode(error), ISH_ERR_INVALID_ARG.rawValue)
+        }
+
+        XCTAssertEqual(observed.count, 3)
+        XCTAssertEqual(observed.first?.0, "/workspace/source")
+        XCTAssertEqual(observed.first?.1, "/workspace/renamed")
+        XCTAssertTrue(observed.allSatisfy { $0.2 > 0 && $0.2 <= 5_000 })
+        XCTAssertEqual(native.counts().rename, 3)
+        try instance.shutdown()
+    }
+
+    func testAtomicRenameReportsOlderNativeBinaryClearly() throws {
+        let native = LifecycleNativeHarness()
+        let instance = IshInstance(nativeCalls: native.nativeCalls())
+        try instance.boot(.init(rootfsPath: "/unused-test-rootfs"))
+
+        XCTAssertThrowsError(
+            try instance.renameNoReplace(from: "/source", to: "/destination")
+        ) { error in
+            XCTAssertEqual(ishErrorCode(error), ishUnsupported)
+            XCTAssertTrue(String(describing: error).contains("abi.7"))
+        }
+        try instance.shutdown()
+    }
+
+    func testAtomicRenameLeaseBlocksConcurrentShutdown() throws {
+        let entered = DispatchSemaphore(value: 0)
+        let release = DispatchSemaphore(value: 0)
+        let finished = DispatchSemaphore(value: 0)
+        let native = LifecycleNativeHarness(
+            renameBody: { _, _, _, guestErrno in
+                entered.signal()
+                release.wait()
+                guestErrno.pointee = 0
+                return 0
+            })
+        let instance = IshInstance(nativeCalls: native.nativeCalls())
+        try instance.boot(.init(rootfsPath: "/unused-test-rootfs"))
+
+        DispatchQueue.global().async {
+            try? instance.renameNoReplace(from: "/source", to: "/destination")
+            finished.signal()
+        }
+        XCTAssertEqual(entered.wait(timeout: .now() + 1), .success)
+        XCTAssertThrowsError(try instance.shutdown()) { error in
+            XCTAssertEqual(ishErrorCode(error), ISH_ERR_BUSY.rawValue)
+        }
+        release.signal()
+        XCTAssertEqual(finished.wait(timeout: .now() + 1), .success)
+        try instance.shutdown()
+    }
+
     func testFailedSpawnReleasesInstanceLease() throws {
         let native = LifecycleNativeHarness(spawnResult: -15)
         let instance = IshInstance(nativeCalls: native.nativeCalls())
diff --git a/c-tests/lifecycle_test.c b/c-tests/lifecycle_test.c
index ddc4aeb..fad1f75 100644
--- a/c-tests/lifecycle_test.c
+++ b/c-tests/lifecycle_test.c
@@ -60,6 +60,7 @@ enum fake_mode {
     FAKE_SPAWN_ARGUMENT_BOUND,
     FAKE_WRITER_LOCK_HOLD,
     FAKE_WRITER_PRECOMMIT_DEADLINE,
+    FAKE_RENAME_NOREPLACE,
 };
 
 enum malformed_event_kind {
@@ -140,6 +141,11 @@ static int g_oneshot_terminate_status;
 static int g_oneshot_signal_attempts;
 static int g_oneshot_signal_status;
 static enum malformed_event_kind g_malformed_event_kind;
+static atomic_int g_rename_spawn_valid;
+static int g_rename_waiting;
+static int g_release_rename;
+
+static void fake_emit_error(uint32_t sid, int32_t err, const char *message);
 
 static int io_write_full(int fd, const void *buf, size_t len) {
     const uint8_t *p = buf;
@@ -201,6 +207,94 @@ static void fake_emit_exit(uint32_t sid, int32_t code, int32_t sig) {
     (void)fake_emit(ISH_FT_EXITED, 0, sid, body, sizeof(body));
 }
 
+static void fake_emit_stdout_record(uint32_t sid, const char *record) {
+    size_t record_len = strlen(record);
+    uint8_t body[8 + 32];
+    if (record_len > sizeof(body) - 8) abort();
+    ish_proto_put_u64(body, 1);
+    memcpy(body + 8, record, record_len);
+    (void)fake_emit(ISH_FT_STDOUT_DATA, ISH_FF_SEQ_PRESENT, sid,
+                    body, (uint32_t)(8 + record_len));
+}
+
+static int fake_spawn_take_string(const uint8_t *body, size_t body_len,
+                                  size_t *offset, const uint8_t **bytes,
+                                  uint32_t *length) {
+    if (!body || !offset || !bytes || !length ||
+        *offset > body_len || body_len - *offset < 4)
+        return -1;
+    *length = ish_proto_get_u32(body + *offset);
+    *offset += 4;
+    if (*offset > body_len || (size_t)*length > body_len - *offset)
+        return -1;
+    *bytes = body + *offset;
+    *offset += *length;
+    return 0;
+}
+
+static int fake_spawn_string_equals(const uint8_t *bytes, uint32_t length,
+                                    const char *expected) {
+    size_t expected_len = strlen(expected);
+    return expected_len == length &&
+        memcmp(bytes, expected, expected_len) == 0;
+}
+
+static void fake_handle_rename_spawn(uint32_t sid, const uint8_t *body,
+                                     uint32_t body_len) {
+    size_t offset = 0;
+    const uint8_t *bytes = NULL;
+    uint32_t length = 0;
+    if (fake_spawn_take_string(body, body_len, &offset, &bytes, &length) < 0 ||
+        !fake_spawn_string_equals(bytes, length, "/") ||
+        offset > body_len || body_len - offset < 4)
+        goto invalid;
+    uint32_t argc = ish_proto_get_u32(body + offset);
+    offset += 4;
+    if (argc != 4) goto invalid;
+
+    const uint8_t *argv[4];
+    uint32_t argv_len[4];
+    for (size_t i = 0; i < 4; i++) {
+        if (fake_spawn_take_string(body, body_len, &offset,
+                                   &argv[i], &argv_len[i]) < 0)
+            goto invalid;
+    }
+    if (!fake_spawn_string_equals(argv[0], argv_len[0],
+                                  ish_embed_bundled_supervisor_guest_path) ||
+        !fake_spawn_string_equals(argv[1], argv_len[1],
+                                  "--rename-noreplace") ||
+        !fake_spawn_string_equals(argv[2], argv_len[2], "/source"))
+        goto invalid;
+
+    atomic_store(&g_rename_spawn_valid, 1);
+    if (fake_spawn_string_equals(argv[3], argv_len[3], "/exists"))
+        fake_emit_stdout_record(sid, "17\n");
+    else if (fake_spawn_string_equals(argv[3], argv_len[3], "/malformed"))
+        fake_emit_stdout_record(sid, "oops\n");
+    else if (fake_spawn_string_equals(argv[3], argv_len[3], "/oversized"))
+        fake_emit_stdout_record(sid, "00000000000\n");
+    else if (fake_spawn_string_equals(argv[3], argv_len[3], "/renamed"))
+        fake_emit_stdout_record(sid, "0\n");
+    else if (fake_spawn_string_equals(argv[3], argv_len[3], "/timeout"))
+        return;
+    else if (fake_spawn_string_equals(argv[3], argv_len[3], "/blocked")) {
+        pthread_mutex_lock(&g_fake_lock);
+        g_rename_waiting = 1;
+        pthread_cond_broadcast(&g_fake_cond);
+        while (!g_release_rename)
+            pthread_cond_wait(&g_fake_cond, &g_fake_lock);
+        pthread_mutex_unlock(&g_fake_lock);
+        fake_emit_stdout_record(sid, "0\n");
+    } else
+        goto invalid;
+    fake_emit_exit(sid, 0, 0);
+    return;
+
+invalid:
+    atomic_store(&g_rename_spawn_valid, 0);
+    fake_emit_error(sid, EPROTO, "invalid rename helper spawn");
+}
+
 static void fake_emit_error(uint32_t sid, int32_t err, const char *message) {
     size_t message_len = strlen(message);
     uint8_t body[8 + 64];
@@ -429,6 +523,8 @@ static void *fake_kernel_main(void *unused) {
     }
 
     while (fake_read(&type, &flags, &sid, &body, &body_len) == 0) {
+        if (type == ISH_FT_SPAWN && g_mode == FAKE_RENAME_NOREPLACE)
+            fake_handle_rename_spawn(sid, body, body_len);
         free(body);
         body = NULL;
         if (type == ISH_FT_SPAWN) {
@@ -3372,6 +3468,125 @@ static int test_oneshot_output_limit(void) {
     return 0;
 }
 
+struct rename_call_args {
+    ish_embed_instance_t *inst;
+    int rc;
+    int32_t guest_errno;
+};
+
+static void *rename_call_main(void *opaque) {
+    struct rename_call_args *args = opaque;
+    args->guest_errno = -1;
+    args->rc = ish_embed_rename_noreplace(
+        args->inst, "/source", "/blocked", 2000, &args->guest_errno);
+    return NULL;
+}
+
+static int test_rename_noreplace_api(void) {
+    g_mode = FAKE_RENAME_NOREPLACE;
+    atomic_store(&g_rename_spawn_valid, 0);
+    g_rename_waiting = 0;
+    g_release_rename = 0;
+    ish_embed_instance_t *inst = boot_instance();
+    int32_t guest_errno = -1;
+
+    int rc = ish_embed_rename_noreplace(
+        inst, "relative", "/renamed", 1000, &guest_errno);
+    if (rc != ISH_ERR_INVALID_ARG || guest_errno != -1) {
+        fprintf(stderr, "rename relative validation: rc=%d errno=%d\n",
+                rc, guest_errno);
+        return 1;
+    }
+
+    rc = ish_embed_rename_noreplace(
+        inst, "/source", "/exists", 1000, &guest_errno);
+    int rename_spawn_valid = atomic_load(&g_rename_spawn_valid);
+    if (rc != ISH_OK || guest_errno != EEXIST || !rename_spawn_valid) {
+        fprintf(stderr, "rename existing destination: rc=%d errno=%d valid=%d\n",
+                rc, guest_errno, rename_spawn_valid);
+        return 1;
+    }
+
+    atomic_store(&g_rename_spawn_valid, 0);
+    rc = ish_embed_rename_noreplace(
+        inst, "/source", "/renamed", 1000, &guest_errno);
+    rename_spawn_valid = atomic_load(&g_rename_spawn_valid);
+    if (rc != ISH_OK || guest_errno != 0 || !rename_spawn_valid) {
+        fprintf(stderr, "rename success: rc=%d errno=%d valid=%d\n",
+                rc, guest_errno, rename_spawn_valid);
+        return 1;
+    }
+
+    atomic_store(&g_rename_spawn_valid, 0);
+    rc = ish_embed_rename_noreplace(
+        inst, "/source", "/malformed", 1000, &guest_errno);
+    rename_spawn_valid = atomic_load(&g_rename_spawn_valid);
+    if (rc != ISH_ERR_PROTOCOL || guest_errno != 0 ||
+        !rename_spawn_valid) {
+        fprintf(stderr, "rename malformed record: rc=%d errno=%d valid=%d\n",
+                rc, guest_errno, rename_spawn_valid);
+        return 1;
+    }
+
+    atomic_store(&g_rename_spawn_valid, 0);
+    rc = ish_embed_rename_noreplace(
+        inst, "/source", "/oversized", 1000, &guest_errno);
+    rename_spawn_valid = atomic_load(&g_rename_spawn_valid);
+    if (rc != ISH_ERR_PROTOCOL || guest_errno != 0 ||
+        !rename_spawn_valid) {
+        fprintf(stderr, "rename oversized record: rc=%d errno=%d valid=%d\n",
+                rc, guest_errno, rename_spawn_valid);
+        return 1;
+    }
+
+    atomic_store(&g_rename_spawn_valid, 0);
+    rc = ish_embed_rename_noreplace(
+        inst, "/source", "/timeout", 25, &guest_errno);
+    rename_spawn_valid = atomic_load(&g_rename_spawn_valid);
+    if (rc != ISH_ERR_TIMEOUT || guest_errno != 0 ||
+        !rename_spawn_valid) {
+        fprintf(stderr, "rename timeout: rc=%d errno=%d valid=%d\n",
+                rc, guest_errno, rename_spawn_valid);
+        return 1;
+    }
+
+    struct rename_call_args rename_args = {
+        .inst = inst,
+        .rc = ISH_ERR_INTERNAL,
+        .guest_errno = -1,
+    };
+    pthread_t rename_thread;
+    if (pthread_create(&rename_thread, NULL, rename_call_main,
+                       &rename_args) != 0 ||
+        !wait_fake_flag(&g_rename_waiting, 1000)) {
+        fprintf(stderr, "rename concurrent call did not block\n");
+        return 1;
+    }
+    rc = ish_embed_shutdown(inst, 10);
+    if (rc != ISH_ERR_BUSY) {
+        fprintf(stderr, "rename concurrent shutdown: rc=%d\n", rc);
+        return 1;
+    }
+    pthread_mutex_lock(&g_fake_lock);
+    g_release_rename = 1;
+    pthread_cond_broadcast(&g_fake_cond);
+    pthread_mutex_unlock(&g_fake_lock);
+    if (pthread_join(rename_thread, NULL) != 0 ||
+        rename_args.rc != ISH_OK || rename_args.guest_errno != 0) {
+        fprintf(stderr, "rename concurrent completion: rc=%d errno=%d\n",
+                rename_args.rc, rename_args.guest_errno);
+        return 1;
+    }
+
+    rc = ish_embed_shutdown(inst, 2000);
+    if (rc != ISH_OK) {
+        fprintf(stderr, "rename shutdown: rc=%d\n", rc);
+        return 1;
+    }
+    fprintf(stderr, "atomic no-replace rename API: OK\n");
+    return 0;
+}
+
 int main(int argc, char **argv) {
     if (argc == 3 && strcmp(argv[1], "malformed-event") == 0) {
         if (strcmp(argv[2], "spawned") == 0)
@@ -3392,7 +3607,7 @@ int main(int argc, char **argv) {
         return 2;
     }
     if (argc != 2) {
-        fprintf(stderr, "usage: %s boot-timeout|bad-hello-ack|install-failure|bundled-supervisor-digest-mismatch|bundled-supervisor-path-mismatch|custom-supervisor|boot-null-output|stdin-close-order|control-frame-limit|control-critical-close|control-same-session-close|control-exited-same-session-close|signal-close-order|resize-close-order|terminate-close-order|control-critical-oneshot|control-preblocked-oneshot|control-byte-limit|control-byte-reserve|control-spawn-gate|control-oneshot-spawn-lock|control-streaming-spawn-lock|control-finite-streaming|control-finite-streaming-write|control-streaming-queue-deadline|control-streaming-stdin-deadline|control-streaming-precommit-deadline|streaming-instance-gate|supervisor-error|close-race|backlog|frame-backlog|backlog-control-pressure|borrow-shutdown|double-shutdown|active-call|broken-control|protocol-fatal|protocol-fatal-control-pressure|malformed-event TYPE|output-allocation-failure|spawn-argument-bound|shutdown-drain|log-backpressure|oneshot-timeout|oneshot-output\n", argv[0]);
+        fprintf(stderr, "usage: %s boot-timeout|bad-hello-ack|install-failure|bundled-supervisor-digest-mismatch|bundled-supervisor-path-mismatch|custom-supervisor|boot-null-output|stdin-close-order|control-frame-limit|control-critical-close|control-same-session-close|control-exited-same-session-close|signal-close-order|resize-close-order|terminate-close-order|control-critical-oneshot|control-preblocked-oneshot|control-byte-limit|control-byte-reserve|control-spawn-gate|control-oneshot-spawn-lock|control-streaming-spawn-lock|control-finite-streaming|control-finite-streaming-write|control-streaming-queue-deadline|control-streaming-stdin-deadline|control-streaming-precommit-deadline|streaming-instance-gate|supervisor-error|close-race|backlog|frame-backlog|backlog-control-pressure|borrow-shutdown|double-shutdown|active-call|broken-control|protocol-fatal|protocol-fatal-control-pressure|malformed-event TYPE|output-allocation-failure|spawn-argument-bound|shutdown-drain|log-backpressure|oneshot-timeout|oneshot-output|rename-noreplace\n", argv[0]);
         return 2;
     }
     if (strcmp(argv[1], "boot-timeout") == 0) return test_boot_timeout_cleanup();
@@ -3452,6 +3667,7 @@ int main(int argc, char **argv) {
     if (strcmp(argv[1], "log-backpressure") == 0) return test_log_sink_backpressure();
     if (strcmp(argv[1], "oneshot-timeout") == 0) return test_oneshot_hard_timeout();
     if (strcmp(argv[1], "oneshot-output") == 0) return test_oneshot_output_limit();
+    if (strcmp(argv[1], "rename-noreplace") == 0) return test_rename_noreplace_api();
     fprintf(stderr, "unknown test: %s\n", argv[1]);
     return 2;
 }
diff --git a/c-tests/supervisor_stdin_test.c b/c-tests/supervisor_stdin_test.c
index 50a5358..c9f81a8 100644
--- a/c-tests/supervisor_stdin_test.c
+++ b/c-tests/supervisor_stdin_test.c
@@ -16,6 +16,7 @@ int (*ishsv_test_waitid_hook)(idtype_t, id_t, siginfo_t *, int);
 pid_t (*ishsv_test_waitpid_hook)(pid_t, int *, int);
 int (*ishsv_test_kill_hook)(pid_t, int);
 pid_t (*ishsv_test_tcgetpgrp_hook)(int);
+int (*ishsv_test_rename_noreplace_hook)(const char *, const char *);
 #if defined(__linux__)
 int (*ishsv_test_adopted_scan_hook)(struct proc_child_identity *);
 #endif
@@ -51,6 +52,59 @@ static void read_expected_frame(int fd, uint8_t expected_type,
     if (len > 0) CHECK(read_full(fd, payload, len) == 0);
 }
 
+static int rename_hook_result;
+static int rename_hook_errno;
+static char rename_hook_source[128];
+static char rename_hook_destination[128];
+
+static int capture_rename_noreplace(const char *source,
+                                    const char *destination) {
+    snprintf(rename_hook_source, sizeof(rename_hook_source), "%s", source);
+    snprintf(rename_hook_destination, sizeof(rename_hook_destination), "%s",
+             destination);
+    errno = rename_hook_errno;
+    return rename_hook_result;
+}
+
+static void run_rename_helper_case(int result, int error,
+                                   const char *expected_record) {
+    int output[2];
+    CHECK(pipe(output) == 0);
+    int saved_stdout = dup(STDOUT_FILENO);
+    CHECK(saved_stdout >= 0);
+    CHECK(dup2(output[1], STDOUT_FILENO) == STDOUT_FILENO);
+    close(output[1]);
+
+    rename_hook_result = result;
+    rename_hook_errno = error;
+    rename_hook_source[0] = '\0';
+    rename_hook_destination[0] = '\0';
+    ishsv_test_rename_noreplace_hook = capture_rename_noreplace;
+    char *argv[] = {
+        "ishsv", "--rename-noreplace", "/workspace/source",
+        "/workspace/destination", NULL,
+    };
+    CHECK(run_rename_noreplace_helper(4, argv) == 0);
+    CHECK(dup2(saved_stdout, STDOUT_FILENO) == STDOUT_FILENO);
+    close(saved_stdout);
+
+    char record[32] = {0};
+    ssize_t count = read(output[0], record, sizeof(record));
+    close(output[0]);
+    CHECK(count == (ssize_t)strlen(expected_record));
+    CHECK(memcmp(record, expected_record, (size_t)count) == 0);
+    CHECK(strcmp(rename_hook_source, "/workspace/source") == 0);
+    CHECK(strcmp(rename_hook_destination, "/workspace/destination") == 0);
+    ishsv_test_rename_noreplace_hook = NULL;
+}
+
+static void test_rename_noreplace_helper(void) {
+    run_rename_helper_case(0, 0, "0\n");
+    run_rename_helper_case(-1, EEXIST, "17\n");
+    char *bad_argv[] = {"ishsv", "--rename-noreplace", "/source", NULL};
+    CHECK(run_rename_noreplace_helper(3, bad_argv) == 64);
+}
+
 /* Exercise the production main loop across real host pipes. PID 1 starts
  * before the host writer in the app, so deliberately delay HELLO and prove
  * the blocking handshake does not mistake EAGAIN for EOF/failure. */
@@ -71,7 +125,8 @@ static void test_delayed_hello_full_main(void) {
         close(null_fd);
         close(control[0]);
         close(events[1]);
-        _exit(ishsv_program_main());
+        char *argv[] = {"ishsv", NULL};
+        _exit(ishsv_program_main(1, argv));
     }
 
     close(control[0]);
@@ -168,7 +223,8 @@ static void test_output_flood_does_not_starve_control(void) {
         close(null_fd);
         close(control[0]);
         close(events[1]);
-        _exit(ishsv_program_main());
+        char *argv[] = {"ishsv", NULL};
+        _exit(ishsv_program_main(1, argv));
     }
 
     close(control[0]);
@@ -1441,6 +1497,7 @@ static void test_setsid_double_fork_escape_is_cleaned_before_exit(void) {
 
 int main(void) {
     signal(SIGPIPE, SIG_IGN);
+    test_rename_noreplace_helper();
     test_delayed_hello_full_main();
     test_output_flood_does_not_starve_control();
     test_spawn_parser_rejects_wrapping_lengths();
diff --git a/c-tests/swift_bridge_smoke.c b/c-tests/swift_bridge_smoke.c
new file mode 100644
index 0000000..0f1b240
--- /dev/null
+++ b/c-tests/swift_bridge_smoke.c
@@ -0,0 +1,17 @@
+/* Link-only probe for the Swift source target's weak compatibility fallback.
+ *
+ * ish_embed_strerror forces the established host/ishembed archive member into
+ * the final link. That same member contains the strong rename implementation,
+ * which must override CIshEmbed.c's fallback definition.
+ */
+
+#include "ishembed.h"
+#include "IshEmbedSwiftShim.h"
+
+int main(void) {
+    const char *status = ish_embed_strerror(ISH_OK);
+    int32_t guest_errno = 0;
+    int rc = ish_embed_swift_rename_noreplace(
+        NULL, "/source", "/destination", 1, &guest_errno);
+    return status != NULL && rc == ISH_ERR_INVALID_ARG ? 0 : 1;
+}
diff --git a/docs/README.en.md b/docs/README.en.md
index 8917a97..fd21a30 100644
--- a/docs/README.en.md
+++ b/docs/README.en.md
@@ -14,13 +14,13 @@ primary language; the English mirrors support collaboration and release review.
    authoritative. Stage1 uses exact-match v4 between host and embedded supervisor.
 3. **Swift source and manifest binary**: Stage1 Swift remains v0.3.3-ABI
    compatible and does not call retain/release. The manifest currently pins the
-   public `v0.4.0-abi.5`; the release transaction moves it to the
-   `v0.4.0-abi.6` maintenance binary only after those assets are public and
+   public `v0.4.0-abi.6`; the release transaction moves it to the
+   `v0.4.0-abi.7` maintenance binary only after those assets are public and
    verified.
 4. **RootFS and PocketRoot**: RootFS is an independent asset and PocketRoot is
    the product layer. Neither is completed automatically by a runtime PR or Release.
 
-`v0.4.0-abi.5` and its `v0.4.0-abi.6` maintenance release are native-first
+`v0.4.0-abi.6` and its `v0.4.0-abi.7` maintenance release are native-first
 transition prereleases, not stable v0.4. The complete Swift lifecycle, typed
 statuses, Terminal callback queue, and VT parser changes belong to Stage2.
 
@@ -44,7 +44,7 @@ statuses, Terminal callback queue, and VT parser changes belong to Stage2.
 | [Architecture and lifecycle](architecture.en.md) | How is the runtime implemented? How do ABI 1 and wire v4 differ? |
 | [Testing and acceptance](testing.en.md) | What do native, sanitizer, Swift/iOS 18, documentation, and supply-chain gates prove? |
 | [Troubleshooting](troubleshooting.en.md) | Where should boot, link, protocol, output, shutdown, or release diagnosis start? |
-| [Release transaction](releasing.en.md) | Why does the merged maintenance source still pin `v0.4.0-abi.5`, and when does it become `v0.4.0-abi.6`? |
+| [Release transaction](releasing.en.md) | Why does the merged maintenance source still pin `v0.4.0-abi.6`, and when does it become `v0.4.0-abi.7`? |
 | [Changelog](../CHANGELOG.en.md) | What is Stage1's scope and compatibility boundary? |
 
 ## Architecture on one page
@@ -99,7 +99,7 @@ fixes can still go upstream. See the
   A direct-chain or RET target returns to the dispatcher only when it intersects
   pending dirty code pages; data-only writes may keep chaining.
 - RootFS is outside the package/Release and must not enter Corresponding Source.
-- The current `v0.4.0-abi.6` source change carries no RootFS or prebuilt binary;
+- The current `v0.4.0-abi.7` source change carries no RootFS or prebuilt binary;
   a later release transaction must produce the XCFramework.
 
 ## Authoritative sources
diff --git a/docs/README.md b/docs/README.md
index b23e46f..508f1e8 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -12,12 +12,12 @@
 2. **内部 wire protocol**：权威定义为 [`protocol/proto.h`](../protocol/proto.h)，
    Stage1 是 host 与内嵌 supervisor 精确匹配的 v4。
 3. **Swift 源与 manifest binary**：Stage1 Swift 保持 v0.3.3 ABI 兼容且不调用
-   retain/release。manifest 当前固定已公开的 `v0.4.0-abi.5`；只有
-   `v0.4.0-abi.6` 资产公开并验证后，发布事务才将其切到维护 binary。
+   retain/release。manifest 当前固定已公开的 `v0.4.0-abi.6`；只有
+   `v0.4.0-abi.7` 资产公开并验证后，发布事务才将其切到维护 binary。
 4. **RootFS 与 PocketRoot**：RootFS 是独立资产；PocketRoot 是上层产品。两者均不因
    runtime PR 或 Release 自动完成。
 
-`v0.4.0-abi.5` 与维护版本 `v0.4.0-abi.6` 都是 native-first 过渡预发布，不是稳定
+`v0.4.0-abi.6` 与维护版本 `v0.4.0-abi.7` 都是 native-first 过渡预发布，不是稳定
 v0.4。完整 Swift lifecycle、类型化状态、Terminal callback 队列和 VT parser 改造
 属于 Stage2。
 
@@ -39,7 +39,7 @@ v0.4。完整 Swift lifecycle、类型化状态、Terminal callback 队列和 VT
 | [架构与生命周期](architecture.md) | runtime 怎样实现？ABI 1 与 wire v4 有什么区别？ |
 | [测试与验收](testing.md) | native、sanitizer、Swift/iOS 18、文档与供应链门禁各证明什么？ |
 | [故障排查](troubleshooting.md) | boot、链接、协议、输出、shutdown 或发布失败时从哪里查？ |
-| [发布事务](releasing.md) | 为什么维护源码合入后 manifest 仍是 `v0.4.0-abi.5`？何时变成 `v0.4.0-abi.6`？ |
+| [发布事务](releasing.md) | 为什么维护源码合入后 manifest 仍是 `v0.4.0-abi.6`？何时变成 `v0.4.0-abi.7`？ |
 | [变更日志](../CHANGELOG.md) | Stage1 的范围和兼容边界是什么？ |
 
 ## 一页架构
@@ -85,7 +85,7 @@ Swift 对象不是另一套 runtime。它们包装 C handle；C 层管理线程
 - JIT 单页写及显式 `invalidate_page` 按精确页过滤；仅多页哈希位图可能因碰撞保守多
   失效。下一直链/RET 目标命中待处理代码脏页时才回到 dispatcher；纯数据写可继续直链。
 - RootFS 不属于 package/release，禁止将其混入 Corresponding Source。
-- 当前 `v0.4.0-abi.6` 源码变更不携带 RootFS 或预构建二进制；XCFramework 必须由
+- 当前 `v0.4.0-abi.7` 源码变更不携带 RootFS 或预构建二进制；XCFramework 必须由
   后续发布事务生成。
 
 ## 权威来源
diff --git a/docs/releasing.en.md b/docs/releasing.en.md
index 9027b10..b8d47f1 100644
--- a/docs/releasing.en.md
+++ b/docs/releasing.en.md
@@ -3,29 +3,29 @@
 [简体中文](releasing.md) | English
 
 This guide is for maintainers publishing the XCFramework and matching
-Corresponding Source. `v0.4.0-abi.5` is already public; the only next tag
+Corresponding Source. `v0.4.0-abi.6` is already public; the only next tag
 allowed for preparation is the compatible maintenance release
-`v0.4.0-abi.6`. It remains an ABI-transition prerelease that is **not stable
+`v0.4.0-abi.7`. It remains an ABI-transition prerelease that is **not stable
 v0.4.0**. Publication
 creates a public GitHub Release and updates the default branch, so run it only
 with explicit release authorization.
 
-## State before and after `v0.4.0-abi.6` publication
+## State before and after `v0.4.0-abi.7` publication
 
 ### After the maintenance PR merges, before Release publication
 
-- `Package.swift` still pins the published `v0.4.0-abi.5` URL/checksum;
+- `Package.swift` still pins the published `v0.4.0-abi.6` URL/checksum;
 - Swift source remains v0.3.3-ABI compatible and does not call retain/release;
 - repository source contains the published abi.2 procfs/task lifecycle fixes,
-  abi.3 guest `uname` field bounds, abi.4 internal-SIGUSR1 fix, and abi.5 finite
-  streaming control-path deadline, plus the pending abi.6 Swift-marshalling and
-  stdin-close original-deadline reuse fixes;
-- there is no installable `v0.4.0-abi.6` binary.
+  abi.3 guest `uname` field bounds, abi.4 internal-SIGUSR1 fix, abi.5 finite
+  streaming control-path deadline, and abi.6 Swift-marshalling/stdin-close
+  deadline reuse, plus the pending abi.7 guest-atomic no-replace rename;
+- there is no installable `v0.4.0-abi.7` binary.
 
 This intermediate state is intentional: the default branch never advertises an
 unpublished asset URL that returns 404.
 
-### After successful `v0.4.0-abi.6` publication
+### After successful `v0.4.0-abi.7` publication
 
 - the release commit changes only `Package.swift`, pinning the new XCFramework
   URL/checksum;
@@ -75,7 +75,7 @@ scripts/test-swift-ios.sh --local-binary
 ```
 
 `--manifest-binary` proves that Stage1 Swift still links the currently pinned
-`v0.4.0-abi.5` binary. `--local-binary` proves that the same Swift source links
+`v0.4.0-abi.6` binary. `--local-binary` proves that the same Swift source links
 the maintenance XCFramework. Both boundaries are required.
 
 ## Execute
@@ -83,7 +83,7 @@ the maintenance XCFramework. Both boundaries are required.
 After confirming that the tag is absent and publication is authorized:
 
 ```sh
-scripts/release.sh v0.4.0-abi.6
+scripts/release.sh v0.4.0-abi.7
 ```
 
 The script derives GitHub `prerelease=true` from the SemVer suffix. Only
@@ -91,7 +91,7 @@ The script derives GitHub `prerelease=true` from the SemVer suffix. Only
 that this is not stable v0.4, describes native lifecycle/retain-release/
 join-soft-halt/wire v4, and records the Swift and RootFS boundaries.
 In addition to strict SemVer validation, the Stage1 policy rejects every tag
-except `v0.4.0-abi.6`. Reusing `v0.4.0-abi.5` or accidentally entering
+except `v0.4.0-abi.7`. Reusing `v0.4.0-abi.6` or accidentally entering
 `v0.4.0` therefore fails before any tag, draft, or asset is written.
 
 Do not substitute `v0.4.0`. A stable tag must wait for a separate decision after
@@ -148,9 +148,9 @@ and explicit owner authorization.
 ## Post-publication acceptance
 
 ```sh
-gh release view v0.4.0-abi.6 --repo jacklv-coder/ish-arm64-pkg
+gh release view v0.4.0-abi.7 --repo jacklv-coder/ish-arm64-pkg
 git fetch origin --tags
-git show v0.4.0-abi.6:Package.swift
+git show v0.4.0-abi.7:Package.swift
 git pull --ff-only origin main
 scripts/test-swift-ios.sh --manifest-binary
 ```
@@ -184,8 +184,8 @@ manual recovery.
 
 ## PocketRoot upgrade gate
 
-PocketRoot may move its dependency from `v0.4.0-abi.5` to the maintenance
-release only after the public `v0.4.0-abi.6` assets, manifest update, and
+PocketRoot may move its dependency from `v0.4.0-abi.6` to the maintenance
+release only after the public `v0.4.0-abi.7` assets, manifest update, and
 post-publication real link all pass, followed by its Xcode 16/iOS 18 gates.
 Stage2 and a native Agent Loop are outside this release. Either still requires
 an independent plan, review, tests, documentation, and release decision.
diff --git a/docs/releasing.md b/docs/releasing.md
index 55ce1f3..8d16a5f 100644
--- a/docs/releasing.md
+++ b/docs/releasing.md
@@ -2,25 +2,26 @@
 
 简体中文｜[English](releasing.en.md)
 
-本文用于维护者发布 XCFramework 与匹配的 Corresponding Source。`v0.4.0-abi.5`
-已经公开；当前唯一允许准备的下一个标签是兼容性维护版本 `v0.4.0-abi.6`。它仍是 ABI
+本文用于维护者发布 XCFramework 与匹配的 Corresponding Source。`v0.4.0-abi.6`
+已经公开；当前唯一允许准备的下一个标签是兼容性维护版本 `v0.4.0-abi.7`。它仍是 ABI
 过渡 prerelease，**不是稳定 v0.4.0**。执行发布会创建公开 GitHub Release 和更新
 默认分支，必须在获得明确发布授权后进行。
 
-## `v0.4.0-abi.6` 发布前后状态
+## `v0.4.0-abi.7` 发布前后状态
 
 ### 维护 PR 合入后、Release 发布前
 
-- `Package.swift` 仍固定已发布的 `v0.4.0-abi.5` URL/checksum；
+- `Package.swift` 仍固定已发布的 `v0.4.0-abi.6` URL/checksum；
 - Swift 源保持 v0.3.3 ABI 兼容，不调用 retain/release；
 - 仓库源码包含已发布的 abi.2 procfs/task 生命周期修复、abi.3 guest `uname`
   字段边界修复、abi.4 内部 SIGUSR1 解屏蔽修复、abi.5 有限 streaming control-path
-  deadline，以及待发布 abi.6 的 Swift 参数封送与 stdin-close 原始 deadline 复用修复；
-- 没有可供使用方安装的 `v0.4.0-abi.6` binary。
+  deadline、abi.6 Swift 参数封送与 stdin-close deadline 复用，以及待发布 abi.7 的
+  guest 原子 no-replace rename；
+- 没有可供使用方安装的 `v0.4.0-abi.7` binary。
 
 这个中间状态是刻意设计的：默认分支不会先暴露一个尚未公开、会返回 404 的资产 URL。
 
-### `v0.4.0-abi.6` 成功发布后
+### `v0.4.0-abi.7` 成功发布后
 
 - release commit 只改 `Package.swift`，固定到新 XCFramework URL/checksum；
 - GitHub prerelease 包含 `libIshKernel.xcframework.zip` 与
@@ -63,7 +64,7 @@ scripts/verify-ios-artifact.sh
 scripts/test-swift-ios.sh --local-binary
 ```
 
-`--manifest-binary` 证明 Stage1 Swift 仍能链接当前固定的 `v0.4.0-abi.5` binary；
+`--manifest-binary` 证明 Stage1 Swift 仍能链接当前固定的 `v0.4.0-abi.6` binary；
 `--local-binary` 证明相同 Swift 能链接待发布的 ABI 过渡 XCFramework。两者缺一不可。
 
 ## 执行
@@ -71,14 +72,14 @@ scripts/test-swift-ios.sh --local-binary
 确认标签不存在且获得发布授权后：
 
 ```sh
-scripts/release.sh v0.4.0-abi.6
+scripts/release.sh v0.4.0-abi.7
 ```
 
 脚本根据 SemVer 后缀设置 GitHub `prerelease=true`。只有 `v*-abi.*` 标签会附加专用
 中英文说明，明确它不是稳定 v0.4，列出 native lifecycle/retain-release/
 join-soft-halt/wire v4，并说明 Swift 和 RootFS 边界。
-除了 SemVer 检查，Stage1 版本策略还会硬性拒绝除 `v0.4.0-abi.6` 以外的任何标签。
-因此重用 `v0.4.0-abi.5` 或误输入 `v0.4.0`，都会在任何 tag、draft 或资产写入前失败。
+除了 SemVer 检查，Stage1 版本策略还会硬性拒绝除 `v0.4.0-abi.7` 以外的任何标签。
+因此重用 `v0.4.0-abi.6` 或误输入 `v0.4.0`，都会在任何 tag、draft 或资产写入前失败。
 
 不要用 `v0.4.0` 代替过渡标签。稳定标签必须等 Stage2 合入、迁移与回归完成后另行决定。
 
@@ -125,9 +126,9 @@ LICENSE/NOTICE、对应源码、SBOM、PocketRoot manifest 更新和负责人明
 ## 发布后验收
 
 ```sh
-gh release view v0.4.0-abi.6 --repo jacklv-coder/ish-arm64-pkg
+gh release view v0.4.0-abi.7 --repo jacklv-coder/ish-arm64-pkg
 git fetch origin --tags
-git show v0.4.0-abi.6:Package.swift
+git show v0.4.0-abi.7:Package.swift
 git pull --ff-only origin main
 scripts/test-swift-ios.sh --manifest-binary
 ```
@@ -158,7 +159,7 @@ scripts/test-swift-ios.sh --manifest-binary
 
 ## PocketRoot 升级条件
 
-只有 `v0.4.0-abi.6` 公开资产、manifest 更新和发布后真链接全部通过，PocketRoot 才能
-把依赖从 `v0.4.0-abi.5` 更新到该维护版本并重跑 Xcode 16/iOS 18 门禁。Stage2 与
+只有 `v0.4.0-abi.7` 公开资产、manifest 更新和发布后真链接全部通过，PocketRoot 才能
+把依赖从 `v0.4.0-abi.6` 更新到该维护版本并重跑 Xcode 16/iOS 18 门禁。Stage2 与
 原生 Agent Loop 均不在本次发布范围内；未来启用时仍需独立计划、CR、测试、文档和
 发布决策。
diff --git a/docs/testing.en.md b/docs/testing.en.md
index 1982465..c9929fb 100644
--- a/docs/testing.en.md
+++ b/docs/testing.en.md
@@ -16,25 +16,25 @@ wire v4, and release supply chain.
 | Native integration | `internal-signal-mask`, `procfs_test`, `ishembed_smoke` | internal SIGUSR1 masks on embedded/guest task threads, fakefs, spawn, procfs, a real guest `uname -a`, and the general command path | RootFS provenance/license is trustworthy; compatibility with a particular user tool |
 | Sanitizers | ASan/UBSan and TSan where applicable | bounds, UAF, undefined behavior, and races on covered paths | every schedule is defect-free |
 | RootFS-free Swift | instance/session gates, shutdown retry, public API smoke | oneshot/session leases prevent old-ABI UAF, failure keeps the handle, old public signatures compile | every C call is cancellable or close is always bounded |
-| Swift manifest real link | `test-swift-ios.sh --manifest-binary` | Stage1 Swift links the current `v0.4.0-abi.5` binary | `v0.4.0-abi.6` fixes are public |
+| Swift manifest real link | `test-swift-ios.sh --manifest-binary` | Stage1 Swift links the current `v0.4.0-abi.6` binary | `v0.4.0-abi.7` fixes are public |
 | Swift local real link | `test-swift-ios.sh --local-binary` | the same Swift links the maintenance XCFramework | GitHub assets are published |
 | XCFramework | `build-ios.sh` plus symbol/final-link checks | device/simulator arm64, minimum iOS 18, required symbols | product app behavior |
 | Docs/scripts | positive/negative docs gates, shell syntax, policy tests | bilingual links, diagnostics, release-notes/version/tag/source policy | documentation equals implementation |
 
 ## Confirm the Stage1 state first
 
-Before `v0.4.0-abi.6` publication, all of these should be true:
+Before `v0.4.0-abi.7` publication, all of these should be true:
 
 - `ISH_EMBED_ABI_VERSION` is 1;
 - `ISH_PROTO_VERSION` is 4;
 - Swift source does not call `ish_embed_session_retain/release`;
-- `Package.swift` still pins the public `v0.4.0-abi.5`;
+- `Package.swift` still pins the public `v0.4.0-abi.6`;
 - the locally built XCFramework exports retain/release and required join/soft-halt symbols;
 - RootFS content is absent from Git diff, XCFramework, source archive, and Release manifest.
 
-Only after publication should “manifest pins `v0.4.0-abi.6`” become the expected
+Only after publication should “manifest pins `v0.4.0-abi.7`” become the expected
 state. Do not apply that expectation to a correct pre-publication tree that
-still references the verified `v0.4.0-abi.5`.
+still references the verified `v0.4.0-abi.6`.
 
 ## Fast metadata and script gates
 
diff --git a/docs/testing.md b/docs/testing.md
index d51cb5b..f227850 100644
--- a/docs/testing.md
+++ b/docs/testing.md
@@ -15,24 +15,24 @@ iOS 18 二进制、内部 wire v4 和发布供应链处于同一可解释状态
 | native 集成 | `internal-signal-mask`、`procfs_test`、`ishembed_smoke` | 嵌入/guest task 内部 SIGUSR1 mask、fakefs、spawn、procfs、真实 guest `uname -a`、通用命令链路 | RootFS 来源/许可可信；特定用户工具兼容性 |
 | sanitizer | ASan/UBSan，必要时 TSan | 已覆盖路径上的越界、UAF、未定义行为和数据竞争 | 所有调度组合都无缺陷 |
 | Swift RootFS-free | instance/session gate、shutdown retry、公开 API smoke | oneshot/session lease 阻止旧 ABI UAF、失败保留 handle、旧公开签名可编译 | 任意 C 调用都可取消或 close 始终有界 |
-| Swift manifest 真链接 | `test-swift-ios.sh --manifest-binary` | Stage1 Swift 与当前 `v0.4.0-abi.5` binary 链接 | `v0.4.0-abi.6` 修复已公开 |
+| Swift manifest 真链接 | `test-swift-ios.sh --manifest-binary` | Stage1 Swift 与当前 `v0.4.0-abi.6` binary 链接 | `v0.4.0-abi.7` 修复已公开 |
 | Swift local 真链接 | `test-swift-ios.sh --local-binary` | 同一 Swift 与待发布维护 XCFramework 链接 | GitHub 资产已发布 |
 | XCFramework | `build-ios.sh` + symbol/final-link 检查 | device/simulator arm64、最低 iOS 18、必需符号 | App 产品逻辑 |
 | 文档/脚本 | docs 正负门禁、shell syntax、策略测试 | 双语链接、失败诊断、release notes/version/tag/source policy | 文档本身等于实现 |
 
 ## 先确认 Stage1 状态
 
-`v0.4.0-abi.6` 发布前应同时满足：
+`v0.4.0-abi.7` 发布前应同时满足：
 
 - `ISH_EMBED_ABI_VERSION` 为 1；
 - `ISH_PROTO_VERSION` 为 4；
 - Swift 源不调用 `ish_embed_session_retain/release`；
-- `Package.swift` 仍固定已公开的 `v0.4.0-abi.5`；
+- `Package.swift` 仍固定已公开的 `v0.4.0-abi.6`；
 - 本地构建的新 XCFramework 导出 retain/release、join/soft-halt 等必需符号；
 - RootFS 没有出现在 Git diff、XCFramework、source archive 或 Release 清单中。
 
-发布后才把“manifest 固定到 `v0.4.0-abi.6`”加入预期。不能用发布后的预期否定
-发布前仍引用已验证 `v0.4.0-abi.5` 的正确状态。
+发布后才把“manifest 固定到 `v0.4.0-abi.7`”加入预期。不能用发布后的预期否定
+发布前仍引用已验证 `v0.4.0-abi.6` 的正确状态。
 
 ## 快速元数据与脚本门禁
 
diff --git a/docs/troubleshooting.en.md b/docs/troubleshooting.en.md
index 47c24ac..5b8ca4c 100644
--- a/docs/troubleshooting.en.md
+++ b/docs/troubleshooting.en.md
@@ -29,8 +29,8 @@ checksum, and RootFS provenance, size, and SHA-256. Without this matrix, logs
 may describe different states.
 
 The current correct combination is C ABI 1, wire v4, Swift not calling
-retain/release, and a manifest pointing at the public `v0.4.0-abi.5`. After
-`v0.4.0-abi.6` publication, only the manifest URL/checksum should switch to the
+retain/release, and a manifest pointing at the public `v0.4.0-abi.6`. After
+`v0.4.0-abi.7` publication, only the manifest URL/checksum should switch to the
 maintenance asset.
 
 ## Missing retain/release or other link symbols
@@ -47,24 +47,24 @@ nm -gU path/to/libIshKernel.a | awk '{print $NF}' | sort -u \
   old-ABI-compatible Swift layer rather than expanding this maintenance release.
 - If a local Stage1 XCFramework lacks them, it was built from an old commit,
   gitlink, or cache. Rebuild in an isolated path.
-- If `v0.4.0-abi.6` is public but the manifest is still `v0.4.0-abi.5`, inspect
+- If `v0.4.0-abi.7` is public but the manifest is still `v0.4.0-abi.6`, inspect
   whether the release commit/default-branch fast-forward completed. Never guess
   a checksum.
 
 ## `Package.swift` looks “not updated”
 
-Between the maintenance PR merge and Release publication, a `v0.4.0-abi.5`
+Between the maintenance PR merge and Release publication, a `v0.4.0-abi.6`
 manifest pin is expected. The release script rebuilds and validates assets from
 the merged commit, creates a manifest-only release commit, publishes and
 verifies assets, then fast-forwards the default branch. Thus the branch never
 advertises a 404 URL.
 
-Only after confirming that the `v0.4.0-abi.6` Release is public is an old
+Only after confirming that the `v0.4.0-abi.7` Release is public is an old
 manifest abnormal:
 
 ```sh
-gh release view v0.4.0-abi.6 --repo jacklv-coder/ish-arm64-pkg
-git ls-remote --tags origin refs/tags/v0.4.0-abi.6
+gh release view v0.4.0-abi.7 --repo jacklv-coder/ish-arm64-pkg
+git ls-remote --tags origin refs/tags/v0.4.0-abi.7
 git fetch origin
 git log --oneline --decorate -5 origin/main
 ```
@@ -110,9 +110,10 @@ cannot confirm cleanup, or a later command cannot recover.
   and every guest task thread, allowing guest signals to interrupt blocking
   host syscalls.
 - The published `v0.4.0-abi.5` adds the finite streaming control-path deadline
-  on top of that behavior. Planned `v0.4.0-abi.6` completes Swift-marshalling
-  and stdin-close reuse of the original SPAWN deadline; neither changes guest
-  signal semantics.
+  on top of that behavior. Published `v0.4.0-abi.6` completes Swift-marshalling
+  and stdin-close reuse of the original SPAWN deadline. Planned
+  `v0.4.0-abi.7` adds guest-atomic no-replace rename; none changes guest signal
+  semantics.
 - Source validation should run iSH's `internal-signal-mask` test, package-level
   host/iOS tests, and a real-RootFS “cancel → native termination confirmed →
   later command → shutdown” flow.
diff --git a/docs/troubleshooting.md b/docs/troubleshooting.md
index d55da0e..4bc3563 100644
--- a/docs/troubleshooting.md
+++ b/docs/troubleshooting.md
@@ -26,7 +26,7 @@ git status --short
 来源、大小和 SHA-256。没有这组信息，后续日志可能来自不同状态。
 
 当前正确组合是：C ABI 1、wire v4、Swift 不调用 retain/release、manifest 指向已公开
-的 `v0.4.0-abi.5`。发布 `v0.4.0-abi.6` 后，只有 manifest URL/checksum 应切到维护资产。
+的 `v0.4.0-abi.6`。发布 `v0.4.0-abi.7` 后，只有 manifest URL/checksum 应切到维护资产。
 
 ## 链接缺少 retain/release 或其他符号
 
@@ -44,20 +44,20 @@ nm -gU path/to/libIshKernel.a | awk '{print $NF}' | sort -u \
   旧 ABI 兼容 Swift，而不是扩大本次维护发布范围。
 - 如果检查的是本地 Stage1 XCFramework 而符号缺失，说明构建用了旧 commit、旧 gitlink
   或缓存；用隔离 build 路径重建。
-- 如果 `v0.4.0-abi.6` 已发布但 manifest 仍是 `v0.4.0-abi.5`，检查 release
+- 如果 `v0.4.0-abi.7` 已发布但 manifest 仍是 `v0.4.0-abi.6`，检查 release
   commit/default branch fast-forward 是否完成；不要手工猜 checksum。
 
 ## Package.swift 看起来“还没更新”
 
-维护 PR 合入到 Release 发布前，manifest 固定 `v0.4.0-abi.5` 是预期状态。发布脚本先
+维护 PR 合入到 Release 发布前，manifest 固定 `v0.4.0-abi.6` 是预期状态。发布脚本先
 从合入 commit 重建/验证资产，再创建只更新 manifest 的 release commit，先公开并校验
 资产，最后 fast-forward 默认分支。这样默认分支不会引用 404 URL。
 
-只有已经确认 `v0.4.0-abi.6` Release 公开后，manifest 仍旧才是异常。此时检查：
+只有已经确认 `v0.4.0-abi.7` Release 公开后，manifest 仍旧才是异常。此时检查：
 
 ```sh
-gh release view v0.4.0-abi.6 --repo jacklv-coder/ish-arm64-pkg
-git ls-remote --tags origin refs/tags/v0.4.0-abi.6
+gh release view v0.4.0-abi.7 --repo jacklv-coder/ish-arm64-pkg
+git ls-remote --tags origin refs/tags/v0.4.0-abi.7
 git fetch origin
 git log --oneline --decorate -5 origin/main
 ```
@@ -94,8 +94,9 @@ Linux `new_utsname` 65 字节字段宽度的宿主 hostname 触发。
 - `v0.4.0-abi.4` 已在嵌入启动线程和每个 guest task 线程明确解除内部 SIGUSR1
   屏蔽，使 guest signal 能打断阻塞中的宿主 syscall。
 - 已发布的 `v0.4.0-abi.5` 在此基础上增加有限 streaming control-path deadline。
-  待发布的 `v0.4.0-abi.6` 补全 Swift 参数封送和 stdin close 对原始 SPAWN deadline
-  的复用；两者都不改变 guest signal 语义。
+  已发布的 `v0.4.0-abi.6` 补全 Swift 参数封送和 stdin close 对原始 SPAWN deadline
+  的复用；待发布的 `v0.4.0-abi.7` 新增 guest 原子 no-replace rename；三者都不改变
+  guest signal 语义。
 - 源码验证应运行 iSH 的 `internal-signal-mask` 测试、包级 host/iOS 测试，并在真实
   RootFS 上确认“取消 → native termination confirmed → 后续命令 → shutdown”完整链路。
 
diff --git a/ffi/ish_ffi.c b/ffi/ish_ffi.c
index d168571..102a1ce 100644
--- a/ffi/ish_ffi.c
+++ b/ffi/ish_ffi.c
@@ -363,7 +363,7 @@ int ish_ffi_install_executable(const char *guest_path,
     err = generic_setattrat(AT_PWD, temp_path, a, false);
     if (err < 0) goto fail_temp;
 
-    err = generic_renameat(AT_PWD, temp_path, AT_PWD, guest_path);
+    err = generic_renameat(AT_PWD, temp_path, AT_PWD, guest_path, 0);
     if (err < 0) goto fail_temp;
 
     /* fakefs updates a host file plus SQLite metadata. Reopen and compare the
diff --git a/host/ishembed.c b/host/ishembed.c
index 7442613..31a5fa7 100644
--- a/host/ishembed.c
+++ b/host/ishembed.c
@@ -201,6 +201,10 @@ struct ish_embed_instance {
     /* Private duplicate of the requested supervisor-log sink. A negative fd
      * means logs are drained and discarded. */
     int             kernel_log_fd;
+    /* Immutable guest path of the exact supervisor selected and executed at
+     * boot. Filesystem helpers spawn this same verified binary rather than a
+     * RootFS-owned compatibility path. */
+    char           *supervisor_guest_path;
 
     /* hello handshake */
     int             hello_acked;
@@ -1311,6 +1315,8 @@ int ish_embed_boot(const ish_embed_boot_opts_t *opts,
     size_t off = 0;
     size_t L = strlen(sup);
     if (L + 2 > sizeof(argv_packed)) { err = ISH_ERR_INVALID_ARG; goto fail; }
+    inst->supervisor_guest_path = strdup(sup);
+    if (!inst->supervisor_guest_path) { err = ISH_ERR_OOM; goto fail; }
     memcpy(argv_packed, sup, L); argv_packed[L] = 0; off = L + 1;
     argv_packed[off] = 0;
 
@@ -1436,6 +1442,7 @@ fail:;
     close_fd_slot(&inst->kernel_log_fd);
     if (exit_hook_registered) ish_ffi_register_exit_hook(NULL, NULL);
     destroy_instance_primitives(inst);
+    free(inst->supervisor_guest_path);
     free(inst);
     pthread_mutex_unlock(&g_instance_lock);
     return saved;
@@ -2229,6 +2236,98 @@ int ish_embed_run_oneshot(ish_embed_instance_t *inst,
     return ISH_OK;
 }
 
+static int parse_guest_errno_output(const uint8_t *buf, size_t len,
+                                    int32_t *out_guest_errno) {
+    if (!buf || !out_guest_errno || len < 2 || len > 11 ||
+        buf[len - 1] != '\n')
+        return ISH_ERR_PROTOCOL;
+    uint32_t value = 0;
+    for (size_t i = 0; i + 1 < len; i++) {
+        uint8_t ch = buf[i];
+        if (ch < '0' || ch > '9') return ISH_ERR_PROTOCOL;
+        uint32_t digit = (uint32_t)(ch - '0');
+        if (value > (uint32_t)INT32_MAX / 10u ||
+            (value == (uint32_t)INT32_MAX / 10u &&
+             digit > (uint32_t)INT32_MAX % 10u))
+            return ISH_ERR_PROTOCOL;
+        value = value * 10u + digit;
+    }
+    *out_guest_errno = (int32_t)value;
+    return ISH_OK;
+}
+
+int ish_embed_rename_noreplace(ish_embed_instance_t *inst,
+                               const char *source,
+                               const char *destination,
+                               uint32_t timeout_ms,
+                               int32_t *out_guest_errno) {
+    if (!inst || !source || !destination || !out_guest_errno ||
+        source[0] != '/' || source[1] == '\0' ||
+        destination[0] != '/' || destination[1] == '\0')
+        return ISH_ERR_INVALID_ARG;
+    *out_guest_errno = 0;
+
+    uint64_t deadline = timeout_ms > 0 ? now_ms() + timeout_ms : 0;
+    int gate = instance_call_begin_until(inst, deadline);
+    if (gate != ISH_OK) return gate;
+    char *helper_path = inst->supervisor_guest_path
+        ? strdup(inst->supervisor_guest_path) : NULL;
+    if (!helper_path) {
+        instance_call_end(inst);
+        return ISH_ERR_OOM;
+    }
+
+    uint32_t remaining_ms = 0;
+    if (deadline != 0) {
+        uint64_t now = now_ms();
+        if (now >= deadline) {
+            free(helper_path);
+            instance_call_end(inst);
+            return ISH_ERR_TIMEOUT;
+        }
+        uint64_t remaining = deadline - now;
+        remaining_ms = remaining > UINT32_MAX
+            ? UINT32_MAX : (uint32_t)remaining;
+        if (remaining_ms == 0) {
+            free(helper_path);
+            instance_call_end(inst);
+            return ISH_ERR_TIMEOUT;
+        }
+    }
+
+    const char *argv[] = {
+        helper_path,
+        "--rename-noreplace",
+        source,
+        destination,
+        NULL,
+    };
+    ish_embed_spawn_opts_t opts = {0};
+    opts.argv = argv;
+    opts.cwd = "/";
+    opts.timeout_ms = remaining_ms;
+    ish_embed_oneshot_result_t result;
+    int rc = ish_embed_run_oneshot(inst, &opts, &result);
+    free(helper_path);
+    if (rc != ISH_OK) {
+        instance_call_end(inst);
+        return rc;
+    }
+
+    if (result.timed_out) {
+        rc = ISH_ERR_TIMEOUT;
+    } else if (result.signal != 0 || result.exit_code != 0) {
+        rc = ISH_ERR_SUPERVISOR;
+    } else {
+        rc = parse_guest_errno_output(result.stdout_buf, result.stdout_len,
+                                      out_guest_errno);
+    }
+    ish_embed_free(result.stdout_buf);
+    ish_embed_free(result.stderr_buf);
+    instance_call_end(inst);
+    return rc;
+}
+
 void ish_embed_free(void *p) { free(p); }
 
 int ish_embed_setup_vm_root(ish_embed_instance_t *inst, const char *vm_root) {
@@ -2312,6 +2411,7 @@ int ish_embed_shutdown(ish_embed_instance_t *inst, uint32_t grace_ms) {
     destroy_instance_primitives(inst);
 
     g_instance = NULL;
+    free(inst->supervisor_guest_path);
     free(inst);
     pthread_mutex_unlock(&g_instance_lock);
     return ISH_OK;
@@ -2345,6 +2445,7 @@ const char *ish_embed_strerror(int s) {
         case ISH_ERR_BUSY: return "operation cannot proceed while runtime state is busy";
         case ISH_ERR_SUPERVISOR_INSTALL: return "bundled supervisor installation failed";
         case ISH_ERR_CONTROL_LIMIT: return "host control queue limit reached";
+        case ISH_ERR_UNSUPPORTED: return "feature unavailable in linked native binary";
         case ISH_ERR_INTERNAL: return "internal error";
         default: return "unknown";
     }
diff --git a/include/ishembed.h b/include/ishembed.h
index 80348ba..bac6e43 100644
--- a/include/ishembed.h
+++ b/include/ishembed.h
@@ -104,6 +104,7 @@ typedef enum {
     ISH_ERR_BUSY            = -19, /* operation cannot proceed while state busy */
     ISH_ERR_SUPERVISOR_INSTALL = -20, /* bundled PID 1 install/verification failed */
     ISH_ERR_CONTROL_LIMIT   = -21, /* host-to-guest control queue ceiling reached */
+    ISH_ERR_UNSUPPORTED     = -22, /* feature is unavailable in the linked native binary */
     ISH_ERR_INTERNAL        = -99,
 } ish_embed_status_t;
 
@@ -176,6 +177,22 @@ int ish_embed_run_oneshot(ish_embed_instance_t *inst,
                           const ish_embed_spawn_opts_t *opts,
                           ish_embed_oneshot_result_t *out_result);
 
+/* Atomically rename one guest-absolute path without replacing an existing
+ * destination. The operation runs inside the guest through the exact
+ * supervisor selected at boot; it does not invoke a shell or compose a
+ * check-then-rename sequence.
+ *
+ * Returns an ISH_* transport/lifecycle status. On ISH_OK,
+ * *out_guest_errno is 0 for success or a positive Linux errno (for example,
+ * EEXIST=17 when destination already exists). timeout_ms uses the same
+ * API-entry deadline semantics as run_oneshot; 0 retains the unbounded legacy
+ * behavior. source and destination must be non-empty guest-absolute paths. */
+int ish_embed_rename_noreplace(ish_embed_instance_t *inst,
+                               const char *source,
+                               const char *destination,
+                               uint32_t timeout_ms,
+                               int32_t *out_guest_errno);
+
 void ish_embed_free(void *p);
 
 /* Spawn and return a session handle for streaming I/O. With timeout_ms == 0,
diff --git a/meson.build b/meson.build
index f814047..983e28e 100644
--- a/meson.build
+++ b/meson.build
@@ -259,6 +259,8 @@ test('lifecycle_oneshot_timeout', lifecycle_test,
     args: ['oneshot-timeout'], timeout: 10)
 test('lifecycle_oneshot_output', lifecycle_test,
     args: ['oneshot-output'], timeout: 10)
+test('lifecycle_rename_noreplace', lifecycle_test,
+    args: ['rename-noreplace'], timeout: 10)
 
 # The supervisor runs inside Linux/iSH, but its stdin queue has a host-only
 # deterministic harness. Keep it out of iOS cross builds while running it in
diff --git a/scripts/release-version-policy.sh b/scripts/release-version-policy.sh
index b581ab1..45ef86a 100644
--- a/scripts/release-version-policy.sh
+++ b/scripts/release-version-policy.sh
@@ -5,7 +5,7 @@
 # existing tag and accidentally creating a stable tag before Stage2 is
 # integrated and separately authorized.
 ish_release_stage1_version_allowed() {
-    [[ "$1" == "v0.4.0-abi.6" ]]
+    [[ "$1" == "v0.4.0-abi.7" ]]
 }
 
 # Call only after the release entry point has validated strict SemVer.
@@ -27,23 +27,25 @@ ish_release_abi_transition_notes() {
 
 这不是稳定 v0.4。本预发布交付 native lifecycle 基础：session
 retain/release、可等待 kernel thread、soft-halt 与内部精确匹配 wire protocol v4。
-本维护版本从 Swift API 入口建立绝对 deadline，扣除 argv/env/cwd/chroot 封送耗时后
-将剩余时间交给 native；有限 streaming session 会保留原始 SPAWN deadline，并让 stdin
-close 在控制队列接纳时复用它。过期会返回 timeout，不会重新开始一段等待；active stdin
-write 持有顺序锁时 stdin close 仍会立即返回 busy。
-公开 C ABI 版本仍为 1。Swift 源仍保持 v0.3.3 ABI 兼容且不调用 retain/release；
+本维护版本新增无 shell、无 check-then-rename 竞争窗口的 guest 原子重命名能力。
+`ish_embed_rename_noreplace` 通过与当前 runtime 精确匹配的内容寻址 supervisor 执行
+Linux `renameat2(RENAME_NOREPLACE)`；目标已存在时返回 guest `EEXIST`，不会覆盖文件。
+Swift `IshInstance.renameNoReplace` 提供对应类型化错误，并在链接旧 native binary 时
+明确返回 unsupported。
+公开 C ABI 版本仍为 1；这是向后兼容的新增符号。Swift 源仍不调用 retain/release；
 完整 Swift lifecycle、类型化状态与 Terminal/VT 改造将在 Stage2 交付。
 本 Release 不包含 RootFS，发布脚本也不会上传 RootFS。
 
 This is not stable v0.4. It delivers the native lifecycle foundation: session
 retain/release, a joinable kernel thread, soft-halt, and internal exact-match
-wire protocol v4. This maintenance release establishes an absolute deadline at
-Swift API entry, subtracts argv/env/cwd/chroot marshalling, and passes only the
-remainder to native. Finite streaming sessions retain the original SPAWN
-deadline and reuse it for stdin-close control-queue admission, returning timeout
-instead of starting another wait; stdin close still reports busy while an
-active write owns its order gate. The public C ABI remains
-version 1. Swift source remains v0.3.3-ABI compatible and does not call
+wire protocol v4. This maintenance release adds guest-atomic rename without a
+shell or a check-then-rename race. `ish_embed_rename_noreplace` invokes Linux
+`renameat2(RENAME_NOREPLACE)` through the content-addressed supervisor that
+exactly matches the running runtime. An existing destination returns guest
+`EEXIST` and is never replaced. Swift `IshInstance.renameNoReplace` exposes a
+typed error and reports unsupported when linked to an older native binary. The
+public C ABI remains version 1; the new symbol is additive and backward
+compatible. Swift source still does not call
 retain/release; the complete Swift
 lifecycle, typed statuses, and Terminal/VT changes remain Stage2. This Release
 does not contain a RootFS, and the release script never uploads one.
diff --git a/scripts/release.sh b/scripts/release.sh
index baa4b74..fb318ad 100755
--- a/scripts/release.sh
+++ b/scripts/release.sh
@@ -30,7 +30,7 @@ Environment equivalents:
 Every release contains libIshKernel.xcframework.zip and its matching
 IshEmbed-corresponding-source.tar.gz. This script never publishes a RootFS;
 RootFS provenance, hashing, licensing, and distribution remain a separate flow.
-The Stage1 policy accepts only v0.4.0-abi.6 and publishes it as a prerelease.
+The Stage1 policy accepts only v0.4.0-abi.7 and publishes it as a prerelease.
 A suffix-free stable v0.4.0 remains blocked until the Stage2 policy replaces
 this transition gate.
 EOF
@@ -110,7 +110,7 @@ VERSION_POLICY="$(cd "$(dirname "$0")" && pwd)/release-version-policy.sh"
 # shellcheck source=release-version-policy.sh
 source "$VERSION_POLICY"
 ish_release_stage1_version_allowed "$VERSION" \
-    || fail "Stage1 release policy allows only v0.4.0-abi.6; stable v0.4.0 requires Stage2"
+    || fail "Stage1 release policy allows only v0.4.0-abi.7; stable v0.4.0 requires Stage2"
 GITHUB_PRERELEASE="$(ish_release_github_prerelease "$VERSION")"
 if [[ "$VERSION" == *-* ]]; then
     PRERELEASE="${VERSION#*-}"
diff --git a/scripts/test-release-version-policy.sh b/scripts/test-release-version-policy.sh
index aae0b4d..7dce3d3 100755
--- a/scripts/test-release-version-policy.sh
+++ b/scripts/test-release-version-policy.sh
@@ -6,11 +6,11 @@ PKG_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
 # shellcheck source=release-version-policy.sh
 source "$PKG_ROOT/scripts/release-version-policy.sh"
 
-ish_release_stage1_version_allowed v0.4.0-abi.6 || {
+ish_release_stage1_version_allowed v0.4.0-abi.7 || {
     printf 'error: authorized Stage1 maintenance tag was rejected\n' >&2
     exit 1
 }
-for forbidden in v0.4.0 v0.4.0-abi.1 v0.4.0-abi.2 v0.4.0-abi.3 v0.4.0-abi.4 v0.4.0-abi.5 v0.4.0-abi.7 v0.4.0-rc.1 v1.2.3; do
+for forbidden in v0.4.0 v0.4.0-abi.1 v0.4.0-abi.2 v0.4.0-abi.3 v0.4.0-abi.4 v0.4.0-abi.5 v0.4.0-abi.6 v0.4.0-abi.8 v0.4.0-rc.1 v1.2.3; do
     if ish_release_stage1_version_allowed "$forbidden"; then
         printf 'error: Stage1 policy unexpectedly allowed %s\n' "$forbidden" >&2
         exit 1
@@ -29,12 +29,12 @@ assert_prerelease_flag() {
     }
 }
 
-assert_prerelease_flag v0.4.0-abi.6 true
+assert_prerelease_flag v0.4.0-abi.7 true
 assert_prerelease_flag v1.2.3-rc.1 true
 assert_prerelease_flag v0.4.0 false
 assert_prerelease_flag v1.2.3 false
 
-abi_notes="$(ish_release_abi_transition_notes v0.4.0-abi.6)"
+abi_notes="$(ish_release_abi_transition_notes v0.4.0-abi.7)"
 for expected in \
     '这不是稳定 v0.4' \
     'This is not stable v0.4' \
@@ -42,12 +42,12 @@ for expected in \
     'joinable kernel thread' \
     'soft-halt' \
     'wire protocol v4' \
-    'Swift API entry' \
-    'argv/env/cwd/chroot marshalling' \
-    'original SPAWN' \
-    'stdin-close control-queue admission' \
-    'stdin close still reports busy' \
-    'Swift source remains' \
+    'renameat2(RENAME_NOREPLACE)' \
+    'content-addressed supervisor' \
+    'existing destination returns guest' \
+    'IshInstance.renameNoReplace' \
+    'older native binary' \
+    'public C ABI remains version 1' \
     'Stage2' \
     'does not contain a RootFS'; do
     [[ "$abi_notes" == *"$expected"* ]] || {
diff --git a/scripts/verify-ios-artifact.sh b/scripts/verify-ios-artifact.sh
index 7488970..b4ce01d 100755
--- a/scripts/verify-ios-artifact.sh
+++ b/scripts/verify-ios-artifact.sh
@@ -323,6 +323,7 @@ for library in "$device_lib" "$simulator_lib"; do
         _ish_embed_session_retain \
         _ish_embed_session_release \
         _ish_embed_setup_vm_root \
+        _ish_embed_rename_noreplace \
         _ish_embed_shutdown \
         _ish_embed_bundled_supervisor \
         _ish_embed_bundled_supervisor_len \
@@ -354,6 +355,17 @@ device_clang="$(xcrun --sdk iphoneos --find clang)"
     "$PKG_ROOT/c-tests/smoke.c" "$device_lib" -lsqlite3 \
     -o "$VERIFY_TMP/ishembed-device-link"
 
+"$device_clang" \
+    -target arm64-apple-ios18.0 \
+    -isysroot "$device_sdk" \
+    -Wl,-fatal_warnings \
+    -I"$PKG_ROOT/include" -I"$PKG_ROOT/protocol" \
+    -I"$PKG_ROOT/Sources/CIshEmbed/include" \
+    "$PKG_ROOT/c-tests/swift_bridge_smoke.c" \
+    "$PKG_ROOT/Sources/CIshEmbed/CIshEmbed.c" \
+    "$device_lib" -lsqlite3 \
+    -o "$VERIFY_TMP/ishembed-device-bridge-link"
+
 simulator_sdk="$(xcrun --sdk iphonesimulator --show-sdk-path)"
 simulator_clang="$(xcrun --sdk iphonesimulator --find clang)"
 "$simulator_clang" \
@@ -364,14 +376,37 @@ simulator_clang="$(xcrun --sdk iphonesimulator --find clang)"
     "$PKG_ROOT/c-tests/smoke.c" "$simulator_lib" -lsqlite3 \
     -o "$VERIFY_TMP/ishembed-simulator-link"
 
+"$simulator_clang" \
+    -target arm64-apple-ios18.0-simulator \
+    -isysroot "$simulator_sdk" \
+    -Wl,-fatal_warnings \
+    -I"$PKG_ROOT/include" -I"$PKG_ROOT/protocol" \
+    -I"$PKG_ROOT/Sources/CIshEmbed/include" \
+    "$PKG_ROOT/c-tests/swift_bridge_smoke.c" \
+    "$PKG_ROOT/Sources/CIshEmbed/CIshEmbed.c" \
+    "$simulator_lib" -lsqlite3 \
+    -o "$VERIFY_TMP/ishembed-simulator-bridge-link"
+
 for linked_binary in \
     "$VERIFY_TMP/ishembed-device-link" \
-    "$VERIFY_TMP/ishembed-simulator-link"; do
+    "$VERIFY_TMP/ishembed-simulator-link" \
+    "$VERIFY_TMP/ishembed-device-bridge-link" \
+    "$VERIFY_TMP/ishembed-simulator-bridge-link"; do
     linked_exports="$(nm -gU "$linked_binary" | awk '{print $NF}')"
     ! grep -qx _ish_embed_sha256_matches_hex <<< "$linked_exports"
     ! grep -qx _ish_embed_supervisor_metadata_valid <<< "$linked_exports"
 done
 
+for bridge_binary in \
+    "$VERIFY_TMP/ishembed-device-bridge-link" \
+    "$VERIFY_TMP/ishembed-simulator-bridge-link"; do
+    bridge_symbols="$(nm -m "$bridge_binary")"
+    grep -Eq '\(__TEXT,__text\) external _ish_embed_rename_noreplace$' \
+        <<< "$bridge_symbols"
+    ! grep -Eq '\(__TEXT,__text\) weak external _ish_embed_rename_noreplace$' \
+        <<< "$bridge_symbols"
+done
+
 verify_final_link_build_version() {
     local binary="$1"
     local expected_platform="$2"
diff --git a/supervisor/ishsv.c b/supervisor/ishsv.c
index e7d6732..57103d0 100644
--- a/supervisor/ishsv.c
+++ b/supervisor/ishsv.c
@@ -51,6 +51,7 @@
 #include <sys/stat.h>
 #include <sys/mount.h>
 #if defined(__linux__)
+#include <sys/syscall.h>
 #include <sys/vfs.h>
 #endif
 #if defined(__linux__)
@@ -136,6 +137,7 @@ extern int (*ishsv_test_waitid_hook)(idtype_t, id_t, siginfo_t *, int);
 extern pid_t (*ishsv_test_waitpid_hook)(pid_t, int *, int);
 extern int (*ishsv_test_kill_hook)(pid_t, int);
 extern pid_t (*ishsv_test_tcgetpgrp_hook)(int);
+extern int (*ishsv_test_rename_noreplace_hook)(const char *, const char *);
 #endif
 
 static int supervisor_waitid(idtype_t idtype, id_t id, siginfo_t *info,
@@ -251,6 +253,40 @@ static int read_full(int fd, void *buf, size_t len) {
     return 0;
 }
 
+/* Private process mode used by the host ABI. It deliberately reports the
+ * guest errno as a tiny decimal record on stdout so the parent supervisor can
+ * carry it through the ordinary bounded oneshot path. */
+static int rename_noreplace_guest(const char *source, const char *destination) {
+#ifdef ISH_SUPERVISOR_TESTING
+    if (ishsv_test_rename_noreplace_hook)
+        return ishsv_test_rename_noreplace_hook(source, destination);
+#endif
+#if defined(__linux__) && defined(SYS_renameat2)
+    return (int)syscall(SYS_renameat2, AT_FDCWD, source,
+                        AT_FDCWD, destination, 1u);
+#else
+    (void)source;
+    (void)destination;
+    errno = ENOSYS;
+    return -1;
+#endif
+}
+
+static int run_rename_noreplace_helper(int argc, char **argv) {
+    if (argc != 4 || !argv || strcmp(argv[1], "--rename-noreplace") != 0 ||
+        !argv[2] || !argv[3])
+        return 64;
+    int guest_errno = 0;
+    if (rename_noreplace_guest(argv[2], argv[3]) < 0)
+        guest_errno = errno > 0 ? errno : EIO;
+    char record[32];
+    int len = snprintf(record, sizeof(record), "%d\n", guest_errno);
+    if (len <= 0 || (size_t)len >= sizeof(record) ||
+        write_full(STDOUT_FILENO, record, (size_t)len) < 0)
+        return 74;
+    return 0;
+}
+
 /* ------------------------ frame send (single-locked) ---------------------
  * fd 1 is written from one place only (main loop), so no mutex needed.
  * If we ever multithread the supervisor, add a mutex around emit_frame.   */
@@ -1810,7 +1846,9 @@ static int handshake(void) {
     return emit_frame(ISH_FT_HELLO_ACK, 0, 0, ack, sizeof(ack));
 }
 
-int main(void) {
+int main(int argc, char **argv) {
+    if (argc > 1)
+        return run_rename_noreplace_helper(argc, argv);
     g_instance_fail_closed = 0;
     /* PID 1: become a child subreaper just in case (Linux >= 3.4) */
 #if defined(__linux__) && defined(PR_SET_CHILD_SUBREAPER)
diff --git a/third_party/ish b/third_party/ish
index c36dfd2..3d0b4f6 160000
--- a/third_party/ish
+++ b/third_party/ish
@@ -1 +1 @@
-Subproject commit c36dfd25462737b45559eb48d4b09f799471572e
+Subproject commit 3d0b4f6f55108f6d602ac6a2c86df555935b979d