diff --git a/README.md b/README.md
index 5c7089d..0491fc6 100644
--- a/README.md
+++ b/README.md
@@ -225,7 +225,8 @@ if native_files_supported() {
 - `file_sink(...)` 当前还提供 `append_mode()`；`reopen(append=...)` 在显式传值时会更新后续 reopen 使用的 append 策略
 - `file_sink(...)` 也可直接读取 `path()` 与 `auto_flush_enabled()` 等基础 file 策略状态
 - `file_sink(...)` 还提供 `rotation_enabled()` 与 `rotation_config()`，可直接查询当前 rotation 策略是否启用及其参数
-- `build_logger(...)` 产出的 `ConfiguredLogger` 同样提供 `file_reopen()`、`file_flush()`、`file_close()`、`file_append_mode()`、`file_path()`、`file_auto_flush()`、`file_rotation_enabled()`、`file_rotation_config()` 与对应 file failure 计数访问器，便于配置式接入后继续运维控制
+- `file_sink(...)` 也支持 `set_auto_flush(...)`、`set_rotation(...)`、`clear_rotation()`，可在运行期调整基础写出策略
+- `build_logger(...)` 产出的 `ConfiguredLogger` 同样提供 `file_reopen()`、`file_flush()`、`file_close()`、`file_append_mode()`、`file_path()`、`file_auto_flush()`、`file_rotation_enabled()`、`file_rotation_config()`，以及 `file_set_auto_flush(...)`、`file_set_rotation(...)`、`file_clear_rotation()` 与对应 file failure 计数访问器，便于配置式接入后继续运维控制
 - `sink.text_formatter.template` 当前支持固定 token：`{timestamp}`、`{timestamp_ms}`、`{level}`、`{target}`、`{message}`、`{fields}`
 - 当前可由配置直接组装的 sink 类型：`console`、`json_console`、`text_console`、`file`
 - `queue` 会作为显式包装层附着在最终 sink 外侧；这仍然是同步 drain 模型，不是 async runtime
diff --git a/bitlogger/BitLogger_test.mbt b/bitlogger/BitLogger_test.mbt
index 68edd4a..126f6e8 100644
--- a/bitlogger/BitLogger_test.mbt
+++ b/bitlogger/BitLogger_test.mbt
@@ -236,6 +236,32 @@ test "configured logger reports disabled rotation when file sink has none" {
   ignore(logger.close())
 }
 
+test "configured logger file setters update file sink policy state" {
+  let logger = build_logger(
+    LoggerConfig::new(
+      sink=SinkConfig::new(kind=SinkKind::File, path="config-setters.log"),
+      queue=Some(QueueConfig::new(2, overflow=QueueOverflowPolicy::DropNewest)),
+    ),
+  )
+  inspect(logger.file_auto_flush(), content="true")
+  inspect(logger.file_rotation_enabled(), content="false")
+  inspect(logger.file_set_auto_flush(false), content="true")
+  inspect(logger.file_auto_flush(), content="false")
+  inspect(logger.file_set_rotation(Some(file_rotation(48, max_backups=4))), content="true")
+  inspect(logger.file_rotation_enabled(), content="true")
+  match logger.file_rotation_config() {
+    Some(rotation) => {
+      inspect(rotation.max_bytes, content="48")
+      inspect(rotation.max_backups, content="4")
+    }
+    None => inspect(false, content="true")
+  }
+  inspect(logger.file_clear_rotation(), content="true")
+  inspect(logger.file_rotation_enabled(), content="false")
+  inspect(logger.file_rotation_config() is None, content="true")
+  ignore(logger.close())
+}
+
 test "configured logger can reopen built file sink" {
   let logger = build_logger(
     LoggerConfig::new(
diff --git a/bitlogger/BitLogger_wbtest.mbt b/bitlogger/BitLogger_wbtest.mbt
index 37a1b80..48950e8 100644
--- a/bitlogger/BitLogger_wbtest.mbt
+++ b/bitlogger/BitLogger_wbtest.mbt
@@ -122,6 +122,26 @@ test "file sink rotation config normalizes invalid inputs" {
   }
 }
 
+test "file sink setters update auto flush and rotation state" {
+  let sink = file_sink("bitlogger-setters.log")
+  inspect(sink.auto_flush_enabled(), content="true")
+  inspect(sink.rotation_enabled(), content="false")
+  sink.set_auto_flush(false)
+  inspect(sink.auto_flush_enabled(), content="false")
+  sink.set_rotation(Some(file_rotation(32, max_backups=2)))
+  inspect(sink.rotation_enabled(), content="true")
+  match sink.rotation_config() {
+    Some(config) => {
+      inspect(config.max_bytes, content="32")
+      inspect(config.max_backups, content="2")
+    }
+    None => inspect(false, content="true")
+  }
+  sink.clear_rotation()
+  inspect(sink.rotation_enabled(), content="false")
+  inspect(sink.rotation_config() is None, content="true")
+}
+
 test "file sink tracks rotation failures on unavailable backend" {
   let sink = file_sink("bitlogger-rotate.log", rotation=Some(file_rotation(1, max_backups=1)))
   sink.write(record(Level::Info, "a"))
diff --git a/bitlogger/README.mbt.md b/bitlogger/README.mbt.md
index 35f13de..7b45714 100644
--- a/bitlogger/README.mbt.md
+++ b/bitlogger/README.mbt.md
@@ -224,6 +224,7 @@ test {
 - `append_mode()` exposes the current append policy, and `reopen(append=...)` updates that policy for later reopen calls / `append_mode()` 可读取当前 append 策略，`reopen(append=...)` 会更新后续 reopen 复用的 append 策略
 - `path()` and `auto_flush_enabled()` expose core file sink policy state / `path()` 与 `auto_flush_enabled()` 可读取 file sink 的基础策略状态
 - `rotation_enabled()` and `rotation_config()` expose whether rotation is active and which settings are currently applied / `rotation_enabled()` 与 `rotation_config()` 可读取 rotation 是否启用及当前配置参数
+- `set_auto_flush(...)`, `set_rotation(...)`, and `clear_rotation()` allow runtime tuning of core file sink policies / `set_auto_flush(...)`、`set_rotation(...)`、`clear_rotation()` 可在运行期调整 file sink 的基础策略
 - `open_failures()`、`write_failures()`、`flush_failures()`、`rotation_failures()` expose basic sink health counters / `open_failures()`、`write_failures()`、`flush_failures()`、`rotation_failures()` 可用于观察基础 sink 健康状态
-- `ConfiguredLogger` also forwards file reopen, flush, close, append-mode, path, auto-flush, rotation-config, and failure-counter helpers for config-built file sinks / `ConfiguredLogger` 也会为配置生成的 file sink 转发 reopen、flush、close、append-mode、path、auto-flush、rotation 配置与失败计数访问器
+- `ConfiguredLogger` also forwards file reopen, flush, close, append-mode, path, auto-flush, rotation-config, setter, and failure-counter helpers for config-built file sinks / `ConfiguredLogger` 也会为配置生成的 file sink 转发 reopen、flush、close、append-mode、path、auto-flush、rotation 配置、setter 与失败计数访问器
 - current scope is observability-first, not a full self-healing sink runtime / 当前定位仍以可观测性优先，不是完整自愈型 sink runtime
diff --git a/bitlogger/config.mbt b/bitlogger/config.mbt
index 505e61b..3d1cab6 100644
--- a/bitlogger/config.mbt
+++ b/bitlogger/config.mbt
@@ -271,6 +271,48 @@ pub fn RuntimeSink::file_rotation_config(self : RuntimeSink) -> FileRotation? {
   }
 }
 
+pub fn RuntimeSink::file_set_auto_flush(self : RuntimeSink, enabled : Bool) -> Bool {
+  match self {
+    File(sink) => {
+      sink.set_auto_flush(enabled)
+      true
+    }
+    QueuedFile(sink) => {
+      sink.sink.set_auto_flush(enabled)
+      true
+    }
+    _ => false
+  }
+}
+
+pub fn RuntimeSink::file_set_rotation(self : RuntimeSink, rotation : FileRotation?) -> Bool {
+  match self {
+    File(sink) => {
+      sink.set_rotation(rotation)
+      true
+    }
+    QueuedFile(sink) => {
+      sink.sink.set_rotation(rotation)
+      true
+    }
+    _ => false
+  }
+}
+
+pub fn RuntimeSink::file_clear_rotation(self : RuntimeSink) -> Bool {
+  match self {
+    File(sink) => {
+      sink.clear_rotation()
+      true
+    }
+    QueuedFile(sink) => {
+      sink.sink.clear_rotation()
+      true
+    }
+    _ => false
+  }
+}
+
 pub fn RuntimeSink::file_flush(self : RuntimeSink) -> Bool {
   match self {
     File(sink) => sink.flush()
@@ -375,6 +417,21 @@ pub fn ConfiguredLogger::file_rotation_config(self : ConfiguredLogger) -> FileRo
   self.sink.file_rotation_config()
 }
 
+pub fn ConfiguredLogger::file_set_auto_flush(self : ConfiguredLogger, enabled : Bool) -> Bool {
+  self.sink.file_set_auto_flush(enabled)
+}
+
+pub fn ConfiguredLogger::file_set_rotation(
+  self : ConfiguredLogger,
+  rotation : FileRotation?,
+) -> Bool {
+  self.sink.file_set_rotation(rotation)
+}
+
+pub fn ConfiguredLogger::file_clear_rotation(self : ConfiguredLogger) -> Bool {
+  self.sink.file_clear_rotation()
+}
+
 pub fn ConfiguredLogger::file_flush(self : ConfiguredLogger) -> Bool {
   self.sink.file_flush()
 }
diff --git a/bitlogger/sinks.mbt b/bitlogger/sinks.mbt
index f0ba5b8..bd70939 100644
--- a/bitlogger/sinks.mbt
+++ b/bitlogger/sinks.mbt
@@ -49,8 +49,8 @@ pub struct FileSink {
   append : Ref[Bool]
   handle : Ref[FileHandle?]
   formatter : RecordFormatter
-  auto_flush : Bool
-  rotation : FileRotation?
+  auto_flush : Ref[Bool]
+  rotation : Ref[FileRotation?]
   open_failures : Ref[Int]
   write_failures : Ref[Int]
   flush_failures : Ref[Int]
@@ -88,8 +88,8 @@ pub fn file_sink(
     append: Ref::new(append),
     handle: Ref::new(handle),
     formatter,
-    auto_flush,
-    rotation,
+    auto_flush: Ref::new(auto_flush),
+    rotation: Ref::new(rotation),
     open_failures: Ref::new(if handle is Some(_) { 0 } else { 1 }),
     write_failures: Ref::new(0),
     flush_failures: Ref::new(0),
@@ -123,15 +123,27 @@ pub fn FileSink::path(self : FileSink) -> String {
 }
 
 pub fn FileSink::auto_flush_enabled(self : FileSink) -> Bool {
-  self.auto_flush
+  self.auto_flush.val
 }
 
 pub fn FileSink::rotation_enabled(self : FileSink) -> Bool {
-  self.rotation is Some(_)
+  self.rotation.val is Some(_)
 }
 
 pub fn FileSink::rotation_config(self : FileSink) -> FileRotation? {
-  self.rotation
+  self.rotation.val
+}
+
+pub fn FileSink::set_auto_flush(self : FileSink, enabled : Bool) -> Unit {
+  self.auto_flush.val = enabled
+}
+
+pub fn FileSink::set_rotation(self : FileSink, rotation : FileRotation?) -> Unit {
+  self.rotation.val = rotation
+}
+
+pub fn FileSink::clear_rotation(self : FileSink) -> Unit {
+  self.rotation.val = None
 }
 
 pub fn FileSink::close(self : FileSink) -> Bool {
@@ -214,7 +226,7 @@ fn rotate_file_sink_internal(sink : FileSink, rotation : FileRotation) -> Bool {
 }
 
 fn rotate_if_needed_internal(sink : FileSink, next_line_bytes : Int) -> Bool {
-  match sink.rotation {
+  match sink.rotation.val {
     None => true
     Some(rotation) => match sink.handle.val {
       None => false
@@ -250,7 +262,7 @@ pub impl Sink for FileSink with write(self, rec) {
           Some(active) => {
             let wrote = write_file_handle_internal(active, line)
             if wrote {
-              if self.auto_flush {
+              if self.auto_flush.val {
                 let flushed = flush_file_handle_internal(active)
                 if !flushed {
                   self.flush_failures.val += 1
diff --git a/docs/README-en.md b/docs/README-en.md
index 61cdbbb..d154c0c 100644
--- a/docs/README-en.md
+++ b/docs/README-en.md
@@ -210,7 +210,8 @@ if native_files_supported() {
 - `file_sink(...)` also exposes `append_mode()`. Passing `append=...` to `reopen(...)` updates the current append policy used by later reopen calls.
 - `file_sink(...)` also exposes `path()` and `auto_flush_enabled()` for reading basic file-sink policy state.
 - `file_sink(...)` also exposes `rotation_enabled()` and `rotation_config()` for reading whether rotation is active and which parameters are currently in effect.
-- `ConfiguredLogger` built through `build_logger(...)` also exposes `file_reopen()`, `file_flush()`, `file_close()`, `file_append_mode()`, `file_path()`, `file_auto_flush()`, `file_rotation_enabled()`, `file_rotation_config()`, and the corresponding file failure counters, so config-driven file logging keeps a usable control surface.
+- `file_sink(...)` also supports `set_auto_flush(...)`, `set_rotation(...)`, and `clear_rotation()` for runtime policy updates.
+- `ConfiguredLogger` built through `build_logger(...)` also exposes `file_reopen()`, `file_flush()`, `file_close()`, `file_append_mode()`, `file_path()`, `file_auto_flush()`, `file_rotation_enabled()`, `file_rotation_config()`, plus `file_set_auto_flush(...)`, `file_set_rotation(...)`, `file_clear_rotation()`, and the corresponding file failure counters, so config-driven file logging keeps a usable control surface.
 - `sink.text_formatter.template` currently supports fixed tokens: `{timestamp}`, `{timestamp_ms}`, `{level}`, `{target}`, `{message}`, and `{fields}`.
 - Config-driven sink assembly currently supports `console`, `json_console`, `text_console`, and `file`.
 - `queue` remains a synchronous bounded wrapper around the final sink, not an async runtime.
diff --git a/docs/changes/0.3.0.md b/docs/changes/0.3.0.md
index be3819a..81f9c1b 100644
--- a/docs/changes/0.3.0.md
+++ b/docs/changes/0.3.0.md
@@ -35,6 +35,7 @@ version 0.3.0
 - feat: make file append mode queryable via `append_mode()` / `file_append_mode()` and persist explicit `reopen(append=...)` mode updates for later reopen calls
 - feat: add `path()` / `auto_flush_enabled()` on `FileSink` and `file_path()` / `file_auto_flush()` on `ConfiguredLogger` for basic file-policy introspection
 - feat: add `rotation_enabled()` / `rotation_config()` on `FileSink` and `file_rotation_enabled()` / `file_rotation_config()` on `ConfiguredLogger` for rotation-policy introspection
+- feat: add runtime file-policy mutators `set_auto_flush(...)`, `set_rotation(...)`, `clear_rotation()` and corresponding configured-logger forwarding helpers
 - feat: add `SplitSink`, `split_sink(...)`, and `split_by_level(...)` for routing records into different sinks by predicate or level
 - feat: add `Logger::bind(...)` as an ergonomic context-binding alias and `fields(...)` helper for tuple-based field construction
 
@@ -54,6 +55,7 @@ version 0.3.0
 - test: cover append-mode observability and reopen-mode persistence for direct and config-built file sinks
 - test: cover path and auto-flush introspection for direct and config-built file sinks
 - test: cover rotation introspection for direct and config-built file sinks with and without configured rotation
+- test: cover runtime auto-flush and rotation policy mutation for direct and config-built file sinks
 - test: cover split sink predicate routing and level-based routing behavior
 - test: cover `bind(...)` context composition and `fields(...)` helper behavior
 - test: add async logger lifecycle, config roundtrip, and batching/flush policy test seeds
@@ -74,6 +76,7 @@ version 0.3.0
 - docs: clarify append-mode observability and reopen append-policy semantics
 - docs: document file path and auto-flush introspection helpers
 - docs: document rotation introspection helpers for direct and config-built file sinks
+- docs: document runtime file-policy setter helpers for direct and config-built file sinks
 - docs: add split sink examples for level-based routing
 - docs: add `bind(...)` examples for reusable context binding
 - docs: update root README and English README with async adapter notes and current scope