diff --git a/docs/api/index.md b/docs/api/index.md
index 7581237..070c78b 100644
--- a/docs/api/index.md
+++ b/docs/api/index.md
@@ -382,6 +382,10 @@ BitLogger API navigation.
 - [runtime-sink-file-flush-failures.md](./runtime-sink-file-flush-failures.md)
 - [runtime-sink-file-rotation-failures.md](./runtime-sink-file-rotation-failures.md)
 - [runtime-sink-file-reset-failure-counters.md](./runtime-sink-file-reset-failure-counters.md)
+- [runtime-sink-file-reset-policy.md](./runtime-sink-file-reset-policy.md)
+- [runtime-sink-file-policy.md](./runtime-sink-file-policy.md)
+- [runtime-sink-file-default-policy.md](./runtime-sink-file-default-policy.md)
+- [runtime-sink-file-policy-matches-default.md](./runtime-sink-file-policy-matches-default.md)
 - [configured-logger.md](./configured-logger.md)
 - [configured-logger-flush.md](./configured-logger-flush.md)
 - [configured-logger-drain.md](./configured-logger-drain.md)
diff --git a/docs/api/runtime-sink-file-default-policy.md b/docs/api/runtime-sink-file-default-policy.md
new file mode 100644
index 0000000..40b2dc5
--- /dev/null
+++ b/docs/api/runtime-sink-file-default-policy.md
@@ -0,0 +1,74 @@
+---
+name: runtime-sink-file-default-policy
+group: api
+category: runtime
+update-time: 20260613
+description: Read the initial default file policy associated with a RuntimeSink.
+key-word:
+    - runtime
+    - sink
+    - file
+    - public
+---
+
+## Runtime-sink-file-default-policy
+
+Read the initial default file policy associated with a `RuntimeSink`. This helper exposes the baseline file policy captured when the runtime sink was created.
+
+### Interface
+
+```moonbit
+pub fn RuntimeSink::file_default_policy(self : RuntimeSink) -> FileSinkPolicy {
+```
+
+#### input
+
+- `self : RuntimeSink` - Runtime sink whose default file policy should be inspected.
+
+#### output
+
+- `FileSinkPolicy` - Initial default file policy.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- Plain `File` runtime variants return the default policy captured at creation time.
+- `QueuedFile` runtime variants forward the default policy from the wrapped inner `FileSink`.
+- Non-file runtime variants return the neutral fallback policy `FileSinkPolicy::new(append=false, auto_flush=false, rotation=None)`.
+- This helper is useful when callers need to compare runtime drift or restore defaults later.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Baseline Policy Visibility
+
+When diagnostics should show the original file policy separately from the live one:
+```moonbit
+let defaults = sink.file_default_policy()
+```
+
+In this example, the runtime sink exposes its original file policy snapshot.
+
+#### When Prepare For Policy Reset Logic
+
+When tooling should capture or compare default settings explicitly:
+```moonbit
+let original = sink.file_default_policy()
+```
+
+In this example, callers can reason about factory file policy separately from runtime changes.
+
+### Error Case
+
+e.g.:
+- If the runtime sink is not file-backed, the return value is a neutral fallback policy.
+
+- If callers only need to know whether runtime drift exists, `file_policy_matches_default()` is the simpler API.
+
+### Notes
+
+1. Use this helper when the original file policy matters operationally.
+
+2. It complements `file_policy()` and `file_reset_policy()`.
diff --git a/docs/api/runtime-sink-file-policy-matches-default.md b/docs/api/runtime-sink-file-policy-matches-default.md
new file mode 100644
index 0000000..732f489
--- /dev/null
+++ b/docs/api/runtime-sink-file-policy-matches-default.md
@@ -0,0 +1,76 @@
+---
+name: runtime-sink-file-policy-matches-default
+group: api
+category: runtime
+update-time: 20260613
+description: Read whether the current runtime file policy still matches the RuntimeSink default policy.
+key-word:
+    - runtime
+    - sink
+    - file
+    - public
+---
+
+## Runtime-sink-file-policy-matches-default
+
+Read whether the current runtime file policy still matches the default policy of a `RuntimeSink`. This helper is useful for detecting operational drift on direct sink values.
+
+### Interface
+
+```moonbit
+pub fn RuntimeSink::file_policy_matches_default(self : RuntimeSink) -> Bool {
+```
+
+#### input
+
+- `self : RuntimeSink` - Runtime sink whose runtime policy drift should be checked.
+
+#### output
+
+- `Bool` - Whether the current runtime file policy still matches the default.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- Plain `File` runtime variants compare current runtime file policy against their stored defaults.
+- `QueuedFile` runtime variants forward the comparison from the wrapped inner `FileSink`.
+- Non-file runtime variants return `false`.
+- This helper is a compact drift signal when callers do not need to compare full policy objects directly.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Drift Detection
+
+When diagnostics should report whether file policy changed after startup:
+```moonbit
+let unchanged = sink.file_policy_matches_default()
+```
+
+In this example, the runtime sink exposes whether runtime file policy still matches the baseline.
+
+#### When Gate Reset Logic
+
+When code should only reset policy if drift exists:
+```moonbit
+if !sink.file_policy_matches_default() {
+  ignore(sink.file_reset_policy())
+}
+```
+
+In this example, policy reset only happens when runtime state diverged from defaults.
+
+### Error Case
+
+e.g.:
+- If the runtime sink is not file-backed, the method returns `false`.
+
+- If callers need the exact differences instead of a boolean drift signal, they should inspect both `file_policy()` and `file_default_policy()`.
+
+### Notes
+
+1. Use this helper for compact runtime policy drift checks.
+
+2. It is especially useful before calling reset-style operations.
diff --git a/docs/api/runtime-sink-file-policy.md b/docs/api/runtime-sink-file-policy.md
new file mode 100644
index 0000000..fdafe9b
--- /dev/null
+++ b/docs/api/runtime-sink-file-policy.md
@@ -0,0 +1,75 @@
+---
+name: runtime-sink-file-policy
+group: api
+category: runtime
+update-time: 20260613
+description: Read the current runtime file policy from a RuntimeSink.
+key-word:
+    - runtime
+    - sink
+    - file
+    - public
+---
+
+## Runtime-sink-file-policy
+
+Read the current runtime file policy from a `RuntimeSink`. This helper exposes the active append, auto-flush, and rotation settings as one policy object.
+
+### Interface
+
+```moonbit
+pub fn RuntimeSink::file_policy(self : RuntimeSink) -> FileSinkPolicy {
+```
+
+#### input
+
+- `self : RuntimeSink` - Runtime sink whose current file policy should be inspected.
+
+#### output
+
+- `FileSinkPolicy` - Current runtime file policy.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- Plain `File` runtime variants return the current policy from the wrapped `FileSink`.
+- `QueuedFile` runtime variants forward the policy from the wrapped inner `FileSink`.
+- Non-file runtime variants return the neutral fallback policy `FileSinkPolicy::new(append=false, auto_flush=false, rotation=None)`.
+- This helper is broader than `file_append_mode()` or `file_auto_flush()` because it returns the whole policy object.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Full Runtime Policy Visibility
+
+When diagnostics should inspect the active file policy as one object:
+```moonbit
+let policy = sink.file_policy()
+```
+
+In this example, append, flush, and rotation settings are read together from the runtime sink.
+
+#### When Compare Current And Default Policy
+
+When runtime drift from defaults should be inspected explicitly:
+```moonbit
+let current = sink.file_policy()
+let defaults = sink.file_default_policy()
+```
+
+In this example, callers can compare current runtime settings with the initial policy snapshot.
+
+### Error Case
+
+e.g.:
+- If the runtime sink is not file-backed, the return value is a neutral fallback policy rather than a real active file policy.
+
+- If callers only need one field from the policy, a narrower helper may be simpler.
+
+### Notes
+
+1. Use this helper when file policy should be handled as one object.
+
+2. Pair it with `file_set_policy(...)` for roundtrip-style policy management.
diff --git a/docs/api/runtime-sink-file-reset-policy.md b/docs/api/runtime-sink-file-reset-policy.md
new file mode 100644
index 0000000..268af66
--- /dev/null
+++ b/docs/api/runtime-sink-file-reset-policy.md
@@ -0,0 +1,76 @@
+---
+name: runtime-sink-file-reset-policy
+group: api
+category: runtime
+update-time: 20260613
+description: Reset the runtime file policy of a file-backed RuntimeSink back to its original defaults.
+key-word:
+    - runtime
+    - sink
+    - file
+    - public
+---
+
+## Runtime-sink-file-reset-policy
+
+Reset the runtime file policy of a `RuntimeSink` back to its original defaults. This helper restores append, auto-flush, and rotation policy together on direct sink values.
+
+### Interface
+
+```moonbit
+pub fn RuntimeSink::file_reset_policy(self : RuntimeSink) -> Bool {
+```
+
+#### input
+
+- `self : RuntimeSink` - Runtime sink whose file policy should be restored.
+
+#### output
+
+- `Bool` - Whether the reset was applied.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- Plain `File` runtime variants restore their stored default file policy and return `true`.
+- `QueuedFile` runtime variants forward the reset behavior to the wrapped inner `FileSink` and return `true`.
+- Non-file runtime variants return `false`.
+- This helper is the inverse of runtime policy drift, not a generic reopen or flush action.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need To Undo Runtime Policy Changes
+
+When file policy should return to the original defaults captured by the runtime sink:
+```moonbit
+ignore(sink.file_reset_policy())
+```
+
+In this example, append, auto-flush, and rotation settings are restored together.
+
+#### When Use Drift-aware Recovery
+
+When reset should only happen after runtime changes:
+```moonbit
+if !sink.file_policy_matches_default() {
+  ignore(sink.file_reset_policy())
+}
+```
+
+In this example, reset is only applied when runtime policy has diverged.
+
+### Error Case
+
+e.g.:
+- If the runtime sink is not file-backed, the method returns `false`.
+
+- If callers need to restore only one setting, a narrower setter may be more appropriate than a full policy reset.
+
+### Notes
+
+1. Use this helper when the original bundled file policy should be restored intact.
+
+2. It pairs naturally with `file_policy_matches_default()` and `file_default_policy()`.