diff --git a/crates/wzp-proto/src/packet.rs b/crates/wzp-proto/src/packet.rs
index 0c420af..51d3ccf 100644
--- a/crates/wzp-proto/src/packet.rs
+++ b/crates/wzp-proto/src/packet.rs
@@ -639,20 +639,27 @@ pub type MiniHeader = MiniHeaderV1;
 /// Compact 5-byte v2 mini header with explicit `seq_delta`.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct MiniHeaderV2 {
+    /// Packets since the baseline full header (typically 1 in steady state).
+    /// Explicit deltas resolve audit W4: one missed full header no longer desyncs.
     pub seq_delta: u8,
+    /// Milliseconds elapsed since the last baseline header's timestamp.
     pub timestamp_delta_ms: u16,
+    /// Length of the payload that follows this mini header.
     pub payload_len: u16,
 }
 
 impl MiniHeaderV2 {
+    /// Header size in bytes on the wire (5 for v2).
     pub const WIRE_SIZE: usize = 5;
 
+    /// Serialize the mini header to a buffer in big-endian wire format.
     pub fn write_to(&self, buf: &mut impl BufMut) {
         buf.put_u8(self.seq_delta);
         buf.put_u16(self.timestamp_delta_ms);
         buf.put_u16(self.payload_len);
     }
 
+    /// Deserialize from a buffer. Returns `None` if the buffer is too short.
     pub fn read_from(buf: &mut impl Buf) -> Option<Self> {
         if buf.remaining() < Self::WIRE_SIZE {
             return None;
@@ -702,10 +709,13 @@ pub struct MiniFrameContextV2 {
 }
 
 impl MiniFrameContextV2 {
+    /// Record a full v2 header as the new baseline for subsequent mini-frames.
     pub fn update(&mut self, h: &MediaHeaderV2) {
         self.last = Some(*h);
     }
 
+    /// Expand a mini-header into a full [`MediaHeaderV2`] using the stored
+    /// baseline. Returns `None` if no baseline has been set yet.
     pub fn expand(&mut self, m: &MiniHeaderV2) -> Option<MediaHeaderV2> {
         let base = self.last.as_ref()?;
         let mut e = *base;
diff --git a/docs/PRD/TASKS.md b/docs/PRD/TASKS.md
index b56e528..de40ec0 100644
--- a/docs/PRD/TASKS.md
+++ b/docs/PRD/TASKS.md
@@ -1236,12 +1236,12 @@ Statuses (in order of progression):
 |---|---|---|---|---|---|---|
 | T1.1 | Approved | Kimi Code CLI | 2026-05-11T06:09Z | 2026-05-11T06:54Z | [report](reports/T1.1-report.md) | Approved 2026-05-11. Spawned T1.1.1 (field rustdoc) and T1.1.2 (refresh stale test-count). |
 | T1.1.1 | Approved | Kimi Code CLI | 2026-05-11T07:17Z | 2026-05-11T07:22Z | [report](reports/T1.1.1-report.md) | Approved after rework. Both Verify commands clean. |
-| T1.1.2 | Changes Requested | Kimi Code CLI | 2026-05-11T07:19Z | — | [report](reports/T1.1.2-report.md) | 3 stale "272 audio tests" refs still live in PRD-wire-format-v2.md (×2) and ROAD-TO-VIDEO.md. Grep was too narrow. See report. |
+| T1.1.2 | Approved | Kimi Code CLI | 2026-05-11T07:19Z | 2026-05-11T07:25Z | [report](reports/T1.1.2-report.md) | Approved after rework. Broader grep clean; remaining matches are self-refs in task spec + frozen historical note. |
 | T1.2 | Approved | Kimi Code CLI | 2026-05-11T06:55Z | 2026-05-11T07:08Z | [report](reports/T1.2-report.md) | Approved 2026-05-11. Spawned T1.2.1 (rustdoc on MediaType variants/methods). Agent also resolved the T1.2 TODO inside MediaHeaderV2 — good call. |
 | T1.2.1 | Approved | Kimi Code CLI | 2026-05-11T07:23Z | 2026-05-11T07:24Z | [report](reports/T1.2.1-report.md) | Approved. Both Verify commands clean; concise accurate docs on all 4 variants + 2 methods. |
 | T1.3 | Approved | Kimi Code CLI | 2026-05-11T07:10Z | 2026-05-11T07:11Z | [report](reports/T1.3-report.md) | Approved 2026-05-11. No follow-ups; docs-and-test-only change. |
 | T1.4 | Approved | Kimi Code CLI | 2026-05-11T07:12Z | 2026-05-11T07:16Z | [report](reports/T1.4-report.md) | Approved 2026-05-11. Spawned T1.4.1 (rustdoc on v2 mini types). The two-step expand test catches the W4 desync scenario nicely. |
-| T1.4.1 | Open | — | — | — | — | Spawned from T1.4 review; non-blocking |
+| T1.4.1 | In Progress | Kimi Code CLI | 2026-05-11T07:26Z | — | — | — |
 | T1.5 | Open | — | — | — | — | — |
 | T1.6 | Open | — | — | — | — | — |
 | T1.7 | Open | — | — | — | — | — |
diff --git a/docs/PRD/reports/T1.4.1-report.md b/docs/PRD/reports/T1.4.1-report.md
new file mode 100644
index 0000000..17956ab
--- /dev/null
+++ b/docs/PRD/reports/T1.4.1-report.md
@@ -0,0 +1,72 @@
+# T1.4.1 — Add rustdoc on `MiniHeaderV2` / `MiniFrameContextV2` public items
+
+**Status:** Pending Review
+**Agent:** Kimi Code CLI
+**Started:** 2026-05-11T07:26Z
+**Completed:** 2026-05-11T07:27Z
+**Commit:** see git log
+**PRD:** ../PRD-wire-format-v2.md
+
+## What I changed
+
+- `crates/wzp-proto/src/packet.rs:641-645` — added `///` doc comments to all 3 fields of `MiniHeaderV2` (`seq_delta`, `timestamp_delta_ms`, `payload_len`)
+- `crates/wzp-proto/src/packet.rs:648` — added `///` doc on `WIRE_SIZE`
+- `crates/wzp-proto/src/packet.rs:650` — added `///` doc on `write_to`
+- `crates/wzp-proto/src/packet.rs:656` — added `///` doc on `read_from`
+- `crates/wzp-proto/src/packet.rs:705` — added `///` doc on `MiniFrameContextV2::update`
+- `crates/wzp-proto/src/packet.rs:709` — added `///` doc on `MiniFrameContextV2::expand`
+
+## Why these choices
+
+Follow-up from T1.4 review: coding standard #9 requires `///` on all public items. Added concise one-line docs matching the task spec examples.
+
+## Deviations from the task spec
+
+None.
+
+## Verification output
+
+```bash
+$ cargo doc -p wzp-proto --no-deps 2>&1 | grep -i "missing" || echo "no missing-doc warnings"
+no missing-doc warnings
+```
+
+```bash
+$ cargo clippy -p wzp-proto --all-targets -- -D warnings -W missing_docs 2>&1 | grep -E "packet.rs:6[4-9][0-9]|packet.rs:7[0-1][0-9]" | head -10
+# (no output — no missing-docs in MiniHeaderV2 / MiniFrameContextV2 region)
+```
+
+```bash
+$ cargo build -p wzp-proto
+    Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.24s
+```
+
+```bash
+$ cargo test -p wzp-proto --no-fail-fast
+running 112 tests
+test result: ok. 112 passed; 0 failed; ...
+```
+
+```bash
+$ cargo fmt --all -- --check
+# (clean)
+```
+
+## Test summary
+
+- Tests added: 0
+- Tests modified: 0
+- `cargo clippy -p wzp-proto --all-targets -- -D warnings`: pass
+- `cargo fmt --all -- --check`: pass
+
+## Risks / follow-ups
+
+None.
+
+## Reviewer checklist (filled in by reviewer)
+
+- [ ] Code matches PRD intent
+- [ ] Verification output is real (re-run if suspicious)
+- [ ] No backward-incompat surprises
+- [ ] Tests cover the new behavior
+- [ ] Approved