diff --git a/quest/m3/README.md b/quest/m3/README.md
index 516519d6c..f951f0aa6 100644
--- a/quest/m3/README.md
+++ b/quest/m3/README.md
@@ -40,6 +40,7 @@ generic std gap is planned here even when moq never calls it.
 - [The rest of a vector's methods](/quest/m3/ts-vec-rest.md) - `append`, `resize`, `split_off`, `try_reserve`, and `Vec::from(VecDeque)` translate
 - [A reversed zip's per-pair cost](/quest/m3/ts-zip-rev-overhead.md) - a reversed by-index zip costs per pair what a forward one does, or the gap is explained
 - [Whole writes into a lazy cell or thread-local key](/quest/m3/ts-lazy-writes.md) - a whole write through a `&mut` to a `LazyCell`, `LazyLock`, or `LocalKey` keeps its state
+- [Debug of a LazyCell or a LazyLock](/quest/m3/ts-lazy-debug.md) - `{:?}` of a `LazyCell` and a `LazyLock` writes its value or `<uninit>`, as std's do
 - [Type errors at the Rust that made them](/quest/m3/ts-span-precision.md) - a `tsc` error on output names the tail expression or call argument that made it
 - [An empty iterator of mutable references](/quest/m3/ts-empty-places.md) - `iter::empty::<&mut T>()` given to `zip` or `chain` translates
 - [An Option of numbers in the result slot](/quest/m3/ts-option-slot.md) - `varint_opt`'s `Option` comes back through the slot with no object per call
diff --git a/quest/m3/ts-fmt-calls.md b/quest/m3/ts-fmt-calls.md
index d33c399e3..8513f48d9 100644
--- a/quest/m3/ts-fmt-calls.md
+++ b/quest/m3/ts-fmt-calls.md
@@ -27,6 +27,10 @@ difference. A writer that counts calls or fails partway, like a capped buffer, c
   each run it leaves as is, empty or not, and each escape a `write_str`.
 - Add `writeChar` to the runtime's `Write`, so a crate's own `write_char` override runs.
 - Measure what the extra calls cost `format!` into a `String`.
+- Add a differential case for `Debug` of a `Cell` into a writer that sets that cell in
+  `write_str`. std reads the value before writing `Cell { value: `, and
+  [#484](https://github.com/moq-dev/rust2/pull/484) lowers it that way, but only such a writer
+  can observe the order.
 - Rejected: allowing placeholders with the runtime's chunking. The bytes match, but a
   crate's `write_str` would see calls std doesn't make.
 
diff --git a/quest/m3/ts-lazy-debug.md b/quest/m3/ts-lazy-debug.md
new file mode 100644
index 000000000..e31bb2be4
--- /dev/null
+++ b/quest/m3/ts-lazy-debug.md
@@ -0,0 +1,26 @@
+# [XS] Debug of a LazyCell or a LazyLock
+
+## Goal
+
+[rust2-ts](/ts/README.md) translates `{:?}` of a `LazyCell` and a `LazyLock` as std
+writes them: `LazyCell(..)` of its value once forced, or `LazyCell(<uninit>)` unpadded
+before, and likewise for `LazyLock`. This is proven by differential tests against native
+Rust, plain and `{:#?}`, before and after a force, including a print from within its own
+initialization.
+
+## Plan
+
+Found after [#484](https://github.com/moq-dev/rust2/pull/484) translated `Debug` of the
+other cells and locks. A probe on 2026-11-02 against `main` refused both as an
+"unsupported call to `<LazyCell<..> as Debug>::fmt`".
+
+std reads `get` without forcing. The runtime's `rt.LazyCell` keeps its value and its
+initialized flag in `#private` fields, so it needs a method that reads them, as
+`onceDebug` reads a one-time cell's. `LazyCell::get` and `LazyLock::get` could come with
+it if that is the same method.
+
+Public API: the translator's output.
+
+## Related
+
+- [Whole writes into a lazy cell or thread-local key](/quest/m3/ts-lazy-writes.md) - the same `#private` state