run 26

docs/discovery-notes.md

@@ -5554,3 +5554,88 @@ Best current `EC` model:
   - without `A0`, `EC` falls back toward heartbeat-family behavior
 - This is closer to a controlled state map than where we started, but it is
   still not a stable multi-turn "conversation" ladder.
+
+### HE23: Does `A0` Also Context `E8` And `E9`?
+
+The `EC` branch now strongly suggests that leading `A0` is part of branch
+selection context rather than just a neutral primer. These tests ask whether the
+same is true for `E8` and `E9`.
+
+#### HE23a: `E8` Without Leading `A0`
+
+```powershell
+python scripts/serial_sequence_probe.py --port COM5 --prompt --frame "00 00 E8 40 30 C2" --frame "00 00 00 00 80 DA" --frame "00 00 00 00 80 DA" --repeat 2 --frame-interval 0.20 --read-after-frame 0.30 --read-after-group 0.8 --log captures/rcp-heartbeat-e8-no-a0.txt
+```
+
+#### HE23b: `E9` Without Leading `A0`
+
+```powershell
+python scripts/serial_sequence_probe.py --port COM5 --prompt --frame "00 00 E9 40 30 C3" --frame "00 00 00 00 80 DA" --frame "00 00 00 00 80 DA" --repeat 2 --frame-interval 0.20 --read-after-frame 0.30 --read-after-group 0.8 --log captures/rcp-heartbeat-e9-no-a0.txt
+```
+
+#### HE23c: `A0` Then `E8` Control Repeat
+
+This is just the known-good comparison run so the no-`A0` tests can be read
+against a fresh control captured in the same phase of work.
+
+```powershell
+python scripts/serial_sequence_probe.py --port COM5 --prompt --frame "00 00 A0 00 80 7A" --frame "00 00 E8 40 30 C2" --frame "00 00 00 00 80 DA" --frame "00 00 00 00 80 DA" --repeat 2 --frame-interval 0.20 --read-after-frame 0.30 --read-after-group 0.8 --log captures/rcp-heartbeat-e8-with-a0-control.txt
+```
+
+#### HE23d: `A0` Then `E9` Control Repeat
+
+```powershell
+python scripts/serial_sequence_probe.py --port COM5 --prompt --frame "00 00 A0 00 80 7A" --frame "00 00 E9 40 30 C3" --frame "00 00 00 00 80 DA" --frame "00 00 00 00 80 DA" --repeat 2 --frame-interval 0.20 --read-after-frame 0.30 --read-after-group 0.8 --log captures/rcp-heartbeat-e9-with-a0-control.txt
+```
+
+What would count as a hit:
+
+- `E8` or `E9` without `A0` still producing their known branches:
+  - `07 80 7A 50 26 D1`
+  - `07 80 7A 28 D3 5C`
+- `E8` or `E9` without `A0` collapsing into heartbeat-family transients like
+  `07 80 40 40 30 ED` or `07 80 C0 40 30 6D`
+- a clear difference between no-`A0` and with-`A0` controls that would promote
+  `A0` from "possible primer" to "general selector context"
+
+### 2026-05-13 `A0` Context Test For `E8` / `E9`
+
+Captures:
+
+- `captures/rcp-heartbeat-e8-no-a0.txt`
+- `captures/rcp-heartbeat-e9-no-a0.txt`
+- `captures/rcp-heartbeat-e8-with-a0-control.txt`
+- `captures/rcp-heartbeat-e9-with-a0-control.txt`
+
+Observed outcomes:
+
+| Setup | Group-1 result |
+| --- | --- |
+| `E8` without `A0` | later heartbeat provoked `07 80 40 40 30 ED` |
+| `E9` without `A0` | later heartbeat provoked `07 80 40 40 30 ED` |
+| `A0 -> E8` control | `07 80 7A 50 26 D1` |
+| `A0 -> E9` control | heartbeat only in this repeat |
+
+Interpretation:
+
+- `E8` now clearly matches the `EC` pattern in one important way:
+  without leading `A0`, it falls back into heartbeat-family behavior instead of
+  opening its `7A` branch.
+- `E9` without `A0` also fell back to the same heartbeat-family transient
+  `07 80 40 40 30 ED`.
+- So `A0` is now more plausibly a broader selector-context opener, not just an
+  `EC`-specific quirk.
+- However, `A0` is **not** sufficient to make every selector deterministic:
+  the `A0 -> E9` control repeat produced only heartbeat in this run, even though
+  earlier `A0 -> E9` work did produce `07 80 7A 28 D3 5C`.
+
+Best current read:
+
+- `A0` looks necessary or at least strongly supportive for entering the `E8`
+  and `EC` family spaces.
+- `E9` remains more timing- or state-sensitive than `E8`; `A0` helps define the
+  context, but does not guarantee the `7A 28 D3` branch on every clean repeat.
+- This strengthens the state-map model:
+  - no `A0` -> selector values tend to collapse into heartbeat-family
+    transients
+  - with `A0` -> some selector values can open structured family spaces