step.27.diff.txt -- narrative retro for step.27 (U5.5: THE TRINITY
                    GATE, Phase A). Companion: step.27.gdiff.txt via
                    ../scripts/step_gdiff. NOTE: the STEP is not
                    closed -- Phase B (the operator ceremony) closes
                    the gate; this retro covers the machine half.

Executed (Phase A): 2026-07-22, the sixth step of the day's (p1) arc
(b3u 51-52, b3ubot 22-27). WORK commit a337a17.

## Plan vs actual

+---+--------------------------------------+--------------------------------------+
| # | Planned (brief)                      | Actual                               |
+---+--------------------------------------+--------------------------------------+
| 1 | "one full AP arc ... mock AND live"  | Phase A/B split (the b3u step.49     |
|   |                                      | precedent): the scripted leg ran     |
|   |                                      | ALL PASS first invocation; the       |
|   |                                      | human-adapter live leg is a turnkey  |
|   |                                      | OPERATOR ceremony -- a machine may   |
|   |                                      | not declare a human-witnessed gate   |
|   |                                      | green (C-27-B), so the row stays     |
|   |                                      | active until check passes.           |
| 2 | Q-25-A (delivery placement)          | RESOLVED: explicit post-close arc    |
|   |                                      | (ccs generate), never coupled into   |
|   |                                      | closure (C-27-C) -- evidence         |
|   |                                      | freezes offline; delivery is the     |
|   |                                      | operator's re-runnable act.          |
| 3 | New machinery                        | Deliberately almost none: U5.5       |
|   |                                      | COMPOSES U5.1-U5.4a. Two scripts +   |
|   |                                      | one 3-leg oracle file; everything    |
|   |                                      | else already existed and was          |
|   |                                      | already tested.                      |
+---+--------------------------------------+--------------------------------------+

## Surprises / genuine findings

1. **The gate needed almost no code** -- the entire story (broken
   spec -> real FAIL -> tail-carrying repair -> converge -> close ->
   deliver) ran on first invocation out of parts built in the five
   preceding steps. That is what the composition was FOR; still,
   watching the verdict history read [fail, pass] against the real
   plane in one arc is the first time the whole thesis (AI proposes,
   oracles dispose, the ledger remembers) has run as one motion.
2. **The egress witness is now arithmetic**: exactly as many runs/
   records as provider calls, the repair record carrying the
   diagnostics that left, the plane loopback by construction. "What
   left this machine, when, to whom" is a query, not an assurance.
3. **Rehearsing the ceremony surfaced the data-home hazard
   immediately**: a rehearsal `prepare` against the real ~/.b3ubot
   would have squatted UC.1 and blocked the real ceremony
   (start_state's own duplicate refusal). Every rehearsal ran under
   an isolated $B3UBOT_HOME; the real home is untouched -- and the
   check oracle proved it refuses an un-run ceremony (6 named FAILs,
   exit 1) before it ever gets to say PASS.

## Scope discipline

In: composition, the Q-25-A resolution, the two scripts, the 3-leg
oracle, the ledger transition (via the engine's own CLI). Out and
named: running Phase B for the operator (never), relay-drafting
(Q-27-B, future ceremony variant), P6, (p2). Zero b3u-repo changes.

## Numbers

- New: 2 scripts + 1 test file (3 live legs) + docs. Suite 657 ->
  662 collected (3 new + 2 own-corpus step.27.txt), 634 passed + 28
  skipped, 0 failed -- measured after the last edit.
- trinity_gate.sh: ALL PASS first invocation (arc 3/3, honest-skip
  twin, B-4).
- The day's (p1) arc so far: b3u UB.1+UB.2 (steps 51-52), b3ubot
  U5.1-U5.5-Phase-A (steps 22-27); ONE operator ceremony stands
  between here and P5 CLOSED.

End of retro (Phase A).