Replace the surface-ordered fold with a log-ordered human transcript:
append-origin surface events at their own log positions plus one marker per
landed compaction checkpoint. Command folding, the tool-call index, and the
rev-keyed memo carry over unchanged.
Removes foldDegraded, the padding sentinels, baseSeq, and degradedSeqs() --
they existed only to satisfy the core fold's seq === index assertion. That
also closes the pagination hole A1 exposed: a page can carry a checkpoint
whose shadowed range fell outside the window, and nothing resolves
surfaceOp.start anymore.
Marker scale was deferred in a resolved review thread but only the
compaction-progress half was written down. Deferred now names it, says
where the count comes from (`sourceEventSeqs`), and why it belongs with
progress rather than here.
Adds the prerequisite: the terminal's replay and live replacement branches
are textually identical and 600 lines apart, so marker content needs one
home — fold them into a single `renderReplacement(event)` before giving the
row a payload that must stay consistent across both paths.
Review follow-ups on b9b2e593f, all documentation precision.
The redundancy note on `isCompactCheckpoint` leaned on a reading its call
site does not state: `index.ts` reaches it for surface-eligible non-append
events, which is the same set as replacements only because the marker is
mandatory. Say that instead.
The Agent Note now owns three facts it was leaving to a future reader.
`rebuildTranscript` materializes a component per append-origin event and
runs on mount, color-scheme change, and every reasoning toggle — work
compaction used to bound for exactly the long sessions it serves, so the
cost now tracks session length rather than the surface. `Consequences`
names `surface-replayed-compaction` as the durable evidence for the
live/replay equivalence claim, so the two fixtures that must move together
are findable from the Note rather than the PR thread. `Deferred` records
that a page can now carry a checkpoint whose `surfaceOp.start` fell out of
the window: pagination no longer cuts on the checkpoint's provenance
group, `FoldAdapter` pads with a non-surface sentinel, and `nodes()`
degrades to `degradedSeqs()` — which is already close to the transcript
projection A2 should build deliberately.
Also corrects the definite-assignment comment in the snapshot scenario:
the assertion rests on the awaited setup invoking `beforeMount`, not on
that call being synchronous.
Review follow-ups on the append-origin transcript projection.
The live/replay equivalence claim was stated unconditionally but does not
cover `tool/call`: only replay re-derives call pairing, because a call
event carries no `surfaceOp` of its own and inherits transcript
membership from the `assistant/message` that advertised it — which the
live listener has necessarily just rendered. Narrow the claim in the TUI
README and Agent Note, and record at `rebuildTranscript` why the filter
is replay-only rather than a missing live branch.
Add `surface-replayed-compaction`: the three existing fixtures all come
from the live path, leaving the resume case the bug report leads with
pinned only by a unit test. The new checkpoint mounts with the
replacement already stored and records byte-identical to
`surface-after-compaction-wide`, so the two fixtures now pin the
equivalence they assert. The shared fixture appends move into
`appendPreCompactionLog` / `appendCompactionCheckpoint`.
`MESSAGE_TYPES` is not "human message event types" — it includes
`assistant/message`. Say what the code distinguishes (append-origin
conversation messages vs. model-only replacement copies) at the const,
the `paginate` and `session.history` JSDoc, the apiproxy README, and the
Agent Note.
Also: spell the replace shape as `Extract<SurfaceOp, { op: 'replace' }>`
for symmetry with the module's two other uses; document why
`isCompactCheckpoint` keeps a replacement check that is redundant at both
call sites; say that Ctrl+R toggles reasoning, which rebuilds the
transcript; and qualify "the sole source of derived history" as derived
*model* history now that the transcript is the other projection.
The terminal and history pagination both treated the model-visible surface as
the human transcript. A landed compaction replacement therefore erased the
conversation it summarized — messages the reader had already seen — and a
model-only replacement copy consumed a page's `maxMessages` quota, which could
also split a compaction's provenance from the replacement citing it.
`dsh-session` now exports the marker split `isAppendSurfaceEvent` /
`isReplacementSurfaceEvent`. The terminal replays append-origin surface events,
keeps a shadowed step's tool cards paired through its append-origin assistant
message, and renders one dim marker where a compaction landed; the checkpoint is
recognized through the compaction seam's `isCompactCheckpointSource` contract,
not the shape of the replacement. `session.history` counts only append-origin
human messages. Everything model-facing keeps reading `session.surface`.
Hypatia May