Every read of an action now goes through a single module. `context/lineage.py`
turns a branch's stored lineage into the OR-of-ranges that is "this story", and
history, paging, the newest-action lookups, the index screen and the scripting
history API all select through it. A forgotten clause does not raise — it
quietly assembles a page, or a prompt, out of two different stories — so the
clause lives in one place rather than in a convention.
The read that mattered most was the shortcut: `_from_memory` sliced
`adventure.actions`, which is every branch's actions, not the path. It now cuts
the loaded collection down with the same predicate the SQL uses. Same trap one
layer up, and user-visible: `pipeline._history()` hands user scripts the story,
and was handing them the collection.
Tail reads window the lineage as well as the rows: the newest few entries cover
the context budget, so a story forked twenty times reads its tail with one
clause and costs 1.07x what an unforked story of the same length costs. The
estimate is depth arithmetic, and where a deleted action leaves a gap the read
notices it came up short and widens to the whole ancestry.
Ordering moves from `index` to `depth`, with `id` breaking ties. The two hold
the same numbers until retry stops mutating rows in SP4, but only one of them
is a position along a path.
One thing SP1 did not anticipate: wiring the writers was not enough. From here
a row without a branch is a row no read can see, and "every writer remembers"
has to hold for every fixture, script and test ever written — including the
SP0 baseline, which writes its actions straight to the database and must pass
unmodified. So the session enforces it: `tree.place_new_nodes` runs from
before_flush and places anything unplaced. The call sites keep their explicit
calls, because a node placed at the call site is placed before the code around
it reads it back.
316 tests green: the 297 from SP1, plus 19 in test_branch_clause.py.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017Dvvqn9ZDR4ixeFPHNbww7
Two reads still grew without bound after the snapshot fix.
`Action.variants` holds every discarded retry attempt, but a list response
only needs how many there are — so each retry permanently added ~5 KB to
every later load of that adventure. Defer the column and keep the count
beside it (migration 37, backfilled server-side), with set_variants() as the
one write path that keeps the two in step.
`story_actions()` walked adventure.actions, then every caller threw almost
all of it away: the builder concatenates the story and immediately cuts it
back to the token budget, the NPC check looks at the last 6, retrieval at the
last 4, the cursor clamp only wants a count. A turn on a 200-action adventure
read 839 KB to use ~70 KB, and grew with every turn played. app/context/
history.py serves those shapes from SQL; window_covering() measures the
actions it fetched and projects how many more it needs, fetching only the
part it does not already hold. Memorybank cursors move to position_of_index()
and settled_count()/settled_slice() — same arithmetic, no full list.
The scripting pipeline still receives the whole history per AI Dungeon's API,
and every helper reuses adventure.actions when it is already loaded, so a
scripted adventure pays what it always did and never twice.
Measured at production shape: retry tax 5.1 KB -> 0; turn 200 839 KB -> 129 KB
and flat from ~turn 50; a 200-turn playthrough 84.5 MB -> 23.0 MB; a delete
115 KB -> 5 KB.
Verified the window builds a byte-identical prompt to the full story across
budgets from 1K to 100K tokens, with and without the retry exclusion - this
is a cost change and nothing else. Cursor helpers checked against the old list
arithmetic, including after deleting a middle action. Counts are real
SELECT count(...): Query.count() wraps the entity select in a subquery, so the
SQL named every deferred column and the egress guard could not tell it apart
from a bulk fetch. 139 tests pass; the four new guards verified by sabotage.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UeQVy5bEjLhfgWNc27Efet
