The Elimination Final winners were crossed into the Semi-Finals — EF1's winner
met the QF2 loser and EF2's the QF1 loser. The AFL feeds them straight through:
SF1 is the QF1 loser against the EF1 winner and SF2 the QF2 loser against the
EF2 winner. The crossover in this system lands a round later, at Semi-Final →
Preliminary Final, so a Qualifying Final loser cannot meet the side that just
beat it — that part was already right and is unchanged.
In 2026 that drew Fremantle v Adelaide and Brisbane v Geelong, when Fremantle
played Geelong and Brisbane played Adelaide.
Placement now reconciles both Semi-Final slots on every Elimination Final
result rather than writing the one it was called for, so correcting a recorded
result moves the qualifier instead of leaving the beaten team alive in a semi.
A slot held by anyone who never played an Elimination Final still raises
"already filled", and a Semi-Final that has been played refuses the move rather
than rewriting who contested it.
The simulator paired the Semi-Finals the same crossed way, which biased every
projection running off an undecided Elimination Final; it now feeds straight
through too.
Brackets already advanced under the crossover keep their wrong pairings, since
no admin action re-runs advancement — a completed match cannot be re-submitted.
Admin → the event's bracket gains a "Fix Semi-Final Pairings" button that runs
the same reconciliation over a bracket as it stands.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MSDeNWAXvK7nznJqjxn7Jo
The two Wildcard Round winners were crossed into the Elimination Finals by
which game they came out of — the 7v10 winner always met 6th and the 8v9
winner always met 5th. The AFL pairs those games by ladder position, as the
classic final eight pairs 5v8 and 6v7: the higher host draws the
lower-ranked survivor. So when 10th wins through, 5th should meet 10th, not
the 8v9 winner.
Placement now resolves both games together. A 7v10 winner is placed as soon
as it is decided (7th outranks either possible opponent, 10th is outranked
by both), while an 8v9 winner is held until the other game is decided rather
than being placed and later moved, so results can be entered in either
order.
The simulator paired the Elimination Finals the same fixed way, which biased
every projection that ran off an undecided Wildcard Round; it now re-seeds
too.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VDbHrCce1UhahbkwKkc7hK
An AFL club seeded into an Elimination Final is awarded 15 fantasy points the
moment the bracket is generated — afl_10's entryFloor: 7 — and cannot finish
worse than the 7th-8th tier. Its EV still read 13.
AFLSimulator was stateless with respect to the live bracket. It read only
participants, sourceElo and the regular-season standings, then re-projected the
whole ladder and re-seeded 1-10 from Elo on every one of its 10,000 iterations.
So a team with a locked Elimination Final berth was re-drawn into the Wildcard
Round, or out of the finals entirely, in a slice of them — and there it scores 0.
Even with the ladder complete the Math.random() tiebreaker reshuffled every club
tied on ladder points, which in the AFL is most of the middle of the table.
Games already played were re-played the same way, so a completed Wildcard win was
worth 50% of nothing. Mixing zeroes into a distribution whose floor is 15 is what
produced 13.
afl_10 is the only template that defines entryFloor at all, which is why this
surfaced here and not on LLWS, whose floors only exist once a team has won
something.
The simulator now mirrors llws-simulator's bracket-aware mode:
- readAflBracketSeeds reads the 10 seeds from the slots generateAFL10Bracket
writes them into. The two Elimination Final participant2 slots are TBD by
design and are never read as seeds, leaving exactly 10 named slots. No draw
at all falls back to the ladder projection; a partially seeded, duplicated or
unknown draw throws rather than silently discarding the draw and every
recorded result with it.
- makePlayGame replays a completed match from its recorded result whenever both
recorded teams are the two the simulation routed into that game, so an
already-played result sticks across all iterations.
- simAFLFinals labels each game with the round and match number
generateAFL10Bracket and advanceAFLWinner use, so a result is looked up
against the game it was played in. Its routing was already correct.
EV >= the banked floor now holds by construction, with no clamping: a team seeded
into an Elimination Final is in that game in every iteration. Column sums stay
exactly 1.0 and the 340-point total-EV invariant is unchanged, since teams
outside the bracket simply score nothing.
Fixing the simulator alone would not have held. processMatchResult calls
updateProbabilitiesAfterResult on every result, and its ICM branch re-derives
each still-alive participant's whole distribution from P(1st) alone, knowing
nothing about the bracket — so the next finals result would have put the EV
straight back under the floor. That branch was built for futures-odds seasons.
It now runs only when the season's EVs did not come from a bracket-aware
simulator; when they did, that simulator is re-run instead, since it already
knows the completed matches. Both conditions matter: re-running a bracket-blind
simulator would re-draw the field and hand equity back to knocked-out teams, so
a new manifest `bracketAware` flag limits this to AFL and LLWS. A failed re-run
leaves probabilities untouched rather than falling back to the ICM path that is
being replaced.
The finalized-participant pinning loop now runs after that recalculation rather
than before. A simulation run rewrites every participant in the season, the
finalized ones included; a finalized placement is a fact, not a projection, so it
is written last and wins.
Tests: seeds clear the entry floors their seeding banked, a Qualifying Final
entrant is structurally absent from the 7th-8th tier, the bracket's draw beats
Elo (the weakest club seeded 1, the strongest seeded 10), completed Wildcard and
Qualifying Finals are replayed with the winner banking its floor, teams outside
the bracket are zeroed, and the column sums and 340 total survive. The bracket
fixtures deliberately seed the ten weakest clubs, because seeding the strongest
ten lets the ladder projection reproduce much the same field by accident. Six of
the seven were confirmed to fail against the previous behavior. Plus the
probability-updater branch in each direction, its failure path, and the pin
ordering.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VPxDnSEKVoKx9HFcQ6gmcS
* Add projected-wins input mode to admin Elo Ratings page
Admins can now enter projected season win totals instead of raw Elo
numbers on the Elo Ratings page. Wins are auto-converted to Elo using
the inverse formula and stored as sourceElo, keeping the rest of the
simulation pipeline unchanged.
- Add `projectedWinsToElo` / `eloToProjectedWins` to probability-engine
- Add `simulator-config.ts` centralising per-sport season length, parity
factor, and average opponent Elo (AFL, NFL, NBA, NHL, MLB, WNBA)
- Admin Elo Ratings page: toggle between Elo and Projected Wins input
modes; bulk import parses wins format; existing sourceElo back-fills
the wins field on load
- AFL simulator now reads sourceElo from participantExpectedValues first,
falling back to hardcoded TEAMS_DATA then 1400
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* Fix lint errors in simulator-config tests and probability-engine
- Replace non-null assertions (`!`) with optional chaining (`?.`) in simulator-config tests
- Remove redundant type annotations on default parameters in probability-engine
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---------
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Monte Carlo simulation of the 2026 AFL season and 10-team finals series.
Elo ratings are backsolved from Squiggle's projected season win totals using
the inverse formula: elo = 1500 - 450×log₁₀((1−wins/23)/(wins/23)).
- New `afl_bracket` simulator type (schema + migration)
- `afl-simulator.ts`: projects remaining regular season via Elo, seeds the
AFL_10 finals bracket (Wildcard → QF/EF → SF → PF → Grand Final), and
correctly tracks P5/P6 and P7/P8 as separate scoring tiers
- `afl.ts` standings sync adapter pulling from Squiggle API (no auth required)
- Finals line on standings display set to 10 for AFL seasons
- Substring name matching with longest-key-wins to prevent "Port Adelaide"
colliding with "Adelaide" when matching "Port Adelaide Power"
- 27 unit tests covering bracket logic, column-sum guarantees, and name matching
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
