A simulated fruit-fly brain (FlyWire connectome) plays Game Boy games on a 24/7 stream.
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dev f2dc5d434a flybus: assert the latest-mode guarantee, not the machine's timing
session_over_one_router asserted that a latest subscriber must drop
snapshots. bus-v1 section 7 says a latest subscription replaces an
undelivered value; it lets a consumer miss values, it does not oblige it
to. Under contention the publisher was slow enough that the renderer kept
up, saw all twenty snapshots and the test failed on conforming behaviour:
16 of 40 runs beside four busy loops, and 9 of 20 whole-crate runs.

The renderer is now held until the publisher's completion is observed
rather than until a timer expires, so the coalescing is forced instead of
raced for: the subscription keeps the one delivery in flight and one
replaceable queued value, and the renderer receives snapshots 1 and 20 of
20. The assertions are the guarantees that hold -- what arrives is in
publication order, the last value is the latest published, the stalled
spectator never refuses a publication or drops out of the fan-out, and
every snapshot the renderer missed is counted as a replacement to the
publisher at admission and to the renderer on delivery, so nothing is
lost silently.

Three more tests in the crate asserted the same kind of race:

- latest_replay_is_ordered_ahead_of_a_racing_publish demanded the
  non-coalesced outcome of a race section 7 allows either way ("bounded
  mode preserves that order, while latest mode may coalesce it"). It now
  puts one racing publication to a bounded and a latest subscription at
  once: bounded must deliver the replay and then the publication, and the
  latest branch is chosen by that publication's own replaced count.

- collection_waits_for_every_retained_owner, and the two disconnect
  cleanup tests beside it, read the store directory for the unlink that
  follows the registry update outside the router lock. They use
  settle_files, like every other unlink check in the suite.

- The demo example printed a root count taken before the producer's own
  release had reached the router, so the line the guide quotes was a
  race. It waits for the release, the same way it already waits for
  collection; the printed output is unchanged.

Nothing under flybus/src is touched: no routing defect was found. The
conformance rows for the credit/queue split, the replaced count, the
replay ordering and the latest spectator that cannot refuse a publication
now cite what each rewritten test actually varies.
2026-09-22 17:05:25 +00:00
.forgejo/workflows flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
.github/workflows flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
apps/stage stage(describe): the public repo URL on the card 2026-09-22 02:08:31 +00:00
data/fafb-v783 flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
docs flybus: assert the latest-mode guarantee, not the machine's timing 2026-09-22 17:05:25 +00:00
infra traps: both hunt arms, and row 54 -- the cycle that replaced the one this branch closed 2026-09-22 14:23:00 +00:00
packages session: resolve uncertain calls, and measure each mode in its own process 2026-09-22 15:41:42 +00:00
services flybus: assert the latest-mode guarantee, not the machine's timing 2026-09-22 17:05:25 +00:00
tools flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
.gitignore flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
CLAUDE.md flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
CONTRIBUTING.md flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
LICENSE flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
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Makefile flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
NOTICE flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
package-lock.json feat(session-types): the TypeScript half of the contracts, over the same fixtures 2026-09-22 11:54:13 +00:00
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README.md flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
ROM-POLICY.md flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00

flybrain

A simulated fruit-fly brain that plays video games. A connectome-constrained spiking network reads the screen, its population rates become controller inputs, and a scalar reward nudges a bounded set of Kenyon-cell to MBON gains.

The library is @flybrain/brain in packages/brain. It holds the connectome dataset format, the LIF kernel, the plasticity rule, the population-rate readout and the activity-map geometry. It holds no game, no emulator and no reward rules: those belong to whatever embeds it.

Workspace layout

Path Contents
packages/brain the library (@flybrain/brain)
data/fafb-v783 FlyWire-derived browser artifacts (CC BY-NC 4.0)
tools/ the Python builder that regenerates data/ from official Codex exports
docs/ overview, dataset format, model, plasticity, readout, integration, limitations, verification
services/flysim the Rust service: brain, emulator, snapshot feed, control API, checkpoints
apps/ planned: one directory per game demo
infra/ planned: deployment for the 24/7 stream (see docs/streaming-plan.md)

Quick start

npm ci
npm test
npm run typecheck

76 tests, about 7 seconds. There is no build step. npx tsx packages/brain/examples/node-random-frames.ts 60 runs the full 139,255-neuron brain with the Game Boy readout on noise frames in plain Node (about 0.9x Game Boy real time single-threaded on a WSL laptop).

Usage

import { NeuralAgent, gameboyDecoderConfig, toButtonMask } from '@flybrain/brain';
import { loadBrainDatasetFromDir } from '@flybrain/brain/node';

const dataset = await loadBrainDatasetFromDir('data/fafb-v783');
const agent = new NeuralAgent(dataset, { decoder: gameboyDecoderConfig() });
agent.warmup(firstFrame);                        // 2,500 ms with plasticity off, then calibrate

// every emulator frame:
const { active } = agent.tick(framebuffer, {     // RGBA 160x144 by default; any size via config
  rewards: [{ value: 0.5 }],                     // scalar rewards your game adapter detected
  boot: !inGame,                                 // relaxes Start/Select throttling on title screens
});
emulator.setButtons(toButtonMask(active));

const checkpoint = agent.exportState();          // bit-exact resume, validated on import

The lower layers (LifNetwork, RewardModulatedStdp, PopulationDecoder) are exported too for hosts that want to run the loop themselves.

integration.md has the full per-frame loop, the fractional frame timing and the checkpoint contract.

Documentation

  • Overview: the pipeline, the layer map and the design principles.
  • Dataset format: artifacts, CSR layout, weight encoding, every role and its count, fingerprinting, regeneration, license.
  • Model: the 1-ms LIF kernel step by step, every default constant, the retina projection, the RNG, state export and version strings.
  • Plasticity: edge selection, the eligibility and reinforcement equations, statistics, topology hash and the explicit non-claims.
  • Readout: scores, exclusive groups, pulse channels, the blocked-direction cooldown, the Game Boy preset table and checkpoint versions.
  • Integration: what a game must provide, the Pokemon Red integration as a worked example, and a sketch of a platformer adapter.
  • Limitations: what is not claimed, what is unproven, measured throughput.
  • Verification: the oracle-test strategy and what each test file covers.
  • Streaming plan: headless capture, Twitch, VM design and the phased plan for a 24/7 stream.
  • Artifact builder: how to regenerate and verify data/fafb-v783.
  • Data attribution: source, license and citations.

Provenance

The network, plasticity rule, readout, FlyWire pipeline and activity viewer were extracted from the fly-plays-pokemon prototype so several game demos can share one core. The default configuration reproduces that prototype's kernel bit for bit, and verbatim copies of its modules live in packages/brain/tests/legacy/ as oracles. Built with Astra.

Licensing

The data/fafb-v783 artifacts are derived from the FlyWire FAFB public Codex v783 exports and are licensed CC BY-NC 4.0. That is a non-commercial license, so a commercial demo needs a different data source or separate permission. Citations and the list of modifications are in data/fafb-v783/ATTRIBUTION.md.

No license has been chosen for the code in this repository yet.

ROMs and save states never enter this repository.