A simulated fruit-fly brain (FlyWire connectome) plays Game Boy games on a 24/7 stream.
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acamilo 6d67fa7ed2 session: a retried Acknowledge is not a failed epoch
The bound test failed two runs in thirty under load, and not on the
bound it was testing. Both failures were bootstrap: "a worker did not
acknowledge every lifecycle reply".

ipc-v1 section 5 says already released or unknown ids are ignored, and
the contract type already holds the acknowledged list to a subset of
the request. So the second Acknowledge of the same ids answers with an
empty list by design -- and the section 6 resolution produces exactly
that second Acknowledge whenever the first reply is slower than the
probe. Demanding the whole list back turned a safe, contract-sanctioned
retry into a failed epoch, which is a defect in the coordinator rather
than in the test: a slow lifecycle reply would do it to a real session
too.

The test made itself easy to hit by installing a fifty-millisecond
probe before bootstrap, so bootstrap's own lifecycle calls ran under a
budget meant for the step under test. It now bootstraps at ordinary
deadlines and tightens them afterwards.

The two bounds are also separated by construction rather than by clock.
Each half puts the bound it is not testing out of reach -- u32::MAX
attempts against a fifth of a second, three attempts against an hour --
so no scheduling delay can flip which one fires, and the silent
participant is ten minutes slow against a twenty-second test timeout,
so returning at all proves a bound ended it. The wall-clock assertion
is gone and the attempt count is asserted instead, which
last_resolution_attempts now records. One agent per composition, so the
participant the failure names is not a race either.
2026-09-22 18:47:42 +00:00
.forgejo/workflows flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
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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 docs: v0.4.7 status 2026-09-22 17:46:03 +00:00
infra Merge fix/chat-ring-persist: the on-screen chat ring survives a sim restart via a hot-dir sidecar 2026-09-22 17:45:59 +00:00
packages session: resolve uncertain calls, and measure each mode in its own process 2026-09-22 15:41:42 +00:00
services session: a retried Acknowledge is not a failed epoch 2026-09-22 18:47:42 +00:00
tools flybrain v0.4.0: public tree (history retained privately) 2026-09-21 15:09:46 +00:00
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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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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.