[brainstem-daemon] GH#39 — epic: establish brainstem-daemon as the canonical Spikenaut SNN runtime

[rmems]

Planning attribution

Runtime architecture proposed by GPT-5.6 Sol (ChatGPT/OpenAI) with @rmems on 2026-09-13 after direct inspection of brainstem-daemon, thalamic-relay, corpus-ipc, neuromod, and Spikenaut-SNN.

Decision

Keep brainstem-daemon, thalamic-relay, and corpus-ipc as separate repositories with separate failure domains.

brainstem-daemon becomes the single canonical process that owns and steps the software SNN runtime.

thalamic-relay -> corpus-ipc -> brainstem-daemon -> spikes/readout
 sensory/safety    wire/schema      SNN runtime

Brainstem owns

• model/checkpoint lifecycle and validation
• neuromod::SpikingNetwork construction/restoration
• fixed-rate tick scheduling
• normalized stimulus ingress
• neuromodulator ingress
• runtime plasticity policy/state
• spike/readout egress
• runtime health, shutdown, and model identity/provenance

Brainstem does NOT own

• NVML/GPU collection
• CPU/system telemetry collection
• thermal/power hard thresholds
• GPU power-limit actuation
• mining/game/HFT adapters
• FPGA register/GPIO control
• training/distillation pipelines

Related protocol work

• rmems/corpus-ipc#27 — typed StimulusBatch + neuromodulator ingress
• rmems/corpus-ipc#28 — crates.io v0.1.0 release
• rmems/corpus-ipc#29 — lightweight feature/dependency graph

Exit criteria

• Only brainstem-daemon owns the active software SpikingNetwork tick loop in the Thalamic/Brainstem runtime path.
• Runtime restores a validated nonblank model/checkpoint before live execution.
• corpus-ipc published types replace stale/private wire aliases for live IPC.
• Current neuromod release/MSRV are aligned across the runtime.
• Thalamic can be stopped/restarted independently without moving hardware-safety responsibility into Brainstem.
• End-to-end thalamic-relay -> corpus-ipc -> brainstem-daemon smoke test exists.
• README contains a clear responsibility/failure-domain diagram.

Non-goals

• No monorepo/workspace consolidation.
• Do not absorb corpus-ipc or thalamic-relay source trees.
• Do not move deterministic hardware safety into the learned runtime.
• Do not absorb neuromod primitives into this repo.

Relationships

• Children (track under this epic): [brainstem-daemon] GH#40 — deps: migrate brainstem-daemon to published corpus-ipc and current wire API #40 (published corpus-ipc), [brainstem-daemon] GH#41 — runtime: load and validate a real Spikenaut checkpoint before entering the tick loop #41 (Spikenaut checkpoint), [brainstem-daemon] GH#42 — deps: upgrade brainstem-daemon to current neuromod and align the runtime MSRV #42 (neuromod/MSRV), [brainstem-daemon] GH#43 — integration: add end-to-end Thalamic → corpus-ipc → Brainstem runtime smoke test #43 (e2e smoke)
• Blocked on corpus-ipc crates.io for [brainstem-daemon] GH#40 — deps: migrate brainstem-daemon to published corpus-ipc and current wire API #40 (Crates.io handler owns publish after LN gate; do not mill protocol/CI here)

Release-plan reconciliation — 2026-09-28

This completed architecture epic remains delivery history, not proof of crates.io publication. Remaining release work now has a dedicated active gate, LIM-1447. LIM-1320, LIM-1322 and LIM-1323 were reparented to that gate and re-scoped against main 4788d77; completed checkpoint/dependency/health work is not reopened. Package verification is LIM-1448, existing PR #65 disposition is LIM-1449, and optional scheduler-skip observability is deferred to LIM-1450. See the brainstem-daemon project milestones for the current execution order.

[linear-code]

LIM-1131