One reusable roleplay core for desktop and terminal hosts

Status: accepted direction by owner, 2026-10-29; consolidation implementation in progress.
Owners: src/rp-core.ts, src/studio/scene-turn.ts, src/stage/contracts/chat-store.ts.

Decision

Bunzai keeps one turn engine and one canonical scene/state model. The reusable core exposes the current turn orchestration with injected storage, providers and library readers. Skills, trackers, presets, macros, prompt assembly and Final Cut retain their existing owners. Co-developer improvements are absorbed into these owners as they are reconciled; an alternate default engine and separate session journal are not introduced.

The core owns only in-flight execution state: cancellation, gates, background tracker rounds and accepted task completion. ChatStore owns persisted scenes, versions, checkpoints and deltas. A host creates one runtime for each opened store and reuses it across requests. Independent stores may use colliding identifiers. Storage closes only after accepted work settles. No new turn or recovery operation is admitted after shutdown.

Hosts may schedule background work through afterEvent; the returned promise must cover its writes. Other host jobs remain the host's responsibility. Imported scripts remain sealed under ADR-009; a terminal without an isolated worker refuses applicable regex instead of evaluating it in-process.

Current implementation and limits

• Desktop streaming consumes the reusable source API. Runtime state is explicit and shared by the routes for one open store.
• The terminal session runner accepts an injected core and stores, with scripted send/continue/swipe and regex-refusal tests. A standalone shared-library CLI command is withheld.
• Cross-process recovery requires durable ownership/leases. SQLite transaction serialization alone does not identify whether a checkpoint belongs to a live process. No claim of safe simultaneous independent desktop/CLI library owners is made.
• The API bundles for the browser and executes a scripted turn in Node. These checks do not establish packaged-platform or published-package behavior.
• Broader co-developer patch reconciliation remains separate work under the same integration plan. Old repository ancestry remains excluded.

Owner-authorized amendment, 2026-10-31

The owner requested porting Bunraku commits 5f23a8a7 and e191f864 and explicitly approved their
separate-engine behavior. New scenes use the external LeviTheWeasel/rp-core engine; existing scenes
continue through the canonical Bunzai runtime above. vendor/rp-core is a main-tracking Git submodule,
installed as a local package, not copied into the host source tree. Each committed host version pins
one upstream commit; bun run rp-core:update advances it for review and verification.

Migration 47 adds encrypted core journal tables and scene links without rewriting migrations 44-46.
Linked scenes support send, reply, continue, swipe, review, stop, Director/Memory switches and scene
export. Unsupported transcript edits and legacy scene configuration writes are refused before they
can diverge from the engine journal. Providers currently support OpenAI-chat compatible connections
and native Ollama; other native adapters are explicitly refused. Legacy presets, lore/regex and
tracker configuration are not automatically transferred to the external engine.

Scene export contains the host scene projection and frozen cast, not a complete backup of the
external engine journal or compendium. Old scenes are not migrated to the external engine.
The host tracks external streaming tasks through library shutdown and isolates running sessions
by ChatStore, while the record store enforces database-backed session leases.