0001: External Python service, not an in-process SKSE plugin

Context

Chronicle needs to simulate beliefs, rumors, grudges, and reputation across ~1,000 NPCs, including LLM calls at two of its three tiers. Skyrim's engine constraints (Papyrus's execution model, SKSE plugin threading, no native Python) make this hard to do entirely in-process.

Decision

Chronicle runs as an external Python service. Skyrim-side code (adapters/skyrim/) is a thin seam: it forwards game events out over IPC and accepts state/AI-package injections back in. The simulation itself never runs inside the game process.

Rationale

• LLM inference (local or API) is far more tractable as a normal Python process than embedded in an SKSE DLL.
• Keeps the simulation engine-agnostic (chronicle/ has zero Skyrim imports) — the substrate choice stays reversible even after this decision.
• Precedent exists: Mantella and CHIM both prove the "external service + Papyrus/SKSE bridge" pattern works in practice. See docs/research/ once filed.

Consequences

• Need an IPC/transport layer (HTTP, as Mantella and CHIM both use, is the likely default — confirm against research findings).
• Latency budget between the game and the service becomes a real design constraint, especially for the conversation tier.