deepseek-harness/packages/core

core/ — product API spine

The session log, system-prompt assembly, tool registry, agent vocabulary, and concrete loop that form the harness's default control spine. These are product packages — the stable surface plugins and consumers build against.

Package	Role	ctx key
scope/	Scoped-context registration primitive (scope tags, scope-filtered dispatch)	(library — no ctx key)
session/	Event-sourced session log + in-memory store	ctx.sessions
system-prompt/	Prompt-section + tool-schema assembly registry	ctx.systemPrompt
tools/	Scoped tool registry + pre-policy, guards, around-dispatch, post-policy, and final-result observation	ctx.tools
agent/	Agent interface, live registry, process-local initiator scope, agent/* event vocabulary	ctx.agents
agent-loop/	Concrete plugin implementing the public Agent contract and owning the loop driver	ctx.agentLoop

scope/ is the one non-service package here: a dependency-free library (createScope/scopeOf/scopeTarget) the registries and the loop build per-agent scoping on — it sits below session/ and system-prompt/ in the module graph precisely so they can consume it without a cycle.

agent-loop is the one concrete implementation of the agent seam and lives here because it is the harness's default product loop. It runs each driver inside ctx.agents.withInitiator(). Extension plugins depend on agent, including when they need the initiating Agent, and never on agent-loop directly, so the loop stays swappable.

The default composition that wires this spine into a runnable agent lives in examples/agent-spine-demo: one bundle plugin that loads the control spine plus selected default capabilities (timer + llm + sessions + system-prompt + tools + agents + invariants + the local skill family + tool-bash + workspace-context + agent-loop) and forwards agent-loop's agents list as its own config. It sits in examples/ — ready-to-run demo/reference bundles — not in core/: core/ ships the swappable spine pieces, while a demo bundle picks one concrete composition of them and adds a front door.