deepseek-harness/packages/core

core/ — product API spine

The packages every harness build is assembled from: the session log, the system-prompt assembly, the tool registry, the agent vocabulary, and the one concrete loop that drives them. These are product packages — the stable surface plugins and consumers build against.

Package	Role	ctx key
session/	Event-sourced session log + in-memory store	ctx.sessions
system-prompt/	Prompt-section + tool-schema assembly registry	ctx.systemPrompt
tools/	Tool registry + tools/execute waterfall	ctx.tools
agent/	Agent interface, registry, agent/* event vocabulary	ctx.agents
agent-loop/	The concrete loop plugin: ReactLoopAgent + the loop driver	ctx.agentLoop

agent-loop is the one concrete implementation of the agent seam and lives here because it is the harness's default product loop; everything else in core/ is interface/vocabulary. Plugins depend on the agent vocabulary, never on agent-loop directly, so the loop stays swappable.