deepseek-harness/packages/core

description	kind
The core group map: the session log, system-prompt assembly, tool registry, agent vocabulary, and default loop that form the product API spine.	package-group

packages/core

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Summary

The core group provides the product API spine of the DeepSeek Harness: an append-only session log, system-prompt assembly, a tool registry, the Agent handle, and the concrete loop that drives them. Every composition boots these packages, and plugins and consumers build against their stable contracts. A turn flows through all of them — the loop claims a prompt, opens a turn on the session log, assembles the request through system-prompt, streams the model response, dispatches tool calls through the registry, and appends every model-visible fact back to the log. Choose this group when you build an agent or extend one; the runnable default composition is examples/agent-spine-demo.

Table of Contents

• Packages
• Related documentation
• Dev Note

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Packages

Package	Role	ctx key
scope/	Scoped registration and event routing that isolate one agent's contributions	library — no ctx key
session/	The append-only session event log every agent's history derives from	ctx.sessions
system-prompt/	System-prompt assembly from ordered sections, tool schemas, and variables	ctx.systemPrompt
tools/	The tool registry and guarded execution pipeline the loop dispatches through	ctx.tools
agent-tool-presentation/	Per-agent tool-presentation selector for presets	no ctx key
agent/	The Agent handle plugins program against, plus its live registry and events	ctx.agents
agent-default-model/	The deployment default model selection entry points apply to fresh agents	ctx.agentDefaultModel
agent-loop/	The default agent driver: creates agents and runs the turn and step lifecycle	ctx.agentLoop

scope supplies the shared scoping primitive; agent owns the public Agent contract, while agent-loop is its default implementation, so extension plugins depend on agent and the driver stays swappable. agent-default-model owns the deployment selection an entry point applies when a session has none of its own. Runnable compositions live in examples/agent-spine-demo; this group owns only the swappable spine pieces.

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Related documentation

• Core subsystem — the package-by-package loop map and the Agent handle contracts.
• Session subsystem — the session event vocabulary and derived history.
• System-prompt subsystem — prompt section, dynamic context, and tool-schema types.
• Tools subsystem — the tool execution pipeline and presentation vocabulary.
• Scoped registration subsystem — the scoped-layer primitive these registries build on.
• Architecture — the turn flow and where new behavior goes.
• agent-spine-demo — the default runnable composition.

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Dev Note

Working context for maintainers — click to expand

None.