deepseek-harness/packages/agent

dsh-agent

Agent interface, registry, and agent/* event vocabulary. Every plugin (UI, hooks, orchestrators) programs against the Agent handle defined here — it has zero loop dependency, so the loop is swappable.

Service: AgentRegistry (ctx key: agents)

Tracks live agents so UI, hook, and orchestrator plugins can find them without importing the concrete loop package.

Public API

• ctx.agents.register(agent: Agent): () => void Register a live agent. Disposed with the calling fiber.
• ctx.agents.get(id: string): Agent | undefined
• ctx.agents.list(): Agent[]

Events

The full agent/* event taxonomy is declared via declaration merging in dsh-agent (not dsh-agent-loop), so plugins depend only on this package.

Lifecycle (emit)

• agent/created, agent/disposed — registration/deregistration
• agent/status — idle / running / disposed transition
• agent/queued — message entered inbox (source-resolved, steering flag)

Turn/step boundaries (emit)

• agent/turn-start, agent/turn-end (carries TurnEndReason)
• agent/step-start, agent/step-end

Interception seams (waterfall)

• agent/request — mutate GenerateOptions before the model call (hooks, compaction, model switching, tool filtering)
• agent/step-result — post-process the assembled assistant message before tool dispatch (validates what the log records)
• agent/turn-continuation — override the continue/stop decision (force-continue /loop, force-stop budget guard)

Streaming + tool (emit)

• agent/stream-chunk — raw chunk from the model (token-level UI/log feed)
• agent/steering — steering content injected mid-turn
• agent/error — step/turn error

Agent interface (types.ts)

The handle every plugin programs against:

• agent.send(content, options?) — queue a message; starts a turn when idle
• agent.steer(content, options?) — steer a running turn (inject between steps); behaves like send when idle
• agent.inject(content, options?) — inject in-session context without triggering a turn (context/message event); next request sees it
• agent.abort(reason?) — abort the in-flight step
• agent.session, agent.status, agent.options, agent.id

Extension points

• Agent creation: AgentLoop.create() is the concrete implementation (in dsh-agent-loop). Replace the loop by implementing Agent and registering via ctx.agents.register().
• Event listeners: all agent/* events are declared here — no dependency on the loop package needed.

What is NOT here (TODO)

• Sub-agent spawn/fork — seam on AgentLoop.create(), semantics deferred.