mirror of
https://github.com/deepseek-ai/deepseek-harness
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3e1ca8a425
The prior fix handled a throwing session/event listener on the turn/start append, but the SAME push-before-notify hazard remained on the three FINALIZER appends. Session.append pushes the event before notifying, so a throwing listener on a finalizer event left the event logged but aborted the rest of finalization — stranding the turn open. - failTurn(): set `reason` BEFORE appending the `error` event, and contain a throwing session/event listener on it (the event is already logged either way). Otherwise reason stayed unset, agent/error was skipped, and the caller's closeTurn(false) never ran → open turn. - closeStep(): the try/catch wrapped only the agent/step-end EMIT, not the step/end APPEND. A throwing session/event listener on step/end escaped — fatal when closeStep runs from the outer catch during finalization (turn/start + step/end but no turn/end). Now both the append and the emit are contained and surface as a turn error via failTurn. - closeTurn(): contain a throwing session/event listener on the turn/end append (it would propagate to the runLoop backstop from closeTurn(false), or skip the turn-end emit from closeTurn(true)). turn/end is logged either way, so the turn stays balanced. Regressions: a throwing session/event listener on the error event, on step/end during finalization (driven by a throwing agent/step-start), and on turn/end — each leaves a balanced turn and the loop survives.
dsh-agent-loop
THE concrete agent plugin: LoopAgent and the loop driver. Implements the Agent interface and drives the session/turn/step lifecycle.
This is the only package in the harness that contains concrete loop logic. Everything else is an abstract service or a plugin against extension seams — new behavior goes into plugins, not here.
Service: AgentLoop (ctx key: agentLoop)
Public API
ctx.agentLoop.create(id: string, options?: AgentOptions): LoopAgentCreate an agent, start its loop, and register it inctx.agents. Disposed with the calling fiber.
Injected services
agents, sessions, llm, tools, systemPrompt — all five interface services.
Configuration (schemastery)
interface Config {
agents: Array<{
id: string // required
model?: string
systemPrompt?: string
}>
}
Agents listed in config are auto-created at startup.
Classes
LoopAgent— the concreteAgentimplementation. Owns the inbox (Inbox), the per-stepAbortController, and the loop driver. Everything observable happens through session events and theagent/*event taxonomy.Inbox— per-agent queued + steering FIFOs (enqueue,steer,drainQueued,drainSteering,waitForQueued).
Loop lifecycle (loop.ts)
One invocation of runLoop() drives one agent for its whole lifetime:
forever:
wait for queued messages (idle)
TURN (error-contained):
drain queued → 'turn/start' → session('user/message')
STEP loop:
drain steering
assembly = systemPrompt.assemble()
request = waterfall agent/request
stream llm.stream(request) → session('assistant/chunk')
message = waterfall agent/step-result
session('assistant/message')
each tool-call: session('tool/call') → tools.execute() → session('tool/result')
drain steering → session('steering/message')
cont = waterfall agent/turn-continuation
if !cont: break
session('turn/end')
await session/flush
re-enqueue leftover steering as queued
idle unless more queued
Error containment: a throwing plugin ends the turn, never the loop. Dispose mid-turn emits agent/status('disposed') and ends with reason disposed.
What is NOT here
Everything that goes beyond "call the model, run the tools, repeat" belongs to plugins listening on the event taxonomy:
- Hooks:
agent/request,agent/step-result,tools/execute,agent/turn-continuation - Compaction:
agent/request - Sandbox, permission, plan mode:
tools/execute - Sub-agents: TODO seam on
AgentLoop.create() - Persistence:
session/event+session/flush - UI:
agent/stream-chunk+agent/*events