Implement the agent loop plugin
@deepseek-ai/dsh-agent-loop: LoopAgent (inbox with queued + steering FIFOs, per-step AbortController) and the streaming-first session/turn/step loop. Extension seams: agent/request, agent/step-result, agent/turn-continuation waterfalls; raw chunks logged for replay while BlockAssembler builds the assembled message; steering drains between steps; session/flush awaited at turn end. 16 tests with a scripted mock adapter cover turn lifecycle ordering, tool round-trips, steering, inject(), continuation override/veto, mid-stream abort, queued turn chaining, replay equivalence, and mid-turn fiber disposal (HMR safety).
This commit is contained in:
Tianyi Cui
410
packages/agent-loop/tests/loop.spec.ts
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410
packages/agent-loop/tests/loop.spec.ts
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@@ -0,0 +1,410 @@
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import { describe, expect, it } from 'vitest'
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import { Context } from 'cordis'
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import LlmService, { StreamChunk } from '@deepseek-ai/dsh-llm'
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import SessionStore, { SessionEventType } from '@deepseek-ai/dsh-session'
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import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
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import ToolRegistry from '@deepseek-ai/dsh-tools'
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import AgentRegistry from '@deepseek-ai/dsh-agent'
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import AgentLoop, { LoopAgent } from '@deepseek-ai/dsh-agent-loop'
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import { MockAdapter, textResponse, toolCallResponse } from './mock-adapter.ts'
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async function harness(adapter: MockAdapter) {
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const ctx = new Context()
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await ctx.plugin(LlmService)
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await ctx.plugin(SessionStore)
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await ctx.plugin(SystemPrompt)
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await ctx.plugin(ToolRegistry)
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await ctx.plugin(AgentRegistry)
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await ctx.plugin(AgentLoop, { agents: [] })
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ctx.llm.registerAdapter(['mock'], adapter)
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return ctx
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}
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/**
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* Wait for the agent's NEXT transition to idle. Always event-based: callers
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* invoke this right after send(), when the loop hasn't woken yet (status is
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* still 'idle' synchronously), so polling the current status would lie.
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*/
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function waitForIdle(ctx: Context, agent: LoopAgent): Promise<void> {
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return new Promise((resolve) => {
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const dispose = ctx.on('agent/status', (subject, status) => {
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if (subject === agent && status === 'idle') {
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dispose()
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resolve()
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}
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})
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})
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}
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function send(agent: LoopAgent, text: string) {
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agent.send([{ type: 'text', text }])
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}
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describe('agent loop', () => {
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it('runs a simple turn: queued message → model → idle, with ordered events', async () => {
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const adapter = new MockAdapter([textResponse('hello there')])
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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const order: string[] = []
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for (const name of ['agent/turn-start', 'agent/step-start', 'agent/step-end', 'agent/turn-end'] as const) {
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ctx.on(name, () => void order.push(name))
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}
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send(agent, 'hi')
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await waitForIdle(ctx, agent)
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expect(order).toEqual(['agent/turn-start', 'agent/step-start', 'agent/step-end', 'agent/turn-end'])
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const types = agent.session.events.map(e => e.type)
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// user message recorded before turn/start, assembled message + usage present
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expect(types[0]).toBe('user/message')
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expect(types[1]).toBe('turn/start')
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expect(types).toContain('assistant/message')
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expect(types).toContain('usage')
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expect(types.at(-1)).toBe('turn/end')
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// derived history: user + assistant
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const messages = agent.session.deriveMessages()
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expect(messages.map(m => m.role)).toEqual(['user', 'assistant'])
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expect(messages[1].content).toEqual([{ type: 'text', text: 'hello there' }])
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})
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it('round-trips tool calls: model requests tool → executes → result in next request', async () => {
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const adapter = new MockAdapter([
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toolCallResponse('c1', 'echo', { text: 'ping' }, 'calling echo'),
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textResponse('done'),
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])
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const ctx = await harness(adapter)
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ctx.tools.register({
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name: 'echo',
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description: 'echo back',
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parameters: { type: 'object' },
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async execute(args: any) {
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return [{ type: 'text', text: `echo: ${args.text}` }]
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},
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})
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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send(agent, 'use the tool')
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await waitForIdle(ctx, agent)
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// two model calls happened (tool-call step, then final step)
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expect(adapter.requests).toHaveLength(2)
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// the second request's derived history contains the tool result
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const secondMessages = adapter.requests[1].messages
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const toolResultMessage = secondMessages.find(m =>
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m.content.some(b => b.type === 'tool-result'))
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expect(toolResultMessage).toBeDefined()
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const block = toolResultMessage!.content.find(b => b.type === 'tool-result')!
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expect(block).toMatchObject({ toolCallId: 'c1', isError: false })
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expect((block as any).content).toEqual([{ type: 'text', text: 'echo: ping' }])
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// session log records call + result
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const types = agent.session.events.map(e => e.type)
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expect(types).toContain('tool/call')
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expect(types).toContain('tool/result')
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})
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it('passes assembled system prompt and tool schemas into the request', async () => {
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const adapter = new MockAdapter([textResponse('ok')])
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const ctx = await harness(adapter)
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ctx.systemPrompt.section({ name: 'persona', order: 0, text: 'You are a test agent.' })
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ctx.tools.register({
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name: 'noop',
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description: 'does nothing',
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parameters: { type: 'object' },
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async execute() {
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return []
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},
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})
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const agent = ctx.agentLoop.create('a1', { model: 'mock', systemPrompt: 'Agent-specific suffix.' })
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send(agent, 'hi')
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await waitForIdle(ctx, agent)
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const request = adapter.requests[0]
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expect(request.system).toBe('You are a test agent.\n\nAgent-specific suffix.')
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expect(request.tools?.map(t => t.name)).toEqual(['noop'])
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})
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it('records raw chunks for replay and emits agent/stream-chunk', async () => {
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const adapter = new MockAdapter([textResponse('abc')])
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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const streamed: StreamChunk[] = []
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ctx.on('agent/stream-chunk', (_agent, _turn, _step, chunk) => void streamed.push(chunk))
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send(agent, 'hi')
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await waitForIdle(ctx, agent)
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const chunkEvents = agent.session.events.filter(e => e.type === 'assistant/chunk')
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// textResponse('abc') = block-start + 3 deltas + block-end + usage + finish = 7
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expect(chunkEvents).toHaveLength(7)
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expect(streamed).toHaveLength(7)
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// replay: chunk events alone re-assemble to the recorded assistant message
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const deltaText = chunkEvents
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.map(e => (e.data as any).chunk)
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.filter((c: StreamChunk) => c.type === 'text-delta')
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.map((c: any) => c.text)
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.join('')
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expect(deltaText).toBe('abc')
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})
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it('injects steering between steps and continues the turn', async () => {
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const adapter = new MockAdapter([
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toolCallResponse('c1', 'slow', {}),
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textResponse('addressed the steering'),
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])
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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ctx.tools.register({
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name: 'slow',
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description: '',
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parameters: { type: 'object' },
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async execute() {
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// steer while the turn is running (during tool execution)
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agent.steer([{ type: 'text', text: 'change of plans' }])
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return [{ type: 'text', text: 'tool done' }]
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},
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})
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send(agent, 'start')
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await waitForIdle(ctx, agent)
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const types = agent.session.events.map(e => e.type)
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expect(types).toContain('steering/message')
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// steering recorded before the second step's request derived its history
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const steeringSeq = agent.session.events.find(e => e.type === 'steering/message')!.seq
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const secondStepStart = agent.session.events.filter(e => e.type === 'step/start')[1]
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expect(secondStepStart).toBeDefined()
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expect(steeringSeq).toBeLessThan(secondStepStart!.seq)
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// the second model request saw the steering content
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const secondRequest = adapter.requests[1]
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const flat = JSON.stringify(secondRequest.messages)
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expect(flat).toContain('change of plans')
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})
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it('steering while idle behaves like send (starts a turn)', async () => {
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const adapter = new MockAdapter([textResponse('ok')])
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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agent.steer([{ type: 'text', text: 'hello' }])
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await waitForIdle(ctx, agent)
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expect(agent.session.events.some(e => e.type === 'user/message')).toBe(true)
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})
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it('inject() appends context visible to the next request without starting a turn', async () => {
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const adapter = new MockAdapter([textResponse('ok')])
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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agent.inject([{ type: 'text', text: 'file changed: a.ts' }], { source: { kind: 'plugin', plugin: 'watcher' } })
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// no turn started
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await new Promise(r => setTimeout(r, 20))
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expect(agent.status).toBe('idle')
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expect(adapter.requests).toHaveLength(0)
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send(agent, 'go')
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await waitForIdle(ctx, agent)
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const flat = JSON.stringify(adapter.requests[0].messages)
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expect(flat).toContain('file changed: a.ts')
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expect(flat).toContain('<context source=\\"plugin\\">')
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})
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it('agent/turn-continuation can force-continue (/loop pattern) and force-stop', async () => {
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// force-continue: model never calls tools, but a plugin forces 3 steps
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const adapter = new MockAdapter([
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textResponse('step 1'),
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textResponse('step 2'),
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textResponse('step 3'),
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])
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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let steps = 0
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ctx.on('agent/step-end', () => void steps++)
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ctx.on('agent/turn-continuation', async (_agent, _turn, _defaultDecision, next) => {
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if (steps < 3) return true
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return next()
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})
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send(agent, 'go')
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await waitForIdle(ctx, agent)
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expect(steps).toBe(3)
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expect(adapter.requests).toHaveLength(3)
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})
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it('agent/turn-continuation can veto continuation despite tool calls (budget-guard pattern)', async () => {
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const adapter = new MockAdapter([toolCallResponse('c1', 'echo', { text: 'x' })])
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const ctx = await harness(adapter)
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ctx.tools.register({
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name: 'echo',
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description: '',
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parameters: { type: 'object' },
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async execute(args: any) {
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return [{ type: 'text', text: String(args.text) }]
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},
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})
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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ctx.on('agent/turn-continuation', async () => false as const)
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send(agent, 'go')
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await waitForIdle(ctx, agent)
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// only one model call despite the tool call requesting a follow-up
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expect(adapter.requests).toHaveLength(1)
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// tool still executed before the decision
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expect(agent.session.events.some(e => e.type === 'tool/result')).toBe(true)
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})
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it('agent/request waterfall can rewrite the request (model-switch pattern)', async () => {
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const adapter = new MockAdapter([textResponse('ok')])
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const ctx = await harness(adapter)
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ctx.llm.registerAdapter(['other-model'], adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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ctx.on('agent/request', async (_agent, _turn, _step, options, next) => {
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options.model = 'other-model'
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return next()
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})
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send(agent, 'hi')
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await waitForIdle(ctx, agent)
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expect(adapter.requests[0].model).toBe('other-model')
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})
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it('abort() mid-stream ends the turn with reason aborted', async () => {
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const adapter = new MockAdapter(['hang'])
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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const reasons: any[] = []
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ctx.on('agent/turn-end', (_agent, _turn, reason) => void reasons.push(reason))
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send(agent, 'go')
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// wait until the stream is hanging, then abort
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await new Promise(r => setTimeout(r, 30))
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expect(agent.status).toBe('running')
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agent.abort('user interrupt')
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await waitForIdle(ctx, agent)
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expect(reasons).toEqual([{ kind: 'aborted', reason: 'user interrupt' }])
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})
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it('chains queued messages into consecutive turns', async () => {
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const adapter = new MockAdapter([textResponse('first'), textResponse('second')])
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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const turns: number[] = []
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ctx.on('agent/turn-start', (_agent, turn) => void turns.push(turn))
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// queue two messages while idle — first starts turn 1 immediately;
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// queue the second during turn 1 via a stream-chunk hook
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let queued = false
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ctx.on('agent/stream-chunk', () => {
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if (!queued) {
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queued = true
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send(agent, 'second message')
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}
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})
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send(agent, 'first message')
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await waitForIdle(ctx, agent)
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expect(turns).toEqual([1, 2])
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expect(adapter.requests).toHaveLength(2)
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})
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it('awaits session/flush at turn end (persistence checkpoint)', async () => {
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const adapter = new MockAdapter([textResponse('ok')])
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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let flushed = 0
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let flushedBeforeIdle = false
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ctx.on('session/flush', async (session) => {
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await new Promise(r => setTimeout(r, 10))
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flushed++
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flushedBeforeIdle = agent.status !== 'idle'
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void session
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})
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send(agent, 'hi')
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await waitForIdle(ctx, agent)
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expect(flushed).toBe(1)
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expect(flushedBeforeIdle).toBe(true)
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})
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it('errors from the model surface as agent/error and end the turn', async () => {
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const adapter = new MockAdapter([]) // script exhausted → throws
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const ctx = await harness(adapter)
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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const errors: Error[] = []
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const reasons: any[] = []
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ctx.on('agent/error', (_agent, _turn, _step, error) => void errors.push(error))
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ctx.on('agent/turn-end', (_agent, _turn, reason) => void reasons.push(reason))
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send(agent, 'hi')
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await waitForIdle(ctx, agent)
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expect(errors).toHaveLength(1)
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expect(errors[0].message).toContain('script exhausted')
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expect(reasons[0]).toMatchObject({ kind: 'error' })
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expect(agent.session.events.some(e => e.type === 'error')).toBe(true)
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})
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it('disposing the loop fiber mid-turn stops the loop (HMR safety)', async () => {
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const adapter = new MockAdapter(['hang'])
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const ctx = await harness(adapter)
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let agent!: LoopAgent
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const fiber = await ctx.plugin(Object.assign((inner: Context) => {
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agent = inner.agentLoop.create('scoped', { model: 'mock' })
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}, { inject: ['agentLoop'] }))
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expect(ctx.agents.get('scoped')).toBe(agent)
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send(agent, 'go')
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await new Promise(r => setTimeout(r, 30))
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expect(agent.status).toBe('running')
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await fiber.dispose()
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await agent.done
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expect(agent.status).toBe('disposed')
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expect(ctx.agents.get('scoped')).toBeUndefined()
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expect(() => send(agent, 'too late')).toThrow('disposed')
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})
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it('replays a session log into an identical derived history', async () => {
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const adapter = new MockAdapter([
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toolCallResponse('c1', 'echo', { text: 'x' }),
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textResponse('done'),
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])
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const ctx = await harness(adapter)
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ctx.tools.register({
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name: 'echo',
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description: '',
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parameters: { type: 'object' },
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async execute(args: any) {
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return [{ type: 'text', text: String(args.text) }]
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},
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})
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const agent = ctx.agentLoop.create('a1', { model: 'mock' })
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send(agent, 'run')
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await waitForIdle(ctx, agent)
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const replayed = ctx.sessions.create('replayed', [...agent.session.events])
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expect(replayed.deriveMessages()).toEqual(agent.session.deriveMessages())
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// event-by-event identity of types
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expect(replayed.events.map(e => e.type)).toEqual(
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agent.session.events.map(e => e.type as SessionEventType))
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})
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})
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74
packages/agent-loop/tests/mock-adapter.ts
Normal file
74
packages/agent-loop/tests/mock-adapter.ts
Normal file
@@ -0,0 +1,74 @@
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import type { GenerateOptions, StreamChunk } from '@deepseek-ai/dsh-llm'
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import { LlmAdapter } from '@deepseek-ai/dsh-llm'
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/** Helpers to write scripted responses tersely. */
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export function textResponse(text: string): StreamChunk[] {
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return [
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{ type: 'block-start', index: 0, blockType: 'text' },
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...[...text].map((char): StreamChunk => ({ type: 'text-delta', index: 0, text: char })),
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{ type: 'block-end', index: 0, block: { type: 'text', text } },
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{ type: 'usage', usage: { inputTokens: 10, outputTokens: text.length } },
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{ type: 'finish', reason: { kind: 'stop' } },
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]
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}
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export function toolCallResponse(callId: string, name: string, args: object, text?: string): StreamChunk[] {
|
||||
const argumentsJson = JSON.stringify(args)
|
||||
const chunks: StreamChunk[] = []
|
||||
let index = 0
|
||||
if (text) {
|
||||
chunks.push(
|
||||
{ type: 'block-start', index, blockType: 'text' },
|
||||
{ type: 'text-delta', index, text },
|
||||
{ type: 'block-end', index, block: { type: 'text', text } },
|
||||
)
|
||||
index += 1
|
||||
}
|
||||
chunks.push(
|
||||
{ type: 'block-start', index, blockType: 'tool-call' },
|
||||
{ type: 'tool-call-delta', index, id: callId, name, argumentsDelta: argumentsJson.slice(0, 5) },
|
||||
{ type: 'tool-call-delta', index, id: callId, argumentsDelta: argumentsJson.slice(5) },
|
||||
{
|
||||
type: 'block-end',
|
||||
index,
|
||||
block: { type: 'tool-call', id: callId, name, arguments: argumentsJson },
|
||||
},
|
||||
{ type: 'usage', usage: { inputTokens: 10, outputTokens: 5 } },
|
||||
{ type: 'finish', reason: { kind: 'tool-calls' } },
|
||||
)
|
||||
return chunks
|
||||
}
|
||||
|
||||
/**
|
||||
* Mock adapter driven by a script: each model call consumes the next entry.
|
||||
* Records every request it receives for assertions. An entry may be a
|
||||
* function to compute chunks from the request, or a 'hang' marker that
|
||||
* streams one chunk then waits until aborted.
|
||||
*/
|
||||
export class MockAdapter extends LlmAdapter {
|
||||
requests: GenerateOptions[] = []
|
||||
|
||||
constructor(private script: (StreamChunk[] | ((options: GenerateOptions) => StreamChunk[]) | 'hang')[]) {
|
||||
super()
|
||||
}
|
||||
|
||||
async * stream(options: GenerateOptions): AsyncIterable<StreamChunk> {
|
||||
this.requests.push(options)
|
||||
const entry = this.script.shift()
|
||||
if (!entry) throw new Error('MockAdapter: script exhausted')
|
||||
if (entry === 'hang') {
|
||||
yield { type: 'block-start', index: 0, blockType: 'text' }
|
||||
yield { type: 'text-delta', index: 0, text: 'partial' }
|
||||
await new Promise<void>((resolve, reject) => {
|
||||
if (options.signal?.aborted) return reject(new Error('aborted'))
|
||||
options.signal?.addEventListener('abort', () => reject(new Error('aborted')), { once: true })
|
||||
})
|
||||
return
|
||||
}
|
||||
const chunks = typeof entry === 'function' ? entry(options) : entry
|
||||
for (const chunk of chunks) {
|
||||
if (options.signal?.aborted) throw new Error('aborted')
|
||||
yield chunk
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user