Files
deepseek-harness/packages/core/agent-loop/tests/loop.spec.ts
T

1192 lines
50 KiB
TypeScript

import { describe, expect, it } from 'vitest'
import { Context } from 'cordis'
import LlmService, { createUserMessage, CallId, StreamChunk } from '@deepseek-ai/dsh-llm'
import SessionStore, { SessionId, TurnEndReason } from '@deepseek-ai/dsh-session'
import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
import ToolRegistry, { defineContentToolFixture } from '@deepseek-ai/dsh-tools'
import AgentRegistry, { type Agent } from '@deepseek-ai/dsh-agent'
import AgentLoop from '@deepseek-ai/dsh-agent-loop'
import { MockAdapter, maxTokensResponse, textResponse, toolCallResponse } from './mock-adapter.ts'
function driverDone(agent: Agent): Promise<void> {
return (agent as Agent & { done: Promise<void> }).done
}
async function harness(adapter: MockAdapter, persona = '') {
const ctx = new Context()
await ctx.plugin(LlmService)
await ctx.plugin(SessionStore)
await ctx.plugin(SystemPrompt, { persona })
await ctx.plugin(ToolRegistry)
await ctx.plugin(AgentRegistry)
await ctx.plugin(AgentLoop, { agents: [] })
ctx.llm.registerAdapter(['mock'], adapter)
return ctx
}
/**
* Wait for the agent's NEXT transition to idle. Always event-based: callers
* invoke this right after send(), when the loop hasn't woken yet (status is
* still 'idle' synchronously), so polling the current status would lie.
*/
function waitForIdle(ctx: Context, agent: Agent): Promise<void> {
return new Promise((resolve) => {
const dispose = ctx.on('agent/status', (subject, status) => {
if (subject === agent && status === 'idle') {
dispose()
resolve()
}
})
})
}
function send(agent: Agent, text: string) {
agent.followup(createUserMessage({ content: [{ type: 'text', text }], source: { kind: 'user' } }))
}
describe('agent loop', () => {
it.each([0, -1, 1.5, Number.NaN, Number.MAX_SAFE_INTEGER + 1])(
'rejects invalid AgentOptions.maxTokens %s before publication',
async (maxTokens) => {
const ctx = await harness(new MockAdapter([]))
expect(() => ctx.agentLoop.create(
SessionId('invalid-max-tokens'),
{ provider: 'mock', model: 'mock', maxTokens },
)).toThrow('agent maxTokens must be a positive safe integer')
expect(ctx.agents.list()).toEqual([])
expect(ctx.sessions.list()).toEqual([])
},
)
it('seeds a valid AgentOptions.maxTokens into the first model request', async () => {
const adapter = new MockAdapter([textResponse('bounded')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(
SessionId('valid-max-tokens'),
{ provider: 'mock', model: 'mock', maxTokens: 256 },
)
send(agent, 'use the configured output limit')
await waitForIdle(ctx, agent)
expect(adapter.requests[0]?.maxTokens).toBe(256)
})
it('runs a simple turn: queued message → model → idle, with ordered events', async () => {
const adapter = new MockAdapter([textResponse('hello there')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
// All boundaries — turn and step — are durable session events on the
// session/event feed (no agent/* mirror). Record them in fire order to
// assert the full boundary nesting.
const order: string[] = []
ctx.on('session/event', (_session, event) => {
if (event.type === 'turn/start' || event.type === 'step/start' || event.type === 'step/end' || event.type === 'turn/end') {
order.push(event.type)
}
})
send(agent, 'hi')
await waitForIdle(ctx, agent)
expect(order).toEqual(['turn/start', 'step/start', 'step/end', 'turn/end'])
const types = agent.session.events.map(e => e.type)
// Durable inbox receipt and admission bracket the turn-owned transcript.
expect(types[0]).toBe('agent/inbox/spliced')
expect(types).toContain('turn/start')
expect(types).toContain('user/message')
expect(types).toContain('assistant/message')
const assistantMessage = agent.session.events.find(e => e.type === 'assistant/message')
expect(assistantMessage?.type === 'assistant/message' && assistantMessage.data.usage).toEqual({ inputTokens: 10, outputTokens: 'hello there'.length })
expect(types.at(-1)).toBe('turn/end')
// derived history: user + assistant
const messages = agent.session.deriveMessages()
expect(messages.map(m => m.role)).toEqual(['user', 'assistant'])
expect(messages[1]!.content).toEqual([{ type: 'text', text: 'hello there' }])
})
it('round-trips tool calls: model requests tool → executes → result in next request', async () => {
const adapter = new MockAdapter([
toolCallResponse('c1', 'echo', { text: 'ping' }, 'calling echo'),
textResponse('done'),
])
const ctx = await harness(adapter)
ctx.tools.register(defineContentToolFixture({
name: 'echo',
description: 'echo back',
parameters: { text: { type: 'string' } },
async execute(args) {
return [{ type: 'text', text: `echo: ${args.text}` }]
},
}))
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
send(agent, 'use the tool')
await waitForIdle(ctx, agent)
// two model calls happened (tool-call step, then final step)
expect(adapter.requests).toHaveLength(2)
// the second request's derived history contains the tool result
const secondMessages = adapter.requests[1]!.messages
const toolResultMessage = secondMessages.find(m =>
m.content.some(b => b.type === 'tool-result'))
expect(toolResultMessage).toBeDefined()
const block = toolResultMessage!.content.find(b => b.type === 'tool-result')!
expect(block).toMatchObject({ toolCallId: 'c1', isError: false })
expect((block).content).toEqual([{ type: 'text', text: 'echo: ping' }])
// session log records call + result
const types = agent.session.events.map(e => e.type)
expect(types).toContain('tool/call')
expect(types).toContain('tool/result')
})
it('renders harness identity, then the persona, then tool guidance — with {{variables}} resolved', async () => {
const adapter = new MockAdapter([textResponse('ok')])
// The persona is a TEMPLATE: {{model}} is the loop-registered variable
// projecting this agent's configured model, so the model knows its own name.
const ctx = await harness(adapter, 'You are a test agent on {{model}}.')
ctx.systemPrompt.section({ name: 'tool:noop', order: 100, text: 'Use the noop tool wisely.' })
ctx.tools.register(defineContentToolFixture({
name: 'noop',
description: 'does nothing',
parameters: {},
async execute() {
return []
},
}))
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
send(agent, 'hi')
await waitForIdle(ctx, agent)
const request = adapter.requests[0]
expect(request!.system).toBe('You are an AI agent powered by the DeepSeek Harness SDK.\n\nYou are a test agent on mock.\n\nUse the noop tool wisely.')
expect(request!.tools?.map(t => t.name)).toEqual(['noop'])
})
it('resolves {{cwd}} from the agent session workspace (factory create with meta.cwd)', async () => {
const adapter = new MockAdapter([textResponse('ok')])
const ctx = await harness(adapter, 'Working in {{cwd}}.')
const handle = await ctx.agents.create({
sessionId: SessionId('s-cwd'),
meta: { cwd: '/work/space' },
agentOptions: { provider: 'mock', model: 'mock' },
})
const agent = handle.agent
send(agent, 'hi')
await waitForIdle(ctx, agent)
expect(adapter.requests[0]!.system).toBe('You are an AI agent powered by the DeepSeek Harness SDK.\n\nWorking in /work/space.')
})
it('contains a strict-variable render failure: the turn errors, the loop keeps serving turns', async () => {
// A missing cwd variable must fail one turn without preventing a later valid turn.
const adapter = new MockAdapter([textResponse('ok after rescue')])
const ctx = await harness(adapter, 'In {{cwd}}.')
const errors: Error[] = []
ctx.on('agent/error', (_agent, _turn, _step, error) => {
if (error instanceof Error) errors.push(error)
})
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
send(agent, 'hi')
await waitForIdle(ctx, agent)
expect(adapter.requests).toHaveLength(0) // the request was never sent
expect(errors).toEqual([])
const turnEnd = agent.session.events.find(e => e.type === 'turn/end')
expect(turnEnd?.type === 'turn/end' && turnEnd.data.reason.kind).toBe('error')
expect(turnEnd?.type === 'turn/end' && turnEnd.data.reason.kind === 'error'
? turnEnd.data.reason.error
: '').toContain('no value for this assembly')
// The loop survived: a waterfall listener rescues {{cwd}} and the SAME
// agent completes a real model turn.
ctx.on('system-prompt/assemble', async (assembly, _context, next) => {
assembly.variables['cwd'] = '/rescued'
return next()
})
send(agent, 'again')
await waitForIdle(ctx, agent)
expect(adapter.requests).toHaveLength(1)
expect(adapter.requests[0]!.system).toBe('You are an AI agent powered by the DeepSeek Harness SDK.\n\nIn /rescued.')
const turnEnds = agent.session.events.filter(e => e.type === 'turn/end')
expect(turnEnds).toHaveLength(2)
expect(turnEnds[1]?.type === 'turn/end' && turnEnds[1].data.reason.kind).toBe('completed')
})
it('supports the model-via-agent/request path with a {{model}} persona: the supplier states it via the assemble waterfall', async () => {
// AgentOptions.model unset: the model arrives in the agent/request
// waterfall (the loop's documented fallback — see runStep's no-model
// error). {{model}} renders BEFORE that waterfall, so the SAME plugin
// states the fact early on system-prompt/assemble — the owner of a
// late-bound fact owns stating it wherever it is claimed.
const adapter = new MockAdapter([textResponse('ok')])
const ctx = await harness(adapter, 'You run on {{model}}.')
ctx.on('system-prompt/assemble', async (assembly, _context, next) => {
assembly.variables['provider'] = 'mock'
assembly.variables['model'] = 'mock'
return next()
})
ctx.on('agent/request', async (_agent, _turn, _step, _signal, next) => {
const config = await next()
return { ...config, provider: 'mock', model: 'mock' }
})
const agent = ctx.agentLoop.create(SessionId('a-late-model'), {})
send(agent, 'hi')
await waitForIdle(ctx, agent)
expect(adapter.requests).toHaveLength(1)
expect(adapter.requests[0]!.model).toBe('mock')
expect(adapter.requests[0]!.system).toBe('You are an AI agent powered by the DeepSeek Harness SDK.\n\nYou run on mock.')
})
it('omits the system field when a system-prompt/assemble veto empties the assembly', async () => {
// The documented escape valve: a deployment that must drop the harness
// openers short-circuits the assemble waterfall; the request then carries
// NO system field at all (not an empty string).
const adapter = new MockAdapter([textResponse('ok')])
const ctx = await harness(adapter)
ctx.on('system-prompt/assemble', async () => ({ sections: [], tools: [], variables: {} }))
const agent = ctx.agentLoop.create(SessionId('a-no-system'), { provider: 'mock', model: 'mock' })
send(agent, 'hi')
await waitForIdle(ctx, agent)
expect(adapter.requests).toHaveLength(1)
expect('system' in adapter.requests[0]!).toBe(false)
})
it('records raw chunks for replay as assistant/chunk session events', async () => {
const adapter = new MockAdapter([textResponse('abc')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
send(agent, 'hi')
await waitForIdle(ctx, agent)
const chunkEvents = agent.session.events.filter(e => e.type === 'assistant/chunk')
// textResponse('abc') = block-start + 3 deltas + block-end + usage + finish = 7
expect(chunkEvents).toHaveLength(7)
// replay: chunk events alone re-assemble to the recorded assistant message
const deltaText = chunkEvents
.flatMap(e => e.type === 'assistant/chunk' ? [e.data.chunk] : [])
.filter((c: StreamChunk): c is Extract<StreamChunk, { type: 'text-delta' }> => c.type === 'text-delta')
.map(c => c.text)
.join('')
expect(deltaText).toBe('abc')
})
it('injects steering between steps and continues the turn', async () => {
const adapter = new MockAdapter([
toolCallResponse('c1', 'slow', {}),
textResponse('addressed the steering'),
])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
ctx.tools.register(defineContentToolFixture({
name: 'slow',
description: '',
parameters: {},
async execute() {
// steer while the turn is running (during tool execution)
agent.steer(createUserMessage({ content: [{ type: 'text', text: 'change of plans' }], source: { kind: 'user' } }))
return [{ type: 'text', text: 'tool done' }]
},
}))
send(agent, 'start')
await waitForIdle(ctx, agent)
const steering = agent.session.events.find(e =>
e.type === 'user/message' && JSON.stringify(e.data.content).includes('change of plans'))
expect(steering).toBeDefined()
// Steering is admitted before the second step's request derives history.
const steeringSeq = steering!.seq
const secondStepStart = agent.session.events.filter(e => e.type === 'step/start')[1]
expect(secondStepStart).toBeDefined()
expect(steeringSeq).toBeLessThan(secondStepStart!.seq)
// the second model request saw the steering content
const secondRequest = adapter.requests[1]
const flat = JSON.stringify(secondRequest!.messages)
expect(flat).toContain('change of plans')
})
it('coalesces same-tick idle steering into one turn', async () => {
const adapter = new MockAdapter([textResponse('first')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const idle = waitForIdle(ctx, agent)
agent.steer(createUserMessage({ content: [{ type: 'text', text: 'first idle steer' }], source: { kind: 'user' } }))
agent.steer(createUserMessage({ content: [{ type: 'text', text: 'second idle steer' }], source: { kind: 'user' } }))
await idle
expect(agent.session.events.filter(event => event.type === 'turn/start')).toHaveLength(1)
expect(agent.session.events
.filter(event => event.type === 'user/message')
.map(event => event.data.content)).toEqual([
[{ type: 'text', text: 'first idle steer' }],
[{ type: 'text', text: 'second idle steer' }],
])
expect(agent.session.events.filter(event => event.type === 'steering/message')).toEqual([])
expect(adapter.requests).toHaveLength(1)
expect(JSON.stringify(adapter.requests[0]?.messages)).toContain('first idle steer')
expect(JSON.stringify(adapter.requests[0]?.messages)).toContain('second idle steer')
})
it('contains a throwing step observer and carries steering into a replacement turn', async () => {
const adapter = new MockAdapter([textResponse('recovered')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('failed-steering'), { provider: 'mock', model: 'mock' })
let fail = true
ctx.on('agent/step', (subject) => {
if (subject !== agent || !fail) return
fail = false
subject.steer(createUserMessage({ content: [{ type: 'text', text: 'pending steering' }], source: { kind: 'user' } }))
throw new Error('step failed')
})
send(agent, 'prompt')
await waitForIdle(ctx, agent)
expect(adapter.requests).toHaveLength(1)
expect(agent.session.events.filter(event => event.type === 'turn/start')).toHaveLength(2)
expect(agent.session.events.some(event => event.type === 'steering/message')).toBe(false)
expect(JSON.stringify(adapter.requests[0]?.messages)).toContain('pending steering')
})
it('inject() while idle durably stages context without opening a turn', async () => {
const adapter = new MockAdapter([textResponse('ok')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
agent.inject(createUserMessage({ content: [{ type: 'text', text: 'file changed: a.ts' }], source: { kind: 'plugin', plugin: 'watcher' } }))
expect(agent.status).toBe('idle')
expect(adapter.requests).toHaveLength(0)
expect(agent.session.events.filter(event => event.type === 'turn/start')).toHaveLength(0)
expect(agent.session.events.at(-1)).toMatchObject({
type: 'agent/inbox/spliced',
data: {
target: 'next-step',
inserted: [{
role: 'user',
content: [{ type: 'text', text: 'file changed: a.ts' }],
source: { kind: 'plugin', plugin: 'watcher' },
}],
},
})
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(agent.session.events.filter(event => event.type === 'turn/start')).toHaveLength(1)
const flat = JSON.stringify(adapter.requests[0]!.messages)
expect(flat).toContain('file changed: a.ts')
expect(flat).not.toContain('<context source=')
})
it('inject() persists structured context content verbatim with durable source', async () => {
const adapter = new MockAdapter([textResponse('ok')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('raw-context'), { provider: 'mock', model: 'mock' })
const text = '<system-reminder>Additional instructions from: pkg/AGENTS.md</system-reminder>'
agent.inject(createUserMessage({ content: [{ type: 'text', text }], source: { kind: 'plugin', plugin: 'workspace-context' } }))
send(agent, 'go')
await waitForIdle(ctx, agent)
const contextEvent = agent.session.events.find(event => event.type === 'user/message' && event.data.source.kind === 'plugin')
expect(contextEvent?.type === 'user/message' && contextEvent.data.source)
.toEqual({ kind: 'plugin', plugin: 'workspace-context' })
const requestText = JSON.stringify(adapter.requests[0]!.messages)
expect(requestText).toContain('Additional instructions from: pkg/AGENTS.md')
expect(requestText).not.toContain('<context source=')
})
it('defers inject() during tool execution until after the tool result', async () => {
const adapter = new MockAdapter([
toolCallResponse('c1', 'noticer', {}, 'calling'),
textResponse('done'),
])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
let visibleDuringTool = false
ctx.tools.register(defineContentToolFixture({
name: 'noticer',
description: 'injects a notice',
parameters: {},
async execute() {
await Promise.resolve()
const first = { type: 'text' as const, text: 'mid-turn notice' }
agent.inject(createUserMessage({ content: [first], source: { kind: 'plugin', plugin: 'x' } }))
first.text = 'mutated after inject'
agent.inject(createUserMessage({ content: [{ type: 'text', text: 'second notice' }], source: { kind: 'plugin', plugin: 'x' } }))
visibleDuringTool = agent.session.events.some(e => e.type === 'user/message' && e.data.source.kind === 'plugin')
return [{ type: 'text', text: 'ok' }]
},
}))
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(visibleDuringTool).toBe(false)
// The injection stays in the open turn, but its user-role context cannot
// split the assistant tool call from the provider's tool-result message.
const turnStarts = agent.session.events.filter(e => e.type === 'turn/start')
expect(turnStarts).toHaveLength(1)
const result = agent.session.events.find(e => e.type === 'tool/result')!
const contexts = agent.session.events.filter(e => e.type === 'user/message' && e.data.source.kind === 'plugin')
expect(contexts).toHaveLength(2)
expect(result.seq).toBeLessThan(contexts[0]!.seq)
expect(contexts.flatMap(event => event.type === 'user/message' ? event.data.content : []))
.toEqual([
{ type: 'text', text: 'mid-turn notice' },
{ type: 'text', text: 'second notice' },
])
const secondRequest = adapter.requests[1]!.messages
const resultIndex = secondRequest.findIndex(message =>
message.content.some(block => block.type === 'tool-result'))
const contextIndexes = secondRequest.flatMap((message, index) =>
message.content.some(block => block.type === 'text'
&& (block.text.includes('mid-turn notice') || block.text.includes('second notice')))
? [index]
: [])
expect(resultIndex).toBeGreaterThanOrEqual(0)
expect(contextIndexes).toHaveLength(2)
expect(contextIndexes.every(index => index > resultIndex)).toBe(true)
})
it('rejects non-JSON context before it enters the active tool-batch FIFO', async () => {
const adapter = new MockAdapter([
toolCallResponse('c1', 'invalid-injector', {}, 'calling'),
textResponse('done'),
])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('invalid-context'), { provider: 'mock', model: 'mock' })
ctx.tools.register(defineContentToolFixture({
name: 'invalid-injector',
description: 'attempts an invalid context injection',
parameters: {},
async execute() {
expect(() => {
agent.inject(createUserMessage({ content: [{ type: 'text', text: 'invalid' }], source: { kind: 'plugin', plugin: 'test', bigint: 1n } as never }))
}).toThrow('agent context must be losslessly JSON-serializable')
return [{ type: 'text', text: 'rejected invalid context' }]
},
}))
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(agent.session.events.some(event => event.type === 'user/message' && event.data.source.kind === 'plugin')).toBe(false)
})
it('agent/turn-stopping can steer another step (/loop pattern)', async () => {
const adapter = new MockAdapter([
textResponse('step 1'),
textResponse('step 2'),
textResponse('step 3'),
])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
let steps = 0
ctx.on('session/event', (_session, event) => { if (event.type === 'step/end') steps++ })
ctx.on('agent/turn-stopping', (subject) => {
if (steps < 3) {
subject.steer(createUserMessage({ content: [{ type: 'text', text: 'continue' }], source: { kind: 'plugin', plugin: 'loop-test' } }))
}
})
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(steps).toBe(3)
expect(adapter.requests).toHaveLength(3)
})
it('a tool can conclude the turn despite owing a follow-up request', async () => {
const adapter = new MockAdapter([toolCallResponse('c1', 'echo', { text: 'x' })])
const ctx = await harness(adapter)
ctx.tools.register(defineContentToolFixture({
name: 'echo',
description: '',
parameters: { text: { type: 'string' } },
async execute(args, exec) {
exec.concludeTurn()
return [{ type: 'text', text: String(args.text) }]
},
}))
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
send(agent, 'go')
await waitForIdle(ctx, agent)
// only one model call despite the tool call requesting a follow-up
expect(adapter.requests).toHaveLength(1)
// The tool still executes and durably records its result.
expect(agent.session.events.some(e => e.type === 'tool/result')).toBe(true)
})
it('continues for steering that arrived during a concluding tool step', async () => {
const adapter = new MockAdapter([
toolCallResponse('c1', 'finalize', {}),
textResponse('next turn reply'),
])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
ctx.tools.register(defineContentToolFixture({
name: 'finalize',
description: '',
parameters: {},
async execute(_args, exec) {
// Steering lands while the concluding tool is still executing.
agent.steer(createUserMessage({ content: [{ type: 'text', text: 'late steering' }], source: { kind: 'user' } }))
exec.concludeTurn()
return [{ type: 'text', text: 'final' }]
},
}))
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(adapter.requests).toHaveLength(2)
const events = agent.session.events.map(event => event.type)
expect(events.filter(type => type === 'turn/end')).toHaveLength(1)
expect(JSON.stringify(adapter.requests[1]?.messages)).toContain('late steering')
const texts = adapter.requests[1]!.messages
.flatMap(message => message.content)
.filter(block => block.type === 'text')
.map(block => block.text)
expect(texts).toContain('late steering')
})
it('agent/request waterfall switches models by returning a replacement config; the switch is logged', async () => {
const adapter = new MockAdapter([textResponse('ok')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
ctx.on('agent/request', async (_agent, _turn, _step, _signal, next) => {
const config = await next()
// The seed is frozen — config is not a mutable per-call knob; a switch
// is proposed by returning a replacement, and the loop logs it.
expect(Object.isFrozen(config)).toBe(true)
expect(() => { (config as { model: string }).model = 'other-model' }).toThrow(TypeError)
return { ...config, model: 'other-model' }
})
send(agent, 'hi')
await waitForIdle(ctx, agent)
expect(adapter.requests[0]!.model).toBe('other-model')
// The header event records what the request ACTUALLY used — the switch is
// a reconstructable fact, not silent drift.
const headerEvent = agent.session.events.find(e => e.type === 'request/header')
expect(headerEvent?.type === 'request/header' && headerEvent.data.header.config.model).toBe('other-model')
})
it('agent/step fires once per step before the step is opened', async () => {
const adapter = new MockAdapter([
toolCallResponse('c1', 'echo', {}, 'calling echo'),
textResponse('done'),
])
const ctx = await harness(adapter)
ctx.tools.register(defineContentToolFixture({
name: 'echo', description: 'echo', parameters: {},
async execute() { return [{ type: 'text', text: 'echoed' }] },
}))
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const fires: { turn: number; step: number; signal: AbortSignal }[] = []
ctx.on('agent/step', (subject, turn, step, signal) => {
if (subject === agent) fires.push({ turn, step, signal })
})
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(fires.map(({ turn, step }) => ({ turn, step }))).toEqual([
{ turn: 1, step: 1 },
{ turn: 1, step: 2 },
])
expect(fires.every(({ signal }) => signal instanceof AbortSignal)).toBe(true)
})
it('agent/step fires after its step boundary opens and before the request', async () => {
const adapter = new MockAdapter([textResponse('ok')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
let boundaryOpen = false
ctx.on('agent/step', (subject) => {
if (subject === agent) boundaryOpen = subject.session.events.at(-1)?.type === 'step/start'
})
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(boundaryOpen).toBe(true)
expect(adapter.requests).toHaveLength(1)
})
it('a throwing agent/step listener ends the turn (error), not the loop', async () => {
// Before step/start, a pre-step throw reaches the turn catch: no step needs
// closing, the turn records error, and the loop remains available.
const adapter = new MockAdapter([textResponse('second turn ok')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
let throwOnce = true
ctx.on('agent/step', () => {
if (throwOnce) { throwOnce = false; throw new Error('boom in pre-step') }
})
const errors: Error[] = []
ctx.on('agent/error', (_a, _t, _s, error) => {
if (error instanceof Error) errors.push(error)
})
send(agent, 'first')
await waitForIdle(ctx, agent)
// The first turn failed at step 1 before a model call.
expect(errors).toEqual([])
expect(adapter.requests.length).toBe(0)
const firstTurnEnd = agent.session.events.find(e => e.type === 'turn/end')
expect(firstTurnEnd?.type === 'turn/end' && firstTurnEnd.data.reason).toMatchObject({ kind: 'error' })
// The step opened-and-closed count stays balanced even though it never ran.
const types = agent.session.events.map(e => e.type)
expect(types.filter(t => t === 'step/start').length).toBe(types.filter(t => t === 'step/end').length)
// The loop survived: a second prompt runs a normal completed turn.
send(agent, 'second')
await waitForIdle(ctx, agent)
expect(adapter.requests.length).toBe(1)
const lastTurnEnd = agent.session.events.findLast(e => e.type === 'turn/end')
expect(lastTurnEnd?.type === 'turn/end' && lastTurnEnd.data.reason).toEqual({ kind: 'completed' })
})
it('cancel() mid-stream ends the turn with reason aborted', async () => {
const adapter = new MockAdapter(['hang'])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const reasons: TurnEndReason[] = []
ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
send(agent, 'go')
// wait until the stream is hanging, then cancel
await new Promise(r => setTimeout(r, 30))
expect(agent.status).toBe('running')
agent.cancel({ kind: 'user' })
await waitForIdle(ctx, agent)
expect(reasons).toEqual([{ kind: 'aborted', reason: { kind: 'user' } }])
})
it('surfaces max-tokens as the turn-end reason when the last step is cut off', async () => {
// A single step that ends with a max-tokens finish (no tool calls): the
// turn stops by default and ends max-tokens, not completed.
const adapter = new MockAdapter([maxTokensResponse('truncat')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const reasons: TurnEndReason[] = []
ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(adapter.requests).toHaveLength(1)
expect(reasons).toEqual([{ kind: 'max-tokens' }])
// Assert the durable row, not only the live listener.
const turnEnd = agent.session.events.findLast(e => e.type === 'turn/end')
expect(turnEnd!.data.reason).toEqual({ kind: 'max-tokens' })
})
it('a max-tokens step earlier in a turn still surfaces as max-tokens after a later completed step', async () => {
// Step 1 is cut off (max-tokens, no tool calls → would stop by default), so continuation
// must be FORCED to reach step 2 which finishes normally (stop).
const adapter = new MockAdapter([
maxTokensResponse('first half'),
textResponse('second half'),
])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
let steps = 0
ctx.on('session/event', (_session, event) => { if (event.type === 'step/end') steps++ })
// Force exactly one continuation (step 1 → step 2), then defer to default
// (step 2 is a plain stop with no tool calls → stops).
ctx.on('agent/turn-stopping', (subject) => {
if (steps < 2) {
subject.steer(createUserMessage({ content: [{ type: 'text', text: 'continue after truncation' }], source: { kind: 'plugin', plugin: 'max-tokens-test' } }))
}
})
const reasons: TurnEndReason[] = []
ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(steps).toBe(2)
expect(adapter.requests).toHaveLength(2)
expect(adapter.requests[1]!.messages).toEqual([
{
id: expect.any(String) as unknown,
role: 'user',
content: [{ type: 'text', text: 'go' }],
source: { kind: 'user' },
},
{
id: expect.any(String) as unknown,
role: 'assistant',
content: [{ type: 'text', text: 'first half' }],
source: { kind: 'model', provider: 'mock', model: 'mock' },
},
{
id: expect.any(String) as unknown,
role: 'user',
content: [{ type: 'text', text: 'continue after truncation' }],
source: { kind: 'plugin', plugin: 'max-tokens-test' },
},
])
expect(reasons).toEqual([{ kind: 'completed' }])
})
it('a completed step after no max-tokens keeps the turn completed (max-tokens does not leak across turns)', async () => {
// Two consecutive turns: turn 1 is cut off (max-tokens), turn 2 is a clean
// stop. The per-turn reason must be independent — turn 2 ends completed.
const adapter = new MockAdapter([maxTokensResponse('cut'), textResponse('clean')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const reasons: TurnEndReason[] = []
ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
send(agent, 'first')
await waitForIdle(ctx, agent)
send(agent, 'second')
await waitForIdle(ctx, agent)
expect(reasons).toEqual([{ kind: 'max-tokens' }, { kind: 'completed' }])
})
it('does not dispatch tool calls from a max-tokens-truncated step', async () => {
const callId = CallId('c1')
const adapter = new MockAdapter([[
{ type: 'block-start', index: 0, blockType: 'tool-call' },
{ type: 'tool-call-delta', index: 0, id: callId, name: 'echo', argumentsDelta: '{"text":"x"}' },
{ type: 'block-end', index: 0, block: { type: 'tool-call', id: callId, name: 'echo', arguments: '{"text":"x"}' } },
{ type: 'usage', usage: { inputTokens: 10, outputTokens: 5 } },
{ type: 'finish', reason: { kind: 'max-tokens' } },
]])
const ctx = await harness(adapter)
let executions = 0
ctx.tools.register(defineContentToolFixture({
name: 'echo',
description: '',
parameters: { text: { type: 'string' } },
async execute() {
executions += 1
return [{ type: 'text', text: 'should not run' }]
},
}))
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const reasons: TurnEndReason[] = []
ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(executions).toBe(0)
expect(agent.session.events.some(e => e.type === 'tool/call')).toBe(false)
expect(agent.session.deriveMessages()).toEqual([{
id: expect.any(String) as unknown,
role: 'user',
content: [{ type: 'text', text: 'go' }],
source: { kind: 'user' },
}])
expect(reasons).toEqual([{ kind: 'max-tokens' }])
// Empty content still needs an assistant/message to carry usage; derivation
// skips that host so it does not create a spurious assistant turn.
const assistantMessage = agent.session.events.find(e => e.type === 'assistant/message')
expect(assistantMessage?.type === 'assistant/message' && assistantMessage.data).toEqual({
turn: 1,
step: 1,
message: {
id: expect.any(String) as unknown,
role: 'assistant',
content: [],
source: { kind: 'model', provider: 'mock', model: 'mock' },
},
usage: { inputTokens: 10, outputTokens: 5 },
})
})
it('appends an empty completion anchor for a max-tokens step with no usage', async () => {
// The truncated tool call is dropped from durable content, while the
// successful provider call still needs an exact replay anchor.
const callId = CallId('c1')
const adapter = new MockAdapter([[
{ type: 'block-start', index: 0, blockType: 'tool-call' },
{ type: 'tool-call-delta', index: 0, id: callId, name: 'echo', argumentsDelta: '{"text":"x"}' },
{ type: 'block-end', index: 0, block: { type: 'tool-call', id: callId, name: 'echo', arguments: '{"text":"x"}' } },
{ type: 'finish', reason: { kind: 'max-tokens' } },
]])
const ctx = await harness(adapter)
ctx.tools.register(defineContentToolFixture({
name: 'echo',
description: '',
parameters: { text: { type: 'string' } },
async execute() { return [{ type: 'text', text: 'should not run' }] },
}))
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const reasons: TurnEndReason[] = []
ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(reasons).toEqual([{ kind: 'max-tokens' }])
const assistant = agent.session.events.find(e => e.type === 'assistant/message')!
expect(assistant.type === 'assistant/message' && assistant.data).toEqual({
turn: 1,
step: 1,
message: {
id: expect.any(String) as unknown,
role: 'assistant',
content: [],
source: { kind: 'model', provider: 'mock', model: 'mock' },
},
})
expect(assistant.sourceEventSeqs?.length).toBeGreaterThan(0)
expect(agent.session.deriveMessages()).toEqual([{
id: expect.any(String) as unknown,
role: 'user',
content: [{ type: 'text', text: 'go' }],
source: { kind: 'user' },
}])
})
it('appends an empty completion anchor for a normal stop with no usage', async () => {
// A clean content-less call stays absent from derived messages but remains
// a durable successful-call boundary for replay consumers.
const adapter = new MockAdapter([[{ type: 'finish', reason: { kind: 'stop' } }]])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const reasons: TurnEndReason[] = []
ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(reasons).toEqual([{ kind: 'completed' }])
const assistant = agent.session.events.find(e => e.type === 'assistant/message')!
expect(assistant.type === 'assistant/message' && assistant.data).toEqual({
turn: 1,
step: 1,
message: {
id: expect.any(String) as unknown,
role: 'assistant',
content: [],
source: { kind: 'model', provider: 'mock', model: 'mock' },
},
})
expect(assistant.sourceEventSeqs?.length).toBe(1)
expect(agent.session.deriveMessages()).toEqual([{
id: expect.any(String) as unknown,
role: 'user',
content: [{ type: 'text', text: 'go' }],
source: { kind: 'user' },
}])
})
it('keeps safe max-tokens assistant content while dropping truncated tool calls', async () => {
const callId = CallId('c1')
const adapter = new MockAdapter([[
{ type: 'block-start', index: 0, blockType: 'text' },
{ type: 'text-delta', index: 0, text: 'partial text' },
{ type: 'block-end', index: 0, block: { type: 'text', text: 'partial text' } },
{ type: 'block-start', index: 1, blockType: 'tool-call' },
{ type: 'tool-call-delta', index: 1, id: callId, name: 'echo', argumentsDelta: '{"text"' },
{ type: 'finish', reason: { kind: 'max-tokens' } },
]])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(agent.session.events.some(e => e.type === 'tool/call')).toBe(false)
expect(agent.session.deriveMessages()).toEqual([
{
id: expect.any(String) as unknown,
role: 'user',
content: [{ type: 'text', text: 'go' }],
source: { kind: 'user' },
},
{
id: expect.any(String) as unknown,
role: 'assistant',
content: [{ type: 'text', text: 'partial text' }],
source: { kind: 'model', provider: 'mock', model: 'mock' },
},
])
})
it('contains a step/end observer failure without changing continuation', async () => {
const adapter = new MockAdapter([
toolCallResponse('c1', 'echo', { text: 'x' }),
textResponse('continued after tool call'),
])
const ctx = await harness(adapter)
ctx.tools.register(defineContentToolFixture({
name: 'echo',
description: '',
parameters: { text: { type: 'string' } },
async execute(args) {
return [{ type: 'text', text: String(args.text) }]
},
}))
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
let threw = false
// Post-commit session observers cannot control the loop. The tool call still
// drives the second model request, and the turn completes normally.
ctx.on('session/event', (_session, event) => {
if (event.type === 'step/end' && !threw) { threw = true; throw new Error('bad step/end listener') }
})
send(agent, 'go')
await waitForIdle(ctx, agent)
expect(adapter.requests).toHaveLength(2)
const turnEnd = agent.session.events.findLast(e => e.type === 'turn/end')
expect(turnEnd?.type === 'turn/end' && turnEnd.data.reason.kind).toBe('completed')
})
it('contains a reentrant send attempted during durable inbox publication', async () => {
const adapter = new MockAdapter([textResponse('first')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
let nested = false
ctx.on('session/event', (session, event) => {
if (session !== agent.session || event.type !== 'agent/inbox/spliced'
|| event.data.inserted.length === 0 || nested) return
nested = true
send(agent, 'queued listener message')
})
const idle = waitForIdle(ctx, agent)
send(agent, 'outer message')
await idle
const turns = agent.session.events.filter(event => event.type === 'turn/start')
const messages = agent.session.events
.filter(event => event.type === 'user/message')
.map(event => event.data.content)
expect(turns).toHaveLength(1)
expect(messages).toEqual([[{ type: 'text', text: 'outer message' }]])
})
it('preserves independent turn sources across an adjacent microtask send', async () => {
const adapter = new MockAdapter([textResponse('first'), textResponse('second')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const idle = waitForIdle(ctx, agent)
agent.followup(createUserMessage({ content: [{ type: 'text', text: 'user message' }], source: { kind: 'user' } }))
await Promise.resolve()
agent.followup(createUserMessage({ content: [{ type: 'text', text: 'plugin message' }], source: { kind: 'plugin', plugin: 'test' } }))
await idle
const turns = agent.session.events.filter(event => event.type === 'turn/start')
const sources = agent.session.events
.filter(event => event.type === 'user/message')
.map(event => event.data.source)
expect(turns).toHaveLength(2)
expect(sources).toEqual([
{ kind: 'user' },
{ kind: 'plugin', plugin: 'test' },
])
})
it('keeps a session-listener send after dequeue in the following turn', async () => {
const adapter = new MockAdapter([textResponse('first'), textResponse('second')])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const turns: number[] = []
ctx.on('session/event', (_s, event) => { if (event.type === 'turn/start') turns.push(event.data.turn) })
// queue two messages while idle — first starts turn 1 immediately;
// queue the second during turn 1 when the first assistant chunk streams
let queued = false
ctx.on('session/event', (_s, event) => {
if (event.type === 'assistant/chunk' && !queued) {
queued = true
queueMicrotask(() => { send(agent, 'second message') })
}
})
send(agent, 'first message')
await waitForIdle(ctx, agent)
expect(turns).toEqual([1, 2])
expect(adapter.requests).toHaveLength(2)
expect(JSON.stringify(adapter.requests[1]!.messages)).toContain('first')
expect(JSON.stringify(adapter.requests[1]!.messages)).toContain('second message')
})
it('keeps a model-adapter callback send in the following turn', async () => {
const agentRef: { current?: Agent } = {}
const adapter = new MockAdapter([
() => {
const agent = agentRef.current
if (agent === undefined) throw new Error('model callback ran before agent setup')
send(agent, 'model callback message')
return textResponse('first')
},
textResponse('second'),
])
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
agentRef.current = agent
const idle = waitForIdle(ctx, agent)
send(agent, 'outer message')
await idle
const messages = agent.session.events
.filter(event => event.type === 'user/message')
.map(event => event.data.content)
expect(agent.session.events.filter(event => event.type === 'turn/start')).toHaveLength(2)
expect(messages).toEqual([
[{ type: 'text', text: 'outer message' }],
[{ type: 'text', text: 'model callback message' }],
])
})
it('records normalized model errors on the turn boundary', async () => {
const adapter = new MockAdapter([]) // script exhausted → throws
const ctx = await harness(adapter)
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
const errors: Error[] = []
const reasons: TurnEndReason[] = []
ctx.on('agent/error', (_agent, _turn, _step, error) => {
if (error instanceof Error) errors.push(error)
})
ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
send(agent, 'hi')
await waitForIdle(ctx, agent)
expect(errors).toEqual([])
expect(reasons[0]).toMatchObject({ kind: 'error' })
// The durable failure lives entirely on turn/end.reason (with the failing
// step), not a standalone error event.
const turnEnd = agent.session.events.find(e => e.type === 'turn/end')
expect(turnEnd?.type === 'turn/end' && turnEnd.data.reason).toMatchObject({ kind: 'error' })
})
it('disposing the loop fiber mid-turn stops the loop (HMR safety)', async () => {
const adapter = new MockAdapter(['hang'])
const ctx = await harness(adapter)
let agent!: Agent
const fiber = await ctx.plugin(Object.assign((inner: Context) => {
agent = inner.agentLoop.create(SessionId('scoped'), { provider: 'mock', model: 'mock' })
}, { inject: ['agentLoop'] }))
expect(ctx.agents.get(SessionId('scoped'))).toBe(agent)
send(agent, 'go')
await new Promise(r => setTimeout(r, 30))
expect(agent.status).toBe('running')
await fiber.dispose()
await driverDone(agent)
expect(ctx.agents.get(SessionId('scoped'))).toBeUndefined()
})
it('creates agents from config on startup', async () => {
const adapter = new MockAdapter([textResponse('from config')])
const ctx = new Context()
await ctx.plugin(LlmService)
await ctx.plugin(SessionStore)
await ctx.plugin(SystemPrompt)
await ctx.plugin(ToolRegistry)
await ctx.plugin(AgentRegistry)
await ctx.plugin(AgentLoop, {
agents: [{ id: SessionId('config-agent'), provider: 'mock', model: 'mock' }],
})
ctx.llm.registerAdapter(['mock'], adapter)
const agent = ctx.agents.list()[0]!
expect(agent).toBeDefined()
expect(agent.id).toBe(agent.session.id)
expect(agent.id).toMatch(/^config-agent-session-/)
expect(agent.options.model).toBe('mock')
// the agent is alive: send triggers a turn
send(agent, 'hi')
await waitForIdle(ctx, agent)
expect(adapter.requests).toHaveLength(1)
})
it('attaches config agent cwd to the fresh session header', async () => {
const ctx = new Context()
await ctx.plugin(LlmService)
await ctx.plugin(SessionStore)
await ctx.plugin(SystemPrompt)
await ctx.plugin(ToolRegistry)
await ctx.plugin(AgentRegistry)
await ctx.plugin(AgentLoop, {
agents: [{ id: SessionId('config-agent'), provider: 'mock', model: 'mock', cwd: '/work/project' }],
})
const agent = ctx.agents.list()[0]!
expect(agent.session.header.cwd).toBe('/work/project')
})
it('replays a session log into an identical derived history', async () => {
const adapter = new MockAdapter([
toolCallResponse('c1', 'echo', { text: 'x' }),
textResponse('done'),
])
const ctx = await harness(adapter)
ctx.tools.register(defineContentToolFixture({
name: 'echo',
description: '',
parameters: { text: { type: 'string' } },
async execute(args) {
return [{ type: 'text', text: String(args.text) }]
},
}))
const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
send(agent, 'run')
await waitForIdle(ctx, agent)
const replayed = ctx.sessions.create(SessionId('replayed'), { seed: [...agent.session.events] })
expect(replayed.deriveMessages()).toEqual(agent.session.deriveMessages())
// event-by-event identity of types over the inherited prefix
expect(replayed.events.slice(0, agent.session.seq).map(e => e.type)).toEqual(
agent.session.events.map(e => e.type))
expect(replayed.events.at(-1)?.type).toBe('session/end-seed')
})
})