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deepseek-harness/packages/compact/compact-basic/tests/compact-basic.spec.ts
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TypeScript

import { describe, expect, it, vi } from 'vitest'
import { Context } from 'cordis'
import BasicCompactService from '@deepseek-ai/dsh-compact-basic'
import type { BasicCompactConfig } from '@deepseek-ai/dsh-compact-basic'
import { selectCompactableRange } from '@deepseek-ai/dsh-compact-basic/src/region.ts'
import type { SummarizationInput } from '@deepseek-ai/dsh-compact-basic/src/summarizer.ts'
import { toolPairingBalancedAfter, toolPairingBalancedBefore } from '@deepseek-ai/dsh-compact'
import {
resolveCompactSpec,
resolveConfig,
resolveTargetPolicy,
} from '@deepseek-ai/dsh-compact-basic/src/config.ts'
import type { CompactionResult } from '@deepseek-ai/dsh-compact'
import LlmService, { createUserMessage, CallId, CONTEXT_WINDOW_EXCEEDED_CODE, createToolResultMessage, LlmAdapter , createMessage } from '@deepseek-ai/dsh-llm'
import type {
ContentBlock,
GenerateOptions,
LlmFailure,
LlmResolvedModelInfo,
Message,
StreamChunk,
TokenUsage,
} from '@deepseek-ai/dsh-llm'
import SessionStore, { Session, SessionId } from '@deepseek-ai/dsh-session'
import TokenMeterService from '@deepseek-ai/dsh-token-meter'
import { agentEvents, type Agent, type RequestErrorAction } from '@deepseek-ai/dsh-agent'
import ToolResultPruneService from '@deepseek-ai/dsh-compact-tool-result-prune'
const SIGNAL = new AbortController().signal
const MODEL = 'test-model'
class ContextAdapter extends LlmAdapter {
constructor(private readonly contextWindow: number) {
super()
}
override resolveModel(provider: string, model: string): Promise<LlmResolvedModelInfo> {
return Promise.resolve({
provider,
id: model,
name: model,
context: { contextWindow: this.contextWindow },
})
}
override async * stream(): AsyncIterable<StreamChunk> {
yield { type: 'finish', reason: { kind: 'stop' } }
}
}
class RoutedContextAdapter extends LlmAdapter {
constructor(private readonly windows: Readonly<Record<string, number>>) {
super()
}
override resolveModel(provider: string, model: string): Promise<LlmResolvedModelInfo> {
const contextWindow = this.windows[provider]
return Promise.resolve({
provider,
id: model,
name: model,
...contextWindow === undefined ? {} : { context: { contextWindow } },
})
}
override async * stream(): AsyncIterable<StreamChunk> {
yield { type: 'finish', reason: { kind: 'stop' } }
}
}
function createContext(contextWindow = 1_000): Context {
const ctx = new Context()
void new LlmService(ctx)
void new TokenMeterService(ctx)
ctx.llm.registerAdapter([MODEL, 'actual', 'unlisted-provider'], new ContextAdapter(contextWindow))
return ctx
}
function agent(session: Session, model?: string): Agent {
return {
session,
options: model === undefined ? {} : { provider: model, model },
} as Agent
}
/** Flatten every text fragment the summarizer received, recursing tool-result blocks. */
function summarizedText(input: SummarizationInput): string {
const collect = (blocks: readonly ContentBlock[]): string =>
blocks.map(block =>
block.type === 'text' ? block.text
: block.type === 'tool-result' ? collect(block.content)
: '').join('\n')
return input.messages.map(message => collect(message.content)).join('\n')
}
/** A minimal replayed prefix carrying one user message of the given text. */
function promptInput(text: string): SummarizationInput {
return { messages: [createUserMessage({
content: [{ type: 'text', text }],
source: { kind: 'plugin', plugin: 'test' },
})] }
}
/** Closed two-message turns followed by one open turn for durable compaction events. */
function conversation(turns = 4, text = 'fixture '.repeat(40).trim()): Session {
const session = Session.create(SessionId(`conversation-${turns}`))
for (let turn = 1; turn <= turns; turn += 1) {
session.append('turn/start', { turn })
session.append('user/message', createUserMessage({
content: [{ type: 'text', text: `${text} user ${turn}` }],
source: { kind: 'user' },
}), { surfaceOp: 'append' })
session.append('step/start', { turn, step: 1 })
if (turn === 1) {
session.append('request/header', {
header: { config: { provider: MODEL, model: MODEL } },
reason: 'initial',
})
}
session.append('assistant/message', {
turn,
step: 1,
message: createMessage({
role: 'assistant',
content: [{ type: 'text', text: `${text} assistant ${turn}` }],
source: {
kind: 'model',
...{ provider: MODEL, model: MODEL },
},
}),
}, { surfaceOp: 'append' })
session.append('step/end', { turn, step: 1 })
session.append('turn/end', { turn, reason: { kind: 'completed' } })
}
session.append('turn/start', {
turn: turns + 1,
})
return session
}
function toolConversation(): Session {
const session = Session.create(SessionId('tools'))
for (let turn = 1; turn <= 3; turn += 1) {
const callId = CallId(`call-${turn}`)
session.append('turn/start', { turn })
session.append('user/message', createUserMessage({
content: [{ type: 'text', text: `request ${turn} `.repeat(300) }],
source: { kind: 'user' },
}), { surfaceOp: 'append' })
session.append('step/start', { turn, step: 1 })
if (turn === 1) {
session.append('request/header', {
header: { config: { provider: MODEL, model: MODEL } },
reason: 'initial',
})
}
session.append('assistant/message', {
turn,
step: 1,
message: createMessage({
role: 'assistant',
content: [
{ type: 'text', text: `calling ${turn} `.repeat(300) },
{ type: 'tool-call', id: callId, name: 'read', arguments: '{}' },
],
source: {
kind: 'model',
...{ provider: MODEL, model: MODEL },
},
}),
}, { surfaceOp: 'append' })
session.append('tool/call', { turn, step: 1, callId, name: 'read', arguments: '{}' })
session.append('tool/result', {
turn,
step: 1,
message: createToolResultMessage({
callId,
content: [{ type: 'text', text: `result ${turn} `.repeat(300) }],
isError: false,
}),
}, { surfaceOp: 'append' })
session.append('step/end', { turn, step: 1 })
session.append('turn/end', { turn, reason: { kind: 'completed' } })
}
session.append('turn/start', { turn: 4 })
return session
}
/** One closed routed tool step followed by an open turn for rewrite events. */
function oversizedToolResult(chars = 3_000, withCompactablePrompt = false): Session {
const session = Session.create(SessionId(`oversized-tool-${chars}`))
const callId = CallId('oversized')
session.append('turn/start', { turn: 1 })
if (withCompactablePrompt) {
session.append('user/message', createUserMessage({
content: [{ type: 'text', text: 'older history '.repeat(200) }],
source: { kind: 'user' },
}), { surfaceOp: 'append' })
}
session.append('step/start', { turn: 1, step: 1 })
session.append('request/header', {
header: { config: { provider: MODEL, model: MODEL } },
reason: 'initial',
})
session.append('assistant/message', {
turn: 1,
step: 1,
message: createMessage({
role: 'assistant',
content: [{ type: 'tool-call', id: callId, name: 'bash', arguments: '{}' }],
source: {
kind: 'model',
...{ provider: MODEL, model: MODEL },
},
}),
}, { surfaceOp: 'append' })
session.append('tool/call', { turn: 1, step: 1, callId, name: 'bash', arguments: '{}' })
session.append('tool/result', {
turn: 1,
step: 1,
message: createToolResultMessage({
callId,
content: [{ type: 'text', text: 'X'.repeat(chars) }],
isError: false,
}),
meta: { presentation: 'preserved' },
}, { surfaceOp: 'append' })
session.append('step/end', { turn: 1, step: 1 })
session.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
session.append('turn/start', { turn: 2 })
return session
}
class TestCompactService extends BasicCompactService {
summary: ContentBlock[] = [{ type: 'text', text: 'small checkpoint' }]
rawOutput: ContentBlock[] | undefined
usage: TokenUsage | undefined
summaryProvider = 'summary-provider'
summaryModel = 'summary-model'
error: unknown
mutateDuringSummary: (() => void) | undefined
calls: Array<{ input: SummarizationInput; signal: AbortSignal | undefined }> = []
override async summarize(
input: SummarizationInput,
_agent: Agent,
signal?: AbortSignal,
): Promise<{
summary: ContentBlock[]
rawOutput?: ContentBlock[]
provider: string
model: string
maxTokens?: number
usage?: TokenUsage
}> {
this.calls.push({ input, signal })
this.mutateDuringSummary?.()
if (this.error !== undefined) throw this.error
return {
summary: this.summary,
...this.rawOutput === undefined ? {} : { rawOutput: this.rawOutput },
provider: this.summaryProvider,
model: this.summaryModel,
maxTokens: 123,
...this.usage === undefined ? {} : { usage: this.usage },
}
}
}
function service(
config: BasicCompactConfig = { auto: false },
ctx = createContext(),
): TestCompactService {
return new TestCompactService(ctx, config)
}
async function compactIfNeeded(
compact: BasicCompactService,
session: Session,
trigger: 'pressure' | 'context-overflow' = 'pressure',
model: string | undefined = MODEL,
): Promise<CompactionResult | null> {
return compact.compactIfNeeded(agent(session, model), trigger, SIGNAL)
}
describe('compact configuration and defaults', () => {
it('uses low-friction service-wide defaults', () => {
const resolved = resolveConfig({})
expect(resolved).toEqual({
thresholdRatio: 0.8,
retainRatio: 0.16,
summarizationProvider: '',
summarizationModel: '',
maxTokens: 8192,
compactionRetries: 1,
maxOverflowRetries: 1,
modelPolicies: [],
auto: true,
})
expect(Object.isFrozen(resolved)).toBe(true)
})
it('resolves threshold and retention overrides independently', () => {
const thresholdOnly = resolveConfig({
thresholdRatio: 0.5,
})
expect(thresholdOnly).toMatchObject({
thresholdRatio: 0.5,
retainRatio: 0.16,
})
const retentionOnly = resolveConfig({
retainTokens: 70,
})
expect(retentionOnly).toMatchObject({
thresholdRatio: 0.8,
retainTokens: 70,
})
expect(retentionOnly).not.toHaveProperty('retainRatio')
})
it('merges exact provider/model policy overrides and scales ratios per model', () => {
const config = resolveConfig({
thresholdRatio: 0.8,
retainRatio: 0.1,
modelPolicies: [{
provider: 'small-provider',
model: 'shared-id',
thresholdRatio: 0.5,
retainTokens: 120,
}],
})
const small = resolveTargetPolicy(config, {
provider: 'small-provider',
model: 'shared-id',
})
const otherProvider = resolveTargetPolicy(config, {
provider: 'large-provider',
model: 'shared-id',
})
expect(resolveCompactSpec(small, 1_000)).toMatchObject({
thresholdTokens: 500,
retainTokens: 120,
})
expect(resolveCompactSpec(otherProvider, 2_000)).toMatchObject({
thresholdTokens: 1_600,
retainTokens: 200,
})
const ratioOverride = resolveTargetPolicy(resolveConfig({
retainTokens: 200,
modelPolicies: [{
provider: 'ratio-provider',
model: 'ratio-model',
thresholdRatio: 0.6,
retainRatio: 0.2,
summarizationProvider: 'summary-provider',
summarizationModel: 'summary-model',
maxTokens: 512,
compactionRetries: 2,
maxOverflowRetries: 3,
}],
}), { provider: 'ratio-provider', model: 'ratio-model' })
expect(resolveCompactSpec(ratioOverride, 2_000)).toMatchObject({
thresholdTokens: 1_200,
retainTokens: 400,
summarizationProvider: 'summary-provider',
summarizationModel: 'summary-model',
maxTokens: 512,
compactionRetries: 2,
maxOverflowRetries: 3,
})
})
it('inherits, clears, and replaces the summarization target as a pair', () => {
const config = resolveConfig({
summarizationProvider: 'default-provider',
summarizationModel: 'default-model',
modelPolicies: [
{ provider: 'inherit-provider', model: MODEL },
{
provider: 'clear-provider',
model: MODEL,
summarizationProvider: '',
summarizationModel: '',
},
{
provider: 'replace-provider',
model: MODEL,
summarizationProvider: 'replacement-provider',
summarizationModel: 'replacement-model',
},
],
})
expect(resolveTargetPolicy(config, { provider: 'inherit-provider', model: MODEL }))
.toMatchObject({
summarizationProvider: 'default-provider',
summarizationModel: 'default-model',
})
expect(resolveTargetPolicy(config, { provider: 'clear-provider', model: MODEL }))
.toMatchObject({ summarizationProvider: '', summarizationModel: '' })
expect(resolveTargetPolicy(config, { provider: 'replace-provider', model: MODEL }))
.toMatchObject({
summarizationProvider: 'replacement-provider',
summarizationModel: 'replacement-model',
})
})
it('validates common values and pressure-policy invariants', () => {
const bad = [
[{ maxTokens: 0 }, /maxTokens/],
[{ compactionRetries: -1 }, /compactionRetries/],
[{ maxOverflowRetries: -1 }, /maxOverflowRetries/],
[{ auto: 'yes' }, /auto must be a boolean/],
[{ summarizationProvider: 1 }, /summarizationProvider must be a string/],
[{ summarizationModel: 1 }, /summarizationModel must be a string/],
[{ summarizationProvider: MODEL }, /must be set together/],
[{ summarizationModel: MODEL }, /must be set together/],
[{ summarizationProvider: '' }, /must be set together/],
[{ summarizationModel: '' }, /must be set together/],
[{ thresholdRatio: 0 }, /number in \(0, 1\]/],
[{ thresholdRatio: 1.1 }, /number in \(0, 1\]/],
[{ retainRatio: 0.9 }, /retainRatio \(0.9\) must be less than the resolved thresholdRatio \(0.8\)/],
[{ thresholdRatio: 0.1 }, /retainRatio \(0.16\) must be less than the resolved thresholdRatio \(0.1\)/],
[{ retainTokens: -1 }, /non-negative integer/],
[{ retainRatio: 0.2, retainTokens: 100 }, /mutually exclusive/],
[{ modelPolicies: {} }, /modelPolicies must be an array/],
[{ modelPolicies: [1] }, /modelPolicies\[0\] must be an object/],
[{ modelPolicies: [null] }, /modelPolicies\[0\] must be an object/],
[{ modelPolicies: [[]] }, /modelPolicies\[0\] must be an object/],
[{ modelPolicies: [{ provider: 1, model: MODEL }] }, /provider must be a non-empty string/],
[{ modelPolicies: [{ provider: '', model: MODEL }] }, /provider must be a non-empty string/],
[{ modelPolicies: [{ provider: MODEL, model: 1 }] }, /model must be a non-empty string/],
[{ modelPolicies: [{ provider: MODEL, model: '' }] }, /model must be a non-empty string/],
[{ modelPolicies: [{ provider: MODEL, model: MODEL, summarizationProvider: 1 }] }, /summarizationProvider must be a string/],
[{
summarizationProvider: 'default-provider',
summarizationModel: 'default-model',
modelPolicies: [{ provider: MODEL, model: MODEL, summarizationModel: '' }],
}, /modelPolicies\[0\].*must be set together/],
[{
summarizationProvider: 'default-provider',
summarizationModel: 'default-model',
modelPolicies: [{ provider: MODEL, model: MODEL, summarizationProvider: '' }],
}, /modelPolicies\[0\].*must be set together/],
[{ modelPolicies: [{ provider: MODEL, model: MODEL, retainRatio: 0.2, retainTokens: 100 }] }, /mutually exclusive/],
[
{ modelPolicies: [{ provider: MODEL, model: MODEL, thresholdRatio: 0.1 }] },
/modelPolicies\[0\]: retainRatio \(0.16\).*thresholdRatio \(0.1\)/,
],
[
{ modelPolicies: [{ provider: MODEL, model: MODEL, retainRatio: 0.9 }] },
/modelPolicies\[0\]: retainRatio \(0.9\).*thresholdRatio \(0.8\)/,
],
[{ modelPolicies: [{ provider: MODEL, model: MODEL }, { provider: MODEL, model: MODEL }] }, /duplicate model policy/],
[{ models: { [MODEL]: { retainTokens: 10 } } }, /BasicCompactConfig: unknown key "models"/],
[{ thresholdRato: 0.5 }, /BasicCompactConfig: unknown key "thresholdRato"/],
] as Array<[unknown, RegExp]>
for (const [config, pattern] of bad) {
expect(() => resolveConfig(config as BasicCompactConfig)).toThrow(pattern)
}
const invalidPressure = resolveTargetPolicy(resolveConfig({
thresholdRatio: 0.5,
retainTokens: 500,
}), { provider: MODEL, model: MODEL })
expect(() => resolveCompactSpec(invalidPressure, 1_000)).toThrow(/less than threshold/)
expect(() => resolveCompactSpec(invalidPressure, 1.5)).toThrow(/positive integer/)
expect(() => resolveCompactSpec(invalidPressure, 0)).toThrow(/positive integer/)
})
})
describe('pressure measurement and retention', () => {
const compactConfig: BasicCompactConfig = {
auto: false,
thresholdRatio: 0.5,
retainTokens: 180,
}
it('skips when no durable routed model exists instead of using AgentOptions fallback', async () => {
const compact = service(compactConfig)
const session = Session.create(SessionId('headerless'))
session.append('turn/start', { turn: 1 })
await expect(compact.compactIfNeeded(agent(session, MODEL), 'pressure', SIGNAL))
.resolves.toBeNull()
expect(compact.calls).toHaveLength(0)
})
it('meters an unlisted model when its provider adapter supplies context metadata', async () => {
const compact = service(compactConfig)
const session = conversation()
session.append('request/header', {
header: { config: { provider: 'unlisted-provider', model: 'unlisted-model' } },
reason: 'resume',
})
await expect(compactIfNeeded(compact, session))
.resolves.not.toBeNull()
})
it('forwards turn cancellation to proactive model metadata resolution', async () => {
const ctx = createContext()
const resolveModelInfo = vi.spyOn(ctx.llm, 'resolveModelInfo')
const compact = service(compactConfig, ctx)
const session = conversation()
const signal = new AbortController().signal
await expect(compact.compactIfNeeded(agent(session, MODEL), 'pressure', signal))
.resolves.not.toBeNull()
expect(resolveModelInfo).toHaveBeenCalledWith(MODEL, MODEL, signal)
})
it('re-resolves capacity after a same-model-id provider switch in one session', async () => {
const ctx = new Context()
void new LlmService(ctx)
void new TokenMeterService(ctx)
ctx.llm.registerAdapter(['large', 'small'], new RoutedContextAdapter({
large: 10_000,
small: 1_000,
}))
const compact = service({
auto: false,
thresholdRatio: 0.5,
retainRatio: 0.1,
}, ctx)
const session = conversation(4)
session.append('request/header', {
header: { config: { provider: 'large', model: 'shared-id' } },
reason: 'resume',
})
await expect(compactIfNeeded(compact, session)).resolves.toBeNull()
session.append('request/header', {
header: { config: { provider: 'small', model: 'shared-id' } },
reason: 'change',
})
await expect(compactIfNeeded(compact, session)).resolves.not.toBeNull()
})
it('requires capacity only for proactive pressure, not provider-confirmed overflow', async () => {
const ctx = new Context()
void new LlmService(ctx)
void new TokenMeterService(ctx)
ctx.llm.registerAdapter(['unknown-context'], new ContextAdapter(1_000))
vi.spyOn(ctx.llm, 'resolveModelInfo').mockImplementation((provider, model) => Promise.resolve({
provider,
id: model,
name: model,
}))
const compact = service(compactConfig, ctx)
const session = conversation(4)
session.append('request/header', {
header: { config: { provider: 'unknown-context', model: 'model' } },
reason: 'resume',
})
await expect(compactIfNeeded(compact, session, 'pressure'))
.rejects.toThrow(/no context capacity for unknown-context\/model/)
await expect(compactIfNeeded(compact, session, 'context-overflow'))
.resolves.not.toBeNull()
})
it('declines forced overflow when the whole surface is one indivisible tool pair', async () => {
const compact = service(compactConfig)
const session = Session.create(SessionId('single-tool-pair'))
const callId = CallId('single-call')
session.append('turn/start', { turn: 1 })
session.append('step/start', { turn: 1, step: 1 })
session.append('request/header', {
header: { config: { provider: MODEL, model: MODEL } },
reason: 'initial',
})
session.append('assistant/message', {
turn: 1,
step: 1,
message: createMessage({
role: 'assistant',
content: [{ type: 'tool-call', id: callId, name: 'read', arguments: '{}' }],
source: {
kind: 'model',
...{ provider: MODEL, model: MODEL },
},
}),
}, { surfaceOp: 'append' })
session.append('tool/call', { turn: 1, step: 1, callId, name: 'read', arguments: '{}' })
session.append('tool/result', {
turn: 1,
step: 1,
message: createToolResultMessage({
callId,
content: [{ type: 'text', text: 'result' }],
isError: false,
}),
}, { surfaceOp: 'append' })
session.append('step/end', { turn: 1, step: 1 })
const generation = session.surface.replaceGeneration
await expect(compactIfNeeded(compact, session, 'context-overflow')).resolves.toBeNull()
expect(session.surface.replaceGeneration).toBe(generation)
expect(session.events.some(event => event.type === 'compact/start')).toBe(false)
})
it('does nothing below threshold and compacts a priced head above threshold', async () => {
const compact = service(compactConfig)
expect(await compactIfNeeded(compact, conversation(2))).toBeNull()
const session = conversation(4)
const result = await compactIfNeeded(compact, session)
expect(result).not.toBeNull()
expect(result?.shadowedSeqs.length).toBeGreaterThan(2)
expect(session.surface.nodes.length).toBeLessThan(8)
})
it('counts the durable routed request envelope without putting it on the surface', async () => {
const compact = service({
auto: false,
thresholdRatio: 0.9,
retainTokens: 50,
})
const session = conversation(2, 'x'.repeat(600))
expect(await compactIfNeeded(compact, session)).toBeNull()
session.append('request/header', {
header: {
config: { provider: MODEL, model: MODEL },
system: 's'.repeat(2_000),
},
reason: 'resume',
})
const result = await compactIfNeeded(compact, session)
expect(result).not.toBeNull()
})
it('uses the latest logged request envelope without an AgentOptions override', async () => {
const ctx = createContext()
const compact = service({
auto: false,
thresholdRatio: 0.5,
retainTokens: 180,
}, ctx)
const session = conversation(4)
session.append('request/header', {
header: { config: { provider: 'actual', model: 'actual' } },
reason: 'initial',
})
const measure = vi.spyOn(ctx.tokenMeter, 'measure')
const result = await compactIfNeeded(compact, session, 'pressure', 'fallback')
expect(result).not.toBeNull()
expect(session.requestHeader()?.config.model).toBe('actual')
expect(measure.mock.calls[0]).toEqual([session])
})
it('declines when envelope pressure is high but the surface has no compactable range', async () => {
const compact = service(compactConfig)
const empty = Session.create(SessionId('empty'))
empty.append('turn/start', { turn: 1 })
empty.append('request/header', {
header: { config: { provider: MODEL, model: MODEL }, system: 'x'.repeat(100_000) },
reason: 'initial',
})
expect(await compactIfNeeded(compact, empty)).toBeNull()
const retained = conversation(1)
retained.append('request/header', {
header: { config: { provider: MODEL, model: MODEL }, system: 'x'.repeat(100_000) },
reason: 'resume',
})
expect(await compactIfNeeded(compact, retained)).toBeNull()
})
it('uses one unified measurement for each pressure-and-retention decision', async () => {
const ctx = createContext()
const compact = service(compactConfig, ctx)
const measure = vi.spyOn(ctx.tokenMeter, 'measure')
const stop = new Error('stop after first decision')
vi.spyOn(compact, 'compactRegion').mockRejectedValueOnce(stop)
await expect(compactIfNeeded(compact, conversation(4))).rejects.toBe(stop)
expect(measure).toHaveBeenCalledTimes(1)
})
it('bounds retries when a shrinking checkpoint remains above threshold', async () => {
const compact = service({
auto: false,
compactionRetries: 0,
thresholdRatio: 0.3,
retainTokens: 180,
})
compact.summary = Array.from({ length: 7 }, (_, index) => ({
type: 'text',
text: `summary ${index}`,
}))
await expect(compactIfNeeded(compact, conversation(4)))
.rejects.toThrow(/still above threshold after 1 compaction attempts/)
})
it('rounds a retention cut head-ward to preserve tool-call/result pairing', async () => {
const compact = service({
auto: false,
thresholdRatio: 0.8,
retainTokens: 80,
}, createContext(4_000))
const session = toolConversation()
const result = await compactIfNeeded(compact, session)
expect(result).not.toBeNull()
const messages = session.deriveMessages()
const calls = new Set<string>()
for (const message of messages) {
for (const block of message.content) {
if (block.type === 'tool-call') calls.add(block.id)
if (block.type === 'tool-result') expect(calls.has(block.toolCallId)).toBe(true)
}
}
})
it('rejects a priced surface that is not the current positional surface', () => {
const ctx = createContext()
const session = conversation(2)
const priced = ctx.tokenMeter.measure(session)
expect(() => selectCompactableRange(session, {
...priced,
nodes: priced.nodes.slice(1),
}, 1)).toThrow(/does not match/)
})
it('declines when rounding a cut would consume the only tool pair', () => {
const ctx = createContext()
const session = Session.create(SessionId('one-tool-pair'))
const callId = CallId('only')
session.append('turn/start', { turn: 1 })
session.append('step/start', { turn: 1, step: 1 })
session.append('assistant/message', {
turn: 1,
step: 1,
message: createMessage({
role: 'assistant',
content: [{ type: 'tool-call', id: callId, name: 'read', arguments: '{}' }],
source: {
kind: 'model',
...{ provider: MODEL, model: MODEL },
},
}),
}, { surfaceOp: 'append' })
session.append('tool/call', { turn: 1, step: 1, callId, name: 'read', arguments: '{}' })
session.append('tool/result', {
turn: 1,
step: 1,
message: createToolResultMessage({
callId,
content: [{ type: 'text', text: 'result' }],
isError: false,
}),
}, { surfaceOp: 'append' })
session.append('step/end', { turn: 1, step: 1 })
const priced = ctx.tokenMeter.measure(session)
expect(selectCompactableRange(session, priced, 1)).toBeNull()
})
})
describe('optional model-free tool-result pruning', () => {
const pruneConfig = { thresholdChars: 100, headChars: 20, tailChars: 10 }
it('does not prune a below-pressure session opportunistically', async () => {
const ctx = createContext(10_000)
const prune = new ToolResultPruneService(ctx, pruneConfig)
const compact = new TestCompactService(ctx, {
auto: false,
thresholdRatio: 0.8,
retainTokens: 100,
})
const session = oversizedToolResult()
const pruneSession = vi.spyOn(prune, 'pruneSession')
expect(await compactIfNeeded(compact, session)).toBeNull()
expect(pruneSession).not.toHaveBeenCalled()
expect(compact.calls).toHaveLength(0)
expect(session.surface.replaceGeneration).toBe(0)
})
it('skips LLM summarization when pruning alone clears pressure', async () => {
const ctx = createContext(1_000)
void new ToolResultPruneService(ctx, pruneConfig)
const compact = new TestCompactService(ctx, {
auto: false,
thresholdRatio: 0.5,
retainTokens: 50,
})
const session = oversizedToolResult()
expect(ctx.tokenMeter.measure(session).totalTokens).toBeGreaterThanOrEqual(500)
expect(await compactIfNeeded(compact, session)).toBeNull()
expect(ctx.tokenMeter.measure(session).totalTokens).toBeLessThan(500)
expect(compact.calls).toHaveLength(0)
expect(session.surface.replaceGeneration).toBe(1)
})
it('summarizes the pruned surface when pruning is insufficient', async () => {
const ctx = createContext(2_000)
void new ToolResultPruneService(ctx, pruneConfig)
const compact = new TestCompactService(ctx, {
auto: false,
thresholdRatio: 0.5,
retainTokens: 50,
})
const session = toolConversation()
expect(await compactIfNeeded(compact, session)).not.toBeNull()
expect(compact.calls).toHaveLength(1)
expect(summarizedText(compact.calls[0]!.input)).toContain('tool result middle pruned')
expect(summarizedText(compact.calls[0]!.input)).not.toContain('result 1 '.repeat(300))
})
it('retains the original compact-basic behavior without the optional plugin', async () => {
const ctx = createContext(2_000)
const compact = new TestCompactService(ctx, {
auto: false,
thresholdRatio: 0.5,
retainTokens: 50,
})
const session = oversizedToolResult(3_000, true)
expect(await compactIfNeeded(compact, session)).not.toBeNull()
expect(compact.calls).toHaveLength(1)
const original = session.events.find(event => event.type === 'tool/result')
expect(original?.type === 'tool/result' && original.data.message.content[0].content[0])
.toEqual({ type: 'text', text: 'X'.repeat(3_000) })
expect(session.events.filter(event =>
event.type === 'tool/result' && event.surfaceOp !== 'append')).toHaveLength(0)
})
})
describe('compaction region transaction', () => {
it('lands a framed, replayable checkpoint with exact pricing provenance', async () => {
const compact = service()
compact.rawOutput = [
{ type: 'reasoning', text: 'private compact thought' },
...compact.summary,
]
compact.usage = { inputTokens: 40, outputTokens: 5 }
const session = conversation(3)
const before = [...session.surface.nodes]
const result = await compact.compactRegion(
before[0]!,
before[3]!,
agent(session, MODEL),
SIGNAL,
)
expect(result.shadowedSeqs).toEqual(before.slice(0, 4))
expect(result.shadowedTokenCount).toBeGreaterThan(0)
expect(compact.calls[0]).toMatchObject({ signal: SIGNAL })
expect(summarizedText(compact.calls[0]!.input)).toContain('fixture user 1')
const summary = session.events.findLast(event => event.type === 'compact/summary')
expect(summary?.data).toMatchObject({
shadowedSeqs: result.shadowedSeqs,
shadowedTokenCount: result.shadowedTokenCount,
provider: 'summary-provider',
model: 'summary-model',
maxTokens: 123,
rawOutput: compact.rawOutput,
usage: compact.usage,
})
expect(summary?.data).not.toHaveProperty('llmStreamCall')
const head = session.deriveMessages()[0]!
expect(head.content[0]?.type).toBe('text')
expect(head.content[0]?.type === 'text' ? head.content[0].text : '').toContain('<compacted-summary>')
expect(head.content.at(-1)).toEqual({ type: 'text', text: '</compacted-summary>' })
const replay = Session.create(SessionId('replay'), [...session.events])
expect(replay.deriveMessages()).toEqual(session.deriveMessages())
})
it('replays the latest routed header so the summarizer reuses the cache', async () => {
const compact = service()
const session = conversation(3)
const tools = [{ name: 'do_thing', description: 'd', parameters: { type: 'object' } }]
session.append('request/header', {
header: { config: { provider: MODEL, model: MODEL }, system: 'CONVERSATION SYSTEM', tools },
reason: 'resume',
})
const nodes = session.surface.nodes
await compact.compactRegion(nodes[0]!, nodes[1]!, agent(session, MODEL), SIGNAL)
const { input } = compact.calls[0]!
expect(input.system).toBe('CONVERSATION SYSTEM')
expect(input.tools).toEqual(tools)
expect(summarizedText(input)).toContain('fixture user 1')
})
it.each([
['start missing', 9_001, undefined, /start seq 9001 not found/],
['end missing', undefined, 9_002, /end seq 9002 not found/],
])('rejects %s', async (_label, startOverride, endOverride, pattern) => {
const compact = service()
const session = conversation(2)
const nodes = session.surface.nodes
await expect(compact.compactRegion(
startOverride ?? nodes[0]!,
endOverride ?? nodes[1]!,
agent(session, MODEL),
)).rejects.toThrow(pattern)
})
it('rejects reversed and tool-unbalanced positional boundaries', async () => {
const compact = service()
const plain = conversation(2)
const nodes = plain.surface.nodes
await expect(compact.compactRegion(
nodes[2]!,
nodes[1]!,
agent(plain, MODEL),
)).rejects.toThrow(/is after end/)
const tools = toolConversation()
const toolNodes = tools.surface.nodes
await expect(compact.compactRegion(
toolNodes[2]!,
toolNodes[4]!,
agent(tools, MODEL),
)).rejects.toThrow(/start seq .* not a balanced boundary/)
await expect(compact.compactRegion(
toolNodes[0]!,
toolNodes[1]!,
agent(tools, MODEL),
)).rejects.toThrow(/end seq .* not a balanced boundary/)
})
it('requires an open turn and an idle compaction bracket', async () => {
const compact = service()
const closed = conversation(1)
closed.append('turn/end', { turn: 2, reason: { kind: 'completed' } })
const nodes = closed.surface.nodes
await expect(compact.compactRegion(
nodes[0]!,
nodes[1]!,
agent(closed, MODEL),
)).rejects.toThrow(/no open turn/)
const locked = conversation(1)
locked.append('compact/start', { turn: 2 })
const lockedNodes = locked.surface.nodes
await expect(compact.compactRegion(
lockedNodes[0]!,
lockedNodes[1]!,
agent(locked, MODEL),
)).rejects.toThrow(/already in progress/)
})
it('rejects a session with no turn boundary at all', async () => {
const compact = service()
const session = Session.create(SessionId('turnless'))
session.append('user/message', createUserMessage({
content: [{ type: 'text', text: 'orphan' }],
source: { kind: 'user' },
}), { surfaceOp: 'append' })
const node = session.surface.nodes[0]!
await expect(compact.compactRegion(
node,
node,
agent(session, MODEL),
)).rejects.toThrow(/no open turn/)
})
it('rejects a meter snapshot that changed before summarization began', async () => {
const ctx = createContext()
const meter = ctx.tokenMeter
const original = meter.measure.bind(meter)
vi.spyOn(meter, 'measure').mockImplementationOnce((session) => {
const measurement = original(session)
return { ...measurement, nodes: measurement.nodes.slice(1) }
})
const compact = service({ auto: false }, ctx)
const session = conversation(2)
const nodes = session.surface.nodes
await expect(compact.compactRegion(
nodes[0]!,
nodes[2]!,
agent(session, MODEL),
)).rejects.toThrow(/selected surface changed/)
})
it('records summarizer failures without mutating the surface', async () => {
const compact = service()
compact.error = new Error('summary unavailable')
const session = conversation(2)
const before = session.surface.nodes
await expect(compact.compactRegion(
before[0]!,
before[2]!,
agent(session, MODEL),
)).rejects.toThrow('summary unavailable')
expect(session.surface.nodes).toEqual(before)
expect(session.events.findLast(event => event.type === 'compact/end')?.data)
.toMatchObject({ error: 'summary unavailable' })
})
it('stringifies non-Error failures in the durable end bracket', async () => {
const compact = service()
compact.error = 'plain failure'
const session = conversation(2)
const nodes = session.surface.nodes
await expect(compact.compactRegion(
nodes[0]!,
nodes[2]!,
agent(session, MODEL),
)).rejects.toBe('plain failure')
expect(session.events.findLast(event => event.type === 'compact/end')?.data)
.toMatchObject({ error: 'plain failure' })
})
it('tolerates concurrent log-only appends while the selected surface is stable', async () => {
const compact = service()
const session = conversation(2)
compact.mutateDuringSummary = () => {
session.append('request/header', {
header: { config: { provider: MODEL, model: MODEL } },
reason: 'change',
})
}
const nodes = session.surface.nodes
await expect(compact.compactRegion(
nodes[0]!,
nodes[2]!,
agent(session, MODEL),
)).resolves.toMatchObject({ shadowedSeqs: nodes.slice(0, 3) })
expect(session.events.some(event => event.type === 'compact/summary')).toBe(true)
})
it('rejects concurrent surface appends before committing the replacement', async () => {
const compact = service()
const session = conversation(2)
compact.mutateDuringSummary = () => {
session.append('user/message', createUserMessage({
content: [{ type: 'text', text: 'concurrent surface mutation' }],
source: { kind: 'plugin', plugin: 'test' },
}), { surfaceOp: 'append' })
}
const nodes = session.surface.nodes
await expect(compact.compactRegion(
nodes[0]!,
nodes[2]!,
agent(session, MODEL),
)).rejects.toThrow(/session surface changed/)
expect(session.events.some(event => event.type === 'compact/summary')).toBe(false)
})
it('rejects a non-shrinking framed summary under the conversation meter', async () => {
const compact = service()
compact.summary = Array.from({ length: 100 }, (_, index) => ({
type: 'text',
text: `verbose ${index}`,
}))
const session = conversation(2)
const nodes = session.surface.nodes
await expect(compact.compactRegion(
nodes[0]!,
nodes[2]!,
agent(session, MODEL),
)).rejects.toThrow(/summary is not smaller/)
expect(session.events.some(event => event.type === 'compact/summary')).toBe(false)
})
it('lets a model-independent custom summarizer compact without a conversation model', async () => {
const compact = service()
const session = Session.create(SessionId('model-less-region'))
session.append('turn/start', { turn: 1 })
session.append('user/message', createUserMessage({
content: [{ type: 'text', text: 'history '.repeat(100) }],
source: { kind: 'user' },
}), { surfaceOp: 'append' })
session.append('step/start', { turn: 1, step: 1 })
session.append('assistant/message', {
turn: 1,
step: 1,
message: createMessage({
role: 'assistant',
content: [{ type: 'text', text: 'answer '.repeat(100) }],
source: {
kind: 'model',
...{ provider: 'historical', model: 'historical' },
},
}),
}, { surfaceOp: 'append' })
session.append('step/end', { turn: 1, step: 1 })
const nodes = session.surface.nodes
await expect(compact.compactRegion(
nodes[0]!,
nodes[1]!,
agent(session),
)).resolves.toMatchObject({ shadowedSeqs: [nodes[0]!, nodes[1]!] })
})
})
class ScriptedAdapter extends LlmAdapter {
lastOptions: GenerateOptions | undefined
usage: TokenUsage | undefined
constructor(
private readonly blocks: readonly ContentBlock[],
private readonly finish: (StreamChunk & { type: 'finish' })['reason'] = { kind: 'stop' },
) {
super()
}
override async * stream(options: GenerateOptions): AsyncIterable<StreamChunk> {
this.lastOptions = options
for (const [index, block] of this.blocks.entries()) {
yield { type: 'block-start', index, blockType: block.type }
if (block.type === 'text') {
yield { type: 'text-delta', index, text: block.text }
} else if (block.type === 'reasoning') {
yield { type: 'reasoning-delta', index, text: block.text }
} else {
yield { type: 'block-end', index, block }
}
}
if (this.usage !== undefined) yield { type: 'usage', usage: this.usage }
yield { type: 'finish', reason: this.finish }
}
}
class ExposedCompactService extends BasicCompactService {
runSummarize(
input: SummarizationInput,
owner: Agent,
signal?: AbortSignal,
): Promise<{
summary: ContentBlock[]
rawOutput?: ContentBlock[]
provider: string
model: string
maxTokens?: number
usage?: TokenUsage
}> {
return this.summarize(input, owner, signal)
}
}
async function summarizerHarness(
blocks: readonly ContentBlock[],
finish?: (StreamChunk & { type: 'finish' })['reason'],
model = MODEL,
config: BasicCompactConfig = { auto: false },
): Promise<{ ctx: Context; adapter: ScriptedAdapter; compact: ExposedCompactService }> {
const ctx = new Context()
await ctx.plugin(LlmService)
void new TokenMeterService(ctx)
const adapter = new ScriptedAdapter(blocks, finish)
ctx.llm.registerAdapter([model], adapter)
const compact = new ExposedCompactService(ctx, config)
return { ctx, adapter, compact }
}
describe('default one-shot summarizer', () => {
it('uses configured model/default cap, forwards cancellation, and keeps only safe text', async () => {
const { adapter, compact } = await summarizerHarness([
{ type: 'reasoning', text: 'private' },
{ type: 'text', text: 'public summary' },
{ type: 'tool-call', id: CallId('unexpected'), name: 'x', arguments: '{}' },
], undefined, MODEL, {
auto: false,
summarizationProvider: MODEL,
summarizationModel: MODEL,
maxTokens: 321,
})
const session = conversation(1)
adapter.usage = { inputTokens: 12, outputTokens: 3 }
const output = await compact.runSummarize(promptInput('transcript'), agent(session, 'fallback'), SIGNAL)
expect(output).toEqual({
summary: [{ type: 'text', text: 'public summary' }],
rawOutput: [
{ type: 'reasoning', text: 'private' },
{ type: 'text', text: 'public summary' },
{ type: 'tool-call', id: CallId('unexpected'), name: 'x', arguments: '{}' },
],
llmStreamCall: true,
provider: MODEL,
model: MODEL,
maxTokens: 321,
usage: adapter.usage,
})
expect(adapter.lastOptions).toMatchObject({
provider: MODEL,
model: MODEL,
maxTokens: 321,
signal: SIGNAL,
sessionId: session.id,
purpose: 'compaction',
})
const instruction = adapter.lastOptions?.messages.at(-1)?.content[0]
expect(instruction?.type === 'text' ? instruction.text : '').toContain('## Primary Request and Intent')
})
it('replays the conversation prefix and appends the instruction as the final message', async () => {
const { adapter, compact } = await summarizerHarness([{ type: 'text', text: 'summary' }])
const tools = [{ name: 'do_thing', description: 'd', parameters: { type: 'object' } }]
const prefix: Message = createUserMessage({
content: [{ type: 'text', text: 'earlier turn' }],
source: { kind: 'plugin', plugin: 'test' },
})
await compact.runSummarize({
system: 'REPLAYED SYSTEM',
tools,
messages: [prefix],
}, agent(conversation(1), MODEL))
expect(adapter.lastOptions?.system).toBe('REPLAYED SYSTEM')
expect(adapter.lastOptions?.tools).toEqual(tools)
const messages = adapter.lastOptions?.messages ?? []
expect(messages[0]).toEqual(prefix)
const last = messages.at(-1)?.content[0]
const lastText = last?.type === 'text' ? last.text : ''
expect(lastText).toContain('Write concise English engineering prose.')
expect(lastText).toContain('numeric values, function signatures, and syntax fragments.')
expect(lastText).toContain('## Primary Request and Intent')
})
it('applies the routed model policy without changing the replayed prefix', async () => {
const { ctx, compact } = await summarizerHarness(
[{ type: 'text', text: 'unused default summary' }],
undefined,
MODEL,
{
auto: false,
maxTokens: 111,
modelPolicies: [{
provider: MODEL,
model: MODEL,
summarizationProvider: 'policy-summary',
summarizationModel: 'policy-summary',
maxTokens: 222,
}],
},
)
const policyAdapter = new ScriptedAdapter([{ type: 'text', text: 'policy summary' }])
ctx.llm.registerAdapter(['policy-summary'], policyAdapter)
const prefix: Message = createUserMessage({
content: [{ type: 'text', text: 'warm prefix' }],
source: { kind: 'plugin', plugin: 'test' },
})
const output = await compact.runSummarize({
system: 'WARM SYSTEM',
messages: [prefix],
}, agent(conversation(1), 'fallback'))
expect(output).toMatchObject({
provider: 'policy-summary',
model: 'policy-summary',
maxTokens: 222,
})
expect(policyAdapter.lastOptions).toMatchObject({
provider: 'policy-summary',
model: 'policy-summary',
maxTokens: 222,
system: 'WARM SYSTEM',
})
expect(policyAdapter.lastOptions?.messages[0]).toEqual(prefix)
})
it('resolves the latest routed provider/model before the AgentOptions pair', async () => {
const { adapter, compact } = await summarizerHarness([{ type: 'text', text: 'summary' }], undefined, 'routed')
const session = conversation(1)
session.append('request/header', {
header: { config: { provider: 'routed', model: 'routed' } },
reason: 'initial',
})
const output = await compact.runSummarize(promptInput('history'), agent(session, 'fallback'))
expect(output.provider).toBe('routed')
expect(output.model).toBe('routed')
expect(adapter.lastOptions?.provider).toBe('routed')
expect(adapter.lastOptions?.model).toBe('routed')
})
it('records the model actually dispatched after one-shot stream routing', async () => {
const { ctx, compact } = await summarizerHarness([{ type: 'text', text: 'unused' }])
const routedAdapter = new ScriptedAdapter([{ type: 'text', text: 'routed summary' }])
ctx.llm.registerAdapter(['routed-summary-provider'], routedAdapter)
ctx.on('llm/stream', (options, next) => {
options.provider = 'routed-summary-provider'
options.model = 'routed-summary-model'
return next()
})
const session = conversation(3, 'large history '.repeat(500))
const nodes = session.surface.nodes
await compact.compactRegion(nodes[0]!, nodes[3]!, agent(session, MODEL), SIGNAL)
expect(session.events.findLast(event => event.type === 'compact/summary')?.data).toMatchObject({
summary: [{ type: 'text', text: 'routed summary' }],
llmStreamCall: true,
provider: 'routed-summary-provider',
model: 'routed-summary-model',
})
expect(routedAdapter.lastOptions?.provider).toBe('routed-summary-provider')
expect(routedAdapter.lastOptions?.model).toBe('routed-summary-model')
})
it('fails clearly when no complete summarization target can be resolved', async () => {
const ctx = new Context()
await ctx.plugin(LlmService)
void new TokenMeterService(ctx)
const compact = new ExposedCompactService(ctx, { auto: false })
await expect(compact.runSummarize(promptInput('history'), agent(Session.create(SessionId('model-less')))))
.rejects.toThrow(/no provider\/model available for summarization/)
})
it('uses a complete AgentOptions target when no durable route exists', async () => {
const { adapter, compact } = await summarizerHarness([{ type: 'text', text: 'summary' }])
const session = Session.create(SessionId('headerless-summary'))
await expect(compact.runSummarize(promptInput('history'), agent(session, MODEL))).resolves.toMatchObject({
provider: MODEL,
model: MODEL,
})
expect(adapter.lastOptions).toMatchObject({ provider: MODEL, model: MODEL })
})
it.each([
{ provider: '', model: MODEL },
{ provider: MODEL },
{ provider: MODEL, model: '' },
])('rejects incomplete AgentOptions target %#', async (options) => {
const { compact } = await summarizerHarness([{ type: 'text', text: 'unused' }])
const owner = {
session: Session.create(SessionId(`incomplete-${String(options.model)}`)),
options,
} as Agent
await expect(compact.runSummarize(promptInput('history'), owner))
.rejects.toThrow(/no provider\/model available for summarization/)
})
it.each([
[{ kind: 'error', failure: { message: 'provider failed', code: 'PROVIDER' } }, 'PROVIDER', /provider failed/],
[{ kind: 'error', failure: { message: 'opaque', code: 'UNKNOWN' } }, 'UNKNOWN', /opaque/],
[{ kind: 'aborted', failure: { message: 'summarization aborted', code: 'ABORTED' } }, 'ABORTED', /aborted/],
[{ kind: 'max-tokens' }, 'MAX_TOKENS', /token cap/],
] as Array<[(StreamChunk & { type: 'finish' })['reason'], string | undefined, RegExp]>) (
'rejects terminal finish %#',
async (finish, code, pattern) => {
const { compact } = await summarizerHarness([], finish)
let thrown: unknown
try {
await compact.runSummarize(promptInput('history'), agent(conversation(1), MODEL))
} catch (error: unknown) {
thrown = error
}
expect(thrown).toBeInstanceOf(Error)
expect((thrown as Error).message).toMatch(pattern)
expect((thrown as Error & { code?: string }).code).toBe(code)
},
)
it('rejects empty or reasoning-only successful output', async () => {
const { compact } = await summarizerHarness([{ type: 'reasoning', text: 'private' }])
await expect(compact.runSummarize(promptInput('history'), agent(conversation(1), MODEL)))
.rejects.toThrow(/no text summary content/)
})
})
describe('automatic listener and loader composition', () => {
function preStep(ctx: Context, owner: Agent, signal = SIGNAL) {
return agentEvents(ctx, owner).waterfall(
'agent/pre-step', { messages: [], turn: 1, step: 1, signal },
() => Promise.resolve({ kind: 'enter' as const, messages: [] }),
)
}
function recover(
ctx: Context,
owner: Agent,
error: Error & { code?: string },
signal = SIGNAL,
next: () => Promise<RequestErrorAction> = () => Promise.resolve(undefined),
): Promise<boolean> {
const failure: LlmFailure = { message: error.message, code: error.code ?? 'UNKNOWN' }
const turn = owner.session.events.findLast(event => event.type === 'turn/start')?.data.turn ?? 1
return agentEvents(ctx, owner).waterfall(
'agent/request-error',
{ turn, step: 1, provider: 'test', failure, retryPolicy: undefined, signal },
next,
).then(action => action?.kind === 'retry')
}
function overflow(message = 'provider overflow'): Error & { code: string } {
return Object.assign(new Error(message), { code: CONTEXT_WINDOW_EXCEEDED_CODE })
}
it('compacts before a step above threshold using the durable routed model and remains idle below it', async () => {
const ctx = createContext()
const compact = new TestCompactService(ctx, {
thresholdRatio: 0.5,
retainTokens: 180,
})
const pressured = conversation(4)
await preStep(ctx, agent(pressured, 'unconfigured-agent-fallback'))
expect(pressured.events.some(event => event.type === 'compact/summary')).toBe(true)
const small = conversation(1)
await preStep(ctx, agent(small, MODEL))
expect(small.events.some(event => event.type === 'compact/start')).toBe(false)
expect(compact.calls).toHaveLength(1)
})
it('skips pre-step pressure when the step signal is already aborted', async () => {
const ctx = createContext()
const compact = new TestCompactService(ctx, {
thresholdRatio: 0.5,
retainTokens: 180,
})
const pressured = conversation(4)
const compactIfNeeded = vi.spyOn(compact, 'compactIfNeeded')
await expect(preStep(ctx, agent(pressured, MODEL), AbortSignal.abort('step aborted')))
.resolves.toEqual({ kind: 'enter', messages: [] })
expect(compactIfNeeded).not.toHaveBeenCalled()
expect(pressured.events.some(event => event.type === 'compact/start')).toBe(false)
})
it('warns and continues after operational failures, including non-Errors', async () => {
const ctx = createContext()
const warnings: string[] = []
ctx.logger.warn = ((message: string) => void warnings.push(message)) as typeof ctx.logger.warn
const compact = new TestCompactService(ctx, {
thresholdRatio: 0.5,
retainTokens: 180,
})
compact.error = 'temporary failure'
const session = conversation(4)
await expect(preStep(ctx, agent(session, MODEL))).resolves.toEqual({ kind: 'enter', messages: [] })
expect(warnings).toContainEqual(expect.stringContaining('temporary failure'))
expect(session.events.some(event => event.type === 'compact/summary')).toBe(false)
})
it('warns once per routed target when proactive pressure has no context metadata', async () => {
const ctx = createContext()
const warnings: string[] = []
ctx.logger.warn = ((message: string) => void warnings.push(message)) as typeof ctx.logger.warn
vi.spyOn(ctx.llm, 'resolveModelInfo').mockImplementation((provider, model) => Promise.resolve({
provider,
id: model,
name: model,
}))
void new TestCompactService(ctx, {
thresholdRatio: 0.5,
retainTokens: 180,
})
const session = conversation(4)
await preStep(ctx, agent(session, MODEL))
await preStep(ctx, agent(session, MODEL))
expect(warnings).toEqual([
expect.stringContaining(`no context capacity for ${MODEL}/${MODEL}`),
])
})
it('warns once per routed target when absolute retention exceeds its resolved threshold', async () => {
const ctx = createContext()
const warnings: string[] = []
ctx.logger.warn = ((message: string) => void warnings.push(message)) as typeof ctx.logger.warn
void new TestCompactService(ctx, {
thresholdRatio: 0.5,
retainTokens: 500,
})
const session = conversation(4)
await preStep(ctx, agent(session, MODEL))
await preStep(ctx, agent(session, MODEL))
expect(warnings).toEqual([
expect.stringContaining('retainTokens (500) must be less than threshold tokens 500'),
])
})
it('force-compacts below normal pressure for canonical overflow and retries only after replacement', async () => {
const ctx = createContext(10_000)
void new TestCompactService(ctx, {
thresholdRatio: 1,
retainTokens: 900,
})
const session = conversation(3)
const beforeGeneration = session.surface.replaceGeneration
const retainedSeq = session.surface.nodes.at(-1)!
const threshold = 10_000
expect(ctx.tokenMeter.measure(session).totalTokens).toBeLessThan(threshold)
const decision = await recover(ctx, agent(session, 'unconfigured-agent-fallback'), overflow())
expect(decision).toBe(true)
expect(session.surface.replaceGeneration).toBe(beforeGeneration + 1)
expect(session.events.some(event => event.type === 'compact/summary')).toBe(true)
expect(session.surface.nodes).toContain(retainedSeq)
})
it('authorizes overflow retry when pruning alone advances an indivisible surface', async () => {
const ctx = createContext(10_000)
void new ToolResultPruneService(ctx, {
thresholdChars: 100,
headChars: 20,
tailChars: 10,
})
const compact = new TestCompactService(ctx, {
thresholdRatio: 1,
retainTokens: 900,
})
const session = oversizedToolResult()
expect(await recover(ctx, agent(session, MODEL), overflow())).toBe(true)
expect(session.surface.replaceGeneration).toBe(1)
expect(session.events.some(event => event.type === 'compact/summary')).toBe(false)
expect(compact.calls).toHaveLength(0)
})
it('continues overflow recovery with summarization on the pruned surface', async () => {
const ctx = createContext(10_000)
void new ToolResultPruneService(ctx, {
thresholdChars: 100,
headChars: 20,
tailChars: 10,
})
const compact = new TestCompactService(ctx, {
thresholdRatio: 1,
retainTokens: 900,
})
const session = toolConversation()
expect(await recover(ctx, agent(session, MODEL), overflow())).toBe(true)
expect(session.events.some(event => event.type === 'compact/summary')).toBe(true)
expect(compact.calls).toHaveLength(1)
expect(summarizedText(compact.calls[0]!.input)).toContain('tool result middle pruned')
})
it('retries from a durable prune when later overflow summarization throws', async () => {
const ctx = createContext(10_000)
const warnings: string[] = []
ctx.logger.warn = ((message: string) => void warnings.push(message)) as typeof ctx.logger.warn
void new ToolResultPruneService(ctx, {
thresholdChars: 100,
headChars: 20,
tailChars: 10,
})
const compact = new TestCompactService(ctx, {
thresholdRatio: 1,
retainTokens: 900,
})
compact.error = new Error('summary unavailable after prune')
const session = oversizedToolResult(3_000, true)
expect(await recover(ctx, agent(session, MODEL), overflow())).toBe(true)
expect(session.surface.replaceGeneration).toBe(1)
expect(session.events.filter(event => event.type === 'tool/result')).toHaveLength(2)
expect(session.events.findLast(event => event.type === 'compact/end')?.data)
.toMatchObject({ error: 'summary unavailable after prune' })
expect(warnings).toContainEqual(expect.stringContaining('retrying from the replacement surface'))
})
it('lets cancellation win when summary throws after a durable prune', async () => {
const ctx = createContext(10_000)
const controller = new AbortController()
void new ToolResultPruneService(ctx, {
thresholdChars: 100,
headChars: 20,
tailChars: 10,
})
const compact = new TestCompactService(ctx, {
thresholdRatio: 1,
retainTokens: 900,
})
compact.mutateDuringSummary = () => { controller.abort('cancelled during summary') }
compact.error = new Error('summary cancelled after prune')
const session = oversizedToolResult(3_000, true)
expect(await recover(ctx, agent(session, MODEL), overflow(), controller.signal)).toBe(false)
expect(session.surface.replaceGeneration).toBe(1)
})
it('preserves the newest whole tool-call/result pair during forced overflow compaction', async () => {
const ctx = createContext()
void new TestCompactService(ctx, {
thresholdRatio: 1,
retainTokens: 90,
})
const session = toolConversation()
const newestAssistant = session.surface.nodes.at(-2)!
const newestResult = session.surface.nodes.at(-1)!
expect(await recover(ctx, agent(session, MODEL), overflow())).toBe(true)
const currentAssistant = session.surface.nodes.find(node => node === newestAssistant)
const currentResult = session.surface.nodes.find(node => node === newestResult)
expect(currentAssistant).toBeDefined()
expect(currentResult).toBeDefined()
expect(toolPairingBalancedBefore(session, currentAssistant!)).toBe(true)
expect(toolPairingBalancedAfter(session, currentResult!)).toBe(true)
})
it('does not retry when a backend reports success without replacing the surface', async () => {
const ctx = createContext()
const compact = new TestCompactService(ctx)
const session = conversation(2)
const fakeResult: CompactionResult = {
startSeq: 1,
summarySeq: 2,
endSeq: 3,
summary: [{ type: 'text', text: 'fake' }],
shadowedRange: { start: 1, end: 2 },
shadowedSeqs: [1, 2],
shadowedTokenCount: 10,
}
vi.spyOn(compact, 'compactIfNeeded').mockResolvedValue(fakeResult)
expect(await recover(ctx, agent(session, MODEL), overflow())).toBe(false)
expect(session.surface.replaceGeneration).toBe(0)
})
it('delegates downstream exactly once when no replacement is available', async () => {
const ctx = createContext()
const compact = new TestCompactService(ctx)
vi.spyOn(compact, 'compactIfNeeded').mockResolvedValue(null)
const downstream = new Error('downstream recovery failed')
let calls = 0
await expect(recover(
ctx,
agent(conversation(2), MODEL),
overflow(),
SIGNAL,
() => {
calls += 1
return Promise.reject(downstream)
},
)).rejects.toBe(downstream)
expect(calls).toBe(1)
})
it('preserves the original provider error when recovery throws', async () => {
const ctx = createContext()
const warnings: string[] = []
ctx.logger.warn = ((message: string) => void warnings.push(message)) as typeof ctx.logger.warn
const compact = new TestCompactService(ctx)
compact.error = new Error('summary unavailable')
const original = overflow('original provider overflow')
expect(await recover(ctx, agent(conversation(3), MODEL), original)).toBe(false)
expect(original).toMatchObject({
message: 'original provider overflow',
code: CONTEXT_WINDOW_EXCEEDED_CODE,
})
expect(warnings).toContainEqual(expect.stringContaining('preserving the original request error'))
})
it('delegates once when overflow recovery throws a non-Error value', async () => {
const ctx = createContext()
const warnings: string[] = []
ctx.logger.warn = ((message: string) => void warnings.push(message)) as typeof ctx.logger.warn
const compact = new TestCompactService(ctx)
compact.error = 'non-error recovery failure'
const session = conversation(3)
const generation = session.surface.replaceGeneration
const original = overflow('original provider failure')
let delegations = 0
const decision = await recover(ctx, agent(session, MODEL), original, SIGNAL, () => {
delegations += 1
return Promise.resolve(undefined)
})
expect(decision).toBe(false)
expect(delegations).toBe(1)
expect(session.surface.replaceGeneration).toBe(generation)
expect(original).toMatchObject({
message: 'original provider failure',
code: CONTEXT_WINDOW_EXCEEDED_CODE,
})
expect(warnings).toContainEqual(expect.stringContaining('non-error recovery failure'))
})
it('recovers an overflow for an unlisted routed model', async () => {
const ctx = createContext()
void new TestCompactService(ctx)
const session = conversation(2)
session.append('request/header', {
header: { config: { provider: 'unknown-routed-provider', model: 'unknown-routed-model' } },
reason: 'resume',
})
expect(await recover(ctx, agent(session, MODEL), overflow('unlisted-model overflow')))
.toBe(true)
})
it('delegates canonical overflow when no durable routed target exists', async () => {
const ctx = createContext()
void new TestCompactService(ctx)
const session = Session.create(SessionId('headerless-overflow'))
session.append('turn/start', {
turn: 1,
})
await expect(recover(ctx, agent(session, MODEL), overflow())).resolves.toBe(false)
})
it('honors retry caps and ignores non-context failures', async () => {
const ctx = createContext()
const compact = new TestCompactService(ctx, { maxOverflowRetries: 1 })
const compactSpy = vi.spyOn(compact, 'compactIfNeeded')
const owner = agent(conversation(3), MODEL)
expect(await recover(ctx, owner, Object.assign(new Error('rate limit'), { code: 'RATE_LIMIT' })))
.toBe(false)
expect(await recover(ctx, owner, overflow())).toBe(true)
compactSpy.mockClear()
expect(await recover(ctx, owner, overflow())).toBe(false)
expect(compactSpy).not.toHaveBeenCalled()
})
it('applies the routed model override to the overflow retry cap', async () => {
const ctx = createContext()
const compact = new TestCompactService(ctx, {
maxOverflowRetries: 2,
modelPolicies: [{
provider: MODEL,
model: MODEL,
maxOverflowRetries: 1,
}],
})
const compactSpy = vi.spyOn(compact, 'compactIfNeeded')
const owner = agent(conversation(3), MODEL)
expect(await recover(ctx, owner, overflow())).toBe(true)
compactSpy.mockClear()
expect(await recover(ctx, owner, overflow())).toBe(false)
expect(compactSpy).not.toHaveBeenCalled()
})
it('does not retry when cancellation lands during an awaited compaction', async () => {
const ctx = createContext()
const compact = new TestCompactService(ctx)
const controller = new AbortController()
compact.mutateDuringSummary = () => { controller.abort('cancelled during summary') }
const session = conversation(3)
const generation = session.surface.replaceGeneration
expect(await recover(ctx, agent(session, MODEL), overflow(), controller.signal)).toBe(false)
expect(session.surface.replaceGeneration).toBe(generation + 1)
})
it('maxOverflowRetries:0 disables recovery without disabling post-step pressure', async () => {
const ctx = createContext()
void new TestCompactService(ctx, {
maxOverflowRetries: 0,
thresholdRatio: 0.5,
retainTokens: 180,
})
const session = conversation(4)
await preStep(ctx, agent(session, MODEL))
const summaries = session.events.filter(event => event.type === 'compact/summary').length
expect(summaries).toBe(1)
expect(await recover(ctx, agent(session, MODEL), overflow())).toBe(false)
expect(session.events.filter(event => event.type === 'compact/summary')).toHaveLength(summaries)
})
it('auto:false installs neither automatic listener', async () => {
const ctx = createContext()
void new TestCompactService(ctx, {
auto: false,
thresholdRatio: 0.5,
retainTokens: 180,
})
const session = conversation(4)
await preStep(ctx, agent(session, MODEL))
expect(session.events.some(event => event.type === 'compact/start')).toBe(false)
expect(await recover(ctx, agent(session, MODEL), overflow())).toBe(false)
})
it('loads and disposes the real zero-config service stack', async () => {
const ctx = new Context()
await ctx.plugin(LlmService)
await ctx.plugin(SessionStore)
const meterFiber = await ctx.plugin(TokenMeterService)
const compactFiber = await ctx.plugin(BasicCompactService, { auto: false })
expect(ctx.get('compact')).toBeInstanceOf(BasicCompactService)
await compactFiber.dispose()
expect(ctx.get('compact')).toBeUndefined()
await meterFiber.dispose()
expect(ctx.get('tokenMeter')).toBeUndefined()
})
it('removes its automatic listener with the plugin fiber', async () => {
const ctx = new Context()
await ctx.plugin(LlmService)
await ctx.plugin(TokenMeterService)
const fiber = await ctx.plugin(TestCompactService, {
thresholdRatio: 0.5,
retainTokens: 180,
})
await fiber.dispose()
const session = conversation(4)
await preStep(ctx, agent(session, MODEL))
expect(session.events.some(event => event.type === 'compact/start')).toBe(false)
expect(await recover(ctx, agent(session, MODEL), overflow())).toBe(false)
})
})