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Merged
lizradway merged 10 commits into from
Sep 11, 2026
+605 −258
Merged

feat(context-ts): add context strategy presets + rewire defaults to use class #4256

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00ce3dc
feat(context-manager): add strategy presets and rewire auto/agentic t…
lizradway Sep 9, 2026
d09765a
fix(context-manager): bypass utilization gates on overflow recovery
lizradway Sep 9, 2026
761249c
fix(context-manager): extend overflow bypass to emergency truncate
lizradway Sep 9, 2026
22101bd
fix(context-manager): validate unknown strategy preset names
lizradway Sep 9, 2026
d52f622
refactor(context-manager): deduplicate auto preset and fix class docs…
lizradway Sep 9, 2026
e51bfdf
fix(context-manager): honor pinned messages in offload strategies
lizradway Sep 10, 2026
82402b3
fix(context-manager): preserve pinned metadata through repairAlternat…
lizradway Sep 10, 2026
d778af4
fix(context-manager): address review feedback round 2
lizradway Sep 10, 2026
b05df8e
style(context-manager): fix prettier formatting
lizradway Sep 10, 2026
ab518bc
fix(context-manager): clear overflow bypass before emergency truncate…
lizradway Sep 10, 2026
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97 changes: 28 additions & 69 deletions strands-ts/src/agent/__tests__/agent.context-manager.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -2,12 +2,8 @@ import { describe, expect, it } from 'vitest'
import { Agent } from '../agent.js'
import { MockMessageModel } from '../../__fixtures__/mock-message-model.js'
import { SlidingWindowConversationManager } from '../../conversation-manager/sliding-window-conversation-manager.js'
import { SummarizingConversationManager } from '../../conversation-manager/summarizing-conversation-manager.js'
import { NullConversationManager } from '../../conversation-manager/null-conversation-manager.js'
import { ContextOffloader } from '../../vended-plugins/context-offloader/plugin.js'
import { InMemoryStorage as LegacyInMemoryStorage } from '../../vended-plugins/context-offloader/storage.js'
import { ContextManager } from '../../context-manager/context-manager.js'
import { NAMESPACED } from '../../storage/storage.js'
import type { ConversationManager } from '../../conversation-manager/conversation-manager.js'

function internals(agent: Agent): any {
Expand All @@ -18,10 +14,6 @@ function getConversationManager(agent: Agent): ConversationManager {
return internals(agent)._conversationManager
}

function getPending(agent: Agent): any[] {
return internals(agent)._pluginRegistry._pending
}

describe('Agent contextManager', () => {
describe('when undefined (default)', () => {
it('uses SlidingWindowConversationManager', () => {
Expand All @@ -30,76 +22,53 @@ describe('Agent contextManager', () => {
expect(getConversationManager(agent)).toBeInstanceOf(SlidingWindowConversationManager)
})

it('does not add ContextOffloader plugin', () => {
it('does not set contextManager', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const agent = new Agent({ model })
const pending = getPending(agent)
expect(pending.find((p: any) => p.name === 'strands:context-offloader')).toBeUndefined()
expect(agent.contextManager).toBeUndefined()
})
})

describe('when "auto"', () => {
it('uses SummarizingConversationManager', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const agent = new Agent({ model, contextManager: 'auto' })
expect(getConversationManager(agent)).toBeInstanceOf(SummarizingConversationManager)
})

it('sets summaryRatio to 0.3', () => {
it('uses NullConversationManager', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const agent = new Agent({ model, contextManager: 'auto' })
const conversationManager = getConversationManager(agent) as any
expect(conversationManager._summaryRatio).toBe(0.3)
expect(getConversationManager(agent)).toBeInstanceOf(NullConversationManager)
})

it('enables proactive compression at 0.85', () => {
it('creates a ContextManager instance', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const agent = new Agent({ model, contextManager: 'auto' })
const conversationManager = getConversationManager(agent) as any
expect(conversationManager._compressionThreshold).toBe(0.85)
expect(agent.contextManager).toBeInstanceOf(ContextManager)
})

it('adds ContextOffloader plugin with benchmark defaults', async () => {
it('registers ContextManager as a plugin', async () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const agent = new Agent({ model, contextManager: 'auto' })
await agent.invoke('hi')
const plugins = internals(agent)._pluginRegistry._plugins
const offloader = plugins.get('strands:context-offloader') as any
expect(offloader).toBeDefined()
expect(offloader._maxResultTokens).toBe(1500)
expect(offloader._previewTokens).toBe(750)
expect(NAMESPACED in offloader._storage).toBe(true)
expect(plugins.get('strands:context-manager')).toBe(agent.contextManager)
})
})

describe('coexistence with conversationManager', () => {
it('respects user-provided conversationManager', () => {
it('ignores user-provided conversationManager', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const userCm = new SlidingWindowConversationManager({ windowSize: 20 })
const agent = new Agent({ model, contextManager: 'auto', conversationManager: userCm })
expect(getConversationManager(agent)).toBe(userCm)
expect(getConversationManager(agent)).toBeInstanceOf(NullConversationManager)
})
})

it('still adds ContextOffloader when user provides conversationManager', () => {
describe('when "agentic"', () => {
it('uses NullConversationManager', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const userCm = new SlidingWindowConversationManager({ windowSize: 20 })
const agent = new Agent({ model, contextManager: 'auto', conversationManager: userCm })
const pending = getPending(agent)
expect(pending.find((p: any) => p.name === 'strands:context-offloader')).toBeDefined()
const agent = new Agent({ model, contextManager: 'agentic' })
expect(getConversationManager(agent)).toBeInstanceOf(NullConversationManager)
})

it('does not add duplicate ContextOffloader if user provides one', () => {
it('creates a ContextManager instance', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const userOffloader = new ContextOffloader({
storage: new LegacyInMemoryStorage(),
maxResultTokens: 3000,
previewTokens: 1000,
})
const agent = new Agent({ model, contextManager: 'auto', plugins: [userOffloader] })
const pending = getPending(agent)
const offloaders = pending.filter((p: any) => p.name === 'strands:context-offloader')
expect(offloaders).toHaveLength(1)
expect((offloaders[0] as any)._maxResultTokens).toBe(3000)
const agent = new Agent({ model, contextManager: 'agentic' })
expect(agent.contextManager).toBeInstanceOf(ContextManager)
})
})

Expand Down Expand Up @@ -128,37 +97,27 @@ describe('Agent contextManager', () => {
const agent = new Agent({ model, contextManager: false, conversationManager: userCm })
expect(getConversationManager(agent)).toBe(userCm)
})

it('does not set contextManager', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const agent = new Agent({ model, contextManager: false })
expect(agent.contextManager).toBeUndefined()
})
})

describe('when ContextManager instance', () => {
describe('when ContextManagerConfig object', () => {
it('uses NullConversationManager', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const cm = new ContextManager({ strategies: [{ name: 'noop', apply: async () => false }] })
const agent = new Agent({ model, contextManager: cm })
const agent = new Agent({ model, contextManager: { strategies: [{ name: 'noop', apply: async () => false }] } })
expect(getConversationManager(agent)).toBeInstanceOf(NullConversationManager)
})

it('registers ContextManager as a plugin', async () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const cm = new ContextManager({ strategies: [{ name: 'noop', apply: async () => false }] })
const agent = new Agent({ model, contextManager: cm })
const agent = new Agent({ model, contextManager: { strategies: [{ name: 'noop', apply: async () => false }] } })
await agent.invoke('hi')
const plugins = internals(agent)._pluginRegistry._plugins
expect(plugins.get('strands:context-manager')).toBe(cm)
})

it('throws if ContextManager is passed in both param and plugins', async () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const cm = new ContextManager({ strategies: [{ name: 'noop', apply: async () => false }] })
const agent = new Agent({ model, contextManager: cm, plugins: [cm] })
await expect(agent.invoke('hi')).rejects.toThrow('plugin already registered')
})
})

describe('unsupported value', () => {
it('throws for invalid contextManager value', () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
expect(() => new Agent({ model, contextManager: 'manual' as any })).toThrow('Unsupported contextManager value')
expect(plugins.get('strands:context-manager')).toBeInstanceOf(ContextManager)
})
})
})
50 changes: 7 additions & 43 deletions strands-ts/src/agent/__tests__/agent.storage.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -2,61 +2,25 @@ import { describe, expect, it } from 'vitest'
import { Agent } from '../agent.js'
import { MockMessageModel } from '../../__fixtures__/mock-message-model.js'
import { InMemoryStorage } from '../../storage/in-memory-storage.js'
import { NAMESPACED } from '../../storage/storage.js'
import { ContextOffloader } from '../../vended-plugins/context-offloader/plugin.js'
import { SessionManager } from '../../session/session-manager.js'

function internals(agent: Agent): any {
return agent as any
}

describe('Agent storage', () => {
describe('agent-level storage flows to ContextOffloader', () => {
it('auto-created offloader uses agent storage when provided', async () => {
describe('agent-level storage flows to ContextManager stash', () => {
it('auto-created ContextManager uses agent storage when provided', async () => {
const storage = new InMemoryStorage()
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const agent = new Agent({ model, contextManager: 'auto', storage })
await agent.invoke('hi')
const plugins = internals(agent)._pluginRegistry._plugins
const offloader = plugins.get('strands:context-offloader') as any
expect(offloader._storage).toBeDefined()
expect(NAMESPACED in offloader._storage).toBe(true)

await offloader._storage.write('test-key', new TextEncoder().encode('test-value'))
const stored = await storage.read('offloader/test-key')
expect(stored).not.toBeNull()
expect(new TextDecoder().decode(stored!)).toBe('test-value')
expect(agent.contextManager).toBeDefined()
expect(agent.contextManager!.stash).toBeDefined()
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})

it('auto-created offloader falls back to InMemoryStorage when no agent storage', async () => {
it('auto-created ContextManager uses InMemoryStorage when no agent storage', async () => {
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const agent = new Agent({ model, contextManager: 'auto' })
await agent.invoke('hi')
const plugins = internals(agent)._pluginRegistry._plugins
const offloader = plugins.get('strands:context-offloader') as any
expect(offloader._storage).toBeDefined()
expect(NAMESPACED in offloader._storage).toBe(true)
})

it('explicit offloader storage overrides agent storage', async () => {
const agentStorage = new InMemoryStorage()
const offloaderStorage = new InMemoryStorage()
const model = new MockMessageModel().addTurn({ type: 'textBlock', text: 'hi' })
const agent = new Agent({
model,
storage: agentStorage,
plugins: [new ContextOffloader({ storage: offloaderStorage, maxResultTokens: 1500, previewTokens: 750 })],
contextManager: 'auto',
})
await agent.invoke('hi')
const plugins = internals(agent)._pluginRegistry._plugins
const offloader = plugins.get('strands:context-offloader') as any

await offloader._storage.write('test-key', new TextEncoder().encode('test-value'))
const inOffloader = await offloaderStorage.read('offloader/test-key')
expect(inOffloader).not.toBeNull()
const inAgent = await agentStorage.read('offloader/test-key')
expect(inAgent).toBeNull()
expect(agent.contextManager).toBeDefined()
expect(agent.contextManager!.stash).toBeDefined()
})
})

Expand Down
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