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[codex] Harden context compression history handling (#848)

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* Use token threshold for chat compression

* Add compression settings controls

* Use config for chat compression

* Cover protected messages in compression tests

* Remove message-count compression limit

* Harden compression window fallback

* Rebuild stale compression snapshots

* Harden stale compression snapshots

* Update changelog for compression hardening

* Prefer local history session details
This commit is contained in:
ekko
2026-05-19 17:58:39 +08:00
committed by GitHub
parent 84e343fc22
commit 0547fd6b6a
22 changed files with 1255 additions and 56 deletions
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packages/server/src/services/hermes/run-chat/compression.ts
+109 -19
View File
@@ -10,14 +10,88 @@ import {
import { getCompressionSnapshot } from '../../../db/hermes/compression-snapshot'
import { ChatContextCompressor, SUMMARY_PREFIX } from '../../../lib/context-compressor'
import { getModelContextLength } from '../model-context'
import { readConfigYamlForProfile } from '../../config-helpers'
import { logger } from '../../logger'
import { bridgeLogger } from '../../logger'
import { calcAndUpdateUsage, estimateUsageTokensFromMessages } from './usage'
import { isAssistantMessageSendable } from './message-format'
import type { ChatMessage } from '../../../lib/context-compressor'
import type { ChatMessage, CompressionConfig as CompressorConfig } from '../../../lib/context-compressor'
import type { SessionState, BridgeCompressionResult } from './types'
const compressor = new ChatContextCompressor()
interface RunChatCompressionConfig {
enabled: boolean
triggerTokens: number
compressor: Partial<CompressorConfig>
}
function isSnapshotUsable(
snapshot: { lastMessageIndex: number } | null,
history: ChatMessage[],
): boolean {
return !!snapshot && snapshot.lastMessageIndex >= 0 && snapshot.lastMessageIndex < history.length
}
function buildSnapshotHistory(
snapshot: { summary: string; lastMessageIndex: number } | null,
history: ChatMessage[],
compressionConfig?: Partial<CompressorConfig>,
): ChatMessage[] | null {
if (!snapshot) return null
const headCount = compressionConfig?.headMessageCount || 0
const tailCount = compressionConfig?.tailMessageCount || 0
const protectedHead = headCount > 0 ? history.slice(0, headCount) : []
const summaryMessage = { role: 'user', content: SUMMARY_PREFIX + '\n\n' + snapshot.summary } as ChatMessage
if (isSnapshotUsable(snapshot, history)) {
return [
...protectedHead,
summaryMessage,
...history.slice(snapshot.lastMessageIndex + 1),
]
}
const tailStart = Math.max(protectedHead.length, history.length - tailCount)
return [
...protectedHead,
summaryMessage,
...history.slice(tailStart),
]
}
function clampRatio(value: unknown, fallback: number, min: number, max: number): number {
const n = typeof value === 'number' && Number.isFinite(value) ? value : fallback
return Math.min(max, Math.max(min, n))
}
function clampInt(value: unknown, fallback: number, min: number, max: number): number {
const n = typeof value === 'number' && Number.isFinite(value) ? Math.floor(value) : fallback
return Math.min(max, Math.max(min, n))
}
async function getRunChatCompressionConfig(profile: string, contextLength: number): Promise<RunChatCompressionConfig> {
let raw: Record<string, any> = {}
try {
raw = (await readConfigYamlForProfile(profile))?.compression || {}
} catch (err) {
logger.warn(err, '[context-compress] failed to read compression config for profile %s, using defaults', profile)
}
const threshold = clampRatio(raw.threshold, 0.5, 0.05, 0.95)
const targetRatio = clampRatio(raw.target_ratio, 0.2, 0.01, 0.8)
const protectLastN = clampInt(raw.protect_last_n, 20, 0, 500)
const protectFirstN = clampInt(raw.protect_first_n, 3, 0, 100)
return {
enabled: raw.enabled !== false,
triggerTokens: Math.floor(contextLength * threshold),
compressor: {
triggerTokens: Math.floor(contextLength * threshold),
summaryBudget: Math.max(1_000, Math.floor(contextLength * targetRatio)),
headMessageCount: protectFirstN,
tailMessageCount: protectLastN,
},
}
}
/**
* Load conversation history from DB with full message structure (user/assistant/tool).
@@ -77,12 +151,7 @@ export function estimateSnapshotAwareHistoryUsage(
history: ChatMessage[],
): { messageCount: number; tokenCount: number } {
const snapshot = getCompressionSnapshot(sessionId)
const messages = snapshot
? [
{ role: 'user', content: SUMMARY_PREFIX + snapshot.summary },
...history.slice(snapshot.lastMessageIndex + 1),
]
: history
const messages = buildSnapshotHistory(snapshot, history) || history
const usage = estimateUsageTokensFromMessages(messages)
return {
messageCount: messages.length,
@@ -108,29 +177,45 @@ export async function buildCompressedHistory(
model: modelContext.model,
provider: modelContext.provider,
})
const triggerTokens = Math.floor(contextLength / 2)
const compressionConfig = await getRunChatCompressionConfig(profile, contextLength)
const triggerTokens = compressionConfig.triggerTokens
if (!compressionConfig.enabled) {
logger.info('[context-compress] session=%s: compression disabled by config', sessionId)
return history
}
const cState = getOrCreateSession(sessionMap, sessionId)
const assembledTokens = await calcAndUpdateUsage(sessionId, cState, emit)
const totalTokens = assembledTokens.inputTokens + assembledTokens.outputTokens
let totalTokens = assembledTokens.inputTokens + assembledTokens.outputTokens
const snapshot = getCompressionSnapshot(sessionId)
const staleSnapshot = snapshot && !isSnapshotUsable(snapshot, history)
if (staleSnapshot) {
logger.warn('[context-compress] session=%s: stale snapshot index %d for %d history messages; using summary plus safe tail',
sessionId, snapshot.lastMessageIndex, history.length)
const staleHistory = buildSnapshotHistory(snapshot, history, compressionConfig.compressor) || history
const staleUsage = estimateUsageTokensFromMessages(staleHistory)
totalTokens = staleUsage.inputTokens + staleUsage.outputTokens
}
if (snapshot) {
if (snapshot && !staleSnapshot) {
const newMessages = history.slice(snapshot.lastMessageIndex + 1)
logger.info('[context-compress] session=%s: snapshot at %d, %d new messages, assembled ~%d tokens (threshold %d)',
sessionId, snapshot.lastMessageIndex, newMessages.length, totalTokens, triggerTokens)
if (totalTokens <= triggerTokens && newMessages.length <= 150) {
history = [
{ role: 'user', content: SUMMARY_PREFIX + '\n\n' + snapshot.summary },
...newMessages,
] as ChatMessage[]
if (totalTokens <= triggerTokens) {
history = buildSnapshotHistory(snapshot, history, compressionConfig.compressor) || history
} else {
history = await compressHistory(history, newMessages, sessionId, upstream, apiKey, cState, totalTokens, emit, sessionMap, modelContext)
history = await compressHistory(history, newMessages, sessionId, upstream, apiKey, cState, totalTokens, emit, sessionMap, modelContext, compressionConfig.compressor)
}
} else if (snapshot && staleSnapshot) {
if (totalTokens <= triggerTokens) {
history = buildSnapshotHistory(snapshot, history, compressionConfig.compressor) || history
} else {
history = await compressHistory(history, null, sessionId, upstream, apiKey, cState, totalTokens, emit, sessionMap, modelContext, compressionConfig.compressor)
}
} else if (history.length > 4) {
if (totalTokens <= triggerTokens && history.length <= 150) {
if (totalTokens <= triggerTokens) {
logger.info('[context-compress] session=%s: %d messages, ~%d tokens — under threshold, skip', sessionId, history.length, totalTokens)
} else {
history = await compressHistory(history, null, sessionId, upstream, apiKey, cState, totalTokens, emit, sessionMap, modelContext)
history = await compressHistory(history, null, sessionId, upstream, apiKey, cState, totalTokens, emit, sessionMap, modelContext, compressionConfig.compressor)
}
}
@@ -152,6 +237,7 @@ export async function compressHistory(
emit: (event: string, payload: any) => void,
sessionMap: Map<string, SessionState>,
modelContext: { model?: string | null; provider?: string | null } = {},
compressionConfig?: Partial<CompressorConfig>,
): Promise<ChatMessage[]> {
const msgCount = newMessagesOnly ? newMessagesOnly.length : history.length
pushState(sessionMap, sessionId, 'compression.started', {
@@ -163,6 +249,7 @@ export async function compressHistory(
try {
const session = getSession(sessionId)
const compressor = new ChatContextCompressor({ config: compressionConfig })
const result = await compressor.compress(history, upstream, apiKey, sessionId, {
profile: session?.profile,
model: modelContext.model || session?.model,
@@ -244,6 +331,8 @@ export async function forceCompressBridgeHistory(
const upstream = ''
const apiKey = undefined
const session = getSession(sessionId)
const contextLength = getModelContextLength({ profile, model: session?.model, provider: session?.provider })
const compressionConfig = await getRunChatCompressionConfig(session?.profile || profile, contextLength)
const beforeUsage = estimateSnapshotAwareHistoryUsage(sessionId, history)
const totalTokens = beforeUsage.tokenCount
bridgeLogger.info({
@@ -256,6 +345,7 @@ export async function forceCompressBridgeHistory(
snapshotAware: true,
}, '[chat-run-socket] bridge forced compression started')
const compressor = new ChatContextCompressor({ config: compressionConfig.compressor })
const result = await compressor.compress(history, upstream, apiKey, sessionId, {
profile: session?.profile || profile,
model: session?.model,
packages/server/src/services/hermes/run-chat/handle-api-run.ts
+1 -1
View File
@@ -38,7 +38,7 @@ export async function loadSessionStateFromDb(sid: string, _sessionMap: Map<strin
let inputTokens: number
let outputTokens: number
const snapshot = getCompressionSnapshot(sid)
if (snapshot) {
if (snapshot && snapshot.lastMessageIndex >= 0 && snapshot.lastMessageIndex < messages.length) {
const newMessages = messages.slice(snapshot.lastMessageIndex + 1)
const newUsage = estimateUsageTokensFromMessages(newMessages)
inputTokens = countTokens(SUMMARY_PREFIX + snapshot.summary) +
packages/server/src/services/hermes/run-chat/usage.ts
+1 -1
View File
@@ -53,7 +53,7 @@ export async function calcAndUpdateUsage(
const snapshot = getCompressionSnapshot(sid)
let inputTokens: number
let outputTokens: number
if (snapshot && msgs.length) {
if (snapshot && msgs.length && snapshot.lastMessageIndex >= 0 && snapshot.lastMessageIndex < msgs.length) {
const newMessages = msgs.slice(snapshot.lastMessageIndex + 1)
const newUsage = estimateUsageTokensFromMessages(newMessages)
inputTokens = countTokens(SUMMARY_PREFIX + snapshot.summary) +