import { BusEvent } from "@/bus/bus-event"import { Bus } from "@/bus"import { Session } from "."import { Identifier } from "../id/id"import { Instance } from "../project/instance"import { Provider } from "../provider/provider"import { MessageV2 } from "./message-v2"import z from "zod"import { SessionPrompt } from "./prompt"import { Token } from "../util/token"import { Log } from "../util/log"import { SessionProcessor } from "./processor"import { fn } from "@/util/fn"import { Agent } from "@/agent/agent"import { Plugin } from "@/plugin"import { Config } from "@/config/config" export namespace SessionCompaction { const log = Log.create({ service: "session.compaction" }) export const Event = { Compacted: BusEvent.define( "session.compacted", z.object({ sessionID: z.string(), }), ), } export async function isOverflow(input: { tokens: MessageV2.Assistant["tokens"]; model: Provider.Model }) { const config = await Config.get() if (config.compaction?.auto === false) return false const context = input.model.limit.context if (context === 0) return false const count = input.tokens.input + input.tokens.cache.read + input.tokens.output const output = Math.min(input.model.limit.output, SessionPrompt.OUTPUT_TOKEN_MAX) || SessionPrompt.OUTPUT_TOKEN_MAX const usable = input.model.limit.input || context - output return count > usable } export const PRUNE_MINIMUM = 20_000 export const PRUNE_PROTECT = 40_000 const PRUNE_PROTECTED_TOOLS = ["skill", "artifact"] // goes backwards through parts until there are 40_000 tokens worth of tool // calls. then erases output of previous tool calls. idea is to throw away old // tool calls that are no longer relevant. export async function prune(input: { sessionID: string }) { const config = await Config.get() if (config.compaction?.prune === false) return log.info("pruning") const msgs = await Session.messages({ sessionID: input.sessionID }) let total = 0 let pruned = 0 const toPrune = [] let turns = 0 loop: for (let msgIndex = msgs.length - 1; msgIndex >= 0; msgIndex--) { const msg = msgs[msgIndex] if (msg.info.role === "user") turns++ if (turns < 2) continue if (msg.info.role === "assistant" && msg.info.summary) break loop for (let partIndex = msg.parts.length - 1; partIndex >= 0; partIndex--) { const part = msg.parts[partIndex] // Preserve RLM state blocks — they carry planner progress if (part.type === "text" && part.text.includes("<rlm_state>")) continue if (part.type === "tool") if (part.state.status === "completed") { if (PRUNE_PROTECTED_TOOLS.includes(part.tool)) continue if (part.state.time.compacted) break loop const estimate = Token.estimate(part.state.output) total += estimate if (total > PRUNE_PROTECT) { pruned += estimate toPrune.push(part) } } } } log.info("found", { pruned, total }) if (pruned > PRUNE_MINIMUM) { for (const part of toPrune) { if (part.state.status === "completed") { part.state.time.compacted = Date.now() await Session.updatePart(part) } } log.info("pruned", { count: toPrune.length }) } } export async function process(input: { parentID: string messages: MessageV2.WithParts[] sessionID: string abort: AbortSignal auto: boolean }) { const userMessage = input.messages.findLast((m) => m.info.id === input.parentID)!.info as MessageV2.User const agent = await Agent.get("compaction") const model = agent.model ? await Provider.getModel(agent.model.providerID, agent.model.modelID) : await Provider.getModel(userMessage.model.providerID, userMessage.model.modelID) const msg = (await Session.updateMessage({ id: Identifier.ascending("message"), role: "assistant", parentID: input.parentID, sessionID: input.sessionID, mode: "compaction", agent: "compaction", summary: true, path: { cwd: Instance.directory, root: Instance.worktree, }, cost: 0, tokens: { output: 0, input: 0, reasoning: 0, cache: { read: 0, write: 0 }, }, modelID: model.id, providerID: model.providerID, time: { created: Date.now(), }, })) as MessageV2.Assistant const processor = SessionProcessor.create({ assistantMessage: msg, sessionID: input.sessionID, model, abort: input.abort, }) // Allow plugins to inject context or replace compaction prompt const compacting = await Plugin.trigger( "experimental.session.compacting", { sessionID: input.sessionID }, { context: [], prompt: undefined }, ) const defaultPrompt = "Provide a detailed prompt for continuing our conversation above. Focus on information that would be helpful for continuing the conversation, including what we did, what we're doing, which files we're working on, and what we're going to do next considering new session will not have access to our conversation." const promptText = compacting.prompt ?? [defaultPrompt, ...compacting.context].join("\n\n") const result = await processor.process({ user: userMessage, agent, abort: input.abort, sessionID: input.sessionID, tools: {}, system: [], messages: [ ...MessageV2.toModelMessages(input.messages, model), { role: "user", content: [ { type: "text", text: promptText, }, ], }, ], model, }) if (result === "continue" && input.auto) { const continueMsg = await Session.updateMessage({ id: Identifier.ascending("message"), role: "user", sessionID: input.sessionID, time: { created: Date.now(), }, agent: userMessage.agent, model: userMessage.model, }) await Session.updatePart({ id: Identifier.ascending("part"), messageID: continueMsg.id, sessionID: input.sessionID, type: "text", synthetic: true, text: "Continue if you have next steps", time: { start: Date.now(), end: Date.now(), }, }) } if (processor.message.error) return "stop" Bus.publish(Event.Compacted, { sessionID: input.sessionID }) return "continue" } export const create = fn( z.object({ sessionID: Identifier.schema("session"), agent: z.string(), model: z.object({ providerID: z.string(), modelID: z.string(), }), auto: z.boolean(), }), async (input) => { const msg = await Session.updateMessage({ id: Identifier.ascending("message"), role: "user", model: input.model, sessionID: input.sessionID, agent: input.agent, time: { created: Date.now(), }, }) await Session.updatePart({ id: Identifier.ascending("part"), messageID: msg.id, sessionID: msg.sessionID, type: "compaction", auto: input.auto, }) }, )}
import { BusEvent } from "@/bus/bus-event"
import { Bus } from "@/bus"
import { Session } from "."
import { Identifier } from "../id/id"
import { Instance } from "../project/instance"
import { Provider } from "../provider/provider"
import { MessageV2 } from "./message-v2"
import z from "zod"
import { SessionPrompt } from "./prompt"
import { Token } from "../util/token"
import { Log } from "../util/log"
import { SessionProcessor } from "./processor"
import { fn } from "@/util/fn"
import { Agent } from "@/agent/agent"
import { Plugin } from "@/plugin"
import { Config } from "@/config/config"
export namespace SessionCompaction {
const log = Log.create({ service: "session.compaction" })
export const Event = {
Compacted: BusEvent.define(
"session.compacted",
z.object({
sessionID: z.string(),
}),
),
}
export async function isOverflow(input: { tokens: MessageV2.Assistant["tokens"]; model: Provider.Model }) {
const config = await Config.get()
if (config.compaction?.auto === false) return false
const context = input.model.limit.context
if (context === 0) return false
const count = input.tokens.input + input.tokens.cache.read + input.tokens.output
const output = Math.min(input.model.limit.output, SessionPrompt.OUTPUT_TOKEN_MAX) || SessionPrompt.OUTPUT_TOKEN_MAX
const usable = input.model.limit.input || context - output
return count > usable
}
export const PRUNE_MINIMUM = 20_000
export const PRUNE_PROTECT = 40_000
const PRUNE_PROTECTED_TOOLS = ["skill", "artifact"]
// goes backwards through parts until there are 40_000 tokens worth of tool
// calls. then erases output of previous tool calls. idea is to throw away old
// tool calls that are no longer relevant.
export async function prune(input: { sessionID: string }) {
const config = await Config.get()
if (config.compaction?.prune === false) return
log.info("pruning")
const msgs = await Session.messages({ sessionID: input.sessionID })
let total = 0
let pruned = 0
const toPrune = []
let turns = 0
loop: for (let msgIndex = msgs.length - 1; msgIndex >= 0; msgIndex--) {
const msg = msgs[msgIndex]
if (msg.info.role === "user") turns++
if (turns < 2) continue
if (msg.info.role === "assistant" && msg.info.summary) break loop
for (let partIndex = msg.parts.length - 1; partIndex >= 0; partIndex--) {
const part = msg.parts[partIndex]
// Preserve RLM state blocks — they carry planner progress
if (part.type === "text" && part.text.includes("<rlm_state>")) continue
if (part.type === "tool")
if (part.state.status === "completed") {
if (PRUNE_PROTECTED_TOOLS.includes(part.tool)) continue
if (part.state.time.compacted) break loop
const estimate = Token.estimate(part.state.output)
total += estimate
if (total > PRUNE_PROTECT) {
pruned += estimate
toPrune.push(part)
}
}
}
}
log.info("found", { pruned, total })
if (pruned > PRUNE_MINIMUM) {
for (const part of toPrune) {
if (part.state.status === "completed") {
part.state.time.compacted = Date.now()
await Session.updatePart(part)
}
}
log.info("pruned", { count: toPrune.length })
}
}
export async function process(input: {
parentID: string
messages: MessageV2.WithParts[]
sessionID: string
abort: AbortSignal
auto: boolean
}) {
const userMessage = input.messages.findLast((m) => m.info.id === input.parentID)!.info as MessageV2.User
const agent = await Agent.get("compaction")
const model = agent.model
? await Provider.getModel(agent.model.providerID, agent.model.modelID)
: await Provider.getModel(userMessage.model.providerID, userMessage.model.modelID)
const msg = (await Session.updateMessage({
id: Identifier.ascending("message"),
role: "assistant",
parentID: input.parentID,
sessionID: input.sessionID,
mode: "compaction",
agent: "compaction",
summary: true,
path: {
cwd: Instance.directory,
root: Instance.worktree,
},
cost: 0,
tokens: {
output: 0,
input: 0,
reasoning: 0,
cache: { read: 0, write: 0 },
},
modelID: model.id,
providerID: model.providerID,
time: {
created: Date.now(),
},
})) as MessageV2.Assistant
const processor = SessionProcessor.create({
assistantMessage: msg,
sessionID: input.sessionID,
model,
abort: input.abort,
})
// Allow plugins to inject context or replace compaction prompt
const compacting = await Plugin.trigger(
"experimental.session.compacting",
{ sessionID: input.sessionID },
{ context: [], prompt: undefined },
)
const defaultPrompt =
"Provide a detailed prompt for continuing our conversation above. Focus on information that would be helpful for continuing the conversation, including what we did, what we're doing, which files we're working on, and what we're going to do next considering new session will not have access to our conversation."
const promptText = compacting.prompt ?? [defaultPrompt, ...compacting.context].join("\n\n")
const result = await processor.process({
user: userMessage,
agent,
abort: input.abort,
sessionID: input.sessionID,
tools: {},
system: [],
messages: [
...MessageV2.toModelMessages(input.messages, model),
{
role: "user",
content: [
{
type: "text",
text: promptText,
},
],
},
],
model,
})
if (result === "continue" && input.auto) {
const continueMsg = await Session.updateMessage({
id: Identifier.ascending("message"),
role: "user",
sessionID: input.sessionID,
time: {
created: Date.now(),
},
agent: userMessage.agent,
model: userMessage.model,
})
await Session.updatePart({
id: Identifier.ascending("part"),
messageID: continueMsg.id,
sessionID: input.sessionID,
type: "text",
synthetic: true,
text: "Continue if you have next steps",
time: {
start: Date.now(),
end: Date.now(),
},
})
}
if (processor.message.error) return "stop"
Bus.publish(Event.Compacted, { sessionID: input.sessionID })
return "continue"
}
export const create = fn(
z.object({
sessionID: Identifier.schema("session"),
agent: z.string(),
model: z.object({
providerID: z.string(),
modelID: z.string(),
}),
auto: z.boolean(),
}),
async (input) => {
const msg = await Session.updateMessage({
id: Identifier.ascending("message"),
role: "user",
model: input.model,
sessionID: input.sessionID,
agent: input.agent,
time: {
created: Date.now(),
},
})
await Session.updatePart({
id: Identifier.ascending("part"),
messageID: msg.id,
sessionID: msg.sessionID,
type: "compaction",
auto: input.auto,
})
},
)
}