eve/dist/src/harness/compaction.js

Filesystem-first framework for durable backend AI agents that run anywhere.

import{generateText}from"ai";const COMPACTION_SYSTEM_PROMPT=[`You are a conversation summarizer.`,`Write a concise but useful summary for continuing the work.`,`Preserve the goal, important instructions, technical decisions, discoveries, open work, and relevant tool results.`,`Use the same language as the conversation.`,`Prefer short labeled sections such as Goal, Instructions, Discoveries, Accomplished, and Next steps when helpful.`,`Do not answer questions or invent facts.`].join(` `);function estimateTokens(e){return JSON.stringify(e).length/4}function getInputTokenCount(e,t){let n=t.lastKnownInputTokens,r=t.lastKnownPromptMessageCount;return n===void 0||r===void 0||!Number.isInteger(r)||r<0||r>e.length?estimateTokens(e):n+estimateTokens(e.slice(r))}function shouldCompact(e,t){return getInputTokenCount(e,t)>t.threshold}async function resolveCompactionModel(e){let t=e.compactionModelReference??e.modelReference;return{model:t===e.modelReference?e.model:await e.resolveModel(t),providerOptions:t.providerOptions}}async function compactMessages(n,r,i,a,o,s){let c=selectRecentWindowSize(n,i);for(;;){let{older:l,recent:u}=splitMessagesForCompaction(n,c);if(l.length===0)return keepNonToolResultMessages(u);let d=await generateText({headers:s,model:r,prompt:formatCompactionPrompt(l.map(e=>({content:summarizeCompactionMessageContent(e),role:e.role}))),providerOptions:a,system:COMPACTION_SYSTEM_PROMPT,telemetry:o?{...o,functionId:`eve.compaction`}:void 0,temperature:0}),f=keepNonToolResultMessages(u),p=f.at(-1)?.role,m=p===void 0||p===`assistant`?[{role:`user`,content:`Continue.`}]:[],h=[{content:`Summary of our conversation so far:`,role:`user`},{content:d.text,role:`assistant`},...f,...m];if(estimateTokens(h)<=i.threshold||c===0)return h;--c}}function keepNonToolResultMessages(e){let t=[];for(let n of e)if(n.role!==`tool`){if(n.role===`assistant`){let e=assistantMessageText(n);e.length>0&&t.push({content:e,role:`assistant`});continue}t.push(n)}return t}function assistantMessageText(e){return typeof e.content==`string`?e.content.trim():e.content.filter(e=>e.type===`text`).map(e=>e.text).join(``).trim()}function selectRecentWindowSize(e,t){let n=Math.min(t.recentWindowSize,Math.max(e.length-1,0)),r=resolveCompactionSummaryReserve(t),i=0,a=0;for(let o=e.length-1;o>=0&&i<n;--o){let n=e[o];if(n===void 0)continue;let s=estimateTokens([n]);if(a+s+r>t.threshold)break;a+=s,i+=1}return i}function resolveCompactionSummaryReserve(e){return Math.min(2048,Math.max(64,Math.floor(e.threshold/4)))}function splitMessagesForCompaction(e,t){return t<=0?{older:[...e],recent:[]}:{older:e.slice(0,-t),recent:e.slice(-t)}}function formatCompactionPrompt(e){let t=e.filter(e=>e.content.trim().length>0).map(e=>`### ${e.role}\n${e.content.trim()}`);return t.length===0?`Summarize the conversation so far.`:[`Conversation transcript:`,...t].join(`

`)}function summarizeCompactionMessageContent(e){return typeof e.content==`string`?summarizeText(e.content):e.content.map(e=>summarizeCompactionContentPart(e)).filter(e=>e.length>0).join(`
`).trim()}function summarizeCompactionContentPart(e){switch(e.type){case`text`:return summarizeText(e.text);case`reasoning`:return``;case`file`:return e.filename?`Attached file ${e.filename} (${e.mediaType})`:`Attached file attachment (${e.mediaType})`;case`tool-call`:return summarizeToolCallPart(e);case`tool-result`:return summarizeToolResultPart(e);default:return``}}function summarizeToolCallPart(e){let t=e.input===void 0?``:summarizeCompactValue(e.input);return t?`Called ${e.toolName} with ${t}`:`Called ${e.toolName}`}function summarizeToolResultPart(e){let t=e.output===void 0?``:summarizeCompactValue(e.output),n=e.isError?`errored`:`returned`;return t?`Tool ${e.toolName} ${n} ${t}`:`Tool ${e.toolName} ${n}`}function summarizeCompactValue(e,t=0){if(e===null)return`null`;if(e===void 0)return``;if(typeof e==`string`)return summarizeText(e);if(typeof e==`number`||typeof e==`boolean`||typeof e==`bigint`)return String(e);if(Array.isArray(e)){if(e.length===0)return`array(0)`;if(t>=2)return`array(${e.length})`;let n=e.slice(0,3).map(e=>summarizeCompactValue(e,t+1)),r=e.length>3?`, …`:``;return`array(${e.length}: ${n.join(`, `)}${r})`}if(typeof e==`object`){let n=Object.entries(e);if(n.length===0)return`object(0)`;if(t>=2)return`object(${n.length} keys)`;let r=n.slice(0,3).map(([e,n])=>`${e}=${summarizeCompactValue(n,t+1)}`),i=n.length>3?`, …`:``;return`object(${r.join(`, `)}${i})`}return``}function summarizeText(e){let t=e.replace(/\s+/g,` `).trim();return t.length<=280?t:`${t.slice(0,280).trimEnd()}…`}export{compactMessages,estimateTokens,getInputTokenCount,resolveCompactionModel,shouldCompact};