Actually vendor harness

2026-09-11 13:41:22 -04:00
parent 1acd371668
commit 04e013b090
52 changed files with 8550 additions and 1 deletions
@@ -0,0 +1,273 @@
+/**
+ * Context compaction: heuristic fallback + optional one-shot LLM summary.
+ */
+
+const truncate = require('./truncate.js');
+
+const CHAR_PER_TOKEN = 3;
+const THRESHOLD = 0.68;
+const MIN_SUMMARY = 80;
+const COMPACT_PROMPT =
+  'Summarize this coding-agent conversation. Use exactly these sections:\n' +
+  '1. Goal\n' +
+  '2. Done\n' +
+  '3. Files / decisions\n' +
+  '4. Open work\n' +
+  '5. Next action\n' +
+  'Be specific (paths, names, errors). Do not say the conversation was compacted.';
+
+function contentChars(content) {
+  if (content == null) return 0;
+  if (typeof content === 'string') return content.length;
+  if (Array.isArray(content)) {
+    let n = 0;
+    for (let i = 0; i < content.length; i++) {
+      const p = content[i];
+      if (p == null) continue;
+      if (typeof p === 'string') n += p.length;
+      else if (p.text) n += String(p.text).length;
+      else if (p.type === 'image_url' || p.image_url) n += 1600;
+      else n += JSON.stringify(p).length;
+    }
+    return n;
+  }
+  return JSON.stringify(content).length;
+}
+
+function messageChars(m) {
+  if (!m) return 0;
+  let n = contentChars(m.content);
+  if (m.tool_calls) n += JSON.stringify(m.tool_calls).length;
+  if (m.name) n += String(m.name).length;
+  return n + 8;
+}
+
+function estimateTokens(messages, tools) {
+  let n = 0;
+  for (const m of messages || []) n += messageChars(m);
+  n += JSON.stringify(tools || []).length;
+  return Math.ceil(n / CHAR_PER_TOKEN);
+}
+
+function historyBudget(ctxSize, tools, attempt) {
+  const cap = ctxSize > 0 ? Number(ctxSize) : 8192;
+  const toolTok = Math.ceil(JSON.stringify(tools || []).length / CHAR_PER_TOKEN);
+  const reserve = Math.max(384, Math.floor(cap * (0.18 + (Number(attempt) || 0) * 0.08)));
+  return Math.max(240, Math.floor(cap * 0.72) - toolTok - reserve);
+}
+
+function shouldCompact(messages, tools, ctxSize) {
+  const cap = ctxSize > 0 ? ctxSize : 8192;
+  return estimateTokens(messages, tools) > Math.floor(cap * THRESHOLD);
+}
+
+function isOverflowError(err) {
+  const s = String((err && err.message) || err || '');
+  return /context window|context.?length|too many tokens|maximum context|prompt too (?:long|large)|prompt exceeds|ContextOverflow|reduce the prompt size/i.test(
+    s
+  );
+}
+
+function usage(messages, tools, ctxSize) {
+  return snapshot(estimateTokens(messages, tools), ctxSize);
+}
+
+function snapshot(used, ctxSize) {
+  const limit = ctxSize > 0 ? Number(ctxSize) : 8192;
+  const n = Math.max(0, Math.round(Number(used) || 0));
+  const pct = limit ? Math.min(100, Math.round((n / limit) * 1000) / 10) : 0;
+  return {
+    used: n,
+    limit,
+    pct,
+    threshold: Math.round(THRESHOLD * 100),
+    over: n > Math.floor(limit * THRESHOLD),
+  };
+}
+
+function isDegenerate(summary) {
+  const s = String(summary || '').trim();
+  if (s.length < MIN_SUMMARY) return true;
+  if (/conversation compacted/i.test(s)) return true;
+  if (/^\s*\[earlier conversation compacted\]\s*$/i.test(s)) return true;
+  return false;
+}
+
+function isRealUser(m) {
+  if (!m || m.role !== 'user') return false;
+  const c = String(m.content || '');
+  if (c.indexOf('<system-reminder>') >= 0) return false;
+  if (c.indexOf('[conversation summary]') >= 0) return false;
+  if (c.indexOf('[memory]') === 0) return false;
+  if (c.indexOf('[git status]') === 0) return false;
+  return true;
+}
+
+function rebuildHistory(messages, summary) {
+  const list = Array.isArray(messages) ? messages : [];
+  const sys =
+    list[0] && list[0].role === 'system'
+      ? { role: 'system', content: list[0].content }
+      : { role: 'system', content: '' };
+  let lastUser = null;
+  for (let i = list.length - 1; i >= 0; i--) {
+    if (isRealUser(list[i])) {
+      lastUser = { role: 'user', content: list[i].content };
+      break;
+    }
+  }
+  const tail = [];
+  for (let i = list.length - 1; i >= 1 && tail.length < 6; i--) {
+    const m = list[i];
+    if (!m || m.role === 'system') continue;
+    if (lastUser && m.role === 'user' && m.content === lastUser.content) continue;
+    tail.unshift({ role: m.role, content: m.content, name: m.name, tool_call_id: m.tool_call_id });
+  }
+  const out = [sys, { role: 'user', content: '[conversation summary]\n' + String(summary || '').trim() }];
+  if (lastUser) out.push(lastUser);
+  return out.concat(tail);
+}
+
+function truncateMsg(m, maxChars) {
+  if (!m) return m;
+  const copy = Object.assign({}, m);
+  const c = copy.content;
+  if (typeof c === 'string' && c.length > maxChars) {
+    copy.content = truncate.truncateWithMarker(c, maxChars);
+  } else if (Array.isArray(c)) {
+    copy.content = c.map((part) => {
+      if (!part || typeof part !== 'object') return part;
+      if (typeof part.text === 'string' && part.text.length > maxChars) {
+        return Object.assign({}, part, { text: truncate.truncateWithMarker(part.text, maxChars) });
+      }
+      return part;
+    });
+  }
+  return copy;
+}
+
+function lastRealUserIndex(list) {
+  for (let i = list.length - 1; i >= 0; i--) {
+    if (isRealUser(list[i])) return i;
+  }
+  return -1;
+}
+
+function heuristicCompact(messages, opts) {
+  opts = opts || {};
+  const budget = opts.budgetTokens || 6000;
+  const aggressive = !!opts.aggressive;
+  let keep = messages.slice();
+  while (estimateTokens(keep, opts.tools) > budget && keep.length > 4) {
+    let idx = keep.findIndex((m, i) => i > 0 && m.role === 'tool');
+    if (idx < 0) idx = keep.findIndex((m, i) => i > 1 && m.role === 'assistant');
+    if (idx < 0) break;
+    keep.splice(idx, 1);
+  }
+  const maxMsg = aggressive ? 1200 : 3200;
+  if (estimateTokens(keep, opts.tools) > budget) {
+    const lastUser = lastRealUserIndex(keep);
+    keep = keep.map((m, i) => (i === 0 || i === lastUser ? m : truncateMsg(m, maxMsg)));
+  }
+  if (estimateTokens(keep, opts.tools) > budget && keep.length > 3) {
+    const head = keep[0];
+    const lastUserIdx = lastRealUserIndex(keep);
+    const lastUser = lastUserIdx >= 0 ? keep[lastUserIdx] : null;
+    const tail = [];
+    for (let i = keep.length - 1; i >= 1 && tail.length < (aggressive ? 2 : 4); i--) {
+      if (i === lastUserIdx) continue;
+      tail.unshift(keep[i]);
+    }
+    keep = [head, { role: 'user', content: '[conversation summary]\nEarlier turns were compacted to fit the model window.' }];
+    if (lastUser) keep.push(lastUser);
+    keep = keep.concat(tail);
+    keep = keep.map((m, i) => (i === 0 ? m : truncateMsg(m, aggressive ? 700 : 1800)));
+  }
+  while (estimateTokens(keep, opts.tools) > budget && keep.length > 3) {
+    const dropAt = keep.findIndex((m, i) => i > 1 && !isRealUser(m));
+    if (dropAt < 0) break;
+    keep.splice(dropAt, 1);
+  }
+  return keep;
+}
+
+function compact(messages, opts) {
+  return heuristicCompact(messages, opts);
+}
+
+function transcript(messages) {
+  return (messages || [])
+    .map((m) => {
+      const role = m && m.role ? m.role : 'unknown';
+      const name = m && m.name ? ' ' + m.name : '';
+      return role + name + ':\n' + String(m && m.content != null ? m.content : '');
+    })
+    .join('\n\n');
+}
+
+function autoContinue(messages) {
+  const list = messages || [];
+  const last = list[list.length - 1];
+  if (!last) return null;
+  if (last.role === 'tool' || last.role === 'assistant') {
+    return {
+      role: 'user',
+      content:
+        '<system-reminder>\nContinue the work from the summary. Do not wait for a new user request.\n</system-reminder>',
+    };
+  }
+  return null;
+}
+
+function compactReminder() {
+  return (
+    '<system-reminder>\n' +
+    'Context was compacted. Trust the summary and the last user request. Re-read files before further edits. Follow AGENTS.md if present.\n' +
+    '</system-reminder>'
+  );
+}
+
+async function compactWithLlm(messages, opts) {
+  opts = opts || {};
+  const fallback = () => heuristicCompact(messages, opts);
+  const complete = opts.complete;
+  if (typeof complete !== 'function') return fallback();
+  const cap =
+    opts.maxTranscriptChars ||
+    Math.max(1500, Math.min(24000, Math.floor((opts.budgetTokens || 4000) * CHAR_PER_TOKEN * 0.45)));
+  const body = truncate.truncateWithMarker(transcript(messages), cap);
+  try {
+    const result = await complete({
+      history: [
+        { role: 'system', content: 'Reply with the five summary sections only. No tools.' },
+        { role: 'user', content: COMPACT_PROMPT + '\n\n---\n\n' + body },
+      ],
+      tools: [],
+    });
+    const summary = result && result.text;
+    if (isDegenerate(summary)) return fallback();
+    return rebuildHistory(messages, summary);
+  } catch (_) {
+    return fallback();
+  }
+}
+
+module.exports = {
+  CHAR_PER_TOKEN,
+  THRESHOLD,
+  MIN_SUMMARY,
+  COMPACT_PROMPT,
+  estimateTokens,
+  historyBudget,
+  shouldCompact,
+  isOverflowError,
+  usage,
+  snapshot,
+  isDegenerate,
+  rebuildHistory,
+  heuristicCompact,
+  compact,
+  autoContinue,
+  compactReminder,
+  compactWithLlm,
+};