Auditor self-test branch: real-world pipelines + cohesion Phase C + KB index (PR #8)

Bundles 12 commits validating the auditor + scrum_master architecture end-to-end:

- enrich_prd_pipeline / hard_task_escalation / scrum_master_pipeline stress tests
- Tree-split + scrum_reviews.jsonl + kb_query surfacing
- Verdict → audit_lessons feedback loop (closed)
- kb_index aggregator with confidence-based severity policy
- 9-run + 5-run empirical tests proved the predictive-compounding property
- Level 1 correction: temp=0 cloud inference for deterministic per-claim verdicts
- audit_one.ts dry-run CLI
- Fixes: static quoted-string guard, empirical-claim classification, symbol-resolver gate, repo-file size cap

See PR #8 for run-by-run commit history.

auditor/checks/kb_query.ts

@@ -8,6 +8,7 @@
 // What this check reads (all file-backed, append-only or periodic):
 //   data/_kb/outcomes.jsonl         — per-scenario outcomes (kb.ts)
 //   data/_kb/error_corrections.jsonl — fail→succeed deltas on same sig
+//   data/_kb/scrum_reviews.jsonl     — scrum-master accepted reviews
 //   data/_observer/ops.jsonl         — observer ring → disk stream
 //   data/_bot/cycles/*.json          — bot cycle results
 //
@@ -17,14 +18,17 @@
 import { readFile, readdir, stat } from "node:fs/promises";
 import { join } from "node:path";
 import type { Claim, Finding } from "../types.ts";
+import { aggregate, ratingSeverity, formatAgg } from "../kb_index.ts";
 
 const KB_DIR = "/home/profit/lakehouse/data/_kb";
 const OBSERVER_OPS = "/home/profit/lakehouse/data/_observer/ops.jsonl";
 const BOT_CYCLES_DIR = "/home/profit/lakehouse/data/_bot/cycles";
+const SCRUM_REVIEWS_JSONL = "/home/profit/lakehouse/data/_kb/scrum_reviews.jsonl";
+const AUDIT_LESSONS_JSONL = "/home/profit/lakehouse/data/_kb/audit_lessons.jsonl";
 const TAIL_LINES = 500;
 const MAX_BOT_CYCLE_FILES = 30;
 
-export async function runKbCheck(claims: Claim[]): Promise<Finding[]> {
+export async function runKbCheck(claims: Claim[], prFiles: string[] = []): Promise<Finding[]> {
   const findings: Finding[] = [];
 
   // 1. Recent scenario outcomes: are strong-claim-style phrases showing
@@ -48,6 +52,27 @@ export async function runKbCheck(claims: Claim[]): Promise<Finding[]> {
   const obsFindings = await checkObserverStream();
   findings.push(...obsFindings);
 
+  // 5. Scrum-master reviews — surface prior accepted reviews for any
+  //    file in this PR's diff. Cohesion plan Phase C wire: the
+  //    auditor gets to "borrow" the scrum-master's deeper per-file
+  //    analysis instead of re-doing that work.
+  if (prFiles.length > 0) {
+    const scrumFindings = await checkScrumReviews(prFiles);
+    findings.push(...scrumFindings);
+  }
+
+  // 6. Audit-lessons feedback loop — summarize the top recurring
+  //    patterns from prior audits' block/warn findings. If the same
+  //    pattern signature has fired 3+ times across prior audits,
+  //    emit it as a block-severity finding so reviewers know this
+  //    is a known-recurring class, not a one-off. Does NOT couple
+  //    to the current audit's static/inference findings (those run
+  //    in parallel and we can't see them here) — the amplification
+  //    is emergent: if the current audit's finding-summary matches
+  //    a top recurrence, the reviewer sees both.
+  const auditLessonFindings = await checkAuditLessons();
+  findings.push(...auditLessonFindings);
+
   return findings;
 }
 
@@ -181,3 +206,90 @@ function observerBySource(ops: any[]): string {
   }
   return Object.entries(c).sort((a, b) => b[1] - a[1]).map(([k, v]) => `${k}=${v}`).join(", ") || "empty";
 }
+
+// Audit-lessons — reads data/_kb/audit_lessons.jsonl (populated by
+// every audit's appendAuditLessons). Uses the shared kb_index
+// aggregator: groups by `signature`, distinct-scopes keyed by PR
+// number, severity from ratingSeverity(agg) which applies the
+// confidence × count rating (see kb_index.ts). This is the same
+// aggregation any other KB reader uses — shared discipline, not
+// per-check custom logic.
+async function checkAuditLessons(): Promise<Finding[]> {
+  const bySig = await aggregate<any>(AUDIT_LESSONS_JSONL, {
+    keyFn: (r) => r?.signature,
+    scopeFn: (r) => (r?.pr_number !== undefined ? `pr-${r.pr_number}` : undefined),
+    checkFn: (r) => r?.check,
+    tailLimit: TAIL_LINES * 4,
+  });
+  if (bySig.size === 0) return [];
+
+  const findings: Finding[] = [];
+  for (const [sig, agg] of bySig) {
+    // Silent on first-ever occurrence — not yet signal.
+    if (agg.count < 2) continue;
+    const sev = ratingSeverity(agg);
+    findings.push({
+      check: "kb_query",
+      severity: sev,
+      summary: `recurring audit pattern (${agg.distinct_scopes} distinct PRs, ${agg.count} flaggings, conf=${agg.confidence.toFixed(2)}): ${agg.representative_summary.slice(0, 160)}`,
+      evidence: [
+        `signature=${sig}`,
+        `checks: ${agg.checks.join(",")}`,
+        `scopes: ${agg.scopes.slice(-6).join(",")}`,
+        formatAgg(agg),
+      ],
+    });
+  }
+  return findings;
+}
+
+// Scrum-master reviews — the scrum pipeline writes one row per
+// accepted per-file review. We match reviews whose `file` matches
+// any path in the PR's diff, then surface the *preview* + which
+// model the escalation ladder had to reach. If the scrum-master
+// needed the 123B specialist or larger to resolve a file, that's
+// a meaningful signal about the code's complexity — and it's
+// surfaced to the PR without the auditor having to re-run the
+// escalation ladder itself.
+async function checkScrumReviews(prFiles: string[]): Promise<Finding[]> {
+  const rows = await tailJsonl<any>(SCRUM_REVIEWS_JSONL, TAIL_LINES);
+  if (rows.length === 0) return [];
+
+  // Match by exact file OR filename suffix — PR files arrive as
+  // `auditor/audit.ts`-style relative paths; scrum stores the same.
+  const norm = (p: string) => p.replace(/^\/+/, "").replace(/^home\/profit\/lakehouse\//, "");
+  const prSet = new Set(prFiles.map(norm));
+
+  // Keep only the most recent review per file (last-wins).
+  const latestByFile = new Map<string, any>();
+  for (const r of rows) {
+    const f = norm(String(r.file ?? ""));
+    if (!f) continue;
+    if (!prSet.has(f)) continue;
+    latestByFile.set(f, r);
+  }
+  if (latestByFile.size === 0) return [];
+
+  const findings: Finding[] = [];
+  for (const [file, r] of latestByFile) {
+    const model = String(r.accepted_model ?? "?");
+    const attempt = r.accepted_on_attempt ?? "?";
+    const treeSplit = !!r.tree_split_fired;
+    // Heuristic: if the scrum-master had to escalate past attempt 3,
+    // or had to tree-split, that's context the PR reviewer should see.
+    // Severity: info for low-escalation, warn if escalated far up
+    // the ladder (cloud specialist required).
+    const heavyEscalation = Number(attempt) >= 4;
+    const sev: "warn" | "info" = heavyEscalation ? "warn" : "info";
+    findings.push({
+      check: "kb_query",
+      severity: sev,
+      summary: `scrum-master review for \`${file}\` — accepted on attempt ${attempt} by \`${model}\`${treeSplit ? " (tree-split)" : ""}`,
+      evidence: [
+        `reviewed_at: ${r.reviewed_at ?? "?"}`,
+        `preview: ${String(r.suggestions_preview ?? "").slice(0, 300).replace(/\n/g, " ")}`,
+      ],
+    });
+  }
+  return findings;
+}