feat(miner): AMS min-rank calibration loop over the local event ledger

packages/loopover-engine/src/ams-policy-spec.ts

@@ -105,6 +105,10 @@ export type AmsPolicySpec = {
    *  -- no additions beyond the always-on OS-registry/git-remote defaults. INERT until #7857's OS-level
    *  enforcement mechanism is built; see {@link AmsNetworkAllowlist}'s own doc comment. */
   networkAllowlist: AmsNetworkAllowlist;
+  /** Whether the min-rank skip threshold may self-adjust from backtest evidence (#8187, epic #8172). The
+   *  FIRST of the double gates: with this OFF (the default) the apply/revert commands refuse and any
+   *  previously-applied override reads as absent; the second gate is the per-apply `--approve` flag. */
+  minRankAutotuneEnabled: boolean;
 };
 
 /** The tolerant parser result for `.loopover-ams.yml`. Mirrors `ParsedMinerGoalSpec`'s present/warnings shape. */
@@ -127,6 +131,7 @@ export const DEFAULT_AMS_POLICY_SPEC: Readonly<AmsPolicySpec> = Object.freeze({
   maxTurnsPerIteration: 6,
   selfLoopAutonomy: "auto",
   networkAllowlist: Object.freeze({ ecosystems: [], extraHosts: [] }),
+  minRankAutotuneEnabled: false,
 });
 
 const MAX_AMS_POLICY_SPEC_BYTES = 8_192;
@@ -144,13 +149,21 @@ function cloneDefaultAmsPolicySpec(): AmsPolicySpec {
       ecosystems: [...DEFAULT_AMS_POLICY_SPEC.networkAllowlist.ecosystems],
       extraHosts: [...DEFAULT_AMS_POLICY_SPEC.networkAllowlist.extraHosts],
     },
+    minRankAutotuneEnabled: DEFAULT_AMS_POLICY_SPEC.minRankAutotuneEnabled,
   };
 }
 
 function emptyAmsPolicySpec(warnings: string[] = []): ParsedAmsPolicySpec {
   return { present: false, spec: cloneDefaultAmsPolicySpec(), warnings };
 }
 
+function normalizeBooleanFlag(value: unknown, field: string, fallback: boolean, warnings: string[]): boolean {
+  if (value === undefined || value === null) return fallback;
+  if (typeof value === "boolean") return value;
+  warnings.push(`AmsPolicySpec field "${field}" must be a boolean; falling back to ${fallback}.`);
+  return fallback;
+}
+
 function normalizeSubmissionMode(value: unknown, fallback: AmsSubmissionMode, warnings: string[]): AmsSubmissionMode {
   if (value === undefined || value === null) return fallback;
   if (value === "observe" || value === "enforce") return value;
@@ -307,7 +320,8 @@ function hasConfiguredPolicyFields(spec: AmsPolicySpec): boolean {
     // means the operator configured something, so length alone is the right "differs from default" check;
     // no need to compare contents.
     spec.networkAllowlist.ecosystems.length > 0 ||
-    spec.networkAllowlist.extraHosts.length > 0
+    spec.networkAllowlist.extraHosts.length > 0 ||
+    spec.minRankAutotuneEnabled !== DEFAULT_AMS_POLICY_SPEC.minRankAutotuneEnabled
   );
 }
 
@@ -356,6 +370,12 @@ export function parseAmsPolicySpec(raw: unknown): ParsedAmsPolicySpec {
       warnings,
     ),
     networkAllowlist: normalizeNetworkAllowlist(record.networkAllowlist, DEFAULT_AMS_POLICY_SPEC.networkAllowlist, warnings),
+    minRankAutotuneEnabled: normalizeBooleanFlag(
+      record.minRankAutotuneEnabled,
+      "minRankAutotuneEnabled",
+      DEFAULT_AMS_POLICY_SPEC.minRankAutotuneEnabled,
+      warnings,
+    ),
   };
   if (!hasConfiguredPolicyFields(spec)) {
     warnings.push("AmsPolicySpec contained no recognized non-default policy fields; falling back to safe defaults.");

packages/loopover-engine/src/calibration/ams-rank-corpus.ts

@@ -0,0 +1,107 @@
+// AMS min-rank corpus + advisory backtest (#8184, epic #8172 phase 2) -- the miner-side twin of the ORB
+// threshold backtest (#8138), over the miner's OWN taken-opportunity history instead of ORB signal events.
+// The opportunity ranker's score is an equal-weight clamped product in [0, 1] (opportunity-ranker.ts -- no
+// scalar weights), so the SKIP THRESHOLD is the tunable, and the counterfactual question is: "had the
+// min-rank floor been X, which taken opportunities would have been skipped, and were those the ones that
+// went badly?" Labels come from realized outcomes: a MERGED take was a good take (label "confirmed"); a
+// CLOSED take was a bad one -- skipping it would have been right (label "reversed"). That polarity lines
+// up exactly with buildConfidenceThresholdClassifier's positive class ("predicted reversed" when the score
+// sits below the threshold), so the whole ORB replay stack -- splitBacktestCorpus, runThresholdBacktest's
+// scoreBacktest + compareBacktestScores Pareto floor -- is reused untouched, zero new math.
+//
+// Same purity contract as the rest of this module family: no IO, no randomness, no wall-clock reads.
+
+import type { BacktestCase } from "./backtest-corpus.js";
+import type { BacktestComparison } from "./backtest-compare.js";
+import { runThresholdBacktest } from "./backtest-threshold.js";
+import { splitBacktestCorpus } from "./backtest-split.js";
+
+/** The synthetic rule id AMS min-rank replay cases carry (namespaced away from every ORB rule id). */
+export const AMS_MIN_RANK_RULE_ID = "ams_min_rank_skip";
+
+// The #8121 split discipline transposed: a fixed seed so held-out membership never reshuffles between
+// evaluations, and never-on-noise sample floors sized like the satisfaction floor's (the miner's local
+// history is closer to that corpus's scale than to the AI knob's firehose).
+export const AMS_MIN_RANK_SPLIT_SEED = "ams-min-rank-skip-v1";
+export const AMS_MIN_RANK_HELD_OUT_FRACTION = 0.25;
+export const AMS_MIN_RANK_MIN_VISIBLE_CASES = 20;
+export const AMS_MIN_RANK_MIN_HELD_OUT_CASES = 5;
+
+/** One taken opportunity with a realized terminal outcome -- the join of a `discovered_issue` rank record
+ *  and the miner's own `pr_outcome` for the PR that issue produced. Assembled miner-side (the ledger join
+ *  lives in @loopover/miner's ams-calibration module); this module only replays. */
+export type AmsTakenOpportunity = {
+  repoFullName: string;
+  issueNumber: number;
+  /** The ranker's clamped-product score at discovery time, in [0, 1]. */
+  rankScore: number;
+  realizedDecision: "merged" | "closed";
+  /** When the opportunity was discovered/ranked (ISO). */
+  discoveredAt: string;
+  /** When the terminal outcome was recorded (ISO). */
+  decidedAt: string;
+};
+
+/**
+ * Shape taken opportunities into {@link BacktestCase}s for the min-rank replay: `metadata.confidence`
+ * carries the rank score (the value the threshold classifier replays against), a CLOSED take labels
+ * "reversed" (skipping would have been right), a MERGED take labels "confirmed". Records with a
+ * non-finite or out-of-[0,1] rank score are dropped -- a case the classifier cannot honestly replay must
+ * not default to confidence 1. Deterministic order (repo#issue, then discoveredAt), so downstream splits
+ * see a stable corpus.
+ */
+export function buildAmsRankCorpus(takes: readonly AmsTakenOpportunity[]): BacktestCase[] {
+  const cases: BacktestCase[] = [];
+  for (const take of takes) {
+    if (!Number.isFinite(take.rankScore) || take.rankScore < 0 || take.rankScore > 1) continue;
+    cases.push({
+      ruleId: AMS_MIN_RANK_RULE_ID,
+      targetKey: `${take.repoFullName}#issue-${take.issueNumber}`,
+      outcome: "take",
+      label: take.realizedDecision === "closed" ? "reversed" : "confirmed",
+      firedAt: take.discoveredAt,
+      decidedAt: take.decidedAt,
+      metadata: { confidence: take.rankScore },
+    });
+  }
+  cases.sort((left, right) => {
+    const key = left.targetKey.localeCompare(right.targetKey);
+    return key !== 0 ? key : left.firedAt.localeCompare(right.firedAt);
+  });
+  return cases;
+}
+
+export type AmsMinRankBacktestResult = {
+  ruleId: string;
+  currentThreshold: number;
+  candidateThreshold: number;
+  visibleCases: number;
+  heldOutCases: number;
+  visible: BacktestComparison;
+  heldOut: BacktestComparison;
+};
+
+/**
+ * Advisory replay of a candidate min-rank skip threshold against the taken-opportunity corpus -- the
+ * #8138 discipline verbatim: the fixed-seed split, then {@link runThresholdBacktest} (scoreBacktest +
+ * the symmetric compareBacktestScores Pareto floor, per #8184's required pattern) on EACH slice. Null --
+ * never a guess -- when either slice misses its sample floor. Report-only by construction: this function
+ * returns comparisons; it never moves a knob.
+ */
+export function runAmsMinRankBacktest(
+  cases: readonly BacktestCase[],
+  currentThreshold: number,
+  candidateThreshold: number,
+): AmsMinRankBacktestResult | null {
+  const { visible, heldOut } = splitBacktestCorpus(cases, AMS_MIN_RANK_HELD_OUT_FRACTION, AMS_MIN_RANK_SPLIT_SEED);
+  if (visible.length < AMS_MIN_RANK_MIN_VISIBLE_CASES || heldOut.length < AMS_MIN_RANK_MIN_HELD_OUT_CASES) return null;
+  return {
+    ruleId: AMS_MIN_RANK_RULE_ID,
+    currentThreshold,
+    candidateThreshold,
+    visibleCases: visible.length,
+    heldOutCases: heldOut.length,
+    visible: runThresholdBacktest(AMS_MIN_RANK_RULE_ID, visible, currentThreshold, candidateThreshold),
+    heldOut: runThresholdBacktest(AMS_MIN_RANK_RULE_ID, heldOut, currentThreshold, candidateThreshold),
+  };
+}

packages/loopover-engine/src/index.ts

@@ -166,6 +166,7 @@ export * from "./calibration/signal-tracking.js";
 export * from "./calibration/backtest-corpus.js";
 export * from "./calibration/repo-corpus-slice.js";
 export * from "./calibration/ams-prediction-corpus.js";
+export * from "./calibration/ams-rank-corpus.js";
 export * from "./calibration/counterfactual-contract.js";
 export * from "./calibration/counterfactual-fixtures.js";
 export * from "./calibration/backtest-score.js";

packages/loopover-engine/test/ams-rank-corpus.test.ts

@@ -0,0 +1,30 @@
+import assert from "node:assert/strict";
+import { test } from "node:test";
+
+import { AMS_MIN_RANK_RULE_ID, buildAmsRankCorpus, runAmsMinRankBacktest, type AmsTakenOpportunity } from "../dist/index.js";
+
+function take(issueNumber: number, rankScore: number, realizedDecision: "merged" | "closed"): AmsTakenOpportunity {
+  return {
+    repoFullName: "acme/widgets",
+    issueNumber,
+    rankScore,
+    realizedDecision,
+    discoveredAt: "2026-07-01T00:00:00.000Z",
+    decidedAt: "2026-07-02T00:00:00.000Z",
+  };
+}
+
+test("barrel: the public entrypoint re-exports the AMS min-rank corpus + backtest (#8184)", () => {
+  assert.equal(typeof buildAmsRankCorpus, "function");
+  assert.equal(typeof runAmsMinRankBacktest, "function");
+  assert.equal(AMS_MIN_RANK_RULE_ID, "ams_min_rank_skip");
+});
+
+test("runAmsMinRankBacktest: a raise that skips exactly the bad takes is improved on both slices", () => {
+  const takes = Array.from({ length: 60 }, (_, i) => take(i + 1, 0.15, "closed"));
+  takes.push(take(101, 0.4, "merged"), take(102, 0.4, "merged"));
+  const result = runAmsMinRankBacktest(buildAmsRankCorpus(takes), 0, 0.2);
+  assert.ok(result);
+  assert.equal(result.visible.verdict, "improved");
+  assert.equal(result.heldOut.verdict, "improved");
+});

packages/loopover-miner/docs/miner-selfimprove-calibration.md

@@ -110,6 +110,30 @@ From any contributor-safe tool in this batch:
   auto-tune hold-only flag, or any autonomy configuration.
 - **No de-anonymizing or write-capable telemetry** — local-only or HMAC-anonymized, read-only.
 
+## The min-rank calibration loop (#8172: #8184-#8187)
+
+The first knob to graduate past measure-only: the **min-rank skip threshold** (portfolio-discovery's
+`minRankScore`, shipped default 0). The loop is the ORB backtest discipline transposed onto the miner's own
+event ledger, end to end:
+
+1. **Corpus** — `discovered_issue` rank records joined to the miner's own `pr_outcome` events by
+   `(repo, issueNumber)` (the pairing rides on outcome rows written since #8184; older rows never join). A
+   MERGED take labels `confirmed`, a CLOSED take labels `reversed` — "skipping it would have been right".
+2. **Advisory backtest** — `loopover-miner calibration backtest-threshold --candidate <x>`: fixed-seed
+   held-out split, Pareto floor via `compareBacktestScores`, rendered with the shared comparison renderer,
+   persisted as an `ams_threshold_backtest_run` ledger event. Exit code never reflects the verdict.
+3. **Track record + proposals** — the calibration report prints the REGRESSED-verdict track record over
+   every persisted run (`computeRegressedVerdictTrackRecord`, the same aggregation ORB uses) and any
+   backtest-cleared proposals; `doctor` mirrors the proposals line. Display only.
+4. **Double-gated self-adjustment (#8187)** — `calibration apply-min-rank --candidate <x> --approve`
+   moves the knob ONLY when: `.loopover-ams.yml` sets `minRankAutotuneEnabled: true` (gate one, default
+   OFF), the per-apply `--approve` is passed (gate two), the candidate sits inside the hard bounds
+   `(0, 0.5]` declared next to the shipped constant, AND a recent persisted run actually cleared that exact
+   candidate — evidence is not optional. Every apply/revert is a typed ledger event carrying the evidence;
+   `calibration revert-min-rank --approve` is the one-command revert. Consumption happens at exactly one
+   point (discover's enqueue), re-validating bounds and the flag on every read, so flipping the flag off
+   restores the shipped default on the very next run.
+
 ## The neighborhood
 
 - Contributor-safe (this batch): drift detector, calibration dashboard + extension panel, prediction ledger, metrics