feat(quality-rails): typed evaluator core — statuses, digested definitions, per-subject sets (#1275)

packages/quality-rails/src/evaluator/adapter.ts

@@ -0,0 +1,67 @@
+import { spawn } from 'node:child_process';
+import type { ChildProcess } from 'node:child_process';
+
+import type { AdapterOutcome, AdapterRequest, ProcessAdapter } from './types.js';
+
+/**
+ * Default thin process adapter (spawn-based). Runs a command to completion with
+ * a hard timeout and reports exit code + captured output — it owns NO verdict
+ * logic. Interpreting the outcome is always the check implementation's job.
+ */
+export function createSpawnProcessAdapter(): ProcessAdapter {
+  return {
+    run(request: AdapterRequest): Promise<AdapterOutcome> {
+      return new Promise((resolve) => {
+        let child: ChildProcess;
+        try {
+          child = spawn(request.file, request.args, {
+            cwd: request.cwd,
+            stdio: ['ignore', 'pipe', 'pipe'],
+          });
+        } catch (error) {
+          resolve({
+            ok: false,
+            kind: 'spawn-error',
+            message: error instanceof Error ? error.message : String(error),
+          });
+          return;
+        }
+
+        let stdout = '';
+        let stderr = '';
+        let settled = false;
+
+        const timer = setTimeout(() => {
+          if (settled) return;
+          settled = true;
+          child.kill('SIGKILL');
+          resolve({
+            ok: false,
+            kind: 'timeout',
+            message: `process timed out after ${request.timeoutMs}ms: ${request.file}`,
+          });
+        }, request.timeoutMs);
+
+        const settle = (outcome: AdapterOutcome): void => {
+          if (settled) return;
+          settled = true;
+          clearTimeout(timer);
+          resolve(outcome);
+        };
+
+        child.stdout?.on('data', (chunk: Buffer) => {
+          stdout += chunk.toString('utf8');
+        });
+        child.stderr?.on('data', (chunk: Buffer) => {
+          stderr += chunk.toString('utf8');
+        });
+        child.on('error', (error: Error) => {
+          settle({ ok: false, kind: 'spawn-error', message: error.message });
+        });
+        child.on('close', (code: number | null) => {
+          settle({ ok: true, exitCode: code, stdout, stderr });
+        });
+      });
+    },
+  };
+}

packages/quality-rails/src/evaluator/definitions.ts

@@ -0,0 +1,258 @@
+import { constants } from 'node:fs';
+import { access } from 'node:fs/promises';
+import { isAbsolute, resolve } from 'node:path';
+
+import { digestOfPolicy, digestOfSpec } from './digest.js';
+import type {
+  CheckContext,
+  CheckDefinition,
+  CheckDefinitionSpec,
+  CheckOutcome,
+  CheckSetPolicy,
+  CheckSetPolicySpec,
+  SubjectKind,
+} from './types.js';
+
+// Check definitions for the RI-N4 evaluator (card RI-3-002). Each definition is
+// DATA with a version and a content digest (see digest.ts); the executable
+// half is attached via defineCheck. Check-set SELECTION is per subject kind
+// (probe-inventory gap 7): this monorepo does not match the node template's
+// file list, so the QC-19 definition carries a distinct file set for the
+// `monorepo` subject kind and the policy selects checks per kind.
+
+export function defineCheck(
+  spec: CheckDefinitionSpec,
+  evaluate: (ctx: CheckContext) => Promise<CheckOutcome>,
+): CheckDefinition {
+  return { ...spec, definitionDigest: digestOfSpec(spec), evaluate };
+}
+
+async function fileExists(filePath: string): Promise<boolean> {
+  try {
+    await access(filePath, constants.F_OK);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+// ─── QC-19: downstream rails presence ────────────────────────────────────────
+//
+// Typed absorption of the former presence-only `quality-rails check` loop in
+// cli.ts. The scaffold-kind file lists below are carried over VERBATIM so the
+// evaluator's typed verdicts are parity-equivalent with the presence loop on
+// the same fixture; the `monorepo` list is new (per-subject check sets).
+
+const qc19Spec: CheckDefinitionSpec = {
+  id: 'qc-19-rails-files-present',
+  version: '1.0.0',
+  canonicalCheck: 'QC-19',
+  description:
+    'The subject still carries its quality-rails files. Typed absorption of the former presence-only check loop; presence is necessary, not sufficient (RI-N4).',
+  appliesTo: ['node', 'python', 'rust', 'monorepo', 'unknown'],
+  params: {
+    expectedFilesByKind: {
+      node: ['.eslintrc', 'biome.json', '.githooks/pre-commit', 'PR-CHECKLIST.md'],
+      python: ['pyproject.toml', '.githooks/pre-commit', 'PR-CHECKLIST.md'],
+      rust: ['rustfmt.toml', '.githooks/pre-commit', 'PR-CHECKLIST.md'],
+      monorepo: [
+        '.husky/pre-commit',
+        '.husky/pre-push',
+        'eslint.config.mjs',
+        '.prettierrc',
+        '.lintstagedrc',
+      ],
+      unknown: ['.githooks/pre-commit', 'PR-CHECKLIST.md'],
+    },
+  },
+};
+
+async function evaluateQc19(ctx: CheckContext): Promise<CheckOutcome> {
+  const byKind = ctx.params['expectedFilesByKind'] as Record<string, readonly string[]> | undefined;
+  if (byKind === undefined) {
+    return { status: 'error', reason: 'definition params missing expectedFilesByKind' };
+  }
+  const expected = byKind[ctx.subject.kind];
+  if (expected === undefined) {
+    // Fail-closed: an undefined file set for a declared subject kind is a
+    // definition gap, never a green outcome.
+    return {
+      status: 'blocked',
+      reason: `no expected-file set defined for subject kind '${ctx.subject.kind}'`,
+    };
+  }
+
+  const missing: string[] = [];
+  for (const relativePath of expected) {
+    if (!(await fileExists(resolve(ctx.subject.path, relativePath)))) {
+      missing.push(relativePath);
+    }
+  }
+  if (missing.length > 0) {
+    return {
+      status: 'failed',
+      reason: `missing rails files (${ctx.subject.kind}): ${missing.join(', ')}`,
+    };
+  }
+  return { status: 'passed' };
+}
+
+// ─── QC-20: downstream enforcement verification (behavioral probe) ──────────
+//
+// The planted-commit behavioral probe (framework tools/quality/scripts/verify.sh)
+// stays a THIN SHELL ADAPTER: the TS evaluator invokes it and OWNS the verdict
+// parsing (RI-N4: grep-on-output verdict logic moves into the typed evaluator).
+// Probe contract (verify.sh): exit 0 ⇔ every sub-probe passed, exit 1 ⇔ at
+// least one sub-probe failed; sub-probe verdicts appear as `PASS:` / `FAIL:`
+// marker lines and the script always prints a `Verification Summary` section.
+// Any deviation from that contract (other exit codes, unparseable output,
+// missing probe, process failure, timeout) is `error`/`blocked` — never
+// `passed`.
+
+const qc20Spec: CheckDefinitionSpec = {
+  id: 'qc-20-enforcement-verify',
+  version: '1.0.0',
+  canonicalCheck: 'QC-20',
+  description:
+    'The behavioral planted-commit probe runs against the subject and every sub-probe blocks as intended. The shell probe is a thin adapter; verdict parsing is owned by this evaluator.',
+  appliesTo: ['node', 'python', 'rust', 'unknown'],
+  params: {
+    command: 'bash',
+    timeoutMs: 120_000,
+    passMarker: 'PASS:',
+    failMarker: 'FAIL:',
+    summaryMarker: 'Verification Summary',
+  },
+};
+
+function linesWith(text: string, marker: string): string[] {
+  return text
+    .split('\n')
+    .map((line) => line.trim())
+    .filter((line) => line.includes(marker));
+}
+
+async function evaluateQc20(ctx: CheckContext): Promise<CheckOutcome> {
+  const rawProbePath = ctx.inputs['probePath'];
+  if (typeof rawProbePath !== 'string' || rawProbePath.trim().length === 0) {
+    return {
+      status: 'blocked',
+      reason:
+        'missing input: probePath — the behavioral probe script must be provided (e.g. the framework verify.sh)',
+    };
+  }
+  const probePath = isAbsolute(rawProbePath)
+    ? rawProbePath
+    : resolve(ctx.subject.path, rawProbePath);
+  if (!(await fileExists(probePath))) {
+    return { status: 'blocked', reason: `probe script not found: ${probePath}` };
+  }
+
+  const command = typeof ctx.params['command'] === 'string' ? ctx.params['command'] : 'bash';
+  const timeoutMs = typeof ctx.params['timeoutMs'] === 'number' ? ctx.params['timeoutMs'] : 120_000;
+  const passMarker =
+    typeof ctx.params['passMarker'] === 'string' ? ctx.params['passMarker'] : 'PASS:';
+  const failMarker =
+    typeof ctx.params['failMarker'] === 'string' ? ctx.params['failMarker'] : 'FAIL:';
+  const summaryMarker =
+    typeof ctx.params['summaryMarker'] === 'string'
+      ? ctx.params['summaryMarker']
+      : 'Verification Summary';
+
+  const outcome = await ctx.adapter.run({
+    file: command,
+    args: [probePath],
+    cwd: ctx.subject.path,
+    timeoutMs,
+  });
+
+  if (!outcome.ok) {
+    // Process error or timeout: the probe never produced a trustworthy result.
+    return {
+      status: 'error',
+      reason: `probe process ${outcome.kind}: ${outcome.message}`,
+    };
+  }
+
+  const output = `${outcome.stdout}\n${outcome.stderr}`;
+  const failLines = linesWith(output, failMarker);
+  const passLines = linesWith(output, passMarker);
+
+  if (outcome.exitCode === 0) {
+    // A green exit must be corroborated by a parseable green transcript:
+    // at least one pass marker, no fail markers, and the summary section.
+    if (passLines.length > 0 && failLines.length === 0 && output.includes(summaryMarker)) {
+      return { status: 'passed' };
+    }
+    return {
+      status: 'error',
+      reason: `malformed probe output: exit 0 without a parseable pass transcript (${passLines.length} pass markers, ${failLines.length} fail markers, summary ${output.includes(summaryMarker) ? 'present' : 'absent'})`,
+    };
+  }
+
+  if (outcome.exitCode === 1) {
+    if (failLines.length === 0) {
+      return {
+        status: 'error',
+        reason: 'malformed probe output: exit 1 without parseable FAIL markers',
+      };
+    }
+    return {
+      status: 'failed',
+      reason: `enforcement probe reported ${failLines.length} failing sub-probe(s): ${failLines.join(' | ')}`,
+    };
+  }
+
+  return {
+    status: 'error',
+    reason: `probe exited with unexpected code ${String(outcome.exitCode)} — outcome not interpretable`,
+  };
+}
+
+// ─── Per-subject check-set policy ───────────────────────────────────────────
+//
+// Gap 7 of the probe inventory: check sets must be selected per subject, not
+// one global list. Downstream scaffold kinds get the presence check plus the
+// behavioral probe (QC-20 blocks until a probePath input is provided — an
+// unverified subject can never evaluate green). The monorepo subject is this
+// repository itself: its rails are the husky hooks + shared lint/format
+// configs, covered by QC-19; the downstream planted-commit probe does not
+// apply to it (this repo's own commit gates are QC-13/QC-14, outside this
+// evaluator's owned checks).
+
+const checkSetPolicySpec: CheckSetPolicySpec = {
+  version: '1.0.0',
+  byKind: {
+    node: ['qc-19-rails-files-present', 'qc-20-enforcement-verify'],
+    python: ['qc-19-rails-files-present', 'qc-20-enforcement-verify'],
+    rust: ['qc-19-rails-files-present', 'qc-20-enforcement-verify'],
+    unknown: ['qc-19-rails-files-present', 'qc-20-enforcement-verify'],
+    monorepo: ['qc-19-rails-files-present'],
+  },
+};
+
+export const CHECK_SET_POLICY: CheckSetPolicy = {
+  ...checkSetPolicySpec,
+  policyDigest: digestOfPolicy(checkSetPolicySpec),
+};
+
+export const QC_19_RAILS_FILES_PRESENT = defineCheck(qc19Spec, evaluateQc19);
+export const QC_20_ENFORCEMENT_VERIFY = defineCheck(qc20Spec, evaluateQc20);
+
+/** Built-in check definitions, keyed by id. */
+export function builtInDefinitions(): CheckDefinition[] {
+  return [QC_19_RAILS_FILES_PRESENT, QC_20_ENFORCEMENT_VERIFY];
+}
+
+export function checkSetForKind(
+  kind: SubjectKind,
+  policy: CheckSetPolicy = CHECK_SET_POLICY,
+): readonly string[] {
+  const selected = policy.byKind[kind];
+  if (selected === undefined) {
+    // Fail-closed selection: an unknown kind yields an EMPTY set only to the
+    // caller; the runner treats an empty result list as `blocked`, never green.
+    return [];
+  }
+  return selected;
+}

packages/quality-rails/src/evaluator/digest.ts

@@ -0,0 +1,45 @@
+import { createHash } from 'node:crypto';
+
+import type { CheckDefinitionSpec, CheckSetPolicySpec } from './types.js';
+
+// Deterministic JSON: object keys sorted at every level so two specs with the
+// same content always produce the same bytes (and thus the same digest).
+export function canonicalJson(value: unknown): string {
+  if (value === null || typeof value !== 'object') {
+    return JSON.stringify(value);
+  }
+  if (Array.isArray(value)) {
+    return `[${value.map((entry) => canonicalJson(entry)).join(',')}]`;
+  }
+  const record = value as Record<string, unknown>;
+  const keys = Object.keys(record).sort();
+  return `{${keys.map((key) => `${JSON.stringify(key)}:${canonicalJson(record[key])}`).join(',')}}`;
+}
+
+/** sha256 over the canonical JSON of `value`. */
+export function digestContent(value: unknown): string {
+  return createHash('sha256').update(canonicalJson(value), 'utf8').digest('hex');
+}
+
+/**
+ * Content digest of a check definition: covers the declarative spec (id,
+ * version, canonical check, description, applicability, params) — everything a
+ * reviewer reasons about — while excluding the executable function object.
+ * Changing any covered field changes the digest, so a recorded digest always
+ * identifies exactly which definition content produced a verdict.
+ */
+export function digestOfSpec(spec: CheckDefinitionSpec): string {
+  return digestContent({
+    id: spec.id,
+    version: spec.version,
+    canonicalCheck: spec.canonicalCheck,
+    description: spec.description,
+    appliesTo: spec.appliesTo,
+    params: spec.params,
+  });
+}
+
+/** Content digest of the per-subject check-set policy. */
+export function digestOfPolicy(spec: CheckSetPolicySpec): string {
+  return digestContent(spec);
+}

packages/quality-rails/src/evaluator/runner.ts

@@ -0,0 +1,183 @@
+import { constants } from 'node:fs';
+import { access, stat } from 'node:fs/promises';
+import { join, resolve } from 'node:path';
+
+import { createSpawnProcessAdapter } from './adapter.js';
+import { builtInDefinitions, CHECK_SET_POLICY, checkSetForKind } from './definitions.js';
+import type {
+  AggregateState,
+  CheckResult,
+  CheckStatus,
+  EvaluateOptions,
+  EvaluationReport,
+  ProcessAdapter,
+  Subject,
+  SubjectKind,
+} from './types.js';
+import { detectProjectKind } from '../detect.js';
+
+async function pathExists(targetPath: string): Promise<boolean> {
+  try {
+    await access(targetPath, constants.F_OK);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+async function isDirectory(targetPath: string): Promise<boolean> {
+  try {
+    return (await stat(targetPath)).isDirectory();
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * Subject-kind detection for the evaluator. Extends the scaffold detection
+ * (detect.ts) with the `monorepo` kind: a pnpm workspace is this repository's
+ * own subject shape and carries a different rails file set (probe-inventory
+ * gap 7 — check sets are per subject, not one global file list).
+ */
+export async function detectSubjectKind(subjectPath: string): Promise<SubjectKind> {
+  if (await pathExists(join(subjectPath, 'pnpm-workspace.yaml'))) {
+    return 'monorepo';
+  }
+  const kind = await detectProjectKind(subjectPath);
+  return kind;
+}
+
+/**
+ * Aggregate state, MACP-style discipline: `passed` only when at least one
+ * check produced a verdict AND every verdict is `passed` or an explicitly
+ * qualified `not-applicable`. Precedence is fail-closed: error > blocked >
+ * failed > passed; an empty result list aggregates to `blocked`.
+ */
+export function aggregateState(results: readonly CheckResult[]): AggregateState {
+  if (results.length === 0) {
+    return 'blocked';
+  }
+  const has = (status: CheckStatus): boolean => results.some((result) => result.status === status);
+  if (has('error')) {
+    return 'error';
+  }
+  if (has('blocked')) {
+    return 'blocked';
+  }
+  if (has('failed')) {
+    return 'failed';
+  }
+  return 'passed';
+}
+
+function reasonFrom(error: unknown): string {
+  return error instanceof Error ? error.message : String(error);
+}
+
+/**
+ * Evaluate one subject against a set of checks, producing typed verdicts.
+ *
+ * Fail-closed invariants (RI-N4):
+ * - unknown check id            → `error` (never passed)
+ * - subject directory absent    → every verdict `blocked`
+ * - check implementation threw  → `error`
+ * - non-passed without a reason → `error` (no unqualified skips)
+ * - check not applicable        → `not-applicable` WITH a reason
+ */
+export async function evaluateSubject(options: EvaluateOptions): Promise<EvaluationReport> {
+  const subjectPath = resolve(options.subjectPath);
+  const subject: Subject = {
+    path: subjectPath,
+    kind: await detectSubjectKind(subjectPath),
+  };
+
+  const definitions = options.definitions ?? builtInDefinitions();
+  const byId = new Map(definitions.map((definition) => [definition.id, definition]));
+  const requested = options.checkIds ?? checkSetForKind(subject.kind);
+  const adapter: ProcessAdapter = options.adapter ?? createSpawnProcessAdapter();
+
+  const results: CheckResult[] = [];
+  const definitionDigests: Record<string, string> = {};
+
+  for (const checkId of requested) {
+    const definition = byId.get(checkId);
+    if (definition === undefined) {
+      const known = definitions.map((entry) => entry.id).join(', ');
+      results.push({
+        status: 'error',
+        checkId,
+        checkVersion: 'unknown',
+        subject: subjectPath,
+        reason: `unknown check id '${checkId}' — no registered definition (known: ${known})`,
+      });
+      continue;
+    }
+
+    definitionDigests[checkId] = definition.definitionDigest;
+
+    if (!(await isDirectory(subjectPath))) {
+      results.push({
+        status: 'blocked',
+        checkId,
+        checkVersion: definition.version,
+        subject: subjectPath,
+        reason: `subject directory does not exist: ${subjectPath}`,
+      });
+      continue;
+    }
+
+    if (!definition.appliesTo.includes(subject.kind)) {
+      results.push({
+        status: 'not-applicable',
+        checkId,
+        checkVersion: definition.version,
+        subject: subjectPath,
+        reason: `check '${checkId}' does not apply to subject kind '${subject.kind}'`,
+      });
+      continue;
+    }
+
+    try {
+      const inputs = options.inputs?.[checkId] ?? {};
+      const outcome = await definition.evaluate({
+        subject,
+        params: definition.params,
+        inputs,
+        adapter,
+      });
+      if (outcome.status !== 'passed' && (outcome.reason === undefined || outcome.reason === '')) {
+        results.push({
+          status: 'error',
+          checkId,
+          checkVersion: definition.version,
+          subject: subjectPath,
+          reason: `check returned status '${outcome.status}' without a reason — treated as error`,
+        });
+        continue;
+      }
+      results.push({
+        status: outcome.status,
+        checkId,
+        checkVersion: definition.version,
+        subject: subjectPath,
+        reason: outcome.reason,
+      });
+    } catch (error) {
+      results.push({
+        status: 'error',
+        checkId,
+        checkVersion: definition.version,
+        subject: subjectPath,
+        reason: `check implementation threw: ${reasonFrom(error)}`,
+      });
+    }
+  }
+
+  return {
+    subject,
+    results,
+    definitionDigests,
+    checkSetVersion: CHECK_SET_POLICY.version,
+    state: aggregateState(results),
+  };
+}

packages/quality-rails/src/evaluator/types.ts

@@ -0,0 +1,148 @@
+// Evaluator core types — RI-N4 (card RI-3-002, SDLC-D-037 second half).
+//
+// The quality-rails evaluator is the SOLE authoritative producer of check
+// verdicts for the checks it owns. Every verdict is typed and fail-closed:
+// missing implementations, missing inputs, unknown check ids, process errors,
+// timeouts, and malformed adapter output can never become `passed` or an
+// unqualified skip — they surface as `blocked` or `error` with a reason.
+// (Vocabulary mirrors MACP's GateStatus discipline from packages/macp.)
+
+/**
+ * Typed verdict for a single check execution.
+ *
+ * - `passed` — the check really ran and its condition held.
+ * - `failed` — the check really ran and its condition did NOT hold.
+ * - `blocked` — the check could not run at all (missing subject, missing
+ *   input). Never a green outcome.
+ * - `error` — the check attempted to run but its outcome cannot be trusted
+ *   (unknown check id, implementation threw, process error, timeout, malformed
+ *   adapter output). Never a green outcome.
+ * - `not-applicable` — the check definition explicitly declares it does not
+ *   apply to this subject (a qualified skip, always with a reason).
+ */
+export type CheckStatus = 'passed' | 'failed' | 'blocked' | 'error' | 'not-applicable';
+
+/** Aggregate outcome, MACP-style: `passed` only when every result is green. */
+export type AggregateState = 'passed' | 'failed' | 'blocked' | 'error';
+
+/** Kinds of subjects the evaluator can assess. */
+export type SubjectKind = 'node' | 'python' | 'rust' | 'monorepo' | 'unknown';
+
+/**
+ * A single check verdict. This is the canonical result shape: `status`,
+ * `checkId`, `checkVersion`, `subject`, `reason`. `reason` is REQUIRED
+ * (enforced by the runner) for every status other than `passed`.
+ */
+export interface CheckResult {
+  status: CheckStatus;
+  checkId: string;
+  checkVersion: string;
+  subject: string;
+  reason?: string;
+}
+
+/** The project being evaluated. */
+export interface Subject {
+  /** Absolute path. */
+  path: string;
+  kind: SubjectKind;
+}
+
+/**
+ * The data half of a check definition. Definitions live as DATA with a version
+ * and a content digest (see `digestOfSpec`); the executable half is attached
+ * separately so the digest covers only reviewable, declarative content.
+ */
+export interface CheckDefinitionSpec {
+  /** Stable id, e.g. `qc-19-rails-files-present`. */
+  id: string;
+  /** Semver of this definition's data+semantics. */
+  version: string;
+  /** Canonical check id from docs/release-integrity/probe-inventory.md (QC-n). */
+  canonicalCheck: string;
+  description: string;
+  /** Subject kinds this check can assess (others yield `not-applicable`). */
+  appliesTo: readonly SubjectKind[];
+  /** Declarative parameters (file lists, markers, timeouts) — digest-covered. */
+  params: Record<string, unknown>;
+}
+
+/** A fully assembled check definition: spec + digest + implementation. */
+export interface CheckDefinition extends CheckDefinitionSpec {
+  /** sha256 content digest of the spec (canonical JSON projection). */
+  definitionDigest: string;
+  evaluate(ctx: CheckContext): Promise<CheckOutcome>;
+}
+
+/** What a check implementation returns; the runner stamps id/version/subject. */
+export interface CheckOutcome {
+  status: CheckStatus;
+  reason?: string;
+}
+
+/** Caller-provided inputs for one check invocation (e.g. the QC-20 probe path). */
+export type CheckInputs = Record<string, unknown>;
+
+/** Everything a check implementation may use. */
+export interface CheckContext {
+  subject: Subject;
+  params: Record<string, unknown>;
+  inputs: CheckInputs;
+  adapter: ProcessAdapter;
+}
+
+/** Outcome of running a shell probe through the thin process adapter. */
+export type AdapterOutcome =
+  | { ok: true; exitCode: number | null; stdout: string; stderr: string }
+  | { ok: false; kind: 'spawn-error' | 'timeout'; message: string };
+
+/** Request for the process adapter. */
+export interface AdapterRequest {
+  file: string;
+  args: string[];
+  cwd: string;
+  timeoutMs: number;
+}
+
+/**
+ * Thin process adapter: runs a command, owns NO verdict logic. Verdict parsing
+ * always lives in the check implementation (TS), never in the shell probe.
+ */
+export interface ProcessAdapter {
+  run(request: AdapterRequest): Promise<AdapterOutcome>;
+}
+
+/** Per-subject-kind check-set selection policy (versioned and digested). */
+export interface CheckSetPolicySpec {
+  version: string;
+  byKind: Record<SubjectKind, readonly string[]>;
+}
+
+export interface CheckSetPolicy extends CheckSetPolicySpec {
+  /** sha256 content digest of the policy spec. */
+  policyDigest: string;
+}
+
+/** Full typed evaluation report for one subject. */
+export interface EvaluationReport {
+  subject: Subject;
+  results: CheckResult[];
+  /** checkId → content digest of the definition that produced the verdicts. */
+  definitionDigests: Record<string, string>;
+  /** Version of the check-set policy used for subject selection. */
+  checkSetVersion: string;
+  state: AggregateState;
+}
+
+/** Options for `evaluateSubject`. */
+export interface EvaluateOptions {
+  subjectPath: string;
+  /** Restrict to these check ids; defaults to the subject kind's check set. */
+  checkIds?: string[];
+  /** Per-check inputs, keyed by check id (e.g. `{ 'qc-20-enforcement-verify': { probePath } }`). */
+  inputs?: Record<string, CheckInputs>;
+  /** Replace the built-in definitions (tests / future batches). */
+  definitions?: CheckDefinition[];
+  /** Inject a process adapter (tests / instrumentation). */
+  adapter?: ProcessAdapter;
+}

packages/quality-rails/src/index.ts

@@ -3,3 +3,35 @@ export * from './detect.js';
 export * from './scaffolder.js';
 export * from './templates.js';
 export * from './types.js';
+
+// RI-N4 evaluator (card RI-3-002): the public, programmatic entry points.
+export {
+  builtInDefinitions,
+  CHECK_SET_POLICY,
+  checkSetForKind,
+  defineCheck,
+  QC_19_RAILS_FILES_PRESENT,
+  QC_20_ENFORCEMENT_VERIFY,
+} from './evaluator/definitions.js';
+export { canonicalJson, digestContent, digestOfPolicy, digestOfSpec } from './evaluator/digest.js';
+export { createSpawnProcessAdapter } from './evaluator/adapter.js';
+export { aggregateState, detectSubjectKind, evaluateSubject } from './evaluator/runner.js';
+export type {
+  AdapterOutcome,
+  AdapterRequest,
+  AggregateState,
+  CheckContext,
+  CheckDefinition,
+  CheckDefinitionSpec,
+  CheckInputs,
+  CheckOutcome,
+  CheckResult,
+  CheckSetPolicy,
+  CheckSetPolicySpec,
+  CheckStatus,
+  EvaluateOptions,
+  EvaluationReport,
+  ProcessAdapter,
+  Subject,
+  SubjectKind,
+} from './evaluator/types.js';