diff --git a/src/immune/__tests__/lane-a-dryrun.test.ts b/src/immune/__tests__/lane-a-dryrun.test.ts
new file mode 100644
index 00000000..35cc45d8
--- /dev/null
+++ b/src/immune/__tests__/lane-a-dryrun.test.ts
@@ -0,0 +1,86 @@
+/**
+ * lane-a-dryrun.test.ts — the inert Lane A thread (D-145): precommit -> acceptance -> receipt -> would-write
+ * experimental shadow row. Proves the chain holds end to end while writing NOTHING, and that it can never claim
+ * independence (same_controller only). Teeth: break the satisfaction->verdict collapse and the delta sign flips.
+ */
+// experimental-repid eagerly imports src/db, whose config loader throws without SUPABASE creds. Factory-mock it.
+jest.mock('../../db', () => ({ db: {} }));
+import { generateKeyPairSync } from 'node:crypto';
+import { runLaneADryRun, satisfactionToVerdict, type LaneADryRunInput } from '../lane-a-dryrun';
+import { specWorkStatementHash, parseWorkStatement } from '../../services/work-statement-spec';
+import type { SettlementKeys } from '../trusted-settler';
+
+const gen = (): SettlementKeys => { const k = () => generateKeyPairSync('ed25519').privateKey; return { harness: k(), evaluation: k(), settlement: k(), composite: k() }; };
+const AGENT = '00000000-0000-0000-0000-000000000abc';
+
+const SPEC = {
+  deliverable: 'A 500-word sourced brief on OC recuperative-care discharge options.',
+  acceptance_criteria: [
+    { n: 1, text: 'Every claimed program includes a verifiable public source URL.' },
+    { n: 2, text: 'No eligibility rule is stated that the cited source does not support.' },
+  ],
+  agreed_price: { amount_usdc_raw: 500000, currency: 'USDC' },
+  deadline: '2026-12-01T00:00:00.000Z',
+};
+
+const base = (ratings: unknown): LaneADryRunInput => ({
+  spec: SPEC,
+  ratings,
+  contractId: 'contract-abc-123',
+  makerAgentId: AGENT,
+  deliverableArtifact: 'the produced brief text (data only, hashed, never executed)',
+  keys: gen(),
+});
+
+describe('Lane A dry-run — inert precommit -> acceptance -> receipt -> would-write (D-145)', () => {
+  it('all criteria met -> correct -> would-write +1, verified, same-controller, nothing authoritative', async () => {
+    const out = await runLaneADryRun(base([{ n: 1, met: true }, { n: 2, met: true }]));
+    expect(out.ok).toBe(true);
+    if (!out.ok) return;
+    const parsed = parseWorkStatement(SPEC);
+    expect(parsed.ok).toBe(true);
+    if (parsed.ok) expect(out.work_statement_hash).toBe(specWorkStatementHash(parsed.canonical)); // third-party-recomputable precommit
+    expect(out.satisfaction_score).toBe(1);
+    expect(out.verified_correct).toBe('correct');
+    expect(out.receipt_verified).toBe(true);
+    expect(out.receipt_authoritative).toBe(false);              // a demonstration, never a trust anchor
+    expect(out.immune_dryrun_status).not.toBe('settled');       // the P0 gate / mode-off: nothing was written
+    expect(out.eligibility).toBe('same_controller_measured');   // NEVER independent
+    expect(out.experiment_id).toBe('contract-abc-123');         // transitive bind to work_statement_hash
+    expect(out.would_write?.delta).toBe(1);
+    expect(out.would_write?.domain).toBe('t12-exp-v1');
+    expect(out.would_write?.mode).toBe('shadow');
+    expect(out.would_write?.eligibility).toBe('same_controller_measured');
+  });
+
+  it('a criterion unmet -> satisfaction < threshold -> incorrect -> a LEGITIMATE negative would-write (-1)', async () => {
+    const out = await runLaneADryRun(base([{ n: 1, met: true }, { n: 2, met: false }]));
+    expect(out.ok).toBe(true);
+    if (!out.ok) return;
+    expect(out.satisfaction_score).toBe(0.5);
+    expect(out.verified_correct).toBe('incorrect');
+    expect(out.would_write?.delta).toBe(-1);
+    expect(out.eligibility).toBe('same_controller_measured');
+  });
+
+  it('refuses at the precommit stage on an invalid spec', async () => {
+    const out = await runLaneADryRun(base([{ n: 1, met: true }]) as LaneADryRunInput);
+    // (ratings cover only n=1 but SPEC has two criteria) -> acceptance stage refusal
+    expect(out.ok).toBe(false);
+    if (out.ok) return;
+    expect(out.stage).toBe('acceptance');
+  });
+
+  it('refuses a spec with no acceptance criteria at the precommit stage', async () => {
+    const bad = { ...base([{ n: 1, met: true }]), spec: { deliverable: 'too short', agreed_price: { amount_usdc_raw: 1, currency: 'USDC' }, deadline: '2026-12-01T00:00:00.000Z', acceptance_criteria: [] } };
+    const out = await runLaneADryRun(bad);
+    expect(out.ok).toBe(false);
+    if (out.ok) return;
+    expect(out.stage).toBe('precommit');
+  });
+
+  it('the collapse is a reversible knob: threshold 0.5 would accept a half-met deliverable', () => {
+    expect(satisfactionToVerdict(0.5, 1)).toBe('incorrect');
+    expect(satisfactionToVerdict(0.5, 0.5)).toBe('correct');
+  });
+});
diff --git a/src/immune/lane-a-dryrun.ts b/src/immune/lane-a-dryrun.ts
new file mode 100644
index 00000000..5cd6f652
--- /dev/null
+++ b/src/immune/lane-a-dryrun.ts
@@ -0,0 +1,199 @@
+/**
+ * immune/lane-a-dryrun.ts — stand up ONE real-economic E2E as an INERT dry-run thread (Lane A, D-145).
+ *
+ * Threads the pieces that already exist, writing NOTHING and moving no money / RepID / on-chain state:
+ *
+ *   precommit   work-statement-spec -> work_statement_hash          // the contract, hashed BEFORE the work
+ *   acceptance  parseCriterionRatings -> satisfaction_score          // MULTI-criterion
+ *   collapse    satisfaction >= threshold -> correct|incorrect       // VERSIONED, default-OFF, reversible knob
+ *   receipt     runTrustedSettlement (dry-run)                       // signed + independently verified
+ *   credit      buildImmuneExperimentalRow (would-write, shadow)     // the repid_experimental_events row it WOULD write
+ *
+ * WHY A HARNESS AND NOT NEW PRIMITIVES. Each leg above already exists and is tested; nothing here is forked.
+ * What was missing is the THREAD: no production caller joins the precommit world (multi-criterion acceptance,
+ * work_statement_hash on service_contracts) to the immune-receipt world (single binary verdict, experiment_id).
+ * This file is that thread, inert, so the end-to-end shape is demonstrable and testable before any live wiring.
+ *
+ * THE JOIN, kept deliberately small (Claude+Grok concur, D-145):
+ *  - The receipt is bound to the contract via `experiment_id = contractId` — a TRANSITIVE bind to the immutable
+ *    work_statement_hash on service_contracts. This file does NOT add a field to, or otherwise change, the signed
+ *    public combined receipt. Promoting work_statement_hash to a first-class bound receipt field is a public-receipt
+ *    change and is Sean's MAJOR gate, not done here.
+ *  - The multi-criterion satisfaction score is collapsed to the receipt's binary verdict by ONE versioned, reversible
+ *    threshold (LANE_A_ACCEPTANCE_VERSION / LANE_A_ACCEPT_THRESHOLD, default 1.0 = every criterion met). The collapse
+ *    is explicit on the output, never silent.
+ *
+ * HONESTY (hard rules):
+ *  - SAME-CONTROLLER throughout. eligibility can only ever be same_controller_measured here; this is NOT
+ *    independent-counterparty commerce and must never be described as such.
+ *  - The demo receipt is authoritative:false — a DEMONSTRATION, not a trust anchor. settleImmuneReceipt's P0 gate
+ *    correctly refuses it (status 'not_authoritative'); the would-write row is computed separately, honestly labelled.
+ *  - Keys are caller PARAMETERS (throwaway Ed25519), never env secrets (D-129).
+ *  - Default is dry-run; nothing is written, nothing is authoritative, no canonical RepID moves.
+ *
+ * OWNER (MAJOR) GATES, all left undone: an authoritative receipt (engine authenticates origin), the
+ * EXPERIMENTAL_REPID_MODE + IMMUNE_SETTLE_ENABLED flags to move even shadow credit, the real testnet USDC
+ * payment (x402) + ERC-8004 / EAS writes, a first-class work_statement_hash receipt field, and any canonical credit.
+ */
+import { createHash } from 'node:crypto';
+import {
+  parseWorkStatement,
+  parseCriterionRatings,
+  specWorkStatementHash,
+} from '../services/work-statement-spec';
+import { EXPERIMENTAL_LABEL, type ExperimentalEventRow } from '../services/experimental-repid';
+import {
+  fixtureOracle,
+  runTrustedSettlement,
+  type SettlementKeys,
+} from './trusted-settler';
+import {
+  buildImmuneExperimentalRow,
+  settleImmuneReceipt,
+  type ImmuneSettleResult,
+} from './experimental-settlement';
+
+export const LANE_A_ACCEPTANCE_VERSION = 'lane-a-accept-v1';
+
+const sha256Hex = (s: string): string => createHash('sha256').update(s, 'utf8').digest('hex');
+
+/** The fraction of acceptance criteria that must be met for the deliverable to count 'correct'. Reversible knob; default 1.0 (all). */
+export function acceptanceThreshold(raw: string | undefined = process.env['LANE_A_ACCEPT_THRESHOLD']): number {
+  const t = (raw ?? '').trim();
+  if (t === '') return 1; // Number('') is 0, which would accept anything — default to "all criteria met".
+  const n = Number(t);
+  return Number.isFinite(n) && n >= 0 && n <= 1 ? n : 1;
+}
+
+/** Collapse a multi-criterion satisfaction score (0..1) to the receipt's binary verdict. Explicit on the output. */
+export function satisfactionToVerdict(score: number, threshold: number = acceptanceThreshold()): 'correct' | 'incorrect' {
+  return score >= threshold ? 'correct' : 'incorrect';
+}
+
+export interface LaneADryRunInput {
+  /** The precommit work statement: deliverable, acceptance_criteria[], agreed_price, deadline. */
+  spec: unknown;
+  /** The buyer's per-criterion ratings: [{ n, met }]. Must cover every numbered criterion. */
+  ratings: unknown;
+  /** The exchange/contract id. Becomes the receipt's experiment_id (transitive bind to work_statement_hash). */
+  contractId: string;
+  /** The maker agent, as a repid_agents uuid. */
+  makerAgentId: string;
+  /** The produced deliverable. DATA ONLY — hashed, never executed. */
+  deliverableArtifact: string;
+  /** Four throwaway Ed25519 signing authorities (parameters, never env). */
+  keys: SettlementKeys;
+  /** Fallbacks when the spec is a loose payload. */
+  priceUsdcRaw?: number;
+  deadline?: string | Date | null;
+}
+
+export type LaneADryRun =
+  | { ok: false; stage: 'precommit' | 'acceptance' | 'receipt'; reasons: string[] }
+  | {
+      ok: true;
+      /** EXPERIMENTAL / same-controller disclaimer. This is not independent commerce. */
+      label: string;
+      // precommit
+      work_statement_hash: string;
+      deliverable_sha256: string;
+      // acceptance (multi-criterion) + its explicit collapse to the receipt's binary verdict
+      satisfaction_score: number;
+      acceptance_version: string;
+      threshold: number;
+      verified_correct: 'correct' | 'incorrect';
+      // receipt (bound to the contract via experiment_id; NOT modified here)
+      experiment_id: string;
+      receipt_content_hash: string;
+      receipt_verified: boolean;
+      receipt_authoritative: boolean;
+      /** What settleImmuneReceipt did with this demo receipt — expected 'not_authoritative' or 'off' (nothing written). */
+      immune_dryrun_status: ImmuneSettleResult['status'];
+      // the experimental shadow row this WOULD write once the owner gates open. Not written.
+      would_write: ExperimentalEventRow | null;
+      eligibility: 'same_controller_measured';
+      owner_gates: string[];
+    };
+
+const OWNER_GATES = [
+  'authoritative receipt — the engine must authenticate origin (IMMUNE_ENGINE_AUTHORITY); this dry-run is authoritative:false',
+  'EXPERIMENTAL_REPID_MODE=shadow|active + IMMUNE_SETTLE_ENABLED=1 to move even shadow experimental credit',
+  'real testnet USDC payment (x402) + ERC-8004 / EAS on-chain writes',
+  'promote work_statement_hash to a first-class bound receipt field (public-receipt change)',
+  'any CANONICAL RepID credit',
+];
+
+/**
+ * Run the Lane A thread as a dry-run. Reads nothing from the DB, writes nothing, moves no money/RepID/chain.
+ * Returns the full bound record (precommit -> acceptance -> receipt -> would-write experimental shadow row), or a
+ * refusal naming the stage. eligibility is hardcoded same_controller_measured: this harness never claims independence.
+ */
+export async function runLaneADryRun(input: LaneADryRunInput): Promise<LaneADryRun> {
+  // 1. PRECOMMIT — hash the contract spec.
+  const spec = parseWorkStatement(input.spec, { priceUsdcRaw: input.priceUsdcRaw, deadline: input.deadline });
+  if (!spec.ok) return { ok: false, stage: 'precommit', reasons: [spec.error, spec.message] };
+
+  // 2. ACCEPTANCE — rate every criterion -> fractional satisfaction score.
+  const rated = parseCriterionRatings(input.ratings, spec.canonical);
+  if (!rated.ok) return { ok: false, stage: 'acceptance', reasons: [rated.error, rated.message] };
+
+  // 3. COLLAPSE — multi-criterion -> binary verdict, by a versioned, reversible threshold. Explicit on output.
+  const threshold = acceptanceThreshold();
+  const verified_correct = satisfactionToVerdict(rated.score, threshold);
+
+  // 4. RECEIPT — build + independently verify a combined trust receipt via the existing settler (dry-run, same-controller).
+  //    The receipt binds experiment_id = contractId (transitive bind to the immutable work_statement_hash). The signed
+  //    receipt is NOT modified; the deliverable hash is surfaced on the Lane A record separately.
+  const deliverable_sha256 = '0x' + sha256Hex(input.deliverableArtifact);
+  const verdict = JSON.stringify({ id: input.contractId, verdict: verified_correct === 'correct' ? 'TRUE' : 'FALSE' });
+  const verdict_sha256 = '0x' + sha256Hex(verdict);
+  const oracle = fixtureOracle(
+    [{ id: input.contractId, claim: spec.canonical.deliverable.slice(0, 120), expected: 'TRUE' }],
+    `lane-a:${input.contractId}`,
+  );
+  const settled = runTrustedSettlement({
+    bundle: {
+      verdict,
+      verdict_sha256,
+      sandbox_receipt: { mission_id: input.contractId, airlock_decision: 'promote', artifact_sha256: verdict_sha256, profile_checks: [{ name: 'lane-a-dryrun', passed: true }] },
+    },
+    oracle,
+    keys: input.keys,
+    context: {
+      experiment_id: input.contractId,
+      claim_id: input.contractId,
+      maker_id: input.makerAgentId,
+      maker_controller: 'same-controller',
+      checker_id: 'lane-a-oracle',
+      checker_controller: 'same-controller', // same controller: independence is never claimed here
+    },
+  });
+  if (!settled.ok) return { ok: false, stage: 'receipt', reasons: settled.refused };
+
+  // 5. CREDIT — prove the P0 gate refuses our (non-authoritative) demo receipt, AND compute the would-write row.
+  //    settleImmuneReceipt with default deps writes nothing (mode off / not authoritative / no store).
+  const immune = await settleImmuneReceipt(
+    { receipt: settled.receipt, verification: settled.verification, agentId: input.makerAgentId },
+    {},
+  );
+  const would_write = buildImmuneExperimentalRow(settled.receipt, input.makerAgentId, 'same_controller_measured', 'shadow', null);
+
+  return {
+    ok: true,
+    label: `${EXPERIMENTAL_LABEL} Lane A dry-run: same-controller, nothing written.`,
+    work_statement_hash: specWorkStatementHash(spec.canonical),
+    deliverable_sha256,
+    satisfaction_score: rated.score,
+    acceptance_version: LANE_A_ACCEPTANCE_VERSION,
+    threshold,
+    verified_correct,
+    experiment_id: input.contractId,
+    receipt_content_hash: settled.receipt.content_hash,
+    receipt_verified: settled.verification.ok,
+    receipt_authoritative: settled.verification.authoritative,
+    immune_dryrun_status: immune.status,
+    would_write,
+    eligibility: 'same_controller_measured',
+    owner_gates: OWNER_GATES,
+  };
+}