refactor(benchmarks): address PR #15 code-review findings

- neuron-plugins: drop extraneous 6th constructor arg in resolveParam
  (StateNumberParameter takes 5).
- neuron-js adapter: add default case throwing on unhandled scenario.
- cold-start: adapters now expose a named `adapter` export; cold-start-child
  imports `{ adapter }` instead of Object.values(...)[0].
- extract shared readPath into harness/read-path.ts; reuse in neuron-plugins
  and the hand-coded adapter (removes duplication).
- scenarios: pricing decide/canonical derive from shared PRICING_* constants
  instead of a hardcoded subtotal duplicated in data.

Re-ran yarn benchmark + benchmark:charts; lint/test/examples/build/docs:build
all green; no chaos-vault strings in dist.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: sdieguez-wotc

benchmarks/harness/adapters/hand-coded-typescript.ts

@@ -1,14 +1,6 @@
+import { readPath } from "../read-path.ts";
 import type { Adapter, Decision, Runner, ScenarioDef } from "../types.ts";
 
-function readPath(data: Record<string, unknown>, path: string): unknown {
-  return path.split(".").reduce<unknown>((current, segment) => {
-    if (current && typeof current === "object" && segment in current) {
-      return (current as Record<string, unknown>)[segment];
-    }
-    return undefined;
-  }, data);
-}
-
 /**
  * Hand-coded TypeScript baseline. No engine: a direct `>=` comparison, the
  * floor cost any rules engine is measured against.
@@ -23,3 +15,6 @@ export const handCodedAdapter: Adapter = {
     };
   },
 };
+
+/** Canonical export consumed by the cold-start probe. */
+export const adapter = handCodedAdapter;

benchmarks/harness/adapters/json-logic-js.ts

@@ -18,3 +18,6 @@ export const jsonLogicAdapter: Adapter = {
     };
   },
 };
+
+/** Canonical export consumed by the cold-start probe. */
+export const adapter = jsonLogicAdapter;

benchmarks/harness/adapters/json-rules-engine.ts

@@ -29,3 +29,6 @@ export const jsonRulesEngineAdapter: Adapter = {
     };
   },
 };
+
+/** Canonical export consumed by the cold-start probe. */
+export const adapter = jsonRulesEngineAdapter;

benchmarks/harness/adapters/neuron-js.ts

@@ -57,7 +57,14 @@ export const neuronJsAdapter: Adapter = {
             slaHours: workflow.slaHours as number,
           };
         }
+        default:
+          throw new Error(
+            `Unhandled scenario in neuronJsAdapter: ${scenario.id}`,
+          );
       }
     };
   },
 };
+
+/** Canonical export consumed by the cold-start probe. */
+export const adapter = neuronJsAdapter;

benchmarks/harness/adapters/rule-engine-js.ts

@@ -19,3 +19,6 @@ export const ruleEngineJsAdapter: Adapter = {
     };
   },
 };
+
+/** Canonical export consumed by the cold-start probe. */
+export const adapter = ruleEngineJsAdapter;

benchmarks/harness/cold-start-child.ts

@@ -12,11 +12,9 @@ const scenario =
   scenarios.find((item) => item.id === scenarioId) ?? scenarios[0];
 
 const start = performance.now();
-const moduleExports = (await import(`./adapters/${adapterFile}.ts`)) as Record<
-  string,
-  Adapter
->;
-const adapter = Object.values(moduleExports)[0];
+const { adapter } = (await import(`./adapters/${adapterFile}.ts`)) as {
+  adapter: Adapter;
+};
 const runner = adapter.prepare(scenario);
 await runner();
 const ms = performance.now() - start;

benchmarks/harness/neuron-plugins.ts

@@ -13,17 +13,13 @@ import {
   type Neuron,
   type ParameterInterface,
 } from "../../dist/esm/index.js";
+import { readPath } from "./read-path.ts";
 
 export function readStatePath(
   context: ExecutionContext,
   path: string,
 ): unknown {
-  return path.split(".").reduce<unknown>((current, segment) => {
-    if (current && typeof current === "object" && segment in current) {
-      return (current as Record<string, unknown>)[segment];
-    }
-    return undefined;
-  }, context.state);
+  return readPath(context.state, path);
 }
 
 export class StateNumberParameter {
@@ -71,7 +67,6 @@ function resolveParam(
         param.name,
         param.value,
         param.options,
-        param.defaultValue,
       ).getValue(context)
     : null;
 }

benchmarks/harness/read-path.ts

@@ -0,0 +1,9 @@
+/** Reads a dot-path (e.g. "cart.subtotal") from a nested object; undefined if absent. */
+export function readPath(source: unknown, path: string): unknown {
+  return path.split(".").reduce<unknown>((current, segment) => {
+    if (current && typeof current === "object" && segment in current) {
+      return (current as Record<string, unknown>)[segment];
+    }
+    return undefined;
+  }, source);
+}

benchmarks/harness/scenarios.ts

@@ -19,6 +19,12 @@ import workflowScript from "../../examples/workflow-routing/rules.json" with {
 };
 import type { Decision, ScenarioDef } from "./types.ts";
 
+// Pricing inputs, declared once so the scenario data and the decision derivation
+// stay in sync (matches examples/pricing-rules).
+const PRICING_SUBTOTAL = 125;
+const PRICING_PERCENT = 16;
+const PRICING_DISCOUNT = Math.round(PRICING_SUBTOTAL * (PRICING_PERCENT / 100));
+
 /**
  * The three NJS-GROWTH-07 scenarios. Each is a single numeric-threshold decision
  * whose canonical output matches the runnable example expected-output fixtures, so
@@ -29,22 +35,24 @@ export const scenarios: ScenarioDef[] = [
     id: "pricing-discount",
     neuronScript: pricingScript,
     neuronInput: pricingInput as ExecutionContext,
-    data: { cart: { subtotal: 125, currency: "USD" } },
+    data: { cart: { subtotal: PRICING_SUBTOTAL, currency: "USD" } },
     factPath: "cart.subtotal",
-    flatFacts: { subtotal: 125 },
+    flatFacts: { subtotal: PRICING_SUBTOTAL },
     flatFactName: "subtotal",
     threshold: 100,
     decide(matched: boolean): Decision {
       if (!matched) return { matched: false };
-      const subtotal = 125;
-      const discountAmount = Math.round(subtotal * (16 / 100));
       return {
         matched: true,
-        discountAmount,
-        finalTotal: subtotal - discountAmount,
+        discountAmount: PRICING_DISCOUNT,
+        finalTotal: PRICING_SUBTOTAL - PRICING_DISCOUNT,
       };
     },
-    canonical: { matched: true, discountAmount: 20, finalTotal: 105 },
+    canonical: {
+      matched: true,
+      discountAmount: PRICING_DISCOUNT,
+      finalTotal: PRICING_SUBTOTAL - PRICING_DISCOUNT,
+    },
   },
   {
     id: "eligibility-approval",