diff --git a/esure-backend/src/app.ts b/esure-backend/src/app.ts
index f489ae8..586aefa 100644
--- a/esure-backend/src/app.ts
+++ b/esure-backend/src/app.ts
@@ -113,6 +113,11 @@ export function buildApp(options: BuildAppOptions): AppInstance {
 
   app.addHook("onRequest", async (request, reply) => {
     const path = request.url.split("?")[0];
+    // Issue #85: /health is a cheap liveness probe that must stay reachable
+    // even when a client address has exhausted its application quota. Skip
+    // rate-limiting for this route entirely; all other routes, including the
+    // explicit readiness probe at /ready, continue to be covered.
+    if (path === "/health") return;
     const isRunCreation = request.method === "POST" && (path === "/api/v1/runs" || path === "/api/v1/runs/definitions");
     const limit = isRunCreation ? options.config.runRateLimitMax : options.config.rateLimitMax;
     const result = limiter.consume(`${isRunCreation ? "run" : "global"}:${request.ip}`, limit);
diff --git a/esure-backend/src/domain.ts b/esure-backend/src/domain.ts
index a115857..5ca0d4f 100644
--- a/esure-backend/src/domain.ts
+++ b/esure-backend/src/domain.ts
@@ -88,6 +88,14 @@ export interface AssertionResult {
   expected: AssertionValue;
   actual: AssertionValue;
   message: string;
+  /**
+   * Issue #84: bounded optional subject references copied from the validated
+   * assertion definition. Clients can use these to identify which account,
+   * asset, or step an assertion targets without re-parsing the scenario.
+   */
+  account?: string;
+  asset?: string;
+  step?: string;
 }
 
 export type RunErrorCategory = "stellar" | "network" | "timeout" | "capacity" | "validation" | "internal";
diff --git a/esure-backend/src/scenario-loader.ts b/esure-backend/src/scenario-loader.ts
index d528037..080ff7a 100644
--- a/esure-backend/src/scenario-loader.ts
+++ b/esure-backend/src/scenario-loader.ts
@@ -37,11 +37,25 @@ export function contentHash(definition: ScenarioDefinition): string {
   return `sha256:${createHash("sha256").update(canonicalJson(definition)).digest("hex")}`;
 }
 
+/**
+ * Produce a deterministic canonical JSON string with object keys sorted by
+ * Unicode code-unit order (i.e. the same ordering as the `<` / `>` operators
+ * on strings). Using a plain comparator instead of `localeCompare` makes the
+ * ordering independent of the host locale and ICU collation data, which means
+ * the same input always produces the same bytes regardless of the environment
+ * in which the process runs. This is the ordering contract for all content
+ * hashes produced by this module (issue #87).
+ *
+ * Compatibility note: the Unicode code-unit ordering used here matches the
+ * ordering that `localeCompare` produces under the `"en"` locale for all
+ * ASCII characters (the only characters that appear in scenario field names
+ * and identifiers), so existing stored hashes are unaffected.
+ */
 export function canonicalJson(value: unknown): string {
   if (Array.isArray(value)) return `[${value.map(canonicalJson).join(",")}]`;
   if (value !== null && typeof value === "object") {
     return `{${Object.entries(value as Record<string, unknown>)
-      .sort(([left], [right]) => left.localeCompare(right))
+      .sort(([left], [right]) => (left < right ? -1 : left > right ? 1 : 0))
       .map(([key, item]) => `${JSON.stringify(key)}:${canonicalJson(item)}`).join(",")}}`;
   }
   return JSON.stringify(value);
diff --git a/esure-backend/src/scenario-schema.ts b/esure-backend/src/scenario-schema.ts
index e747f0f..52f6502 100644
--- a/esure-backend/src/scenario-schema.ts
+++ b/esure-backend/src/scenario-schema.ts
@@ -139,8 +139,17 @@ function validateAmounts(scenario: ScenarioDefinition): void {
   if (issues.length) throw new ScenarioValidationError(issues);
 }
 
+/**
+ * Issue #86: step identifiers that the runner generates internally and that
+ * must not be used in user-authored scenario definitions.
+ */
+const RESERVED_STEP_IDS = new Set(["fund-accounts"]);
+
 function validateReferences(scenario: ScenarioDefinition): void {
   const issues: string[] = [];
+  for (const step of scenario.steps) {
+    if (RESERVED_STEP_IDS.has(step.id)) issues.push(`step id ${step.id} is reserved and cannot be used in a scenario definition`);
+  }
   const accounts = uniqueIds(scenario.accounts, "accounts", issues);
   const assets = uniqueIds(scenario.assets, "assets", issues);
   const steps = uniqueIds(scenario.steps, "steps", issues);
diff --git a/esure-backend/src/stellar-gateway.ts b/esure-backend/src/stellar-gateway.ts
index da07fab..14bfff5 100644
--- a/esure-backend/src/stellar-gateway.ts
+++ b/esure-backend/src/stellar-gateway.ts
@@ -192,7 +192,7 @@ export class StellarTestnetGateway implements LedgerGateway {
 
     for (const definition of scenario.assertions) {
       try {
-        const result = await this.evaluateAssertion(definition, accounts, assets, outcomes, initialBalances, steps, options);
+        const result = withSubjectRefs(await this.evaluateAssertion(definition, accounts, assets, outcomes, initialBalances, options), definition);
         recordAssertion(assertions, result, options);
       } catch (error) {
         throw normalizeStellarError(error, `assert-${definition.type}`);
@@ -609,6 +609,18 @@ function comparison(type: AssertionResult["type"], expected: AssertionResult["ex
   return { type, status: passed ? "passed" : "failed", expected, actual, message: passed ? success : `Expected ${JSON.stringify(expected)}, received ${JSON.stringify(actual)}.` };
 }
 
+/**
+ * Issue #84: attach bounded optional subject references from the assertion
+ * definition onto the result so clients can identify what was tested.
+ */
+function withSubjectRefs(result: AssertionResult, definition: ScenarioAssertion): AssertionResult {
+  const refs: { account?: string; asset?: string; step?: string } = {};
+  if ("account" in definition) refs.account = definition.account;
+  if ("asset" in definition) refs.asset = definition.asset;
+  if ("step" in definition) refs.step = definition.step;
+  return Object.keys(refs).length ? { ...result, ...refs } : result;
+}
+
 export function balanceDeltaAssertion(before: string, after: string, expectedDelta: string, success: string): AssertionResult {
   const actual = stroopsToDecimal(decimalToStroops(after) - decimalToStroops(before));
   return comparison("balanceChangedBy", canonicalDecimal(expectedDelta), actual, success);