diff --git a/src/application/JavaScriptApplicationService.test.ts b/src/application/JavaScriptApplicationService.test.ts
index f43d3ce19..b0dd97a80 100644
--- a/src/application/JavaScriptApplicationService.test.ts
+++ b/src/application/JavaScriptApplicationService.test.ts
@@ -2,12 +2,47 @@ import { writeFile } from "node:fs/promises";
 import { join } from "node:path";
 
 import { describe, expect, it } from "vitest";
+import { z } from "zod";
 
 import { createTestTempDirectory } from "../../tests/fixtures/temporaryDirectory.js";
 import { projectAnalysisError } from "../domain/analysisErrorProjection.js";
 import { analyzeJavaScriptApplication } from "./JavaScriptApplicationService.js";
 
 describe("JavaScript application failure diagnostics", () => {
+  it("identifies the rejected result field in caller-visible diagnostics", async () => {
+    const inputPath = await createTestTempDirectory("rea-js-schema-failure-");
+    await writeFile(join(inputPath, "main.js"), "export const value = 1;\n");
+    const cause = new z.ZodError([
+      {
+        code: "custom",
+        path: ["semantic_graph", "nodes", 42, "application_node_ids", 0],
+        message: "Semantic node references an absent application node",
+      },
+    ]);
+    const result = await analyzeJavaScriptApplication(
+      { input_path: inputPath, format: "directory" },
+      {
+        progress: {
+          report: async (event) => {
+            if (event.terminal) throw cause;
+          },
+        },
+      },
+    );
+
+    expect(result.ok).toBe(false);
+    if (result.ok) throw new Error("Expected analysis failure");
+    expect(result.error.cause).toBe(cause);
+    expect(projectAnalysisError(result.error)).toMatchObject({
+      code: "unreadable_output",
+      details: {
+        operation: "analyze_javascript_application",
+        reason:
+          "Result schema rejected 1 issue at /semantic_graph/nodes/42/application_node_ids/0 (custom)",
+      },
+    });
+  });
+
   it("retains unexpected failures and their input identity in caller-visible diagnostics", async () => {
     const inputPath = await createTestTempDirectory("rea-js-failure-");
     await writeFile(join(inputPath, "main.js"), "export const value = 1;\n");
diff --git a/src/application/JavaScriptApplicationService.ts b/src/application/JavaScriptApplicationService.ts
index b2389cb68..b47b6ed5e 100644
--- a/src/application/JavaScriptApplicationService.ts
+++ b/src/application/JavaScriptApplicationService.ts
@@ -7,7 +7,7 @@ import {
 } from "../domain/javascriptApplicationAnalysis.js";
 import {
   AnalysisInputError,
-  AnalysisProtocolError,
+  AnalysisOutputError,
 } from "../domain/analysisErrorCore.js";
 import { ArtifactOperationError } from "../domain/artifactOperationError.js";
 import { type AnalysisError } from "../domain/analysisErrorBase.js";
@@ -79,10 +79,9 @@ export const analyzeJavaScriptApplicationValidated = async (
       );
     if (cause instanceof z.ZodError)
       return err(
-        new AnalysisProtocolError(
-          "JavaScript application analysis produced an invalid result",
-          { cause },
-        ),
+        new AnalysisOutputError(OPERATION, describeResultSchemaFailure(cause), {
+          cause,
+        }),
       );
     if (
       cause instanceof Error &&
@@ -109,6 +108,22 @@ export const analyzeJavaScriptApplicationValidated = async (
   }
 };
 
+const describeResultSchemaFailure = (cause: z.ZodError): string => {
+  const issue = cause.issues[0];
+  if (issue === undefined) return "Result schema rejected an unknown issue";
+  const path = issue.path.flatMap((part) =>
+    typeof part === "string" || typeof part === "number" ? [part] : [],
+  );
+  const pointer =
+    path.length === 0
+      ? "/"
+      : `/${path.map((part) => escapePointerPart(String(part))).join("/")}`;
+  return `Result schema rejected ${String(cause.issues.length)} ${cause.issues.length === 1 ? "issue" : "issues"} at ${pointer} (${issue.code})`;
+};
+
+const escapePointerPart = (part: string): string =>
+  part.replaceAll("~", "~0").replaceAll("/", "~1");
+
 const FILESYSTEM_ERROR_CODES = new Set([
   "ENOENT",
   "EACCES",