diff --git a/src/cliJsonInput.ts b/src/cliJsonInput.ts
index 44199b79e..8bb2d105a 100644
--- a/src/cliJsonInput.ts
+++ b/src/cliJsonInput.ts
@@ -37,9 +37,9 @@ export const parseCliJsonInput = async (
 /**
  * Resolve named string fields of CLI-supplied JSON against the operator
  * working directory. Each entry is a key path from the document root; only
- * fields holding strings are resolved, everything else passes through
- * untouched. Shared MCP contracts reject relative paths, so CLI workflows
- * resolve operator-relative values before validation.
+ * fields holding nonblank strings are resolved, everything else passes through
+ * untouched so shared schemas can reject blank paths. Shared MCP contracts reject
+ * relative paths, so CLI workflows resolve operator-relative values before validation.
  */
 export const resolveCliJsonPaths = (
   value: unknown,
@@ -61,7 +61,12 @@ const resolveJsonPath = (
     ([key, entry]: readonly [string, unknown]): readonly [string, unknown] => {
       if (key !== head) return [key, entry];
       if (tail.length === 0)
-        return [key, typeof entry === "string" ? resolve(entry) : entry];
+        return [
+          key,
+          typeof entry === "string" && entry.trim().length > 0
+            ? resolve(entry)
+            : entry,
+        ];
       return [key, resolveJsonPath(entry, tail)];
     },
   );
diff --git a/src/cliJsonPaths.test.ts b/src/cliJsonPaths.test.ts
new file mode 100644
index 000000000..936bfacea
--- /dev/null
+++ b/src/cliJsonPaths.test.ts
@@ -0,0 +1,59 @@
+import { resolve } from "node:path";
+
+import { describe, expect, it } from "vitest";
+
+import { resolveCliJsonPaths } from "./cliJsonInput.js";
+import { electronActiveObservationInputSchema } from "./domain/javascript/electronActiveObservation.js";
+
+const paths = [
+  ["executable_path"],
+  ["application_path"],
+  ["application_root"],
+] as const;
+
+describe("CLI JSON path normalization", () => {
+  it.each([
+    ["executable_path", ""],
+    ["executable_path", " \t "],
+    ["application_path", ""],
+    ["application_path", " \t "],
+    ["application_root", ""],
+    ["application_root", " \t "],
+  ])(
+    "keeps blank %s (%j) invalid at the shared input boundary",
+    (field, value) => {
+      const input = {
+        executable_path: "/synthetic/electron",
+        application_path: "/synthetic/app",
+        application_root: "/synthetic",
+        [field]: value,
+      };
+      const parsed = electronActiveObservationInputSchema.safeParse(
+        resolveCliJsonPaths(input, paths),
+      );
+      expect(parsed.success).toBe(false);
+      if (parsed.success) throw new Error("Expected blank path rejection");
+      expect(parsed.error.issues).toEqual(
+        expect.arrayContaining([expect.objectContaining({ path: [field] })]),
+      );
+      expect(input).toHaveProperty(field, value);
+    },
+  );
+
+  it("resolves selected relative paths without trimming names or changing unrelated fields", () => {
+    const input = {
+      browser: { executable_path: " browser ", label: "relative-label" },
+      application_path: "app",
+    };
+    expect(
+      resolveCliJsonPaths(input, [["browser", "executable_path"]]),
+    ).toEqual({
+      browser: {
+        executable_path: resolve(" browser "),
+        label: "relative-label",
+      },
+      application_path: "app",
+    });
+    expect(input.browser.executable_path).toBe(" browser ");
+  });
+});
diff --git a/tests/acceptance/applications/electronBlankPathCli.test.ts b/tests/acceptance/applications/electronBlankPathCli.test.ts
new file mode 100644
index 000000000..f060aed34
--- /dev/null
+++ b/tests/acceptance/applications/electronBlankPathCli.test.ts
@@ -0,0 +1,32 @@
+import { expect } from "vitest";
+
+import { cliTest } from "../../support/cli/cliFixture.js";
+
+cliTest.for(["", " \t "])(
+  "rejects blank Electron application_root (%j) before filesystem or provider work",
+  async (applicationRoot, { cli }) => {
+    const response = await cli.run({
+      arguments: [
+        "capture-electron-scenario",
+        JSON.stringify({
+          executable_path: "/synthetic/missing-electron",
+          application_path: "/synthetic/missing-app",
+          application_root: applicationRoot,
+        }),
+        "--json",
+      ],
+      environment: { REA_LOG_LEVEL: "silent" },
+      timeoutMs: 15000,
+    });
+    expect(response.exitCode).toBe(1);
+    expect(response.json).toMatchObject({
+      code: "invalid_request",
+      details: {
+        operation: "capture_electron_scenario",
+        issues: expect.arrayContaining([
+          { path: ["application_root"], reason: "out_of_range", minimum: 1 },
+        ]),
+      },
+    });
+  },
+);