diff --git a/apps/server/src/diagnostics/ProcessDiagnostics.test.ts b/apps/server/src/diagnostics/ProcessDiagnostics.test.ts
index 7d16a11c829..54f486faee8 100644
--- a/apps/server/src/diagnostics/ProcessDiagnostics.test.ts
+++ b/apps/server/src/diagnostics/ProcessDiagnostics.test.ts
@@ -1,8 +1,9 @@
-import { describe, expect, it } from "@effect/vitest";
+import { assert, describe, it } from "@effect/vitest";
 import * as DateTime from "effect/DateTime";
 import * as Effect from "effect/Effect";
 import * as Layer from "effect/Layer";
 import * as Option from "effect/Option";
+import * as Schema from "effect/Schema";
 import * as Sink from "effect/Sink";
 import * as Stream from "effect/Stream";
 import { ChildProcessSpawner } from "effect/unstable/process";
@@ -11,6 +12,7 @@ import { HostProcessPlatform } from "@t3tools/shared/hostProcess";
 import * as ProcessDiagnostics from "./ProcessDiagnostics.ts";
 
 const encoder = new TextEncoder();
+const encodeUnknownJson = Schema.encodeUnknownSync(Schema.UnknownFromJsonString);
 
 function mockHandle(result: {
   readonly stdout?: string;
@@ -42,7 +44,7 @@ describe("ProcessDiagnostics", () => {
         ].join("\n"),
       );
 
-      expect(rows).toEqual([
+      assert.deepStrictEqual(rows, [
         {
           pid: 10,
           ppid: 1,
@@ -126,15 +128,21 @@ describe("ProcessDiagnostics", () => {
         ],
       });
 
-      expect(diagnostics.serverPid).toBe(100);
-      expect(DateTime.formatIso(diagnostics.readAt)).toBe("2026-05-05T10:00:00.000Z");
-      expect(diagnostics.processCount).toBe(2);
-      expect(diagnostics.totalRssBytes).toBe(6_000);
-      expect(diagnostics.totalCpuPercent).toBe(4.75);
-      expect(diagnostics.processes.map((process) => process.pid)).toEqual([101, 102]);
-      expect(diagnostics.processes.map((process) => process.depth)).toEqual([0, 1]);
-      expect(Option.getOrNull(diagnostics.processes[0]!.pgid)).toBe(100);
-      expect(diagnostics.processes[0]?.childPids).toEqual([102]);
+      assert.equal(diagnostics.serverPid, 100);
+      assert.equal(DateTime.formatIso(diagnostics.readAt), "2026-05-05T10:00:00.000Z");
+      assert.equal(diagnostics.processCount, 2);
+      assert.equal(diagnostics.totalRssBytes, 6_000);
+      assert.equal(diagnostics.totalCpuPercent, 4.75);
+      assert.deepStrictEqual(
+        diagnostics.processes.map((process) => process.pid),
+        [101, 102],
+      );
+      assert.deepStrictEqual(
+        diagnostics.processes.map((process) => process.depth),
+        [0, 1],
+      );
+      assert.equal(Option.getOrNull(diagnostics.processes[0]!.pgid), 100);
+      assert.deepStrictEqual(diagnostics.processes[0]?.childPids, [102]);
     }),
   );
 
@@ -177,7 +185,10 @@ describe("ProcessDiagnostics", () => {
         ],
       });
 
-      expect(diagnostics.processes.map((process) => process.pid)).toEqual([101, 102, 103]);
+      assert.deepStrictEqual(
+        diagnostics.processes.map((process) => process.pid),
+        [101, 102, 103],
+      );
     }),
   );
 
@@ -210,8 +221,11 @@ describe("ProcessDiagnostics", () => {
         Effect.provide(layer),
       );
 
-      expect(diagnostics.processes.map((process) => process.pid)).toEqual([4242]);
-      expect(commands).toEqual([
+      assert.deepStrictEqual(
+        diagnostics.processes.map((process) => process.pid),
+        [4242],
+      );
+      assert.deepStrictEqual(commands, [
         {
           command: "ps",
           args: ["-axo", "pid=,ppid=,pgid=,stat=,pcpu=,rss=,etime=,command="],
@@ -241,23 +255,129 @@ describe("ProcessDiagnostics", () => {
         Effect.flip,
       );
 
-      expect(error).toMatchObject({
-        _tag: "ProcessDiagnosticsQueryFailedError",
-        command: "ps",
-        argCount: 2,
-        cwd: process.cwd(),
-        exitCode: 17,
-        stdoutBytes: 22,
-        stderrBytes: 21,
-        stdoutTruncated: false,
-        stderrTruncated: false,
-      });
-      expect(error.message).toBe(
+      if (error._tag !== "ProcessDiagnosticsQueryFailedError") {
+        assert.fail(`Expected ProcessDiagnosticsQueryFailedError, got ${error._tag}`);
+      }
+      assert.deepStrictEqual(
+        {
+          command: error.command,
+          argCount: error.argCount,
+          cwd: error.cwd,
+          exitCode: error.exitCode,
+          stdoutBytes: error.stdoutBytes,
+          stderrBytes: error.stderrBytes,
+          stdoutTruncated: error.stdoutTruncated,
+          stderrTruncated: error.stderrTruncated,
+        },
+        {
+          command: "ps",
+          argCount: 2,
+          cwd: process.cwd(),
+          exitCode: 17,
+          stdoutBytes: 22,
+          stderrBytes: 21,
+          stdoutTruncated: false,
+          stderrTruncated: false,
+        },
+      );
+      assert.equal(
+        error.message,
         `Process diagnostics query 'ps' failed with exit code 17 in '${process.cwd()}'.`,
       );
     }),
   );
 
+  it.effect("decodes Windows process JSON through Schema and skips invalid records", () =>
+    Effect.gen(function* () {
+      const commands: Array<{ readonly command: string; readonly args: ReadonlyArray<string> }> =
+        [];
+      const spawnerLayer = Layer.succeed(
+        ChildProcessSpawner.ChildProcessSpawner,
+        ChildProcessSpawner.make((command) => {
+          const childProcess = command as unknown as {
+            readonly command: string;
+            readonly args: ReadonlyArray<string>;
+          };
+          commands.push({ command: childProcess.command, args: childProcess.args });
+          return Effect.succeed(
+            mockHandle({
+              stdout: encodeUnknownJson([
+                {
+                  ProcessId: process.pid,
+                  ParentProcessId: 1,
+                  Name: "node.exe",
+                  CommandLine: "t3 server",
+                  Status: "",
+                  WorkingSetSize: 1024,
+                  PercentProcessorTime: 0,
+                },
+                {
+                  ProcessId: 4242,
+                  ParentProcessId: process.pid,
+                  Name: "agent.exe",
+                  CommandLine: null,
+                  Status: "Running",
+                  WorkingSetSize: 2048.6,
+                  PercentProcessorTime: 1.25,
+                },
+                {
+                  ProcessId: "invalid",
+                  ParentProcessId: process.pid,
+                  Name: "bad.exe",
+                },
+              ]),
+            }),
+          );
+        }),
+      );
+
+      const rows = yield* ProcessDiagnostics.readProcessRows.pipe(
+        Effect.provide(spawnerLayer),
+        Effect.provideService(HostProcessPlatform, "win32"),
+      );
+
+      assert.deepStrictEqual(commands, [
+        {
+          command: "powershell.exe",
+          args: [
+            "-NoProfile",
+            "-NonInteractive",
+            "-Command",
+            [
+              "$processes = Get-CimInstance Win32_Process | ForEach-Object {",
+              '$perf = Get-CimInstance Win32_PerfFormattedData_PerfProc_Process -Filter "IDProcess = $($_.ProcessId)" -ErrorAction SilentlyContinue;',
+              "[pscustomobject]@{ ProcessId = $_.ProcessId; ParentProcessId = $_.ParentProcessId; Name = $_.Name; CommandLine = $_.CommandLine; Status = $_.Status; WorkingSetSize = $_.WorkingSetSize; PercentProcessorTime = if ($perf) { $perf.PercentProcessorTime } else { 0 } }",
+              "};",
+              "$processes | ConvertTo-Json -Compress -Depth 3",
+            ].join(" "),
+          ],
+        },
+      ]);
+      assert.deepStrictEqual(rows, [
+        {
+          pid: process.pid,
+          ppid: 1,
+          pgid: null,
+          status: "Live",
+          cpuPercent: 0,
+          rssBytes: 1024,
+          elapsed: "",
+          command: "t3 server",
+        },
+        {
+          pid: 4242,
+          ppid: process.pid,
+          pgid: null,
+          status: "Running",
+          cpuPercent: 1.25,
+          rssBytes: 2049,
+          elapsed: "",
+          command: "agent.exe",
+        },
+      ]);
+    }),
+  );
+
   it.effect("does not allow signaling the diagnostics query process", () =>
     Effect.gen(function* () {
       const spawnerLayer = Layer.succeed(
@@ -280,7 +400,7 @@ describe("ProcessDiagnostics", () => {
         Effect.provide(layer),
       );
 
-      expect(result).toEqual({
+      assert.deepStrictEqual(result, {
         pid: 4242,
         signal: "SIGINT",
         signaled: false,
diff --git a/apps/server/src/diagnostics/ProcessDiagnostics.ts b/apps/server/src/diagnostics/ProcessDiagnostics.ts
index b39d560a228..b0a91eb3034 100644
--- a/apps/server/src/diagnostics/ProcessDiagnostics.ts
+++ b/apps/server/src/diagnostics/ProcessDiagnostics.ts
@@ -28,9 +28,22 @@ export interface ProcessRow {
   readonly command: string;
 }
 
-const PROCESS_QUERY_TIMEOUT_MS = 1_000;
+const PROCESS_QUERY_TIMEOUT = Duration.seconds(1);
 const POSIX_PROCESS_QUERY_COMMAND = "pid=,ppid=,pgid=,stat=,pcpu=,rss=,etime=,command=";
 const PROCESS_QUERY_MAX_OUTPUT_BYTES = 2 * 1024 * 1024;
+const WindowsProcessJson = Schema.fromJsonString(Schema.Unknown);
+const WindowsProcessRecord = Schema.Struct({
+  ProcessId: Schema.Number,
+  ParentProcessId: Schema.Number,
+  CommandLine: Schema.optional(Schema.OptionFromNullOr(Schema.String)),
+  Name: Schema.optional(Schema.OptionFromNullOr(Schema.String)),
+  Status: Schema.optional(Schema.OptionFromNullOr(Schema.String)),
+  WorkingSetSize: Schema.optional(Schema.OptionFromNullOr(Schema.Number)),
+  PercentProcessorTime: Schema.optional(Schema.OptionFromNullOr(Schema.Number)),
+});
+type WindowsProcessRecord = typeof WindowsProcessRecord.Type;
+const decodeWindowsProcessJson = Schema.decodeUnknownOption(WindowsProcessJson);
+const decodeWindowsProcessRecord = Schema.decodeUnknownOption(WindowsProcessRecord);
 
 export class ProcessDiagnostics extends Context.Service<
   ProcessDiagnostics,
@@ -201,51 +214,72 @@ export function parsePosixProcessRows(output: string): ReadonlyArray<ProcessRow>
   return rows;
 }
 
-function normalizeWindowsProcessRow(value: unknown): ProcessRow | null {
-  if (typeof value !== "object" || value === null) return null;
-  const record = value as Record<string, unknown>;
-  const pid = typeof record.ProcessId === "number" ? record.ProcessId : null;
-  const ppid = typeof record.ParentProcessId === "number" ? record.ParentProcessId : null;
-  const commandLine =
-    typeof record.CommandLine === "string" && record.CommandLine.trim().length > 0
-      ? record.CommandLine
-      : typeof record.Name === "string"
-        ? record.Name
-        : null;
-  const workingSet =
-    typeof record.WorkingSetSize === "number" && Number.isFinite(record.WorkingSetSize)
-      ? Math.max(0, Math.round(record.WorkingSetSize))
-      : 0;
-  const cpuPercent =
-    typeof record.PercentProcessorTime === "number" && Number.isFinite(record.PercentProcessorTime)
-      ? Math.max(0, record.PercentProcessorTime)
-      : 0;
-
-  if (!pid || pid <= 0 || ppid === null || ppid < 0 || !commandLine) return null;
-  return {
-    pid,
-    ppid,
+function optionFromOptional<T>(value: Option.Option<T> | undefined): Option.Option<T> {
+  return value ?? Option.none();
+}
+
+function nonEmptyString(value: Option.Option<string> | undefined): Option.Option<string> {
+  return optionFromOptional(value).pipe(Option.filter((text) => text.trim().length > 0));
+}
+
+function optionalNumberOrElse(
+  value: Option.Option<number> | undefined,
+  onSome: (value: number) => number,
+): number {
+  return Option.match(optionFromOptional(value), {
+    onNone: () => 0,
+    onSome,
+  });
+}
+
+function normalizeWindowsProcessRecord(record: WindowsProcessRecord): Option.Option<ProcessRow> {
+  if (
+    !Number.isInteger(record.ProcessId) ||
+    record.ProcessId <= 0 ||
+    !Number.isInteger(record.ParentProcessId) ||
+    record.ParentProcessId < 0
+  ) {
+    return Option.none();
+  }
+
+  const commandLine = nonEmptyString(record.CommandLine).pipe(
+    Option.orElse(() => nonEmptyString(record.Name)),
+  );
+  if (Option.isNone(commandLine)) return Option.none();
+
+  return Option.some({
+    pid: record.ProcessId,
+    ppid: record.ParentProcessId,
     pgid: null,
-    status: typeof record.Status === "string" && record.Status.length > 0 ? record.Status : "Live",
-    cpuPercent,
-    rssBytes: workingSet,
+    status: Option.getOrElse(nonEmptyString(record.Status), () => "Live"),
+    cpuPercent: optionalNumberOrElse(record.PercentProcessorTime, (value) => Math.max(0, value)),
+    rssBytes: optionalNumberOrElse(record.WorkingSetSize, (value) =>
+      Math.max(0, Math.round(value)),
+    ),
     elapsed: "",
-    command: commandLine,
-  };
+    command: commandLine.value,
+  });
+}
+
+function normalizeWindowsProcessRow(value: unknown): Option.Option<ProcessRow> {
+  return Option.match(decodeWindowsProcessRecord(value), {
+    onNone: () => Option.none(),
+    onSome: normalizeWindowsProcessRecord,
+  });
 }
 
 function parseWindowsProcessRows(output: string): ReadonlyArray<ProcessRow> {
   if (output.trim().length === 0) return [];
-  try {
-    const parsed = JSON.parse(output) as unknown;
-    const records = Array.isArray(parsed) ? parsed : [parsed];
-    return records.flatMap((record) => {
-      const row = normalizeWindowsProcessRow(record);
-      return row ? [row] : [];
-    });
-  } catch {
-    return [];
-  }
+  return Option.match(decodeWindowsProcessJson(output), {
+    onNone: () => [],
+    onSome: (parsed) =>
+      (Array.isArray(parsed) ? parsed : [parsed]).flatMap((record) =>
+        Option.match(normalizeWindowsProcessRow(record), {
+          onNone: () => [],
+          onSome: (row) => [row],
+        }),
+      ),
+  });
 }
 
 export function buildDescendantEntries(
@@ -381,7 +415,7 @@ const runProcess = Effect.fn("runProcess")(function* (input: {
     } satisfies ProcessOutput;
   }).pipe(
     Effect.scoped,
-    Effect.timeoutOption(Duration.millis(PROCESS_QUERY_TIMEOUT_MS)),
+    Effect.timeoutOption(PROCESS_QUERY_TIMEOUT),
     Effect.flatMap((result) =>
       Option.match(result, {
         onNone: () =>
@@ -390,7 +424,7 @@ const runProcess = Effect.fn("runProcess")(function* (input: {
               command: input.command,
               argCount: input.args.length,
               cwd,
-              timeoutMillis: PROCESS_QUERY_TIMEOUT_MS,
+              timeoutMillis: Duration.toMillis(PROCESS_QUERY_TIMEOUT),
             }),
           ),
         onSome: Effect.succeed,