diff --git a/packages/producer/src/renderRequest.test.ts b/packages/producer/src/renderRequest.test.ts
index 55d84b342..e7926b89b 100644
--- a/packages/producer/src/renderRequest.test.ts
+++ b/packages/producer/src/renderRequest.test.ts
@@ -25,6 +25,7 @@ function request() {
       fps: { num: 30, den: 1 },
       quality: "high",
       format: "mp4",
+      gifLoop: 0,
       workers: 3,
       useGpu: true,
       strictness: "best-effort",
@@ -72,9 +73,12 @@ describe("RenderRequest", () => {
       height: 1080,
       format: "mp4",
       chunkSize: 120,
+      strictness: "best-effort",
+      outputResolutionAspectAgnostic: true,
       variables: value.options.variables,
-      producerConfig: { protocolTimeout: 123_456 },
+      engineConfig: { protocolTimeout: 123_456 },
     });
+    expect(distributed).not.toHaveProperty("producerConfig");
   });
 
   it("round-trips distributed adapter fields back into the shared request", () => {
@@ -90,6 +94,12 @@ describe("RenderRequest", () => {
       fps: value.options.fps,
       quality: value.options.quality,
       format: value.options.format,
+      crf: value.options.crf,
+      videoFrameFormat: value.options.videoFrameFormat,
+      outputResolution: value.options.outputResolution,
+      outputResolutionAspectAgnostic: value.options.outputResolutionAspectAgnostic,
+      hdrMode: value.options.hdrMode,
+      strictness: value.options.strictness,
       entryFile: value.options.entryFile,
       variables: value.options.variables,
       distributed: value.options.distributed,
@@ -114,4 +124,50 @@ describe("RenderRequest", () => {
     value.options.fps = { num: 30_000, den: 1_001 };
     expect(() => distributedConfigFromRequest(value)).toThrow("does not support fps");
   });
+
+  it("rejects JSON-unsafe request values before serialization", () => {
+    const cyclic: Record<string, unknown> = {};
+    cyclic.self = cyclic;
+    for (const variables of [
+      { missing: undefined },
+      { callback: () => undefined },
+      { identifier: 1n },
+      { ratio: Number.NaN },
+      { when: new Date(0) },
+      cyclic,
+    ]) {
+      expect(() =>
+        createRenderRequest({
+          projectDir: "/project",
+          outputPath: "/output/video.mp4",
+          options: { fps: { num: 30, den: 1 }, quality: "standard", format: "mp4", variables },
+        }),
+      ).toThrow();
+    }
+  });
+
+  it("rejects malformed optional and distributed fields", () => {
+    const value = request();
+    expect(() =>
+      parseRenderRequest({ ...value, options: { ...value.options, workers: "many" } }),
+    ).toThrow("workers");
+    expect(() =>
+      parseRenderRequest({
+        ...value,
+        options: { ...value.options, distributed: { ...value.options.distributed, width: "wide" } },
+      }),
+    ).toThrow("distributed.width");
+  });
+
+  it("validates the reverse distributed adapter at the wire boundary", () => {
+    const distributed = distributedConfigFromRequest(request());
+    distributed.width = 1921;
+    expect(() =>
+      renderRequestFromDistributedConfig({
+        projectDir: "/project",
+        outputPath: "/output/video.mp4",
+        config: distributed,
+      }),
+    ).toThrow("must be even");
+  });
 });
diff --git a/packages/producer/src/renderRequest.ts b/packages/producer/src/renderRequest.ts
index a686835f2..ef45e38cf 100644
--- a/packages/producer/src/renderRequest.ts
+++ b/packages/producer/src/renderRequest.ts
@@ -1,9 +1,18 @@
-import { resolveConfig, type EngineConfig, type VideoFrameFormat } from "@hyperframes/engine";
-import type { CanvasResolution, Fps } from "@hyperframes/core";
+import {
+  isVideoFrameFormat,
+  resolveConfig,
+  type EngineConfig,
+  type VideoFrameFormat,
+} from "@hyperframes/engine";
+import { VALID_CANVAS_RESOLUTIONS, type CanvasResolution, type Fps } from "@hyperframes/core";
 import type { ProducerLogger } from "./logger.js";
 import type { RenderConfig } from "./services/renderOrchestrator.js";
 import type { DistributedRenderConfig } from "./services/distributed/plan.js";
-import type { SerializableDistributedRenderConfig } from "./services/distributed/renderConfigValidation.js";
+import {
+  validateDistributedRenderConfig,
+  validateJsonSafeValue,
+  type SerializableDistributedRenderConfig,
+} from "./services/distributed/renderConfigValidation.js";
 
 export const RENDER_REQUEST_VERSION = 1 as const;
 
@@ -59,22 +68,123 @@ export interface CreateRenderRequestInput {
 }
 
 function isPlainObject(value: unknown): value is Record<string, unknown> {
-  return typeof value === "object" && value !== null && !Array.isArray(value);
+  if (typeof value !== "object" || value === null || Array.isArray(value)) return false;
+  const proto = Object.getPrototypeOf(value);
+  return proto === Object.prototype || proto === null;
 }
 
 function assertPositiveFps(options: Record<string, unknown>): void {
   const fps = options.fps;
   if (
     !isPlainObject(fps) ||
+    typeof fps.num !== "number" ||
+    typeof fps.den !== "number" ||
     !Number.isInteger(fps.num) ||
     !Number.isInteger(fps.den) ||
-    (fps.num as number) <= 0 ||
-    (fps.den as number) <= 0
+    fps.num <= 0 ||
+    fps.den <= 0
   ) {
     throw new Error("Render request fps must be a positive rational");
   }
 }
 
+function assertOptionalBoolean(options: Record<string, unknown>, field: string): void {
+  if (options[field] !== undefined && typeof options[field] !== "boolean") {
+    throw new Error(`Render request ${field} must be a boolean`);
+  }
+}
+
+function assertOptionalInteger(options: Record<string, unknown>, field: string, min = 0): void {
+  const value = options[field];
+  if (
+    value !== undefined &&
+    (typeof value !== "number" || !Number.isInteger(value) || value < min)
+  ) {
+    throw new Error(`Render request ${field} must be an integer >= ${min}`);
+  }
+}
+
+function assertOptionalString(options: Record<string, unknown>, field: string): void {
+  if (options[field] !== undefined && typeof options[field] !== "string") {
+    throw new Error(`Render request ${field} must be a string`);
+  }
+}
+
+function assertOptionalEnum(
+  options: Record<string, unknown>,
+  field: string,
+  allowed: readonly string[],
+): void {
+  const value = options[field];
+  if (value !== undefined && (typeof value !== "string" || !allowed.includes(value))) {
+    throw new Error(`Render request ${field} is invalid`);
+  }
+}
+
+function isCanvasResolution(value: unknown): value is CanvasResolution {
+  return (
+    typeof value === "string" && VALID_CANVAS_RESOLUTIONS.some((resolution) => resolution === value)
+  );
+}
+
+function assertDistributedOptions(value: unknown): void {
+  if (!isPlainObject(value)) throw new Error("Render request distributed must be an object");
+  for (const field of ["width", "height"] as const) {
+    if (typeof value[field] !== "number" || !Number.isInteger(value[field]) || value[field] <= 0) {
+      throw new Error(`Render request distributed.${field} must be a positive integer`);
+    }
+  }
+  assertOptionalEnum(value, "codec", ["h264", "h265"]);
+  for (const field of [
+    "chunkSize",
+    "maxParallelChunks",
+    "targetChunkFrames",
+    "planDirSizeLimitBytes",
+  ] as const) {
+    assertOptionalInteger(value, field, 1);
+  }
+  assertOptionalEnum(value, "runtimeCap", [
+    "lambda",
+    "temporal",
+    "cloud-run-job",
+    "k8s-job",
+    "none",
+  ]);
+  for (const field of ["rejectOnSystemFonts", "failClosedFontFetch", "cfr"] as const) {
+    assertOptionalBoolean(value, field);
+  }
+}
+
+function assertRequestOptionScalars(options: Record<string, unknown>): void {
+  assertOptionalInteger(options, "gifLoop");
+  assertOptionalInteger(options, "workers", 1);
+  assertOptionalInteger(options, "crf");
+  for (const field of ["useGpu", "debug", "outputResolutionAspectAgnostic"] as const) {
+    assertOptionalBoolean(options, field);
+  }
+  for (const field of ["entryFile", "videoBitrate"] as const) {
+    assertOptionalString(options, field);
+  }
+  assertOptionalEnum(options, "strictness", ["strict", "best-effort"]);
+  assertOptionalEnum(options, "hdrMode", ["auto", "force-hdr", "force-sdr"]);
+  if (options.videoFrameFormat !== undefined && !isVideoFrameFormat(options.videoFrameFormat)) {
+    throw new Error("Render request videoFrameFormat is invalid");
+  }
+  if (options.outputResolution !== undefined && !isCanvasResolution(options.outputResolution)) {
+    throw new Error("Render request outputResolution is invalid");
+  }
+}
+
+function assertRequestOptionObjects(options: Record<string, unknown>): void {
+  if (!isPlainObject(options.engineConfig)) {
+    throw new Error("Render request must contain a resolved engineConfig snapshot");
+  }
+  if (options.variables !== undefined && !isPlainObject(options.variables)) {
+    throw new Error("Render request variables must be a JSON object");
+  }
+  if (options.distributed !== undefined) assertDistributedOptions(options.distributed);
+}
+
 function assertRequestOptions(options: unknown): asserts options is RenderRequestOptions {
   if (!isPlainObject(options)) throw new Error("Render request options must be an object");
   assertPositiveFps(options);
@@ -84,12 +194,8 @@ function assertRequestOptions(options: unknown): asserts options is RenderReques
   if (!["mp4", "webm", "mov", "png-sequence", "gif"].includes(String(options.format))) {
     throw new Error("Render request format is invalid");
   }
-  if (!isPlainObject(options.engineConfig)) {
-    throw new Error("Render request must contain a resolved engineConfig snapshot");
-  }
-  if (options.variables !== undefined && !isPlainObject(options.variables)) {
-    throw new Error("Render request variables must be a JSON object");
-  }
+  assertRequestOptionScalars(options);
+  assertRequestOptionObjects(options);
 }
 
 function assertNonEmptyPath(value: unknown, field: "projectDir" | "outputPath"): void {
@@ -106,6 +212,7 @@ function assertRenderRequest(value: unknown): asserts value is RenderRequest {
   assertNonEmptyPath(value.projectDir, "projectDir");
   assertNonEmptyPath(value.outputPath, "outputPath");
   assertRequestOptions(value.options);
+  validateJsonSafeValue(value, "renderRequest");
 }
 
 export function parseRenderRequest(serialized: string | unknown): RenderRequest {
@@ -129,9 +236,9 @@ export function createRenderRequest(input: CreateRenderRequestInput): RenderRequ
       engineConfig: input.engineConfig ?? resolveConfig(input.engineOverrides),
     },
   } satisfies RenderRequest;
-  // A JSON round-trip both proves serializability and detaches caller-owned
-  // variables/config objects before asynchronous adapters receive them.
-  return parseRenderRequest(JSON.stringify(request));
+  // Validate before serialization so JSON never silently drops or normalizes
+  // caller data at this boundary, then detach it for asynchronous adapters.
+  return parseRenderRequest(serializeRenderRequest(request));
 }
 
 export function renderConfigFromRequest(
@@ -173,6 +280,7 @@ export function distributedConfigFromRequest(
     bitrate: options.videoBitrate,
     videoFrameFormat: options.videoFrameFormat,
     outputResolution: options.outputResolution,
+    outputResolutionAspectAgnostic: options.outputResolutionAspectAgnostic,
     chunkSize: distributed.chunkSize,
     maxParallelChunks: distributed.maxParallelChunks,
     targetChunkFrames: distributed.targetChunkFrames,
@@ -182,49 +290,61 @@ export function distributedConfigFromRequest(
     hdrMode: options.hdrMode === "auto" ? "auto" : "force-sdr",
     cfr: distributed.cfr,
     logger: runtime.logger,
-    producerConfig: options.engineConfig,
     engineConfig: options.engineConfig,
     entryFile: options.entryFile,
+    strictness: options.strictness,
     abortSignal: runtime.abortSignal,
     planDirSizeLimitBytes: distributed.planDirSizeLimitBytes,
     variables: options.variables,
   };
 }
 
+function optionalProperty<Key extends string, Value>(
+  key: Key,
+  value: Value | undefined,
+): Partial<Record<Key, Value>> {
+  return value === undefined ? {} : ({ [key]: value } as Partial<Record<Key, Value>>);
+}
+
 export function renderRequestFromDistributedConfig(input: {
   projectDir: string;
   outputPath: string;
   config: SerializableDistributedRenderConfig;
 }): RenderRequest {
   const { config } = input;
+  validateDistributedRenderConfig(config);
+  const distributed = {
+    width: config.width,
+    height: config.height,
+    ...optionalProperty("codec", config.codec),
+    ...optionalProperty("chunkSize", config.chunkSize),
+    ...optionalProperty("maxParallelChunks", config.maxParallelChunks),
+    ...optionalProperty("targetChunkFrames", config.targetChunkFrames),
+    ...optionalProperty("runtimeCap", config.runtimeCap),
+    ...optionalProperty("rejectOnSystemFonts", config.rejectOnSystemFonts),
+    ...optionalProperty("failClosedFontFetch", config.failClosedFontFetch),
+    ...optionalProperty("cfr", config.cfr),
+    ...optionalProperty("planDirSizeLimitBytes", config.planDirSizeLimitBytes),
+  } satisfies DistributedRenderOptions;
+  const options = {
+    fps: { num: config.fps, den: 1 },
+    quality: config.quality ?? "standard",
+    format: config.format,
+    distributed,
+    ...optionalProperty("crf", config.crf),
+    ...optionalProperty("videoBitrate", config.bitrate),
+    ...optionalProperty("videoFrameFormat", config.videoFrameFormat),
+    ...optionalProperty("outputResolution", config.outputResolution),
+    ...optionalProperty("outputResolutionAspectAgnostic", config.outputResolutionAspectAgnostic),
+    ...optionalProperty("hdrMode", config.hdrMode),
+    ...optionalProperty("strictness", config.strictness),
+    ...optionalProperty("entryFile", config.entryFile),
+    ...optionalProperty("variables", config.variables),
+  } satisfies CreateRenderRequestInput["options"];
   return createRenderRequest({
     projectDir: input.projectDir,
     outputPath: input.outputPath,
     engineConfig: config.engineConfig ?? resolveConfig(),
-    options: {
-      fps: { num: config.fps, den: 1 },
-      quality: config.quality ?? "standard",
-      format: config.format,
-      crf: config.crf,
-      videoBitrate: config.bitrate,
-      videoFrameFormat: config.videoFrameFormat,
-      outputResolution: config.outputResolution,
-      hdrMode: config.hdrMode ?? "force-sdr",
-      entryFile: config.entryFile,
-      variables: config.variables,
-      distributed: {
-        width: config.width,
-        height: config.height,
-        codec: config.codec,
-        chunkSize: config.chunkSize,
-        maxParallelChunks: config.maxParallelChunks,
-        targetChunkFrames: config.targetChunkFrames,
-        runtimeCap: config.runtimeCap,
-        rejectOnSystemFonts: config.rejectOnSystemFonts,
-        failClosedFontFetch: config.failClosedFontFetch,
-        cfr: config.cfr,
-        planDirSizeLimitBytes: config.planDirSizeLimitBytes,
-      },
-    },
+    options,
   });
 }
diff --git a/packages/producer/src/services/distributed/renderConfigValidation.ts b/packages/producer/src/services/distributed/renderConfigValidation.ts
index 0d3168566..fbbf63b4c 100644
--- a/packages/producer/src/services/distributed/renderConfigValidation.ts
+++ b/packages/producer/src/services/distributed/renderConfigValidation.ts
@@ -229,7 +229,12 @@ export function validateVariablesPayload(value: unknown): void {
       `must be a plain JSON object (got ${describeValue(value)})`,
     );
   }
-  walkVariables(value, "config.variables", new WeakSet());
+  validateJsonSafeValue(value, "config.variables");
+}
+
+/** Validate any JSON-boundary value without silently normalizing it. */
+export function validateJsonSafeValue(value: unknown, field: string): void {
+  walkVariables(value, field, new WeakSet());
 }
 
 /** Per-typeof rejection messages for JSON-unsafe leaves. */