diff --git a/packages/core/src/dataset/validate/schemas/chatml.ts b/packages/core/src/dataset/validate/schemas/chatml.ts
index 959149e..00b4ca2 100644
--- a/packages/core/src/dataset/validate/schemas/chatml.ts
+++ b/packages/core/src/dataset/validate/schemas/chatml.ts
@@ -20,6 +20,69 @@ import type { RecordSchemaSpec } from "./types.ts";
 
 const VALID_ROLES = new Set(["system", "user", "assistant", "tool"]);
 
+/** Platform bounds for video sampling rate params (`fps` / `sample_fps`). */
+const VIDEO_FPS_MIN = 0.1;
+const VIDEO_FPS_MAX = 10;
+
+/**
+ * Validate the sampling/clipping params carried by a video content item.
+ * Mode rules (platform spec):
+ *  - path mode (video: string): `fps`, `video_start`, `video_end` allowed; `sample_fps` is not
+ *  - frame-list mode (video: string[]): `sample_fps` allowed; `fps` / `video_start` / `video_end` are not
+ * `fps` / `sample_fps` must be numbers within [0.1, 10] when present.
+ */
+function inspectVideoParams(
+  item: Record<string, unknown>,
+  isFrameList: boolean,
+  lineNo: number,
+  itemPath: string,
+): ValidationIssue[] {
+  const out: ValidationIssue[] = [];
+  const checkFpsRange = (field: "fps" | "sample_fps"): void => {
+    if (!(field in item)) return;
+    const value = item[field];
+    if (typeof value !== "number" || value < VIDEO_FPS_MIN || value > VIDEO_FPS_MAX) {
+      out.push(
+        makeIssue(
+          "error",
+          "INVALID_VIDEO_FPS",
+          `"${field}" must be a number between ${VIDEO_FPS_MIN} and ${VIDEO_FPS_MAX} (got ${JSON.stringify(value)}).`,
+          { line: lineNo, path: `${itemPath}.${field}` },
+        ),
+      );
+    }
+  };
+  checkFpsRange("fps");
+  checkFpsRange("sample_fps");
+
+  const wrongModeFields = isFrameList ? ["fps", "video_start", "video_end"] : ["sample_fps"];
+  const modeName = isFrameList ? "frame-list" : "file-path";
+  for (const field of wrongModeFields) {
+    if (field in item) {
+      out.push(
+        makeIssue(
+          "warning",
+          "VIDEO_PARAM_MODE_MISMATCH",
+          `"${field}" does not apply to ${modeName} video mode and will be ignored by the platform.`,
+          { line: lineNo, path: `${itemPath}.${field}` },
+        ),
+      );
+    }
+  }
+
+  for (const field of ["video_start", "video_end"] as const) {
+    if (field in item && !isFrameList && typeof item[field] !== "number") {
+      out.push(
+        makeIssue("error", "INVALID_VIDEO_CLIP_TIME", `"${field}" must be a number (seconds).`, {
+          line: lineNo,
+          path: `${itemPath}.${field}`,
+        }),
+      );
+    }
+  }
+  return out;
+}
+
 /**
  * Validate a content field that may be:
  *  - A plain string (legacy format)
@@ -112,19 +175,22 @@ export function inspectContentField(
             { line: lineNo, path: `${itemPath}.video` },
           ),
         );
-      } else if (Array.isArray(video)) {
-        for (let frameIdx = 0; frameIdx < video.length; frameIdx++) {
-          if (typeof video[frameIdx] !== "string") {
-            out.push(
-              makeIssue(
-                "error",
-                "INVALID_VIDEO_FRAME",
-                `Video frame list item at index ${frameIdx} must be a string.`,
-                { line: lineNo, path: `${itemPath}.video[${frameIdx}]` },
-              ),
-            );
+      } else {
+        if (Array.isArray(video)) {
+          for (let frameIdx = 0; frameIdx < video.length; frameIdx++) {
+            if (typeof video[frameIdx] !== "string") {
+              out.push(
+                makeIssue(
+                  "error",
+                  "INVALID_VIDEO_FRAME",
+                  `Video frame list item at index ${frameIdx} must be a string.`,
+                  { line: lineNo, path: `${itemPath}.video[${frameIdx}]` },
+                ),
+              );
+            }
           }
         }
+        out.push(...inspectVideoParams(obj, Array.isArray(video), lineNo, itemPath));
       }
     }
   }
@@ -283,13 +349,13 @@ export function inspectMessageObject(
     out.push(...inspectToolCalls(record.tool_calls, lineNo, `${path}.tool_calls`));
   }
 
-  // OpenAI migration guard: name / weight are not supported by Bailian
+  // OpenAI migration guard: the platform rejects data carrying name / weight
   if ("name" in record) {
     out.push(
       makeIssue(
-        "warning",
+        "error",
         "UNSUPPORTED_FIELD_NAME",
-        `Field "name" is not supported by Bailian. Remove it when migrating from OpenAI/Azure.`,
+        `Field "name" is not supported by Bailian and must be removed when migrating from OpenAI/Azure.`,
         { line: lineNo, path: `${path}.name` },
       ),
     );
@@ -297,9 +363,10 @@ export function inspectMessageObject(
   if ("weight" in record) {
     out.push(
       makeIssue(
-        "warning",
+        "error",
         "UNSUPPORTED_FIELD_WEIGHT",
-        `Field "weight" is not supported by Bailian. Remove it when migrating from OpenAI/Azure.`,
+        `Field "weight" is not supported by Bailian and must be removed when migrating from OpenAI/Azure. ` +
+          `All assistant outputs are trained; per-line importance uses "loss_weight" (invite-only).`,
         { line: lineNo, path: `${path}.weight` },
       ),
     );
@@ -419,12 +486,15 @@ export function inspectChatMLRecord(
     );
   }
 
-  // tool_call_id correspondence: every tool response should reference a known call id
+  // tool_call_id correspondence must be one-to-one (platform spec):
+  // every tool response must reference a known call id (hard error), and every
+  // tool_call should receive a response (advisory — trailing calls are dubious
+  // in training data but we cannot rule out platform-side tolerance).
   for (const responseId of toolResponseIds) {
     if (!toolCallIds.has(responseId)) {
       out.push(
         makeIssue(
-          "warning",
+          "error",
           "TOOL_CALL_ID_UNMATCHED",
           `tool message references tool_call_id "${responseId}" which does not match any assistant tool_calls[].id.`,
           { line: lineNo, path: "messages" },
@@ -432,20 +502,37 @@ export function inspectChatMLRecord(
       );
     }
   }
+  for (const callId of toolCallIds) {
+    if (!toolResponseIds.has(callId)) {
+      out.push(
+        makeIssue(
+          "warning",
+          "TOOL_CALL_NO_RESPONSE",
+          `assistant tool_calls[].id "${callId}" has no matching tool response message.`,
+          { line: lineNo, path: "messages" },
+        ),
+      );
+    }
+  }
 
-  // thinking tag check: <think>…</think>` should only appear in the last assistant message
+  // thinking tag check: <think>…</think> should only appear in the last
+  // assistant message. Exemption (platform spec, tool+thinking combo): an
+  // assistant that carries tool_calls may legitimately hold a <think> block
+  // even when it is not the last assistant message.
   if (lastAssistantIdx >= 0) {
     for (let idx = 0; idx < messages.length; idx++) {
       if (idx === lastAssistantIdx) continue;
       const msg = messages[idx] as Record<string, unknown> | null;
       if (msg?.role !== "assistant") continue;
+      if (msg && Array.isArray(msg.tool_calls)) continue;
       const content = msg?.content;
       if (contentHasThinkTag(content)) {
         out.push(
           makeIssue(
             "warning",
             "THINK_TAG_NOT_LAST",
-            `Thinking tags (<think>…</think>) should only appear in the last assistant message, found at messages[${idx}].`,
+            `Thinking tags (<think>…</think>) should only appear in the last assistant message ` +
+              `(or an assistant message carrying tool_calls), found at messages[${idx}].`,
             { line: lineNo, path: `messages[${idx}].content` },
           ),
         );
@@ -453,39 +540,50 @@ export function inspectChatMLRecord(
     }
   }
 
-  // loss_weight validation (record-level, invite-only parameter)
-  if ("loss_weight" in record) {
-    const lossWeight = record.loss_weight;
-    if (typeof lossWeight !== "number" || lossWeight < 0 || lossWeight > 1) {
+  // loss_weight validation (invite-only parameter).
+  // Range is enforced wherever the field appears (record level and message
+  // level); placement follows the spec: only the LAST assistant message line
+  // supports loss_weight — misplaced occurrences are advisory (invite-only
+  // semantics are account-specific, so we do not hard-fail).
+  const checkLossWeightRange = (value: unknown, path: string): void => {
+    if (typeof value !== "number" || value < 0 || value > 1) {
       out.push(
         makeIssue(
           "error",
           "INVALID_LOSS_WEIGHT",
-          `"loss_weight" must be a number between 0.0 and 1.0 (got ${JSON.stringify(lossWeight)}).`,
-          { line: lineNo, path: "loss_weight" },
+          `"loss_weight" must be a number between 0.0 and 1.0 (got ${JSON.stringify(value)}).`,
+          { line: lineNo, path },
+        ),
+      );
+    }
+  };
+  if ("loss_weight" in record) {
+    checkLossWeightRange(record.loss_weight, "loss_weight");
+  }
+  for (let idx = 0; idx < messages.length; idx++) {
+    const msg = messages[idx] as Record<string, unknown> | null;
+    if (!msg || !("loss_weight" in msg)) continue;
+    checkLossWeightRange(msg.loss_weight, `messages[${idx}].loss_weight`);
+    if (!(msg.role === "assistant" && idx === lastAssistantIdx)) {
+      out.push(
+        makeIssue(
+          "warning",
+          "LOSS_WEIGHT_PLACEMENT",
+          `"loss_weight" is only supported on the last assistant message; found at messages[${idx}] (role "${String(msg.role)}").`,
+          { line: lineNo, path: `messages[${idx}].loss_weight` },
         ),
       );
     }
   }
 
-  // OpenAI migration guard at record level
-  if ("name" in record && !("messages" in record)) {
-    // Only warn at record level if it's not inside messages (messages handled above)
-    out.push(
-      makeIssue(
-        "warning",
-        "UNSUPPORTED_FIELD_NAME",
-        `Record-level field "name" is not supported by Bailian.`,
-        { line: lineNo, path: "name" },
-      ),
-    );
-  }
+  // OpenAI migration guard at record level (message-level occurrences are
+  // handled by inspectMessageObject above)
   if ("weight" in record) {
     out.push(
       makeIssue(
-        "warning",
+        "error",
         "UNSUPPORTED_FIELD_WEIGHT",
-        `Record-level field "weight" is not supported by Bailian. Remove it when migrating from OpenAI/Azure.`,
+        `Record-level field "weight" is not supported by Bailian and must be removed when migrating from OpenAI/Azure.`,
         { line: lineNo, path: "weight" },
       ),
     );
diff --git a/packages/core/src/dataset/validate/schemas/dpo.ts b/packages/core/src/dataset/validate/schemas/dpo.ts
index 26c3bcc..86de3aa 100644
--- a/packages/core/src/dataset/validate/schemas/dpo.ts
+++ b/packages/core/src/dataset/validate/schemas/dpo.ts
@@ -18,16 +18,70 @@ function inspectDPORecord(record: Record<string, unknown>, lineNo: number): Vali
   const messages = record.messages;
   if (!Array.isArray(messages) || messages.length === 0) return out;
 
-  // DPO convention: messages should end with a user message (the prompt that
-  // chosen/rejected respond to). If the last message is assistant, it's likely
-  // a structural mistake.
+  /** image / video content items are outside the DPO support matrix */
+  const mediaIssues = (content: unknown, basePath: string): ValidationIssue[] => {
+    if (!Array.isArray(content)) return [];
+    const found: ValidationIssue[] = [];
+    for (let itemIdx = 0; itemIdx < content.length; itemIdx++) {
+      const item = content[itemIdx] as Record<string, unknown> | null;
+      if (!item || typeof item !== "object") continue;
+      for (const mediaField of ["image", "video"] as const) {
+        if (mediaField in item) {
+          found.push(
+            makeIssue(
+              "error",
+              "DPO_UNSUPPORTED_ELEMENT",
+              `DPO training data does not support ${mediaField} inputs; found at ${basePath}.content[${itemIdx}].`,
+              { line: lineNo, path: `${basePath}.content[${itemIdx}].${mediaField}` },
+            ),
+          );
+        }
+      }
+    }
+    return found;
+  };
+
+  // Support matrix (platform spec): DPO is text + thinking ONLY — no image /
+  // video inputs and no tool calling. Reject multimodal items and tool fields
+  // that the SFT-oriented ChatML inspector would otherwise accept.
+  if ("tools" in record) {
+    out.push(
+      makeIssue(
+        "error",
+        "DPO_UNSUPPORTED_ELEMENT",
+        `DPO training data does not support tool calling; remove the "tools" definition.`,
+        { line: lineNo, path: "tools" },
+      ),
+    );
+  }
+  for (let idx = 0; idx < messages.length; idx++) {
+    const msg = messages[idx] as Record<string, unknown> | null;
+    if (!msg) continue;
+    const msgPath = `messages[${idx}]`;
+    if (msg.role === "tool" || "tool_calls" in msg) {
+      out.push(
+        makeIssue(
+          "error",
+          "DPO_UNSUPPORTED_ELEMENT",
+          `DPO training data does not support tool calling; found ${
+            msg.role === "tool" ? `role "tool"` : `"tool_calls"`
+          } at ${msgPath}.`,
+          { line: lineNo, path: msgPath },
+        ),
+      );
+    }
+    out.push(...mediaIssues(msg.content, msgPath));
+  }
+
+  // DPO trains the preference for the LAST user input — messages ending with
+  // any other role make the chosen/rejected pair semantically meaningless.
   const lastMsg = messages[messages.length - 1] as Record<string, unknown> | null;
   if (lastMsg && lastMsg.role !== "user") {
     out.push(
       makeIssue(
-        "warning",
+        "error",
         "DPO_LAST_MSG_NOT_USER",
-        `DPO "messages" should end with a "user" message (the prompt for chosen/rejected). ` +
+        `DPO "messages" must end with a "user" message (the prompt for chosen/rejected). ` +
           `Got "${String(lastMsg.role)}" as the last message.`,
         { line: lineNo, path: `messages[${messages.length - 1}].role` },
       ),
@@ -55,6 +109,7 @@ function inspectDPORecord(record: Record<string, unknown>, lineNo: number): Vali
   }
   if (hasChosen) {
     out.push(...inspectMessageObject(record.chosen, lineNo, "chosen"));
+    out.push(...mediaIssues((record.chosen as Record<string, unknown> | null)?.content, "chosen"));
     const role = (record.chosen as Record<string, unknown> | null)?.role;
     if (typeof role === "string" && role !== "assistant") {
       out.push(
@@ -69,6 +124,9 @@ function inspectDPORecord(record: Record<string, unknown>, lineNo: number): Vali
   }
   if (hasRejected) {
     out.push(...inspectMessageObject(record.rejected, lineNo, "rejected"));
+    out.push(
+      ...mediaIssues((record.rejected as Record<string, unknown> | null)?.content, "rejected"),
+    );
     const role = (record.rejected as Record<string, unknown> | null)?.role;
     if (typeof role === "string" && role !== "assistant") {
       out.push(
diff --git a/packages/core/src/dataset/validate/zip.ts b/packages/core/src/dataset/validate/zip.ts
index da1c362..232a5f9 100644
--- a/packages/core/src/dataset/validate/zip.ts
+++ b/packages/core/src/dataset/validate/zip.ts
@@ -108,18 +108,36 @@ function basenameNoExt(segment: string): string {
   return dot > 0 ? segment.slice(0, dot) : segment;
 }
 
+/**
+ * macOS Finder/zip metadata entries (`__MACOSX/` resource forks, `.DS_Store`,
+ * AppleDouble `._*` files). They are packaging noise, not training data:
+ * exclude them from filename constraints and media counting so Mac-created
+ * archives don't fail on artifacts the user never sees.
+ */
+function isZipMetadataEntry(entry: string): boolean {
+  if (entry === "__MACOSX" || entry.startsWith("__MACOSX/")) return true;
+  const lastSegment =
+    entry
+      .split("/")
+      .filter((segment) => segment.length > 0)
+      .pop() ?? "";
+  return lastSegment === ".DS_Store" || lastSegment.startsWith("._");
+}
+
 /**
  * Validate ZIP entry filenames against platform constraints.
  * Returns issues for charset violations, over-length names, and duplicates.
+ * Exported for direct unit testing (not re-exported by the barrel).
  */
-function validateZipFilenames(entries: string[]): ValidationIssue[] {
+export function validateZipFilenames(entries: string[]): ValidationIssue[] {
   const out: ValidationIssue[] = [];
   const seenBasenames = new Map<string, string>(); // basename (no ext) → first full path
   const MAX_REPORTED = 10;
 
   for (const entry of entries) {
-    // Skip directory entries
+    // Skip directory entries and macOS packaging metadata
     if (entry.endsWith("/")) continue;
+    if (isZipMetadataEntry(entry)) continue;
 
     // Check each path segment (folder names + file name)
     const segments = entry.split("/").filter((s) => s.length > 0);
@@ -383,6 +401,7 @@ export const zipValidator: ValidatorSpec = {
       const imageFiles = entries.filter((entry) => {
         if (entry === "data.jsonl" || entry.endsWith("/data.jsonl")) return false;
         if (entry.endsWith("/")) return false; // directory entries
+        if (isZipMetadataEntry(entry)) return false; // __MACOSX/._x.jpg is not an image
         const dot = entry.lastIndexOf(".");
         const ext = dot >= 0 ? entry.slice(dot).toLowerCase() : "";
         return IMAGE_EXTENSIONS.has(ext);
diff --git a/packages/core/tests/dataset-validate.test.ts b/packages/core/tests/dataset-validate.test.ts
index c1e67c5..b478cca 100644
--- a/packages/core/tests/dataset-validate.test.ts
+++ b/packages/core/tests/dataset-validate.test.ts
@@ -106,13 +106,41 @@ describe("validateDataset — DPO schema", () => {
     expect(r.valid).toBe(true);
   });
 
-  test("DPO messages ending with assistant → DPO_LAST_MSG_NOT_USER warning", async () => {
+  test("DPO messages ending with assistant → DPO_LAST_MSG_NOT_USER error", async () => {
     const p = file("dpo_last_asst.jsonl", [
       '{"messages":[{"role":"user","content":"hi"},{"role":"assistant","content":"yo"}],"chosen":{"role":"assistant","content":"good"},"rejected":{"role":"assistant","content":"bad"}}',
     ]);
     const r = await validateDataset(p, { fullValidate: true, schema: "dpo" });
-    expect(r.valid).toBe(true);
-    expect(codes(r).warnings).toContain("DPO_LAST_MSG_NOT_USER");
+    expect(r.valid).toBe(false);
+    expect(codes(r).errors).toContain("DPO_LAST_MSG_NOT_USER");
+  });
+
+  test("DPO with image content item → DPO_UNSUPPORTED_ELEMENT error", async () => {
+    const p = file("dpo_image.jsonl", [
+      '{"messages":[{"role":"user","content":[{"text":"look"},{"image":"a.jpg"}]}],"chosen":{"role":"assistant","content":[{"text":"good"}]},"rejected":{"role":"assistant","content":[{"text":"bad"}]}}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true, schema: "dpo" });
+    expect(r.valid).toBe(false);
+    expect(codes(r).errors).toContain("DPO_UNSUPPORTED_ELEMENT");
+  });
+
+  test("DPO with tools / tool_calls → DPO_UNSUPPORTED_ELEMENT error", async () => {
+    const p = file("dpo_tools.jsonl", [
+      '{"tools":[{"type":"function","function":{"name":"f","parameters":{}}}],"messages":[{"role":"user","content":"hi"}],"chosen":{"role":"assistant","content":"good"},"rejected":{"role":"assistant","content":"bad"}}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true, schema: "dpo" });
+    expect(r.valid).toBe(false);
+    expect(codes(r).errors).toContain("DPO_UNSUPPORTED_ELEMENT");
+  });
+
+  test("DPO chosen carrying an image item → DPO_UNSUPPORTED_ELEMENT error", async () => {
+    const p = file("dpo_chosen_image.jsonl", [
+      '{"messages":[{"role":"user","content":"hi"}],"chosen":{"role":"assistant","content":[{"text":"good"},{"image":"x.png"}]},"rejected":{"role":"assistant","content":"bad"}}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true, schema: "dpo" });
+    expect(r.valid).toBe(false);
+    const err = r.errors.find((e) => e.code === "DPO_UNSUPPORTED_ELEMENT");
+    expect(err?.path).toContain("chosen");
   });
 });
 
@@ -297,13 +325,23 @@ describe("validateDataset — tool calling (function calling)", () => {
     expect(codes(r).errors).toContain("TOOL_MISSING_CALL_ID");
   });
 
-  test("tool_call_id unmatched → TOOL_CALL_ID_UNMATCHED warning", async () => {
+  test("tool_call_id unmatched → TOOL_CALL_ID_UNMATCHED error", async () => {
     const p = file("tool_unmatched.jsonl", [
       '{"messages":[{"role":"user","content":"hi"},{"role":"assistant","content":"","tool_calls":[{"id":"c1","type":"function","function":{"name":"f","arguments":"{}"}}]},{"role":"tool","tool_call_id":"WRONG_ID","content":"result"},{"role":"assistant","content":"done"}]}',
     ]);
     const r = await validateDataset(p, { fullValidate: true });
-    expect(r.valid).toBe(true);
-    expect(codes(r).warnings).toContain("TOOL_CALL_ID_UNMATCHED");
+    expect(r.valid).toBe(false);
+    expect(codes(r).errors).toContain("TOOL_CALL_ID_UNMATCHED");
+    // The orphaned call side is advisory
+    expect(codes(r).warnings).toContain("TOOL_CALL_NO_RESPONSE");
+  });
+
+  test("tool_calls without a tool response → TOOL_CALL_NO_RESPONSE warning", async () => {
+    const p = file("tool_no_resp.jsonl", [
+      '{"messages":[{"role":"user","content":"hi"},{"role":"assistant","content":"","tool_calls":[{"id":"c1","type":"function","function":{"name":"f","arguments":"{}"}}]},{"role":"assistant","content":"done"}]}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true });
+    expect(codes(r).warnings).toContain("TOOL_CALL_NO_RESPONSE");
   });
 
   test("tool_calls with missing function name → TOOL_CALL_FN_NO_NAME", async () => {
@@ -352,34 +390,68 @@ describe("validateDataset — thinking tags", () => {
     expect(r.valid).toBe(true);
     expect(codes(r).warnings).toContain("THINK_TAG_NOT_LAST");
   });
+
+  test("official tool+thinking combo: think in non-last assistant WITH tool_calls is exempt", async () => {
+    // Mirrors the platform spec's 工具与思考组合 example: the assistant that
+    // issues tool_calls carries the <think> block, the final assistant answers.
+    const p = file("think_tool_combo.jsonl", [
+      JSON.stringify({
+        tools: [
+          {
+            type: "function",
+            function: { name: "get_weather", description: "d", parameters: { type: "object" } },
+          },
+        ],
+        messages: [
+          { role: "user", content: [{ text: "weather in Beijing?" }] },
+          {
+            role: "assistant",
+            content: [{ text: "<think>\nneed the weather tool\n</think>\n" }],
+            tool_calls: [
+              {
+                id: "call_1",
+                type: "function",
+                function: { name: "get_weather", arguments: '{"city":"Beijing"}' },
+              },
+            ],
+          },
+          { role: "tool", tool_call_id: "call_1", content: [{ text: '{"weather":"sunny"}' }] },
+          { role: "assistant", content: [{ text: "It is sunny in Beijing." }] },
+        ],
+      }),
+    ]);
+    const r = await validateDataset(p, { fullValidate: true });
+    expect(r.valid).toBe(true);
+    expect(codes(r).warnings).not.toContain("THINK_TAG_NOT_LAST");
+  });
 });
 
 describe("validateDataset — OpenAI migration guards", () => {
-  test("message-level name field → UNSUPPORTED_FIELD_NAME warning", async () => {
+  test("message-level name field → UNSUPPORTED_FIELD_NAME error", async () => {
     const p = file("openai_name.jsonl", [
       '{"messages":[{"role":"user","content":"hi","name":"alice"},{"role":"assistant","content":"hello"}]}',
     ]);
     const r = await validateDataset(p, { fullValidate: true });
-    expect(r.valid).toBe(true);
-    expect(codes(r).warnings).toContain("UNSUPPORTED_FIELD_NAME");
+    expect(r.valid).toBe(false);
+    expect(codes(r).errors).toContain("UNSUPPORTED_FIELD_NAME");
   });
 
-  test("message-level weight field → UNSUPPORTED_FIELD_WEIGHT warning", async () => {
+  test("message-level weight field → UNSUPPORTED_FIELD_WEIGHT error", async () => {
     const p = file("openai_weight.jsonl", [
       '{"messages":[{"role":"user","content":"hi"},{"role":"assistant","content":"hello","weight":0.5}]}',
     ]);
     const r = await validateDataset(p, { fullValidate: true });
-    expect(r.valid).toBe(true);
-    expect(codes(r).warnings).toContain("UNSUPPORTED_FIELD_WEIGHT");
+    expect(r.valid).toBe(false);
+    expect(codes(r).errors).toContain("UNSUPPORTED_FIELD_WEIGHT");
   });
 
-  test("record-level weight field → UNSUPPORTED_FIELD_WEIGHT warning", async () => {
+  test("record-level weight field → UNSUPPORTED_FIELD_WEIGHT error", async () => {
     const p = file("record_weight.jsonl", [
       '{"messages":[{"role":"user","content":"hi"},{"role":"assistant","content":"hello"}],"weight":1}',
     ]);
     const r = await validateDataset(p, { fullValidate: true });
-    expect(r.valid).toBe(true);
-    expect(codes(r).warnings).toContain("UNSUPPORTED_FIELD_WEIGHT");
+    expect(r.valid).toBe(false);
+    expect(codes(r).errors).toContain("UNSUPPORTED_FIELD_WEIGHT");
   });
 });
 
@@ -428,6 +500,91 @@ describe("validateDataset — loss_weight", () => {
     const r = await validateDataset(p, { fullValidate: true });
     expect(r.valid).toBe(true);
   });
+
+  test("message-level loss_weight on the LAST assistant passes without warning", async () => {
+    const p = file("lw_msg_last.jsonl", [
+      '{"messages":[{"role":"user","content":"hi"},{"role":"assistant","content":"hello","loss_weight":0.8}]}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true });
+    expect(r.valid).toBe(true);
+    expect(codes(r).warnings).not.toContain("LOSS_WEIGHT_PLACEMENT");
+  });
+
+  test("message-level loss_weight on a non-last assistant → LOSS_WEIGHT_PLACEMENT warning", async () => {
+    const p = file("lw_msg_mid.jsonl", [
+      '{"messages":[{"role":"user","content":"a"},{"role":"assistant","content":"b","loss_weight":0.8},{"role":"user","content":"c"},{"role":"assistant","content":"d"}]}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true });
+    expect(codes(r).warnings).toContain("LOSS_WEIGHT_PLACEMENT");
+  });
+
+  test("message-level loss_weight out of range → INVALID_LOSS_WEIGHT", async () => {
+    const p = file("lw_msg_range.jsonl", [
+      '{"messages":[{"role":"user","content":"hi"},{"role":"assistant","content":"hello","loss_weight":2}]}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true });
+    expect(r.valid).toBe(false);
+    expect(codes(r).errors).toContain("INVALID_LOSS_WEIGHT");
+  });
+});
+
+describe("validateDataset — video content params", () => {
+  test("path-mode video with in-range fps and clip times passes", async () => {
+    const p = file("video_path_ok.jsonl", [
+      '{"messages":[{"role":"user","content":[{"text":"desc"},{"video":"v.mp4","fps":3.0,"video_start":0.0,"video_end":3.0}]},{"role":"assistant","content":[{"text":"ok"}]}]}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true });
+    expect(r.valid).toBe(true);
+    expect(codes(r).warnings).not.toContain("VIDEO_PARAM_MODE_MISMATCH");
+  });
+
+  test("fps out of [0.1, 10] → INVALID_VIDEO_FPS error", async () => {
+    const p = file("video_fps_bad.jsonl", [
+      '{"messages":[{"role":"user","content":[{"text":"desc"},{"video":"v.mp4","fps":30}]},{"role":"assistant","content":[{"text":"ok"}]}]}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true });
+    expect(r.valid).toBe(false);
+    expect(codes(r).errors).toContain("INVALID_VIDEO_FPS");
+  });
+
+  test("sample_fps on path-mode video → VIDEO_PARAM_MODE_MISMATCH warning", async () => {
+    const p = file("video_mode_mix.jsonl", [
+      '{"messages":[{"role":"user","content":[{"text":"desc"},{"video":"v.mp4","sample_fps":2.0}]},{"role":"assistant","content":[{"text":"ok"}]}]}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true });
+    expect(codes(r).warnings).toContain("VIDEO_PARAM_MODE_MISMATCH");
+  });
+
+  test("frame-list video with sample_fps passes; fps there is flagged", async () => {
+    const p = file("video_frames.jsonl", [
+      '{"messages":[{"role":"user","content":[{"text":"desc"},{"video":["0.jpg","1.jpg"],"sample_fps":5.0}]},{"role":"assistant","content":[{"text":"ok"}]}]}',
+      '{"messages":[{"role":"user","content":[{"text":"desc"},{"video":["0.jpg"],"fps":2.0}]},{"role":"assistant","content":[{"text":"ok"}]}]}',
+    ]);
+    const r = await validateDataset(p, { fullValidate: true });
+    expect(r.valid).toBe(true);
+    expect(codes(r).warnings).toContain("VIDEO_PARAM_MODE_MISMATCH");
+  });
+});
+
+describe("validateZipFilenames — macOS metadata entries", () => {
+  test("__MACOSX / .DS_Store / ._resource-fork entries are ignored", async () => {
+    const { validateZipFilenames } = await import("../src/dataset/validate/zip.ts");
+    const issues = validateZipFilenames([
+      "data.jsonl",
+      "image_1.jpg",
+      "__MACOSX/._image_1.jpg",
+      "__MACOSX/",
+      ".DS_Store",
+      "train/._clip.wav",
+    ]);
+    expect(issues).toEqual([]);
+  });
+
+  test("real charset violations are still reported", async () => {
+    const { validateZipFilenames } = await import("../src/dataset/validate/zip.ts");
+    const issues = validateZipFilenames(["data.jsonl", "图片1.jpg"]);
+    expect(issues.map((issue) => issue.code)).toContain("INVALID_FILENAME_CHARSET");
+  });
 });
 
 describe("parseDatasetSchemaFlag", () => {