diff --git a/packages/cli/src/sdk/client.ts b/packages/cli/src/sdk/client.ts
index baea96e0..5192df5e 100644
--- a/packages/cli/src/sdk/client.ts
+++ b/packages/cli/src/sdk/client.ts
@@ -224,6 +224,8 @@ export class PlotLink {
     validateNonEmpty("title", title);
     validateNonEmpty("content", content);
     validateNonEmpty("genre", genre);
+    validateTitle(title);
+    validateContentLength(content);
 
     const metadata = JSON.stringify({ title, genre, content });
     const key = `plotlink/storylines/${Date.now()}-${slugify(title)}.json`;
@@ -289,6 +291,7 @@ export class PlotLink {
   ): Promise<ChainPlotResult> {
     this.requireFilebase();
     validateNonEmpty("content", content);
+    validateContentLength(content);
 
     const key = `plotlink/plots/${storylineId}-${Date.now()}.txt`;
     const contentCid = await uploadWithRetry(content, key, this.filebase!);
@@ -667,6 +670,29 @@ function validateNonEmpty(name: string, value: string): void {
   }
 }
 
+// Content limits — mirrored from lib/content.ts in the web app
+const MAX_TITLE_LENGTH = 60;
+const MIN_CONTENT_LENGTH = 500;
+const MAX_CONTENT_LENGTH = 10_000;
+
+function validateTitle(title: string): void {
+  const charCount = [...title].length;
+  if (charCount > MAX_TITLE_LENGTH) {
+    throw new Error(
+      `Title must be ${MAX_TITLE_LENGTH} characters or less (currently: ${charCount})`,
+    );
+  }
+}
+
+function validateContentLength(content: string): void {
+  const charCount = [...content].length;
+  if (charCount < MIN_CONTENT_LENGTH || charCount > MAX_CONTENT_LENGTH) {
+    throw new Error(
+      `Content must be between ${MIN_CONTENT_LENGTH} and ${MAX_CONTENT_LENGTH} characters (currently: ${charCount})`,
+    );
+  }
+}
+
 /**
  * Compute keccak256 hash of content, matching the on-chain contentHash.
  * Same encoding as the web app's hashContent (lib/content.ts).