diff --git a/.claude-plugin/marketplace.json b/.claude-plugin/marketplace.json
index 29fe3de..59c8878 100644
--- a/.claude-plugin/marketplace.json
+++ b/.claude-plugin/marketplace.json
@@ -1,6 +1,7 @@
 {
   "$schema": "https://anthropic.com/claude-code/marketplace.schema.json",
   "name": "newton-skill",
+  "description": "Newton — an opt-in reasoning and sparring-partner skill, distributed as a single-plugin marketplace.",
   "owner": {
     "name": "PBNZ"
   },
@@ -9,7 +10,8 @@
       "name": "newton",
       "source": "./plugins/newton",
       "description": "Reasoning and sparring partner mode.",
-      "version": "0.3.0"
+      "version": "0.3.0",
+      "category": "productivity"
     }
   ]
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 99c0d44..edb2103 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,13 @@ Format follows [Keep a Changelog 1.1.0](https://keepachangelog.com/en/1.1.0/); v
 
 ## [Unreleased]
 
+### Changed
+
+- `category` moved from `plugin.json` to the marketplace entry, and the marketplace manifest
+  gained a top-level `description` — Claude Code reads `category` from the marketplace manifest,
+  not the plugin manifest, and both were flagged by `claude plugin validate` (now zero warnings).
+  No behaviour change.
+
 ## [0.3.0] — 2026-04-20
 
 Context-efficiency restructure and alignment with current-generation models (Opus 4.7). Newton's methodology is unchanged in substance — honest engagement, self-critique before delivery, current sources, reuse before reinvention, simplicity, surgical edits, attribution — but its packaging now matches the anti-ceremony discipline it teaches. Per-invocation context footprint drops by roughly 45% for Claude Code users via progressive disclosure; non-Claude-Code surfaces keep the full methodology in their generated rule files.
diff --git a/plugins/newton/.claude-plugin/plugin.json b/plugins/newton/.claude-plugin/plugin.json
index ed099a6..b4b5381 100644
--- a/plugins/newton/.claude-plugin/plugin.json
+++ b/plugins/newton/.claude-plugin/plugin.json
@@ -9,6 +9,5 @@
   "homepage": "https://github.com/PBNZ/newton-skill",
   "repository": "https://github.com/PBNZ/newton-skill",
   "license": "Apache-2.0",
-  "keywords": ["reasoning", "thinking", "sparring-partner", "research", "agent-skills"],
-  "category": "productivity"
+  "keywords": ["reasoning", "thinking", "sparring-partner", "research", "agent-skills"]
 }