diff --git a/.agents/plugins/marketplace.json b/.agents/plugins/marketplace.json
new file mode 100644
index 0000000..0e6e431
--- /dev/null
+++ b/.agents/plugins/marketplace.json
@@ -0,0 +1,20 @@
+{
+  "name": "docwriter-style",
+  "interface": {
+    "displayName": "DocWriter style"
+  },
+  "plugins": [
+    {
+      "name": "docwriter-style-generator",
+      "source": {
+        "source": "local",
+        "path": "./"
+      },
+      "policy": {
+        "installation": "AVAILABLE",
+        "authentication": "ON_USE"
+      },
+      "category": "Productivity"
+    }
+  ]
+}
diff --git a/.claude-plugin/marketplace.json b/.claude-plugin/marketplace.json
index 88aff1b..15b4601 100644
--- a/.claude-plugin/marketplace.json
+++ b/.claude-plugin/marketplace.json
@@ -3,11 +3,19 @@
   "owner": {
     "name": "DocWriter"
   },
+  "interface": {
+    "displayName": "DocWriter style"
+  },
   "plugins": [
     {
       "name": "docwriter-style-generator",
       "source": "./",
-      "description": "Learn a writing style from samples and produce a portable my-writing-style skill"
+      "description": "Learn a writing style from samples and produce a portable my-writing-style skill",
+      "policy": {
+        "installation": "AVAILABLE",
+        "authentication": "ON_USE"
+      },
+      "category": "Productivity"
     }
   ]
 }
diff --git a/.codex-plugin/plugin.json b/.codex-plugin/plugin.json
new file mode 100644
index 0000000..477c4c4
--- /dev/null
+++ b/.codex-plugin/plugin.json
@@ -0,0 +1,21 @@
+{
+  "name": "docwriter-style-generator",
+  "version": "1.0.0",
+  "description": "Learn a writing style from samples and produce a portable my-writing-style skill",
+  "author": {
+    "name": "DocWriter",
+    "url": "https://github.com/docwriter-org/style"
+  },
+  "homepage": "https://github.com/docwriter-org/style",
+  "repository": "https://github.com/docwriter-org/style",
+  "keywords": ["writing", "style", "skill"],
+  "skills": "./skills/",
+  "interface": {
+    "displayName": "DocWriter style generator",
+    "shortDescription": "Learn a writing style from your own prose",
+    "longDescription": "Measure word-level habits, run a multi-agent pass over words, sentences, and passages, and write a portable my-writing-style skill.",
+    "developerName": "DocWriter",
+    "category": "Productivity",
+    "websiteURL": "https://github.com/docwriter-org/style"
+  }
+}
diff --git a/README.md b/README.md
index 871bf9e..1f840e2 100644
--- a/README.md
+++ b/README.md
@@ -4,37 +4,86 @@ Build a `my-writing-style` skill from your own prose.
 
 Give it a few pieces of your writing — local files, URLs, or pasted text — and
 it measures word-level habits, runs a multi-agent pass over words, sentences,
-and passages, checks each habit with you, and writes a skill to
-`~/.claude/skills/my-writing-style/` that Claude Code loads automatically in
-every project.
+and passages, checks each habit with you, and writes a skill that Claude Code
+and Codex load automatically.
+
+This is the same style-learning flow used in the
+[DocWriter](https://docs.docwriter.org/customize/style) app.
 
 ## Install
 
-Add the marketplace, then install the plugin:
+Add the marketplace, then install the plugin. Use a session **or** the
+terminal — not both.
+
+### Claude Code
+
+Either, in a Claude Code session:
 
 ```
 /plugin marketplace add docwriter-org/style
 /plugin install docwriter-style-generator@docwriter-style
 ```
 
+Or, in the terminal:
+
 ```bash
 claude plugin marketplace add docwriter-org/style
 claude plugin install docwriter-style-generator@docwriter-style
 ```
 
+### Codex
 
-## Use
+Either, in a Codex session, run `/plugins`, add marketplace
+`docwriter-org/style`, then install `docwriter-style-generator`.
+
+Or, in the terminal:
+
+```bash
+codex plugin marketplace add docwriter-org/style
+codex plugin add docwriter-style-generator@docwriter-style
+```
+
+## Update
+
+Refresh the marketplace after we ship a change. Same choice: session **or**
+terminal.
+
+### Claude Code
+
+Either, in a Claude Code session:
 
 ```
-/docwriter-style-generator
+/plugin marketplace update docwriter-style
 ```
 
-Or just ask Claude to learn your writing style — the skill triggers
-automatically. Run it again to add a source or update the habits.
+Or, in the terminal:
+
+```bash
+claude plugin marketplace update docwriter-style
+```
+
+### Codex
+
+Either, in a Codex session, open `/plugins` and refresh marketplace
+`docwriter-style`.
+
+Or, in the terminal:
+
+```bash
+codex plugin marketplace upgrade docwriter-style
+```
+
+
+## Use
+
+In Claude Code run `/docwriter-style-generator`. In Codex run
+`$docwriter-style-generator`. Or just ask to learn your writing style — the
+skill triggers automatically. Run it again to add a source or update the habits.
 
 ## What it produces
 
-A separate skill at `~/.claude/skills/my-writing-style/`:
+A separate skill at `~/.claude/skills/my-writing-style/` (Claude Code) and
+`~/.agents/skills/my-writing-style/` (Codex):
 
 ```
 my-writing-style/
diff --git a/skills/docwriter-style-generator/SKILL.md b/skills/docwriter-style-generator/SKILL.md
index 459419f..13471d6 100644
--- a/skills/docwriter-style-generator/SKILL.md
+++ b/skills/docwriter-style-generator/SKILL.md
@@ -3,21 +3,27 @@ name: docwriter-style-generator
 description: >-
   Build a writing style skill from your own prose. Measures word-level habits,
   then runs a multi-agent pass over words, sentences, and passages, and
-  produces a portable my-writing-style skill that Claude Code loads
+  produces a portable my-writing-style skill that Claude Code and Codex load
   automatically. Run again to add a source or update the habits. Run
-  /docwriter-style-generator to start, or let it trigger when you ask to learn
-  or update a writing style.
+  /docwriter-style-generator or $docwriter-style-generator to start, or let
+  it trigger when you ask to learn or update a writing style.
 ---
 
 # Build a writing style skill
 
 This skill is a generator. It reads your writing, measures word-level habits
 with the bundled analyzer, runs a multi-agent pass, checks each habit with
-you, and writes a separate `my-writing-style` skill to
-`~/.claude/skills/my-writing-style/` that Claude Code picks up automatically in
-every project.
+you, and writes a separate `my-writing-style` skill that Claude Code and
+Codex pick up automatically.
 
-If `~/.claude/skills/my-writing-style/SKILL.md` already exists, ask:
+Write the same files to both homes:
+
+```
+~/.claude/skills/my-writing-style/   ← Claude Code
+~/.agents/skills/my-writing-style/   ← Codex
+```
+
+If either home already has `SKILL.md`, ask:
 
 ```
 AskUserQuestion:
@@ -77,6 +83,7 @@ directories if they do not exist:
 
 ```
 ~/.claude/skills/my-writing-style/sources/<label>.txt
+~/.agents/skills/my-writing-style/sources/<label>.txt
 ```
 
 Use the user's label as the filename (safe slug). On a rebuild, replace
@@ -103,8 +110,8 @@ Do not jump straight to impressions of word choice. Measure first, then read.
 ### 2a. Word-level measurements
 
 This skill ships `scripts/analyze-style.mjs` next to this file. Run it on
-every file in `~/.claude/skills/my-writing-style/sources/` in one invocation,
-and write the report next to them:
+every file in the style skill `sources/` folder in one invocation, and write
+the report to `references/metrics.json` in both homes:
 
 ```bash
 node scripts/analyze-style.mjs \
@@ -115,6 +122,9 @@ node scripts/analyze-style.mjs \
   --measured
 ```
 
+Copy that `metrics.json` to `~/.agents/skills/my-writing-style/references/` as
+well.
+
 `--words` keeps word-level scores. `--measured` drops zeros. A zero is not
 evidence of a habit — do not invent absences from missing metrics.
 
@@ -205,15 +215,15 @@ AskUserQuestion:
   question: "N out of M habits confirmed. Save as your writing style?"
   options:
     - label: "Save it"
-      description: "Write the skill to ~/.claude/skills/my-writing-style/"
+      description: "Write the skill for Claude Code and Codex"
     - label: "Start over"
       description: "Discard and try with different samples"
 ```
 
 ## 4. Write the my-writing-style skill
 
-Write a complete skill to `~/.claude/skills/my-writing-style/`. Create the
-directory if it does not exist.
+Write a complete skill to both homes. Create the directories if they do not
+exist. The two copies must match.
 
 ### SKILL.md
 
@@ -281,5 +291,5 @@ scripts/style-data.json
 ```
 
 After writing, tell the user their style skill is active and will load
-automatically in every Claude Code session. They can run this generator
+automatically in Claude Code and Codex. They can run this generator
 again to add a source or update the habits.
diff --git a/tests/lexical-analysis.mjs b/tests/lexical-analysis.mjs
index a4f9f73..6492aa8 100644
--- a/tests/lexical-analysis.mjs
+++ b/tests/lexical-analysis.mjs
@@ -69,6 +69,8 @@ for (const needle of [
 	'Words and phrases',
 	'multi-agent pass',
 	'~/.claude/skills/my-writing-style/sources/',
+	'~/.agents/skills/my-writing-style/',
+	'$docwriter-style-generator',
 	'Add a source',
 	'Update propositions'
 ]) {
@@ -78,4 +80,34 @@ if (skill.includes('/tmp/source-')) {
 	throw new Error('cleaned sources should live in the style skill, not /tmp');
 }
 
+const marketplace = JSON.parse(readFileSync(join(root, '.claude-plugin/marketplace.json'), 'utf8'));
+if (marketplace.name !== 'docwriter-style') throw new Error('marketplace name should be docwriter-style');
+if (!marketplace.plugins.some((plugin) => plugin.name === 'docwriter-style-generator')) {
+	throw new Error('marketplace must list docwriter-style-generator');
+}
+const codexPlugin = JSON.parse(readFileSync(join(root, '.codex-plugin/plugin.json'), 'utf8'));
+if (codexPlugin.name !== 'docwriter-style-generator' || codexPlugin.skills !== './skills/') {
+	throw new Error('Codex plugin manifest must name the generator and point at ./skills/');
+}
+const agentsMarketplace = JSON.parse(readFileSync(join(root, '.agents/plugins/marketplace.json'), 'utf8'));
+if (agentsMarketplace.name !== 'docwriter-style') throw new Error('Codex marketplace name should be docwriter-style');
+const [codexListing] = agentsMarketplace.plugins;
+if (codexListing?.source?.path !== './' || !codexListing.policy?.installation || !codexListing.category) {
+	throw new Error('Codex marketplace must list ./ with policy and category');
+}
+
+const readme = readFileSync(join(root, 'README.md'), 'utf8');
+for (const needle of [
+	'https://docs.docwriter.org/customize/style',
+	'/plugin marketplace update docwriter-style',
+	'claude plugin marketplace update docwriter-style',
+	'codex plugin marketplace upgrade docwriter-style',
+	'$docwriter-style-generator',
+	'Use a session **or** the',
+	'Either, in a Claude Code session:',
+	'Or, in the terminal:'
+]) {
+	if (!readme.includes(needle)) throw new Error(`README.md is missing ${needle}`);
+}
+
 process.stdout.write(`ok: ${lexical.measurements.length} measured lexical metrics, ${full.measurements.length} measured metrics across four families\n`);