feat: add Codex plugin marketplace

.agents/plugins/marketplace.json

@@ -0,0 +1,20 @@
+{
+  "name": "notebook-intelligence",
+  "interface": {
+    "displayName": "Notebook Intelligence"
+  },
+  "plugins": [
+    {
+      "name": "notebook-intelligence",
+      "source": {
+        "source": "local",
+        "path": "./plugins/notebook-intelligence"
+      },
+      "policy": {
+        "installation": "AVAILABLE",
+        "authentication": "ON_INSTALL"
+      },
+      "category": "Developer Tools"
+    }
+  ]
+}

README.md

@@ -8,6 +8,7 @@ NBI is free and open-source. Connect it to a free or paid LLM provider of your c
 
 - [Requirements](#requirements)
 - [Quick start](#quick-start)
+- [Codex plugin](#codex-plugin)
 - [Concepts](#concepts)
 - [Feature highlights](#feature-highlights)
   - [Claude mode](#claude-mode)
@@ -57,6 +58,21 @@ After restart:
 
 If the panel stays empty or login does nothing, see [Troubleshooting](docs/troubleshooting.md).
 
+## Codex plugin
+
+This repository is also a public [Codex plugin marketplace](https://developers.openai.com/codex/plugins/).
+Add the marketplace and install its Notebook Intelligence operational skill with:
+
+```bash
+codex plugin marketplace add plmbr/notebook-intelligence --ref main
+codex plugin add notebook-intelligence@notebook-intelligence
+```
+
+Start a new Codex task after installation, then ask Codex to install, configure,
+or troubleshoot Notebook Intelligence. The plugin helps Codex operate NBI; the
+JupyterLab extension itself is still installed separately from PyPI with
+`pip install notebook-intelligence`.
+
 ## Concepts
 
 A short glossary you'll see referenced throughout these docs.

plugins/notebook-intelligence/.codex-plugin/plugin.json

@@ -0,0 +1,32 @@
+{
+  "name": "notebook-intelligence",
+  "version": "0.1.0",
+  "description": "Install, configure, and troubleshoot Notebook Intelligence for JupyterLab with Codex.",
+  "author": {
+    "name": "Mehmet Bektas",
+    "email": "mbektasgh@outlook.com",
+    "url": "https://github.com/plmbr"
+  },
+  "homepage": "https://github.com/plmbr/notebook-intelligence",
+  "repository": "https://github.com/plmbr/notebook-intelligence.git",
+  "license": "GPL-3.0",
+  "keywords": ["jupyterlab", "notebooks", "ai", "coding-assistant"],
+  "skills": "./skills/",
+  "interface": {
+    "displayName": "Notebook Intelligence",
+    "shortDescription": "Set up and troubleshoot the JupyterLab AI assistant.",
+    "longDescription": "Helps Codex inspect Python and JupyterLab environments, install or upgrade Notebook Intelligence, configure supported model providers safely, and diagnose extension startup or connectivity problems.",
+    "developerName": "plmbr",
+    "category": "Developer Tools",
+    "capabilities": [
+      "Environment inspection",
+      "Installation guidance",
+      "Configuration guidance",
+      "Diagnostics"
+    ],
+    "websiteURL": "https://github.com/plmbr/notebook-intelligence",
+    "defaultPrompt": [
+      "Set up Notebook Intelligence in my current JupyterLab environment."
+    ]
+  }
+}

plugins/notebook-intelligence/skills/notebook-intelligence/SKILL.md

@@ -0,0 +1,121 @@
+---
+name: notebook-intelligence
+description: Use when the user wants to install, upgrade, configure, inspect, or troubleshoot the Notebook Intelligence (NBI) AI coding assistant for JupyterLab. Covers Python and JupyterLab environment selection, provider setup, extension validation, and common startup or connectivity failures.
+---
+
+# Notebook Intelligence
+
+Help the user operate Notebook Intelligence (NBI), the JupyterLab extension from
+`plmbr/notebook-intelligence`.
+
+## Scope
+
+Use this skill for:
+
+- installing or upgrading NBI;
+- checking whether the server and frontend extensions are enabled;
+- configuring GitHub Copilot, OpenAI-compatible, LiteLLM-compatible, Ollama, or
+  Claude Code providers;
+- diagnosing blank panels, missing commands, authentication failures, model
+  connectivity problems, and extension version mismatches;
+- source-development setup for this repository.
+
+This Codex plugin is an operational assistant. It does not itself expose a
+Jupyter kernel, notebook editor, or NBI's Jupyter UI as a Codex tool. Never
+claim that installing this plugin installs or starts the JupyterLab extension.
+
+## Workflow
+
+### 1. Identify the intended environment
+
+Before installing or changing packages, establish which Python environment
+owns the JupyterLab server the user intends to run.
+
+Inspect, as applicable:
+
+```bash
+python --version
+python -m pip --version
+python -m pip show notebook-intelligence jupyterlab
+command -v python
+command -v jupyter
+jupyter lab --version
+```
+
+Require Python 3.10 or newer and JupyterLab 4.x. If `python` and `jupyter`
+resolve to different environments, stop and explain the mismatch before
+installing anything. Prefer a fresh virtualenv or conda environment.
+
+### 2. Install or upgrade deliberately
+
+For a normal PyPI installation, use the selected interpreter:
+
+```bash
+python -m pip install --upgrade notebook-intelligence
+```
+
+Do not add `--user`, change conda environments, or replace an existing
+environment unless the user requested it. After installation, restart the
+JupyterLab server; a browser refresh alone does not reload the server
+extension.
+
+For source development, follow the repository's `CONTRIBUTING.md` and use its
+declared Yarn/Jupyter build commands. Do not invent a development workflow from
+the PyPI install path.
+
+### 3. Configure the provider safely
+
+Use NBI Settings in JupyterLab for provider selection. Supported paths include
+GitHub Copilot, OpenAI-compatible or LiteLLM-compatible endpoints, Ollama, and
+Claude Code mode.
+
+- Never print, commit, or persist API keys in project files.
+- Redact tokens and credential-bearing URLs from diagnostics.
+- For Claude mode, validate the executable named by `NBI_CLAUDE_CLI_PATH` when
+  the override is set; otherwise verify that the Claude Code CLI is on `PATH`.
+- For Ollama, verify the configured daemon endpoint and model availability.
+- For OpenAI-compatible endpoints, confirm base URL, model name, and
+  authentication separately.
+
+### 4. Verify the installation
+
+Use the same environment chosen in step 1:
+
+```bash
+python -m pip show notebook-intelligence
+jupyter server extension list
+jupyter labextension list
+```
+
+Confirm that the Python package is installed and that both the NBI server
+extension and the `@plmbr/notebook-intelligence` frontend extension are
+reported without errors. Then start or restart JupyterLab and verify that the
+NBI sidebar icon and Settings panel appear.
+
+### 5. Diagnose before changing
+
+Gather the smallest relevant evidence first:
+
+- exact NBI, Python, and JupyterLab versions;
+- the selected provider and model name, with secrets removed;
+- server-extension and labextension status;
+- the first relevant JupyterLab server error;
+- browser-console errors only when the failure is frontend-specific.
+
+Use the project's troubleshooting guide at
+`https://github.com/plmbr/notebook-intelligence/blob/main/docs/troubleshooting.md`
+as the primary reference. Avoid broad reinstalls until the failing layer is
+identified.
+
+## Response contract
+
+End with:
+
+1. the environment that was inspected or changed;
+2. the installed NBI and JupyterLab versions;
+3. the verification result for server and frontend extensions;
+4. any remaining manual action, such as restarting JupyterLab or completing a
+   provider login.
+
+If commands were not run, label the steps as instructions rather than completed
+results.