Add Composer build-and-deploy plugin for desktop preview

.gitignore

@@ -4,3 +4,9 @@ node_modules/
 .env
 .env.*
 !.env.example
+
+# Generated by scripts/package-plugin.mjs from the pinned Composer release.
+/plugins/prisma/skills/prisma-composer-core-concepts/
+/plugins/prisma/assets/
+/plugins/prisma/LICENSE
+/plugins/prisma/upstream.json

README.md

@@ -1,22 +1,156 @@
 # Prisma Plugin
 
+## Composer plugin: desktop-local preview
+
+The first focused preview builds apps with **Prisma Composer** and deploys them to
+**Prisma Compute**. Its portable [Agent Plugins 1.0.0](https://agent-plugins.org/)
+manifest lives in `plugins/prisma/plugin.json`. It includes two skills:
+
+- `prisma-build-and-deploy`: this repository's short workflow for installation,
+  local verification, authentication, targeting, deployment, and recovery.
+- `prisma-composer-core-concepts`: copied unchanged from the published
+  `@prisma/composer@0.21.0` package, with its upstream license and provenance.
+
+The workflow reads the Composer reference for API concepts. Composer remains the
+source of truth for those concepts; this repository owns completing the journey.
+
+The `0.4.0-dev.4` onboarding revision is prepared but **not activated**: it needs
+a released CLI containing `auth login --ui-context prisma-plugin`, followed by a
+verified exact version pin. The installed `0.4.0-dev.3` remains the working
+preview. Do not refresh it from this checkout until that release gate is cleared.
+See [validation](docs/validation.md) for completed checks and remaining acceptance.
+
+### Package and install
+
+These are contributor packaging instructions, not steps for plugin users.
+Prerequisites: Node.js 22.18+ (or a newer supported release), `tar`, internet access
+to the npm registry, and a current Codex CLI with `codex plugin` support. The
+packager uses Node's standard library; there is no dependency-install step in this
+repository. It checks the pinned archive's integrity and never runs npm lifecycle
+scripts or installs Composer into this repository.
+
+From this repository's root, build and check the bundle:
+
+```bash
+node scripts/package-plugin.mjs
+node scripts/package-plugin.mjs --check
+```
+
+After the onboarding release gate above is cleared, install the preview explicitly:
+
+```bash
+codex plugin marketplace add "$PWD/plugins"
+codex plugin add prisma@prisma-preview
+codex plugin list --marketplace prisma-preview --json
+```
+
+This registers the local `prisma-preview` marketplace and installs its Prisma plugin into
+Codex's cache. Open a **new Codex task in an empty app folder** after installation
+so the new skill is available. Select the Prisma plugin if needed; confirm that
+both `prisma:prisma-build-and-deploy` and `prisma:prisma-composer-core-concepts`
+are available (Codex prefixes skills with their plugin name). Enable only the
+focused Prisma preview for acceptance testing, so another Prisma installation
+does not supply additional skills.
+
+### First test
+
+Select the Prisma plugin for the task, then use:
+
+> Build a simple Todo app and deploy it
+
+Use **ChatGPT's desktop app with local execution**. Web and cloud execution,
+including cloud tasks launched from desktop, are deferred. Initial validation
+uses macOS; other operating systems have not been verified.
+
+Selecting Prisma supplies the Composer/Compute defaults, including local and live
+verification. The agent handles tooling, dependencies, and commands. The user
+completes browser signup/consent when needed and answers unresolved target
+questions; they never need a terminal, copied authentication codes, or manual
+credential configuration. Explicit stack or hosting choices
+still take precedence. Merely installing the plugin does not make Prisma the
+default for unrelated tasks.
+
+The skill guides the agent's use of the desktop's local capabilities. Its workflow
+defaults to the project-local **unified `prisma` CLI** for new interactive apps.
+The bundled
+[toolchain reference](plugins/prisma/skills/prisma-build-and-deploy/references/toolchain.md)
+contains the verified installation set, required peer, runtime checks, and command
+sequence, managed browser login, and verification before confirming a connection.
+
+Local Composer development needs no cloud credentials. Before deployment the
+workflow checks for an existing CLI session and verifies workspace access; browser
+login is needed only if that session is missing or expired. New users can create
+an account during sign-in. If the browser does not open, the agent shares the
+authorization link from the same pending attempt. After successful login it checks
+authenticated identity and remote workspace access, then reuses the authorized
+workspace unless another was explicitly requested. Browser signup alone is not
+proof of a working connection. Local work continues while login is pending.
+
+Installing this plugin does not deploy or provision anything. A new demo targets the named `demo` stage
+unless another target is requested. The workflow checks the live app, and reports
+partial provisioning separately from a successful deployment.
+Service-token setup is not a workaround for unsupported web/cloud execution.
+
+See [validation and upstream findings](docs/validation.md) for the acceptance
+scenarios, recorded evidence, and remaining limits of this preview.
+
+### What's maintained here
+
+| File | Responsibility |
+| --- | --- |
+| `plugins/prisma/plugin.json` | Portable identity, display metadata, and starter prompts |
+| `plugins/prisma/skills/prisma-build-and-deploy/` | Authored workflow and its version-specific toolchain reference |
+| `scripts/package-plugin.mjs` | Refreshes only imported content, preserves the authored skill, and verifies the full bundle |
+| `plugins/.agents/plugins/marketplace.json` | Opt-in local preview marketplace, pointing at `./prisma` relative to `plugins/` |
+| `.agents/plugins/marketplace.json` | Preserves the existing root plugin for default repository installs |
+| `.gitignore` | Excludes generated bundle content from this initial local preview |
+
+The plugin's `skills/` directory is discovered automatically. There is no MCP
+server in this focused bundle. The older root skills and tool manifests below
+remain the default repository install. The separate `prisma-preview` marketplace
+installs only the Composer bundle after packaging.
+
+To iterate, edit the maintained files, bump `version` in
+`plugins/prisma/plugin.json`, rerun the packager and `--check`, then run
+`codex plugin add prisma@prisma-preview` again and start a new task. Codex uses its
+installed copy, so edits to this checkout alone do not update active tasks.
+`--check` is offline and detects missing, changed, or additional bundle files.
+To update Composer, review the new upstream skill and change the package version,
+tarball URL, and npm `dist.integrity` together in the packaging script.
+
+Run `node --test scripts/package-plugin.test.mjs` for packaging regression tests
+(requires access to the npm registry). These build an isolated temporary copy and
+verify repeatability, preservation of authored content, and integrity failures.
+
+This is a **local preview**, not a published directory listing. A fresh clone must
+run the packager before installing from this marketplace. Public distribution
+will need to include the complete generated bundle in a release or repository
+and go through the [OpenAI plugin submission](https://platform.openai.com/plugins)
+process. The generated `upstream.json` records exactly which release and files
+were packaged.
+
+## Existing broad plugin
+
 Prisma plugin for agent tools, including curated skills for Prisma ORM, Prisma Client, Prisma Postgres, Prisma Compute, driver adapters, migrations, upgrades, and official Prisma MCP workflows.
 
-## Install
+### Existing installer
+
+This is the repository's previous install route. For the focused Composer preview,
+use the local packaging and installation steps above.
 
 ```bash
 npx plugins add prisma/prisma-plugin
 ```
 
-## Supported Tools
+### Supported Tools
 
 | Tool | Support |
 | --- | --- |
 | OpenAI Codex | Skills and Prisma MCP |
 | Claude Code | Skills and Prisma MCP |
 | Cursor | Rules, skills, and Prisma MCP metadata |
 
-## What's Included
+### What's Included
 
 - Prisma CLI guidance for setup, migrations, database commands, Studio, and MCP
 - Prisma Client guidance for querying, relations, transactions, raw SQL, and configuration
@@ -28,7 +162,7 @@ npx plugins add prisma/prisma-plugin
 - Prisma ORM 7 upgrade guidance
 - Cursor rules for Prisma schema and migration best practices
 
-## Skills
+### Skills
 
 - `prisma-cli`
 - `prisma-client-api`