Mantle

Be the dungeon master. Don’t code every corridor.

Schema. View. Procedure. Trigger. Four atoms from which your world takes shape.
Speak it in plain YAML, and the dungeon wakes—whole, lit from within, and yours to command.

Features · Admin · Get started · Documentation · Examples

Mantle is an embeddable application engine for TypeScript. Define your data, queries, actions, and triggers in a Manifest, then use them through typed APIs, HTTP endpoints, agent tools, and an optional staff console.

Build a publishing site, an internal operations app, or an API for agents. Your application owns its host, storage, and business logic; choose the Mantle modules you need.

Features

• One Manifest, connected interfaces. Schema, View, Procedure, and Trigger describe your data and behavior. The compiled definitions power typed APIs, HTTP routes, MCP tools, and Admin. Manifest features.
• Typed queries and actions. Generate TypeScript bindings for entries, declarative Views, and Procedures. Keep host-only reads private with internal Views. Typed queries.
• Admin that follows your model. Manage live records, publish content, run reports, and invoke business actions. Configure columns, filters, and actions with Manifest uiSchema. Admin customization.
• Tools for browser and remote agents. Admin supports WebMCP using the signed-in staff session. Remote MCP clients connect through authenticated endpoints, with authorization checked on each call. MCP and WebMCP.
• Publishing and discovery. Add localized HTML and Markdown, draft/publish workflows, llms.txt, sitemaps, and search/social metadata. Publishing example.
• Embed in an existing application. Use validation alone, connect Runtime to your storage, or add Web, Admin, and a host adapter. Integration choices.

Admin for people and agents

Give staff a workspace for content, operational records, reports, and actions. In browsers supporting WebMCP, agents can discover and invoke staff tools from Admin, inspect the current page, and navigate alongside the user. Calls use the current staff session and retain server-side authorization and concurrency checks.

Developer UI and application API docs

Explore your application's Schemas, Views, Procedures, Triggers, and their relationships in the owner-only Developer UI. Its HTTP, MCP, and WebMCP docs show the application's projected routes and tool schemas, with links back to the owning definitions.

Developer UI rendered locally from the intake example. The graph describes compiled declarations; it does not certify runtime or deployment health.

Interface	Where to explore it	Integration guide
HTTP	Admin → Developer → API (/admin/dev/docs/api)	HTTP API
Remote MCP	Admin → Developer → MCP (/admin/dev/docs/mcp)	Endpoints, tools, and authentication
Browser WebMCP	Admin → Developer → WebMCP (/admin/dev/docs/webmcp)	Admin and public-page WebMCP

A Manifest in practice

An intake application needs request records, a submission action, and a staff inbox. Its staff View can be as small as:

apiVersion: cms.mantle.aotter.net/v1
kind: View
metadata:
  name: recent-requests
spec:
  title: Recent requests
  surface: staff
  from: requests
  fields: [id, name, email, message, submittedAt]
  orderBy:
    - { field: submittedAt, direction: desc }
  limit: 50

Together with the requests Schema, this defines the read used by the staff report and its MCP tool. A Procedure handles submissions, with Triggers choosing HTTP and MCP exposure. Read the complete intake example.

For other applications, explore commerce, reservations, and procurement.

Get started

With a coding agent

Install the Mantle skill to get guided setup for your application and the features you need:

npx skills add aotter/mantle

Ask your agent to follow the installed skill and describe what you want to build. The installer finds the mantle skill by name. See the agent setup guide for supported editors, plugins, and project instructions.

Build it yourself

Start with the handbook, or follow the runnable minimal Worker. For a staff console, use the local Admin example. The project and CLI guide walks through installation, authoring Manifests, generating typed bindings, and verification.

Using ChatGPT Sites? Follow the Sites integration for content management, sign-in, media, and publishing.

Choose how much to use

Start with	Add when you need
Spec	Manifest parsing, validation, and introspection in an existing system.
Runtime + typed APIs	Queries and actions backed by your storage and handlers.
A host adapter	HTTP and other supported transports on your chosen platform.
Web	Public HTML, Markdown, localization, and discovery metadata.
Admin	A staff API and prebuilt console with Manifest-driven rendering.
Auth	Identity, staff roles, and OAuth / MCP authorization.

Cloudflare is the supported host for the integrated Auth, Admin, and MCP experience. Bun and Vercel adapters are experimental; they support public Views and HTTP Triggers, with authentication and CSRF owned by the host. Compare adapters.

Package reference

Package	Purpose
@aotter/mantle	Core umbrella, CLI, and code generation.
@aotter/mantle-spec	Manifest parsing, validation, and introspection.
@aotter/mantle-runtime	Runtime execution and storage ports.
@aotter/mantle-web	Public rendering and discovery metadata.
@aotter/mantle-admin	Admin API and session integration.
@aotter/mantle-admin-ui	Prebuilt staff console and Developer UI.
@aotter/mantle-auth	Identity, roles, and OAuth authorization.
@aotter/mantle-indexeddb	Browser-local storage.
@aotter/mantle-cloudflare	Workers, D1, and integrated surfaces.
@aotter/mantle-bun	Experimental Bun adapter.
@aotter/mantle-vercel	Experimental Vercel adapter.

Documentation

• Handbook — concepts, setup, and task guides.
• Manifest feature reference — capabilities and their authoring fields.
• SDK and package API — installation, typed bindings, and optional modules.
• CLI guide — validate, generate, and maintain a project.
• Examples — complete Manifests and runnable hosts.
• Releases — changes and upgrade notes.

Contributing

See Contributing for development and review, Support for questions and bugs, and Security for private vulnerability reports. Contributors follow the Code of Conduct.

Apache 2.0. See LICENSE.