# Cessy Builder Docs

## Instructions for AI Agents

- For clean Markdown of any page, append `.md` to the page URL
- For section-specific indexes, append `/llms.txt` to any section URL
- For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.cessy.ai/_mcp/server

## Docs

- [Cessy Builder Docs](https://docs.cessy.ai/start.md): Start here to build event-sourced business apps in Cessy with the Builder UI, Design MCP, runtime APIs, agents, and custom pages.
- [Builder Journey](https://docs.cessy.ai/start/builder-journey.md): Follow the recommended path from business language to a published Cessy app with APIs, agents, and custom pages.
- [Connect Design MCP](https://docs.cessy.ai/start/connect-design-mcp.md): Add the Cessy Design MCP server to Claude, Codex, ChatGPT, or another compatible MCP client so builders and agents can inspect and change app design safely.
- [Quickstart](https://docs.cessy.ai/start/quickstart.md): Connect an AI builder, inspect an app model, publish safely, and smoke-test the generated runtime contract.
- [Public Surface](https://docs.cessy.ai/start/public-surface.md): Inventory Cessy public, generated, builder, and platform-managed surfaces so integrations use the right contract.
- [Platform Model](https://docs.cessy.ai/core-concepts.md): Understand how Cessy turns event-sourced business models into builder workflows, runtime contracts, agents, and custom pages.
- [DomainConfig](https://docs.cessy.ai/core-concepts/domain-config.md): Learn how DomainConfig drives commands, events, projections, policies, permissions, agents, triggers, adapters, and pages.
- [Runtime Model](https://docs.cessy.ai/core-concepts/runtime-model.md): See how published DomainConfigs become REST, GraphQL, MCP, webhooks, subscriptions, projections, and custom pages.
- [Agents And Channels](https://docs.cessy.ai/core-concepts/agents-and-channels.md): Understand how builder agents, runtime agents, channels, DMs, entity threads, and attention levels fit together.
- [Environments](https://docs.cessy.ai/core-concepts/environments.md): Use runtime environments to separate production traffic, previews, test runs, and agent validation.
- [Builder Path](https://docs.cessy.ai/development-process.md): Follow the recommended development process for scoped Cessy app changes from discovery to published runtime verification.
- [Workspaces And Changesets](https://docs.cessy.ai/development-process/workspaces-and-changesets.md): Use Cessy workspaces and changesets to isolate, validate, review, and promote app design changes.
- [Workspace Seeding](https://docs.cessy.ai/development-process/workspace-seeding.md): Prepare Design Workspaces with repeatable runtime data for previews, validation, and agent-driven testing.
- [Publish And Operate](https://docs.cessy.ai/development-process/publish-and-operate.md): Promote a validated Cessy model, verify generated contracts, and operate the published runtime safely.
- [Model A Business App](https://docs.cessy.ai/build-a-backend.md): Turn a business workflow into Cessy commands, events, deciders, projections, policies, permissions, and runtime contracts.
- [Expose Integrations](https://docs.cessy.ai/build-a-backend/expose-integrations.md): Choose REST, GraphQL, Runtime MCP, webhooks, subscriptions, adapters, or a BFF for each Cessy integration.
- [Projection Queries](https://docs.cessy.ai/build-a-backend/projection-queries.md): Query Cessy projections with filters, sorting, pagination, and output shaping while preserving generated runtime contracts.
- [Permissions](https://docs.cessy.ai/build-a-backend/permissions.md): Model Cessy roles, attributes, principals, command execution rules, and projection read rules explicitly in the app.
- [Data And Activity](https://docs.cessy.ai/inspect-and-operate.md): Inspect Cessy runtime state, events, projections, commands, policies, webhooks, agents, and errors during builder verification.
- [Observability](https://docs.cessy.ai/inspect-and-operate/observability.md): Observe Cessy command execution, events, projections, policies, adapters, webhooks, subscriptions, agents, pages, and errors.
- [Errors](https://docs.cessy.ai/inspect-and-operate/errors.md): Understand Cessy error statuses, response envelopes, command failures, policy failures, webhook failures, and troubleshooting order.
- [Agents In Cessy](https://docs.cessy.ai/agents-in-cessy.md): Use Design MCP for builder agents and Runtime MCP for published app agents without mixing design-time and runtime authority.
- [Runtime MCP](https://docs.cessy.ai/agents-in-cessy/runtime-mcp.md): Use generated Runtime MCP tools for published app commands, projection and file reads, event operations, channels, users, DMs, and page refresh.
- [Agent UX Patterns](https://docs.cessy.ai/agents-in-cessy/agent-ux-patterns.md): Design Cessy agent workflows that are inspectable, scoped, useful, and safe for builders, operators, and end users.
- [Agent Docs Contract](https://docs.cessy.ai/agents-in-cessy/agent-docs-contract.md): Keep Cessy documentation useful to human builders and directly actionable for AI agents connected through Design MCP or Runtime MCP.
- [Build Custom Pages](https://docs.cessy.ai/build-a-frontend.md): Build app-specific Cessy pages that use generated runtime contracts instead of duplicating business rules.
- [Frontend SDK Reference](https://docs.cessy.ai/build-a-frontend/frontend-sdk-reference.md): Use the host-provided @ces/app-sdk contract for authenticated, runtime-source-aware Cessy Custom Pages.
- [Frontend Prompting](https://docs.cessy.ai/build-a-frontend/frontend-prompting.md): Prompt AI builders to create Cessy custom pages that respect runtime contracts, permissions, data states, and page preview feedback.
- [BFF Pattern](https://docs.cessy.ai/build-a-frontend/bff-pattern.md): Use a Backend-for-Frontend with Cessy custom pages when UI orchestration belongs outside the event-sourced model.
- [Runtime API](https://docs.cessy.ai/extend-the-app.md): Use Runtime REST endpoints for Cessy commands, projections, agent discovery, channel interaction, event import, projection rebuild, and OpenAPI discovery.
- [GraphQL API](https://docs.cessy.ai/extend-the-app/graph-ql-api.md): Use generated GraphQL command mutations and projection queries for Cessy custom pages and UI-oriented clients.
- [Webhooks](https://docs.cessy.ai/extend-the-app/webhooks.md): Receive external events through Cessy webhook triggers and map authenticated payloads into modeled commands.
- [Subscriptions](https://docs.cessy.ai/extend-the-app/subscriptions.md): Deliver Cessy runtime events to external consumers through webhook, poll, or SSE subscriptions.
- [Adapters](https://docs.cessy.ai/extend-the-app/adapters.md): Use Cessy adapters for controlled outbound service calls from policies, workflows, and custom page support code.
- [Reference](https://docs.cessy.ai/reference.md): Reference index for Cessy Design MCP, Runtime MCP, authentication, generated APIs, permissions, adapters, field types, expressions, and operations.
- [Design MCP](https://docs.cessy.ai/reference/design-mcp.md): Reference the Cessy Design MCP endpoints, OAuth scopes, tool families, and safe client usage for Claude, Codex, ChatGPT, and automation.
- [MCP Reference](https://docs.cessy.ai/reference/mcp-reference.md): Compare Cessy Design MCP and Runtime MCP surfaces for builder and runtime agent workflows.
- [Authentication](https://docs.cessy.ai/reference/authentication.md): Authenticate Cessy Runtime APIs, Design MCP, Runtime MCP, webhooks, subscriptions, adapters, and agent bridge calls.
- [Field Types](https://docs.cessy.ai/reference/field-types.md): Choose Cessy command, event, projection, and permission field types that make runtime validation and generated contracts predictable.
- [Expression Language](https://docs.cessy.ai/reference/expression-language.md): Use Cessy expressions for guards, mappings, policies, projections, and runtime configuration without unsafe dynamic code.
- [Sandboxes](https://docs.cessy.ai/reference/sandboxes.md): Use Cessy sandbox execution for controlled custom code while keeping business decisions in commands, events, projections, and policies.
- [API Versioning](https://docs.cessy.ai/reference/api-versioning.md): Evolve generated Cessy app contracts, platform-owned APIs, MCP tools, and docs without surprising builders or consumers.
- [Runtime API Template Summary](https://docs.cessy.ai/runtime-api-template.md): Summary shown before the generated Runtime API template reference.

## API Docs

- Runtime API Template > Metadata [Get the generated OpenAPI document for this app](https://docs.cessy.ai/runtime-api-template/metadata/get-generated-open-api.md)
- Runtime API Template > Commands [Execute one command](https://docs.cessy.ai/runtime-api-template/commands/execute-command.md)
- Runtime API Template > Commands [Execute commands in best-effort batch](https://docs.cessy.ai/runtime-api-template/commands/execute-command-batch.md)
- Runtime API Template > Agents [List safe runtime agent metadata](https://docs.cessy.ai/runtime-api-template/agents/list-runtime-agents.md)
- Runtime API Template > Channels [Open a user-delegated agent DM channel](https://docs.cessy.ai/runtime-api-template/channels/open-agent-dm-channel.md)
- Runtime API Template > Channels [List user-visible app channels](https://docs.cessy.ai/runtime-api-template/channels/list-channels.md)
- Runtime API Template > Channels [Get a user-visible app channel](https://docs.cessy.ai/runtime-api-template/channels/get-channel.md)
- Runtime API Template > Channels [List channel messages](https://docs.cessy.ai/runtime-api-template/channels/list-channel-messages.md)
- Runtime API Template > Channels [Post a user message into a channel](https://docs.cessy.ai/runtime-api-template/channels/post-channel-message.md)
- Runtime API Template > Channels [Close a channel](https://docs.cessy.ai/runtime-api-template/channels/close-channel.md)
- Runtime API Template > User Channel Views [Mark a channel read for the authenticated user](https://docs.cessy.ai/runtime-api-template/user-channel-views/mark-channel-read.md)
- Runtime API Template > User Channel Views [List visible channel views for the authenticated user](https://docs.cessy.ai/runtime-api-template/user-channel-views/list-user-channel-views.md)
- Runtime API Template > Projections [List projection documents](https://docs.cessy.ai/runtime-api-template/projections/list-projection-documents.md)
- Runtime API Template > Projections [Get one projection document](https://docs.cessy.ai/runtime-api-template/projections/get-projection-document.md)
- Runtime API Template > Events [Bulk import events](https://docs.cessy.ai/runtime-api-template/events/import-events.md)
- Runtime API Template > Operations [Rebuild all projections](https://docs.cessy.ai/runtime-api-template/operations/rebuild-projections.md)

## OpenAPI Specification

The raw OpenAPI 3.1 specification for this API is available at:
- [OpenAPI JSON](https://docs.cessy.ai/openapi.json)
- [OpenAPI YAML](https://docs.cessy.ai/openapi.yaml)