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Domain-Driven CAP ​

The default backend in the AI-Driven Development Model is built on the SAP Cloud Application Programming Model (CAP) — Node.js with TypeScript, CAP v10. CAP is the central abstraction for domain model, services, persistence, and authorization. See also the CAP programming model overview.

  • cds-typer generates @cds-models/* types, imported via #cds-models/<path>.

Project Scaffolding — always via cds CLI facets ​

New CAP projects and features are created with cds init / cds add — never by hand-writing configuration:

bash
cds init <project> --add typescript,sqlite    # typescript facet auto-adds cds-typer
cds add hana --for production
cds add xsuaa            # or: cds add ias
cds add mta

Rationale: facets wire up package.json, tsconfig.json, mta.yaml, and cds-plugin presets consistently; hand-rolled config drifts and breaks cds build tasks.

TypeScript Runtime — tsx is mandatory ​

  • tsx and typescript are required devDependencies in every CAP project.
  • Run plain cds watch — it detects tsconfig.json and runs via tsx automatically ("Detected tsconfig.json. Running with tsx.").

WARNING

Without tsx, cds watch does not run .ts handlers and @cds-models/* are not regenerated on model changes — a recurring failure in past projects.

  • @cds-models/* are build artifacts: excluded from version control, regenerated by the cds-typer plugin during cds watch and by the typescript build task during cds build.

Domain Model & APIs ​

  • Domain model: CDS — Entities, Aggregates, Bounded Contexts via namespaces.
  • APIs: OData v4 first, REST only when useful.
    • CAP v10: Application Services serve only odata-v2 / odata-v4 / odata-x4 by default; widen via cds.protocols.defaults if needed.

Fiori UI Annotations ​

The CDS model carries standard SAP Fiori annotations that the frontend's React Fiori building blocks render out of the box — no per-field UI code. Annotations live in companion files next to each service, all registered in srv/services.cds:

  • <service>-service.ui.cds — Fiori UI annotations: @UI.LineItem (table columns / list report), @UI.HeaderInfo, @UI.Facets / @UI.HeaderFacets (object page), @UI.DataPoint, @UI.FieldGroup.
  • <service>-service.valuehelp.cds — @Common.ValueList definitions (value helps / Wertehilfen).
  • <service>-service.common.cds — field/entity labels and i18n texts (@title, @Common.Label).

Because these annotations are served in the OData $metadata, a single annotated CDS model drives both the API and the UI — the same annotation-driven, source-of-truth principle as SAP Fiori elements, but consumed by React components instead of UI5. See Frontend → Fiori Building Blocks.

Persistence ​

  • Local / dev: SQLite via @cap-js/sqlite (added via cds add sqlite).
    • CAP v10 uses native node:sqlite as the default driver (Node ≥ 22.5).
    • better-sqlite3 / sql.js require an explicit dependency.
  • Production: SAP HANA Cloud via @cap-js/hana (added via cds add hana --for production).
  • No direct driver deps in package.json — services are auto-wired via cds-plugin presets.

AI Layer ​

The AI layer is deliberately flexible — pick per project between SAP's managed AI stack and a direct LLM call:

  • SAP Business AI as the core (SAP AI Core) — the CAP AI plugin (@cap-js/ai for Node.js, cds-starter-ai for Java, since June 2026) integrates SAP AI Core. It auto-resolves service bindings, manages resource groups and model deployments, and exposes a standardized AICore service. Built-in use cases include automatic UI field recommendations (powered by SAP's RPT-1 foundation model) for @Common.ValueList fields in draft-enabled Fiori UIs — no custom handler required. Models offered by SAP Generative AI Hub are reached through this path.
  • Other LLMs directly — alternatively, call an LLM SDK straight from a CAP service handler, e.g. the Anthropic Claude SDK. Add a thin per-provider adapter only when a second provider is introduced.
  • Vector / RAG — optional native CAP vector support (CDL Vector type + cosineSimilarity / l2Distance) for in-CAP RAG on SQLite / PostgreSQL / HANA.

Note

capire documents CAP's built-in AI integration via SAP AI Core (@cap-js/ai). Using arbitrary third-party LLMs is not a dedicated CAP feature — it is a plain SDK call from a handler; the managed, multi-model path runs through SAP AI Core / Generative AI Hub.

See AI-Driven Workflow for how the AI layer fits into the end-to-end development flow.

Auth ​

  • XSUAA or IAS depending on project context (added via cds add xsuaa / cds add ias) — services annotated @(requires: 'user').