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Embabel Worlds

What's intentionally not in a realm

  • Code that runs with host privileges. No JVM bytecode, no native libraries, no classpath contributions. Realm code executes only inside a host-managed sandbox — the code sandbox for dist/ JS handlers, the capability-scoped wasm runtime for dist/handlers.wasm (see Execution hosts) — never as the host itself.
  • Spring beans, host configuration changes.
  • User credentials. Realms carry credential references, never values. Marketplace realms use host-vetted typed slots and auth profiles. Environment-variable references are local or explicitly first-party/org-reviewed compatibility syntax only.
  • World, context, or principal-owned state. A realm ships templates and types; host-owned scopes hold mutable instances and their access policy.

If a capability needs real code, ship it as sandboxed handler code (src/ or wasm/, run on an execution host), via actions/ (LLM in the loop), via mcp/ (sandboxed server, arbitrary code), or as a host-level extension out of band.