lucille-sdk

The stable contract a product builds against to run on the Lucille platform, without importing the Lucille backend.

It is interface only — around 800 lines, no dependencies, stdlib-only by design. A product imports the declaration surface and the capability seams; a host registers concrete providers behind those seams before the product is imported. In-process that host is the Lucille backend; out-of-process it is the product's own runtime.

from lucille_sdk import Integration, IntegrationDescriptor
from lucille_sdk.services import get_message_compose
from lucille_sdk.telegram import settled_text

What is in it

Each seam is a register_*_provider() / get_*() pair, so the product calls a capability without knowing what implements it. The exception is settled_text, a pure rule with no host-specific behaviour, imported directly.

Why it is published

A product repository has to be able to install this in isolation — in CI, and on a contributor's machine — without credentials for the platform's own repository. That is the whole reason it is a separate distribution rather than a package inside the backend.

Versioning

The contract is what other repositories pin, so a breaking change to a seam signature is a major bump. Adding a seam, or a field with a default, is a minor one.