Core SDK

@openclaw/krillswitch-core contains the wire types, flag model, rollout hash, and pure evaluateFlag function. It performs no I/O and has no framework dependency.

Evaluate one flag

import { evaluateFlag, type FlagConfig } from "@openclaw/krillswitch-core";

const flag: FlagConfig = {
  key: "new_nav",
  kind: "boolean",
  enabled: true,
  variations: [
    { id: "off", value: false },
    { id: "on", value: true },
  ],
  offVariationId: "off",
  defaultVariationId: "off",
  targets: [],
  rules: [],
  rollout: {
    variations: [
      { variationId: "on", weight: 10 },
      { variationId: "off", weight: 90 },
    ],
  },
};

const result = evaluateFlag(flag, { key: "user-123" });

The result contains value, variationId, and a structured reason.

Valid configuration

Write paths validate that referenced variations exist, values match the flag kind, and rollout weights total 100. The evaluator still fails loudly if handed corrupt in-memory configuration rather than silently serving an arbitrary value.

When to use it

• server-side evaluation from configuration you already loaded;
• unit tests for targeting behavior;
• shared types around the HTTP evaluation contract;
• custom framework adapters.

Browser applications normally use the React SDK or call the HTTP API.