Models and ensembles

RouteKit owns models; FusionKit owns ensembles.

For FusionKit embedded mode, enable provider sources in the project file:

# .routekit/router.yaml
providers:
  openai: {}
  anthropic: {}
defaultModel: openai/gpt-5.5

For subscription logins, enable the provider and pool any number of named accounts:

# .routekit/router.yaml
providers:
  codex:
    strategy: capacity_weighted
    switchThreshold: 0.9

routekit config import --from .routekit/router.yaml
routekit accounts login codex --name personal
routekit accounts login codex --name work
routekit providers status codex
routekit models list

The import is required before using daemon-backed RouteKit commands with this project policy. It validates and replaces the singleton's complete canonical document; project files are never implicit daemon scopes and are not merged with the existing global file. For embedded-only API providers, fusionkit doctor validates the project catalog without importing it.

RouteKit authenticates every configured provider at startup and publishes a namespaced live catalog. Subscription providers union the models discovered from healthy members and route only to accounts eligible for the requested model. Compose only those provider/model IDs in Fusion:

{
  "version": "fusionkit.fusion.v4",
  "router": { "config": ".routekit/router.yaml" },
  "ensembles": {
    "default": {
      "members": ["openai/gpt-5.5", "anthropic/claude-sonnet-4-5"],
      "judge": "anthropic/claude-sonnet-4-5",
      "synthesizer": "anthropic/claude-sonnet-4-5"
    }
  }
}

The default ensemble is advertised as fusion-panel; other names become fusion-<name>.

fusionkit ensemble add review \
  --member openai/gpt-5.5 \
  --member anthropic/claude-sonnet-4-5 \
  --judge anthropic/claude-sonnet-4-5
fusionkit config set defaultEnsemble review

Use routekit <tool> <provider/model> for a single-model session. FusionKit has no direct mode or provider/model/key launch flags.

An explicit unknown or unnamespaced model fails instead of using the router default.

Claude Code and Codex are the one presentation exception: each native picker shows its matching subscription models under bare provider-native names. Those aliases are accepted only on that native protocol boundary and resolve to the same namespaced RouteKit model and managed account pool.

fusionkit models remains the lifecycle command for the Fusion-owned local MLX cache. It is separate from routekit models list, which performs live provider discovery.