fusionkit
Concepts

Product scope

What the fusionkit CLI uses today and why platform packages still appear in the repository.

FusionKit's daily product surface is the fusionkit CLI and the model-fusion stack it starts. The repository also contains governance, handoff, SDK, and sandbox packages from the underlying Warrant platform. Those packages are still documented because they are real code, tested examples, and release artifacts, but they are not all part of the normal fused coding-agent path.

What most users run

Most users touch these commands:

fusionkit setup
fusionkit init
fusionkit doctor
fusionkit codex
fusionkit claude
fusionkit cursor
fusionkit serve
fusionkit sessions
fusionkit models
fusionkit config show

That path starts @fusionkit/cli, the Node Fusion gateway, an embedded or external RouteKit router, tool integrations, and the internal Python synthesis sidecar. It uses the repository you run it from as the coding workspace.

Product packages

The main product path uses these packages directly.

PackageRole
@fusionkit/cliThe fusionkit command and launch orchestration.
@velum-labs/routekit-gatewayNeutral HTTP routes, wire dialects, endpoint routing, provider egress, and per-call metering.
@velum-labs/routekit-accountsSubscription credentials, pooling, provider relays, and proxy clients.
@fusionkit/gatewayFusion orchestration, sessions, aggregate budgets, trajectories, and local-model lifecycle.
@fusionkit/ensemblePanel execution, worktrees, harness adapters, judge synthesis integration, and runtime-kernel workflows.
@fusionkit/protocolShared records, validators, hashes, and generated model-fusion contracts.
@fusionkit/workspaceGit capture, materialization, safe paths, and output collection.
@velum-labs/routekit-tools and @velum-labs/routekit-tool-*Neutral registry and canonical Codex, Claude Code, Cursor, and OpenCode integrations.
fusionkit-core and fusionkit-serverProvider-neutral Python synthesis engine, RouteKit client, internal sidecar routes, and native run storage.

Platform depth

The repository also contains packages for governed execution, signed receipts, handoff workflows, remote tools, sandbox sessions, and SDK clients. They live under legacy/packages/ (not packages/) and are useful for teams building agent platforms or working on provenance and policy, but they are not required to run fusionkit codex.

Examples include @fusionkit/plane, @fusionkit/runner, @fusionkit/sdk, @fusionkit/handoff, @fusionkit/adapter-compute, @fusionkit/session-hermetic, @fusionkit/session-vercel-sandbox, and @fusionkit/session-harness, all under legacy/packages/.

Why both are documented

The CLI and platform packages share protocol, workspace, and release infrastructure. Keeping them documented together helps contributors understand package boundaries, avoid breaking retained examples, and reason about which code paths are product-critical.

If you only want better answers in an existing coding agent, start with Installation, Quickstart, Models and panels, and the Command reference. If you are building on the platform primitives, continue to Core concepts and the Package map.