by Spectrum Web Co

The stack · by Spectrum Web Co

What’s under the OS.

The KanbanOS stack is four components: Ultrathink, an open-source planning plugin for coding agents; Agent Substrate, the shared layer of runtime, memory, skills, sandboxes and a ledger over MCP and ACP; Agent Swarm, an open-source 15-agent SDLC system with fail-closed gates; and the Kanban operator surface where agents move cards and humans keep the gates.

Not a single binary — a product surface over four components Spectrum Web Co is building and wiring together.

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Four components

What is the KanbanOS stack made of?

Each component is a real project with its own repository, release cadence and status. KanbanOS is the product surface that wires them into one operating layer, so a team can adopt a single component today and the whole OS as the planes come online.

  • Ultrathink — planning plugin, open source, public through v1.2
  • Agent Substrate — shared foundation, in build and in use
  • Agent Swarm — SDLC in motion, open source through v2.0
  • Kanban — the operator surface, in the product model

01 — 01 · Ultrathink

Plan before you code.

Ultrathink is an open-source planning plugin for AI coding agents, published as claude-ultrathink. It rewrites each prompt into an XML spec with a dependency graph, builds a graph of thought with parallel execution waves and asks clarifying questions before the agent writes code.

  • Open source at github.com/swcstudiospace/claude-ultrathink
  • Graph ID ut-… · kickoff / plan / sync / ship
  • GSD after plan · fail-open · never writes .planning/ into cwd

02 — 02 · Agent Substrate

The shared foundation.

Agent Substrate is the shared layer under every AI coding agent a team runs: durable memory of what each agent has worked on, skills and tools synced across sessions, a sandbox per agent and a ledger for claims, dispatch and results, all over MCP and ACP. It is in build, and already in use inside KanbanOS.

  • Runtime · Memory · Skills · Sandbox · Ledger
  • MCP and ACP native
  • Notion / Linear as sources of truth · lanes A / B / C

03 — 03 · Agent Swarm

The SDLC in motion.

Agent Swarm is an open-source multi-agent system that coordinates 15 specialised agents across the full software development lifecycle. An orchestrator delegates to specialists, every artifact has a single writer, quality gates fail closed and stalled work escalates to a human.

  • Open source at github.com/swcstudiospace/agent-swarm
  • swarm.v1 signed message protocol · SQLite-backed task state
  • omp-native install · dry-run and headless execution

04 — 04 · Kanban

The operator surface.

The Kanban surface is where the other three components become operable. Cards carry the Graph ID, agents claim and move them through dependency chains, hooks and linked worktrees, and every gate — including the human merge gate — is a visible move on the board.

  • Parallel cards, worktrees, hooks and dependency chains
  • Agents claim and move; operators see every claim
  • Humans on the gates

Adopt a layer

Start with one component or the whole OS.

Teams often start with Ultrathink inside the agents they already run, add Agent Swarm when they want a governed lifecycle, and move onto the board when more than one person needs to see the work.

  • Ultrathink first: planning in the agents you already run
  • Agent Swarm next: a governed, parallel lifecycle
  • Agent Substrate: shared context across every runtime
  • KanbanOS: the operator surface over all three

FAQ

Stack questions.

Licences, repositories and how the components relate.

01

Which parts of the KanbanOS stack are open source?

Ultrathink and Agent Swarm are open source today, both published by Spectrum Web Co under github.com/swcstudiospace as claude-ultrathink and agent-swarm. Agent Substrate is in build and in use inside KanbanOS, and is being released layer by layer as each part is ready. KanbanOS itself, the product surface over the four components, is licensed AGPL-3.0.

02

What is the difference between Agent Swarm and Agent Substrate?

Agent Substrate is the foundation: the shared memory, skills, sandboxes and ledger every agent draws on, spoken over MCP and ACP. Agent Swarm is the lifecycle that runs on top of it: fifteen specialised agents coordinated by an orchestrator through signed, fail-closed gates. The substrate is what the agents stand on; the swarm is what they do. Inside KanbanOS, Agent Swarm runs on Agent Substrate and both are driven from the board.

03

Can I use Ultrathink without the rest of KanbanOS?

Yes. Ultrathink is a standalone planning plugin for AI coding agents and works on its own with Claude Code, Grok Build, Hermes Agent, Muse Code and Omp. It fails open, never writes planning files into your working directory and needs no board or substrate to be useful. Adopting it first is the most common way teams start, because it improves the plans their agents already make without changing anything else.

04

Which runtimes does the Agent Substrate support?

Agent Substrate is runtime-agnostic by design. It speaks MCP and ACP, so any agent that can use those protocols can read the shared memory, claim skills and write to the ledger. It is used today with Claude Code, Grok Build, Hermes Agent, Omp and Muse Code, and Spectrum Web Co adds runtimes as early-access teams bring them.

Early access

Adopt the stack, one plane at a time.

Start with the open-source components today and join early access for the substrate and the board.

Talk to Spectrum Web Co