// OS · v0.1.1
Mabus OS
A written-down contract for composing four standalone agent substrates.
essence (identity), swarm-lib (work), tribunal (trust), and session-loam (memory) already exist and already compose — but only via tribal knowledge encoded in CLAUDE.md files and shell scripts. Mabus OS is the spec layer that lets them act as a system. POSIX-shaped: a canonical filesystem layout at ~/.mabus/, per-substrate manifests under ~/.mabus/registry/, an append-only event log, and a thin mabus CLI that aggregates without owning.
Tribal composition
CLAUDE.md files tell the agent which substrate to invoke when. New substrates accidentally violate conventions the operator can't articulate.
Schema drift
Essence's portrait, swarm-lib's status.json, tribunal's attestations all evolve independently. No system-level signal when they diverge.
No unified status
Four CLIs to answer "how am I doing?" Compaction loses cross-substrate state because each one checkpoints itself.
The four substrates
Each ships independently. Each has its own CLI, repo, and release cadence. Mabus OS is the layer that names how they compose without coupling them.
IDENTITY · v2.1.1
session-essence
A persistence layer that observes itself. Hooks into Claude Code's lifecycle to synthesize identity portraits that survive compaction. /essence
WORK · v0.2.0
swarm-lib
Filesystem-as-orchestrator for agentic workflows. Atomic-rename queueing + status.json checkpointing. No broker, no daemon, no external database. /swarm
TRUST · v0.5
tribunal
Adversarial multi-model code review with reputation-weighted findings settled on-chain. Trust as surviving scrutiny by identified agents. /tribunal
MEMORY · v0.1.0
session-loam
SQLite + FTS5 memory substrate. Identity-scoped, never-delete with reinforce-on-retrieve. The fourth leg, shipped 2026-05-22. /memory
CAPSTONE · NOT YET BUILT
supervisor
The long-running process that consumes the Mabus OS contract and decides what to work on next. Will be a substrate itself, not Mabus OS.
Why now
The historical analogue is POSIX. Unix grew from one operator's habits at Bell Labs into a portable contract because someone wrote down what the unwritten contract already was. Mabus OS is the same move at a smaller scale — write down the conventions while they're still small enough to fit on a page.
Active composition patterns today: 4–6. Substrates: 4 shipped + 1 planned. Cross-cutting concerns are minimal because the substrate count is minimal. That changes the second a fifth substrate ships against an undocumented contract.
"The spec is the product. There is no privileged Mabus OS process running in the background. The mabus CLI is a thin convention wrapper around the filesystem layout and the event stream; it is not the spec. Anyone who wants to could rewrite the CLI in a different language while preserving the contract; the spec doesn't care."
— SPEC.md §2.1