Guarantees and boundaries

Jixu makes a small set of strong guarantees instead of a broad set of ambiguous claims.

Durable guarantees

• The ordered Event log is the sole authority for a Thread.
• State is a deterministic Event projection.
• An external Effect is durably requested before Driver dispatch.
• Reducers are pure and I/O-free.
• Replay performs no live Effects.
• Fork creates a new Thread and preserves its parent.
• Unknown event types and schema versions fail closed.
• Secrets are excluded from Events, Checkpoints, errors, and Signals.
• One Harness owns exactly one immutable Agent.

Explicit boundaries

Pre-1.0 compatibility

Public APIs and supported persisted schemas may change before 1.0. Current decoders accept only explicitly supported versions and reject unknown data rather than guessing.

External idempotency

Stable Effect identity does not create exactly-once execution by itself. The external system must enforce an idempotency contract before that claim is valid.

Tool containment

The reference permission layer controls dispatch. It is not an OS sandbox, and Bash remains capable of destructive operations with the process's permissions.

One Agent

Jixu core does not route between Agents. A different Agent requires a different Harness. Cross-Agent coordination belongs outside one Harness and one Thread.

Provider behavior

Jixu can make requests and outcomes durable; it cannot make model output deterministic. Provider-native state, cache metadata, and traces never become Thread authority.

Operational rule

When Jixu cannot prove that continuing is safe, it stops at a typed waiting or failure boundary. The user sees the uncertainty instead of receiving a silent retry or invented success.