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Status and limitations | SubstrateWhat the current Substrate development release serves, and what remains absent.Substratestatussubstratestatusadopterdeveloperoperatortroubleshoot

What is available today?

Substrate has a tagged, keyless-signed daemon image and a public, keyless-signed, digest-pinned development contract bundle. Distribution is proven; the bundle remains a development contract because stability is a separate compatibility decision.

Release 0.7.3, published on 5 September 2026, ships the daemon and disposable MCP images with the signed substrate-wire/0.16.0 development bundle.

The current implementation is a Linux host slice. Treat every capability as deployment-specific and verify it through GET /v1/machine.

Served now

AreaCurrent state
personal transportowner-permissioned Unix socket with kernel-derived local identity
production network transportTLS 1.3 HTTPS/WSS with explicit identity files, atomic SIGHUP rotation and five-minute exact-audience Identity admission resolved before every route
workspacesempty or configured, authorized HTTPS Git source; exact-commit materialization, guarded files, bounded Git observations, destruction and leases
execavailable only with the complete probed Linux confinement floor
durabilityoperation reservation before dispatch, persisted terminal observations and output
recoveryoperation lookup, bounded events, reconciliation snapshots, restart-to-unknown
limitsbody, path, output, retention, concurrency, process, memory, CPU, duration, and probe-gated writable-storage bounds
observationsexplicit live and terminal wall, CPU, memory peak/current, process, OOM, block-I/O, and scratch usage facts
sessionsleased raw-pipe and probe-gated PTY modes at /v1/sessions, with one Unix-WebSocket or authority-bound hosted WSS attachment
Rust SDK sourcecomplete promoted-contract coverage over Unix or explicit-root TLS 1.3 HTTPS/WSS, with serializable observations, exact optional facts, keyed mutations, PTY resize, metrics and snapshots
disposable MCPprivate stdio adapter over the SDK; bounded tools/resources, caller operation IDs, portable named refusal and native delegated cleanup evidence; published as a separately signed 0.7.3 image
capsulesdigest-verified read-only runtime material beside a writable workspace
distributionApache-2.0 source plus keyless-signed 0.7.3 daemon and MCP images and the signed 0.16.0 development bundle

Explicitly absent

  • general workspace backup/restore snapshots (reconciliation snapshots recover observed resource state)
  • workloads, images, volumes, and endpoints
  • Docker and Kubernetes drivers
  • cross-machine scheduling
  • stable signed contract-bundle publication

Unsupported capabilities on existing routes produce unserved or a specific refusal. Future resource families have no implemented routes; unknown addresses return HTTP 404 with resource.not-found. Their names in a broader architecture do not imply served endpoints.

Trust limitations

  • The minimum host boundary does not claim protection from kernel compromise.
  • A verified capsule identifies its provided bytes, not the entire host runtime closure.
  • Static-bearer TCP is loopback-only, development-only, and unsuitable for public or shared ingress.
  • Production TLS admits callers only through online Identity resolution. Identity unavailability fails closed, and no cached authority or caller-written identity is used.
  • One daemon is one trust domain; it is not a multi-tenant isolation layer.
  • Release 0.7.3 advertises substrate-wire/0.16.0 and the SHA-256 of its inner bundle.json as one claim. The outer OCI package has its own digest. Version 0.15.0 deliberately replaced /v1/pipe-sessions with /v1/sessions and serves no compatibility alias.
  • Git materialization needs a configured source and transient Connector authority. The conditional workspace.git fact does not authorize arbitrary remote URLs.
  • Sessions publish operation-ledger events; a separate public session.* vocabulary is absent. See model coverage and derivation.

Reading status safely

The homepage describes durable product boundaries. This page carries the changing implementation snapshot. For a real deployment, machine facts take precedence over both: they describe what that specific daemon verified at runtime.

Start with getting started, then read confinement and refusal before enabling execution.