Providers

Harness support is declared in pinned manifests. The machine-readable table is provider-reference.json.

Provider	Support tier	Credentials
opencode	supported	opencode_zen Connection
codex	experimental	optional codex Connection
claude	disabled	n/a
devin	disabled	n/a
grok	disabled	n/a
antigravity	disabled	n/a

A disabled provider cannot be selected. Capability values are supported, unsupported or unknown, and unknown is never treated as supported. For OpenCode, event_stream, model_discovery, native_resume, native_state_export and usage are supported; interrupt, steer, interactive_approval and credential_writeback are not.

Use GET /api/harnesses for the installed catalog, GET /api/models for Connection-scoped model availability and GET /api/executor-backends for executors. These reads have no side effects.

A Harness switch creates a new linked Session with an explicit summary Message. SBX never silently translates hidden context between CLIs.