ACP providers

Known agents can be discovered automatically when their CLI is installed on the host: opencode, omp, grok, and hermes appear as acp-opencode, acp-omp, acp-grok, and acp-hermes-agent. Inspect the target host's catalog with bb provider list and bb provider models <provider-id> using its environment or machine selector.

Agents in the official ACP registry can be added without writing JSON. bb acp registry [--refresh] [--json] lists them with a status: available, added, update available, built in (bb already ships it), or manual install (the agent ships only as a downloadable binary). bb acp add <agent-id> adds the agent as provider acp-<agent-id>, or moves an added agent to the registry's current version while keeping the fields edited by hand. bb acp remove <agent-id> removes it. The plugin's settings page shows the same list. An added agent is an entry in the Custom agents setting that runs npx -y <package> or uvx <package> on the thread's host, so the host needs Node.js or uv. The list is cached for six hours; when the registry cannot be reached the saved copy is shown with the reason.

To hide a detected ACP agent, use bb provider disable acp-opencode, or Disable on Settings → Providers. Restore it with bb provider enable acp-opencode. This leaves other ACP agents and the host CLI intact. Disabled agents skip background capability probing. bb provider list --all includes disabled agents.

Cursor project skills come from .cursor/skills, which can link to .agents/skills. BB lists these linked skills as read-only under cursor-project.

ACP agents may reject unlisted model IDs. OpenCode requires models in its own configuration; BB discovers them there. OpenCode agents are session modes, not models selectable through BB's model field. Grok Build advertises models and thought_level options over ACP, so the picker follows the connected agent (including xhigh on grok-4.6).

BB launches OpenCode sessions with OPENCODE_CLIENT=acp and OPENCODE_ENABLE_QUESTION_TOOL=false, overriding inherited and custom launch values. Native questions have no ACP interaction handler in BB; agents use the ask-user-question plugin’s AskUserQuestion tool instead. This also applies to custom agents with dialect: "opencode" and does not change OpenCode config files.

OpenCode and Grok ACP support the core bb thread compact command; Cursor ACP does not expose compatible compaction. Check the actual agent's capabilities before attempting provider-specific recovery.

OpenCode Go subscription usage is available in Provider usage when the selected machine has OpenCode installed and a Go subscription. Sign in to Go in OpenCode on that machine, then refresh its OpenCode tab. Verify with bb settings usage --machine <id-or-name> --json; the SDK equivalent is bb.sdk.system.usageLimits({ hostId, providerId: "acp-opencode" }). BB reports Go's five-hour, weekly, and monthly usage and reset times, not local session token totals or other OpenCode providers' subscriptions.

The collector checks OPENCODE_API_KEY, then the active official Console account and organization in $XDG_DATA_HOME/opencode/opencode.db, then active v2 credential table API keys or official Console OAuth credentials (opencode-go before opencode), then OPENCODE_AUTH_CONTENT or $XDG_DATA_HOME/opencode/auth.json. The default data directory is ~/.local/share/opencode. Database storage is read only; expired Console sessions must be refreshed by OpenCode. V2 OAuth requires the device login method and account/organization metadata for the official Console server. API-key login prefers the opencode-go credential and accepts the shared opencode credential when Go is subscribed. Custom launch env values take precedence over the host environment. A custom OpenCode wrapper must declare dialect: "opencode" and providerUsage: true to expose its usage. Missing credentials, rejected keys, and collection errors remain unavailable states rather than zero usage. Never print API keys when diagnosing setup.