acp-provider

# 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. 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). OpenCode ACP supports 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 `$XDG_DATA_HOME/opencode/opencode.db`, then `OPENCODE_AUTH_CONTENT` or `$XDG_DATA_HOME/opencode/auth.json`. The default data directory is `~/.local/share/opencode`. Account storage is read only; expired Console sessions must be refreshed by OpenCode. 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.