a5c (default) overview

Default launch recipe for the a5c agent (the babysitter monorepo). Spawns the `a5c` / `babysitter` CLI with no extra argv and no environment overrides. a5c does not bind a single model — model selection flows through adapters to the harness chosen at run-create time (e.g. `--harness claude-code`). The orchestrator stamps an AGENT_SESSION_ID into the harness env file so the bridged session is PID-scoped to the orchestrator's run. Source citations: - packages/babysitter-sdk/src/cli/main/usage.ts (`run:create --harness <name>` and `create-run` argv shapes). - packages/babysitter-sdk/src/cli/main/runCreate.ts (session-id resolution via `--session-id` / `AGENT_SESSION_ID` env / PID-scoped fallback). - packages/babysitter-sdk/src/cli/commands/instructions.ts (harness env file + AGENT_SESSION_ID marker).