Open sourceAdapters
Adapters. One process, any harness.
The harness-agnostic core every Babysitter run sits on. Same process, same journal, same gates and breakpoints across 12 supported harnesses.
01The idea
A harness is described, not hardcoded.
A harness is integrated by describing it: its capabilities, hook model, and command surface, as data in a catalog. The catalog is Atlas. Adding a harness is a data change; the engine stays whole.
Every Babysitter run sits on this core. The process, the journal, the gates, and the breakpoints are the same on every harness.
Naming note: Adapters is the product noun. The old mechanism name was mux; pre-v6 Agent-Mux packages were renamed to Adapters.
02Portability
Skills became portable. Processes did not.
Skills and tools now move between harnesses. Processes stayed behind: per-vendor workflow features are tied to their own harness, and a process written against one runtime is, in practice, stranded there.
Adapters makes the process itself portable. Before v6, Babysitter ran on Claude Code alone. As of v6, it runs on any supported harness: the same process definition, the same journal, the same gates, on all 12.
03Reach
The numbers.
- supported harnesses
- 12
- providers via the proxy adapter
- 140+
- distinct adapter package types
- 20
- one manifest, nine plugin formats
- 1 → 9
04The family
Twenty package types, one contract.
Adapters is a family of 20 distinct package types: triggers, extensions, hooks, proxy, tasks, codecs, transport, observability, gateway, launch, harness-mock, and more. A few carry most of the weight.
- Triggers
- CI entry points for the runtime.
- Extensions
- Plugin compilation: one manifest becomes nine plugin formats.
- Hooks
- The mandatory-stop lifecycle, normalized across harnesses.
- Proxy
- A LiteLLM bridge that reaches 140+ providers.
- Tasks
- Durable breakpoints.
- Codecs
- Per-harness drivers. Native transports for Anthropic, OpenAI chat, OpenAI Responses, and Google.
The rest of the family, by name: transport, observability, gateway, launch, and harness-mock, among others. The full list of all 20 is in the adapter-types reference.
The Hooks Adapter
Each harness has its own continuation model: Claude’s Stop, Gemini’s AfterAgent, openclaw’s daemon agent_end, opencode’s session.idle, Hermes over ACP. The Hooks Adapter normalizes all of them into one contract, so the mandatory stop holds everywhere.
The Breakpoints Adapter
Serverless-durable human approvals with pluggable backends, GitHub Issues or a server, and cryptographic signing on every approval.
05Quickstart
Host-side, three lines.
npm install -g @a5c-ai/adapters-cli
adapters doctor
adapters run claude "explain this codebase"Requires Node.js 20.9 or later. Commands verified July 2026 against the Adapters documentation.
The catalog that describes every harness is itself open.
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