Recursive Harness Builder is a local runtime for building recursive agent workflows out of markdown prompts, optional hooks, and ordinary project files.
It wraps the Claude Agent SDK with a few added design choices: the ability for agents to clone themselves into a forked subagent, unlimited depth of subagents, agent-to-agent messaging, scheduling, and hookable tool behavior.
The harness itself runs at any subscription tier. However, the recursive workflow example — where agents spawn child agents that spawn further children — benefits from the higher rate limits and concurrent sessions available on $100+/month plans (Anthropic Max, OpenAI Pro, or equivalent). Without those limits, deep recursion will hit throttling quickly.
Most agent tools give you one agent in one terminal, with one layer of subagents. Recursive Harness Builder lets you define a harness around the agent:
- Fork work into child agents that inherit context and continue independently.
- Attach hooks to constrain or extend behavior, such as preventing orchestrators from editing files.
- Coordinate agents through inbox messages, artifacts, schedules, and resumable sessions.
- Use Telegram as a UI when you want a phone-friendly or multi-window view of many concurrent agents.
- Route non-Claude models through a CLIProxyAPI-compatible endpoint when you want Codex, GPT, Gemini, or other providers.
The runtime is the harness. The workflow is yours.
Start with the bundled recursive workflow example:
examples/recursive-workflow/— a small project with flat markdown procedures and a guard hook.docs/procedures.md— how procedure files are organized and launched.
The example shows the intended pattern: describe coordination behavior in markdown, point an agent at the right procedure file, and let the harness manage forks, messages, hooks, and artifacts.
The recommended setup path is to let an agent install it for you.
Open Claude Code, Codex, or another coding agent and give it this prompt:
Clone https://github.com/Breedoon/recursive-harness-builder and follow INSTALL.md to set it up for me. Use examples/recursive-workflow as the first project. Ask me for any credentials or Telegram setup values you need.
You will need:
- Python 3.12+
uv- Claude subscription OAuth for the default Claude path
- Optional: Telegram bot credentials for the Telegram UI
- Optional: CLIProxyAPI-compatible proxy for non-Claude models (eg, Codex)
Recursive Harness Builder currently includes:
- a local CLI runtime;
- a Telegram runtime with one topic per agent;
- AgentTask-based forking;
- inbox messaging between agents;
- interval and cron-style schedules;
- hook support for tool calls and lifecycle events;
- cache/proxy support for provider routing.
Telegram is the UI. The core model is markdown-defined workflow procedures running on top of resumable, forkable agent sessions.
Apache License 2.0. See LICENSE.