loopy-loop

loopy-loop runs long-running AI agent workflows inside your repository. It turns a goal file in your repository into an inspectable sequence of agent iterations: plan, implement, evaluate, record evidence, and continue until the goal is met or the loop hits a terminal blocker.

The value is control and durability. Instead of asking one agent to solve a large task in one fragile chat, loopy-loop gives the work a persistent session directory, repeatable workflow prompts, explicit stop conditions, and structured logs. You can pause, resume, audit what happened, adjust the goal, inspect every prompt/result pair, and keep the actual project changes in normal git branches and PRs.

Under the hood, loopy-loop runs a small FastAPI coordinator and one or more workers. The coordinator owns the loop state and chooses the next workflow. The workers run assignments through team-harness, which can delegate to agent CLIs such as Codex, Claude Code, and Gemini. The packaged inner_outer_eval template also uses eval-banana conventions for session-scoped evaluation checks.

Install

Install the CLI from the official PyPI package.

With uv, install it as a command-line tool:

uv tool install loopy-loop

Or with pip:

pip install loopy-loop

For development inside this repository:

uv sync --extra dev

Install the Agent Skill

This repo also ships an Agent Skill that teaches Claude Code, Codex, and compatible agents how to set up and run loopy-loop in another target repo.

npx skills add https://github.com/writeitai/loopy-loop --skill loopy-loop

The skill source lives under skills/loopy-loop/.

Initialize a Target Repo

Run this from the repository you want agents to work on:

loopy init --template inner_outer_eval

This is the recommended starting template. It creates:

• loopy_loop_config.yaml
• loopy_loop_goal.txt
• .loopy_loop/workflow_sets/inner_outer_eval/workflows/outer/
• .loopy_loop/workflow_sets/inner_outer_eval/workflows/inner/
• .loopy_loop/workflow_sets/inner_outer_eval/workflows/eval_reviewer/
• .loopy_loop/workflow_sets/inner_outer_eval/workflows/eval_runner/
• a .gitignore entry for .loopy_loop/sessions/

loopy init is idempotent. It creates missing files and leaves existing files alone.

Write the Goal

The loop goal lives in loopy_loop_goal.txt. Replace the scaffolded example with the real target, including constraints and observable completion criteria.

Example:

Implement passwordless email login.

Completion criteria:
- Users can request a one-time login link from the sign-in page.
- The link expires after 15 minutes and cannot be reused.
- Existing password login keeps working.
- Tests cover token expiry, token reuse, and successful login.
- README documents required environment variables.

Keep the goal specific enough that a reviewer or eval workflow can decide whether the loop is done. For one-off overrides, start the coordinator with --goal-file PATH; the file is copied into the session as goal.md.

Run the Loop

Start the coordinator in one terminal:

loopy coordinator --host 127.0.0.1 --port 8080

Start a worker in another terminal:

loopy worker --coordinator http://127.0.0.1:8080

Useful control commands:

loopy status
loopy stop

If the coordinator stops while a session is still running, restart it with:

loopy coordinator --host 127.0.0.1 --port 8080 --resume

The default templates use team_harness_provider: "codex", so the coordinator uses local Codex authentication. If you switch to an OpenAI-compatible provider, export the environment variable named in team_harness_api_key_env, usually OPENROUTER_API_KEY, in both the coordinator and worker shells.

How It Works

At a high level:

1. loopy init writes a root config, a goal file, and workflow files into the target repo.
2. loopy coordinator loads loopy_loop_config.yaml, resolves the goal text, creates a session under .loopy_loop/sessions/, and exposes two HTTP endpoints: /register and /finished.
3. A worker calls /register, receives the next workflow assignment, renders the workflow prompt with session paths, and runs it through team-harness.
4. team-harness runs a coordinator model and can spawn external worker CLIs such as Codex, Claude Code, or Gemini.
5. The worker writes the rendered prompt, normalized result, result text, harness run id, and harness output path into the iteration directory.
6. The coordinator records the result, checks session control/eval artifacts, and either dispatches the next workflow or stops.

The inner_outer_eval template is organized around four workflows:

• outer: plans, tracks durable project state, reviews evidence, and decides what should happen next.
• inner: implements the selected work in the target repo.
• eval_reviewer: creates or refreshes session-scoped eval-banana checks.
• eval_runner: runs the eval checks and writes goal_check.json.

The loop does not hide state inside a chat transcript. Continuity comes from git state plus files in .loopy_loop/sessions/<session_id>/.

Repo Layout

After initialization, the target repo has this shape:

target repo/
├── loopy_loop_config.yaml
├── loopy_loop_goal.txt
└── .loopy_loop/
    ├── workflow_sets/
    │   └── <workflow_set>/workflows/<workflow_id>/
    │       ├── config.yaml
    │       └── prompt.txt
    └── sessions/
        └── <session_id>/
            ├── goal.md
            ├── session.json
            ├── state.json
            ├── control.json
            ├── updates_from_user.md
            ├── project_state/
            ├── eval_checks/
            ├── eval_results/
            ├── harness_outputs/
            ├── child_requests/
            ├── children/
            └── iterations/

Workflow definitions are part of the repo and should usually be committed. Session directories are runtime output and are ignored by default.

Configuration

Root config lives at loopy_loop_config.yaml:

goal_file: loopy_loop_goal.txt
workflow_set: inner_outer_eval
max_turns: 160
goal_check_consecutive_failures_cap: 3
team_harness_provider: "codex"
team_harness_model: "gpt-5.5"
team_harness_agents:
  - "codex"
  - "claude"
  - "gemini"
team_harness_agent_models:
  codex: "gpt-5.5"
  claude: "claude-opus-4-8"
  gemini: "gemini-3.5-flash"
team_harness_agent_reasoning_efforts:
  codex: "high"
team_harness_api_base: "https://openrouter.ai/api/v1"
team_harness_api_key_env: "OPENROUTER_API_KEY"

Important rules:

• workflow_set selects the default workflow set for new sessions.
• goal_file is resolved relative to loopy_loop_config.yaml.
• Inline goal values in YAML are rejected; the goal should live in a file.
• max_turns is the maximum number of completed workflow iterations.
• team_harness_model controls the team-harness coordinator model.
• team_harness_agent_models controls default models for worker subprocesses.
• team_harness_api_base is normalized by loopy-loop: trailing slash stripped, /v1 appended when missing.
• team_harness_max_retries, team_harness_retry_base_delay_s, and team_harness_retry_max_delay_s are optional retry controls for transient team-harness API/network errors.

Workflow config lives beside each workflow prompt:

enabled: true
priority: 0
run_every: 1
must_follow: null
not_before_iteration: 0
run_on_start: false
run_after_successes: null
emits_goal_check: false
description: ""

Workflow rules:

• The workflow id is the folder name under .loopy_loop/workflow_sets/<workflow_set>/workflows/.
• priority breaks ties among eligible workflows; higher values run first.
• run_every is based on completed iteration count, not wall clock.
• run_on_start=true makes a workflow eligible before any successful workflow has run.
• must_follow and run_after_successes.workflow_id must reference existing workflow ids.
• run_after_successes can schedule a workflow after every N successful runs of another workflow:

run_after_successes:
  workflow_id: inner
  every: 10

• emits_goal_check=true lets a non-goal_check workflow write goal_check.json as an eval artifact. Stopping still requires updating session control.json.

Output and Logging

Each fresh coordinator run creates one session directory:

.loopy_loop/sessions/<session_id>/

Session ids start with a UTC timestamp and include a deterministic goal hash, so session directories sort chronologically and similar goals are easy to compare.

Important session files:

• goal.md: the exact goal text copied into the session.
• session.json: session metadata.
• state.json: coordinator-owned dispatch state.
• events.jsonl: reserved append-only diagnostics log.
• control.json: workflow-owned stop switch.
• updates_from_user.md: human-writable inbox for changes after the session starts.
• project_state/: workflow-owned durable markdown state.
• eval_checks/: session-scoped eval-banana checks.
• eval_results/: raw eval-banana reports.
• harness_outputs/: team-harness coordinator and worker artifacts.
• iterations/: one directory per loopy-loop assignment.

Each iteration directory contains:

.loopy_loop/sessions/<session_id>/iterations/<NNNN>_<workflow_id>/
├── prompt.txt
├── result.json
├── result_text.txt
├── harness_run_id.txt
├── pending_finished_request.json
└── goal_check.json            # only for eval-emitting workflows

prompt.txt is the rendered prompt sent to TeamHarness.run(...). result.json is loopy-loop's normalized result. result_text.txt is the plain-text final response. harness_run_id.txt links the iteration to the corresponding team-harness output under harness_outputs/.

Team-harness outputs are routed here:

.loopy_loop/sessions/<session_id>/harness_outputs/<NNNN>_<workflow_id>/<team_harness_run_id>/

Eval-banana outputs should be routed here:

.loopy_loop/sessions/<session_id>/eval_results/<eval_banana_run_id>/

See docs/session-layout.md for the full session file contract.

Control and Completion

control.json is the session-scoped stop switch. It starts as:

{
  "state": "running",
  "reason": "session active",
  "stop_reason": null,
  "schema_version": 1
}

To stop successfully, a workflow writes:

{
  "state": "stopped",
  "reason": "evals passed",
  "stop_reason": "goal_met",
  "schema_version": 1
}

To stop because the loop cannot continue:

{
  "state": "stopped",
  "reason": "specific terminal blocker",
  "stop_reason": "unresolvable_error",
  "schema_version": 1
}

goal_check.json is a per-iteration eval artifact:

{"goal_met": false, "reason": "docs still missing", "schema_version": 1}

A valid goal_check.json does not stop the loop by itself. It is evidence. Stopping is controlled by session control.json. If goal-check output is missing or invalid repeatedly, the coordinator stops with stop_reason="goal_check_broken" after the configured failure cap.

Workflow Sets and Child Sessions

Workflow sets are mandatory. Even a single-loop repo uses:

.loopy_loop/workflow_sets/main/workflows/...

The older .loopy_loop/workflows/... layout is not loaded.

A workflow can request one sequential child session by writing a JSON file under the active session's child_requests/ directory:

{
  "workflow_set": "pm_planner_dispatcher",
  "goal": "Implement the selected planner item.",
  "schema_version": 1
}

The coordinator creates the child session under the parent session's children/ directory, copies the request goal into the child goal.md, runs the requested workflow set, and resumes the parent after the child reaches a terminal state. v1 is depth-first and single-child-at-a-time.

The packaged pm_planner_dispatcher workflow set uses this contract for PM orchestration:

• planner maintains PM state, selects one work item, and reviews terminal child-session evidence.
• dispatcher writes one child request for the selected work item or imports terminal child evidence back into PM state.

HTTP Contract

The coordinator exposes exactly two endpoints:

• POST /register
• POST /finished

Both return a TaskResponse with action equal to "run" or "stop".

A run response carries workflow_set, workflow_id, session_id, iteration, and a config snapshot. A stop response carries stop_reason.

If /finished receives a stale response for a task that is no longer current, the coordinator does not mutate state. If a worker exits after writing result.json but before /finished is acknowledged, the next /register recovers the completed result from the iteration directory instead of marking the task abandoned.

See docs/http-contract.md for exact JSON payloads.

CLI Reference

loopy init [--template default|inner_outer_eval|pm_planner_dispatcher]

Scaffolds loopy-loop files. The default template creates only the reserved goal_check workflow. inner_outer_eval creates the recommended outer/inner/eval workflow set. pm_planner_dispatcher creates planner/dispatcher workflows for child-session orchestration.

loopy coordinator --host 0.0.0.0 --port 8080 [--resume] [--workflow-set NAME] [--goal-file PATH]

Runs the coordinator. --workflow-set and --goal-file override the root config for the new session. --resume reuses a non-terminal latest session.

loopy worker --coordinator http://127.0.0.1:8080

Runs a blocking worker until the coordinator returns action: "stop".

loopy status
loopy stop

status prints the latest session state. stop sets stop_requested=true in the latest session-local state.

Related Projects

• team-harness: the model and agent-CLI orchestration layer used by loopy-loop workers.
• eval-banana: a lightweight YAML evaluation framework used by the packaged eval workflows.