---
name: Coral Debug
slug: coral-debug
category: Quality
description: Coral Debug verifies and debugs changes to CORAL itself, with the smallest repro loop for each area like grader, daemon, CLI, hooks, manager, workspace, hub, template, config, and web. Use it when editing code under coral/ or investigating a CORAL bug.
github: "https://github.com/Human-Agent-Society/CORAL/tree/main/.claude/skills/coral-debug"
language: Python
stars: 913
forks: 119
install: "npx degit https://github.com/Human-Agent-Society/CORAL/tree/main/.claude/skills/coral-debug ~/.claude/skills/coral-debug"
installs_to: ~/.claude/skills/coral-debug
source_path: .claude/skills/coral-debug/SKILL.md
collection_size: 12
category_size: 1354
collection_url: "https://dirskills.com/collections/Human-Agent-Society/CORAL"
added: 2026-08-22T05:20:49.224Z
last_synced: 2026-08-22T05:20:49.224Z
canonical_url: "https://dirskills.com/skills/coral-debug"
---

# Coral Debug

Coral Debug verifies and debugs changes to CORAL itself, with the smallest repro loop for each area like grader, daemon, CLI, hooks, manager, workspace, hub, template, config, and web. Use it when editing code under coral/ or investigating a CORAL bug.

**Install:**

```bash
npx degit https://github.com/Human-Agent-Society/CORAL/tree/main/.claude/skills/coral-debug ~/.claude/skills/coral-debug
```

## README

# CORAL debug & change-verification workflows

This skill is for people (and Claude Code) hacking on the CORAL package itself, not for users authoring a task. For authoring guides see the siblings:
- `coral-new-task` — creating a new `examples/<task>/` (seed + task.yaml + grader)
- `coral-extend` — extending CORAL itself (new runtime, new CLI command, new bundled skill, ...)

## Reproduce loops

Pick the smallest one that exercises your change.

| Editing... | Fastest reproduce |
|---|---|
| `coral/grader/{task_grader,loader,subprocess_grader}.py` or a builtin grader | `uv run coral validate examples/circle_packing` (or any example with a packaged grader) |
| `coral/grader/daemon.py` (parallel grading, queueing, worktree isolation) | `uv run pytest tests/test_grader_daemon.py -v` |
| `coral/grader/{base,protocol}.py` | `uv run pytest tests/test_grader.py tests/test_subprocess_grader.py -v` |
| `coral/cli/*.py` (argparse, dispatch, output formatting) | Run the command directly: `uv run coral log --help`, `uv run coral status`, etc. against a `latest` run under `examples/<task>/results/` |
| `coral/hooks/post_commit.py` (`submit_eval`) | `uv run pytest tests/test_hooks.py -v`, then end-to-end via `coral start -c task.yaml agents.count=1` and watch `.coral/public/attempts/` |
| `coral/agent/manager.py`, `state.py`, `exit_classifier.py` | `uv run pytest tests/test_manager_reliability.py tests/test_manager_seen_attempts.py -v` |
| `coral/agent/builtin/*.py` (a runtime) | `uv run pytest tests/test_<runtime>.py` if it exists, then `coral start -c task.yaml agents.runtime=<name> agents.count=1` |
| `coral/workspace/{project,worktree,repo,grader_env}.py` | `uv run pytest tests/test_workspace.py tests/test_grader_env.py -v` |
| `coral/hub/{attempts,notes,skills,checkpoint,heartbeat}.py` | `uv run pytest tests/test_hub.py tests/test_checkpoint.py tests/test_heartbeat.py -v` |
| `coral/template/coral_md.py` or templates | `uv run pytest tests/test_template.py -v` |
| `coral/config.py` | `uv run pytest tests/test_config.py -v` |
| `coral/web/*` (dashboard) | `uv run coral ui` against any existing run; reload the browser after edits |

End-to-end smoke (slow but exercises the whole pipeline):
```bash
uv run coral start -c examples/circle_packing/task.yaml agents.count=1 run.session=local
# Wait for one eval to land in .coral/public/attempts/, then:
uv run coral stop
```

## Where to look when X breaks

| Symptom | First place to look |
|---|---|
| Grader hangs / pending attempts pile up | `.coral/public/grader_daemon.pid` (is daemon alive?), `.coral/public/grader_daemon_heartbeat` (mtime), `.coral/public/eval_logs/<hash>/` for grader stdout/stderr |
| `coral eval` errors out | The pending JSON itself: `.coral/public/attempts/<hash>.json` — `status` and `feedback` fields. Source: `coral/hooks/post_commit.py::submit_eval` |
| Agent restart loop | `coral status` shows pause state. Source: `coral/agent/manager.py` (`restart_burst_threshold`, `restart_burst_window`). Per-agent runtime stdout/stderr is captured under the worktree. |
| Stalled agent | `agents.timeout` watchdog in `coral/agent/manager.py`. Grader-queue exemption (`grader_pending_max_age`) skips the watchdog while a recent submission is still pending. |
| Heartbeat actions not firing | `.coral/public/heartbeat/<agent_id>.json` (per-agent action list), `.coral/public/eval_count` (global counter). Logic: `coral/agent/heartbeat.py::HeartbeatRunner.check`. |
| Shared state corrupted / race | `.coral/public/.git/` is a real git repo — `git -C .coral/public log` shows checkpoint history; `coral notes --history` is the friendly view. |
| Worktree symlinks missing | `coral/workspace/worktree.py` — symlinks `.coral/public/` into each agent worktree under the runtime-specific name (`.claude` / `.codex` / `.opencode`). |
| Grader can't import its package | Check `.coral/private/grader_venv/` — `setup_grader_env` ran `uv venv` + `grader.setup` once at run start. Re-running `coral start` on the same `run_dir` does NOT re-bootstrap; delete the venv to force it. |
| Resume picks up wrong task | `coral resume` reads `.coral/config.yaml` and `.coral/config_dir`. The `latest` symlink at `results/<task-slug>/latest` decides which run is resumed. |

## Inspect a live or finished run

```bash
RUN=$(readlink -f results/<task-slug>/latest)
ls "$RUN/.coral/public/"            # attempts/, notes/, skills/, agents/, logs/, eval_logs/, eval_count
cat "$RUN/.coral/public/attempts/<hash>.json" | jq .
ls "$RUN/agents/"                    # one worktree per agent
cat "$RUN/.coral/config.yaml"        # exact config used (post-merge)
```

The web dashboard (`coral ui`) reads the same files; if you're debugging dashboard rendering, `coral/web/api.py` is the route handler and `coral/web/static/` is the built React bundle.

## Test + lint

```bash
uv sync --extra dev                  # one-time, gets pytest + ruff
uv run pytest tests/ -v              # full suite (~seconds, no docker)
uv run pytest tests/test_<thing>.py -v -k <pattern>
uv run ruff check .                  # lint
uv run ruff format .                 # autoformat
```

There is no separate type-check step in CI yet; tests cover the contract.

## Quick task scaffold for ad-hoc testing

When you need a throwaway task to exercise a code change:
```bash
uv run coral init /tmp/coral-scratch
# edit /tmp/coral-scratch/grader/src/coral_scratch_grader/grader.py to return a simple float
uv run coral validate /tmp/coral-scratch
uv run coral start -c /tmp/coral-scratch/task.yaml agents.count=1 run.session=local
```

`coral validate` runs the grader against `seed/` in a tempdir without spawning agents — the fastest way to confirm a grader change compiles and produces a `Score`.

## Conventions

- **No `git` from agents.** All commits go through `coral eval`. If you're adding a feature that needs to commit, route it through `coral/hooks/post_commit.py` or `coral/hub/checkpoint.py`.
- **Atomic writes** for any JSON in `.coral/public/`. Use `coral.hub.attempts.write_attempt` (tmp + rename) as the model.
- **Idempotent setup.** `setup_run_dir`, `setup_grader_env`, `init_checkpoint_repo` must all be safe to call twice.
- **Shared dir is configurable.** Don't hardcode `.claude`; thread `shared_dir` through (see `coral/template/coral_md.py`).
- **Lazy imports in CLI dispatch** (`coral/cli/__init__.py`) — keep `coral --help` fast.