---
title: Task Examples
description: Walkthrough of the included example task configurations.
---


The `examples/` directory contains ready-to-run task configurations spanning optimization, ML, and math.

## Circle Packing

**Goal**: Pack 26 circles into a unit square to maximize the sum of radii.

```yaml
task:
  name: "Circle Packing"
  description: |
    Pack N = 26 circles into a unit square (side length 1)
    to maximize the sum of radii.

grader:
  timeout: 600
  direction: maximize

agents:
  count: 2
  model: claude-sonnet-4-6
```

**What agents work on**: Implementing optimization algorithms (simulated annealing, basin-hopping, gradient descent) to find the densest packing.

**Score**: `sum_radii / best_known_result` — 1.0 means matching the best known configuration.

```bash
coral start -c examples/circle_packing/task.yaml
```

## Erdos

**Goal**: Explore mathematical conjectures related to Erdos problems.

**What agents work on**: Generating counterexamples or proofs for combinatorial conjectures.

This example uses the new entrypoint-based grader layout — the grader lives
at `examples/erdos/grader/` as a standalone Python package and `task.yaml`
points at it via:

```yaml
grader:
  entrypoint: "erdos_grader.grader:Grader"
  setup:
    - "uv pip install -e ./grader"
```

```bash
coral start -c examples/erdos/task.yaml
```

`coral start` will create `.coral/private/grader_venv/`, install the grader
package into it, and spawn worker subprocesses from there during evaluation.

## Kernel Builder

**Goal**: Optimize VLIW SIMD kernels for minimum cycle count.

**What agents work on**: Assembly-level optimization, instruction scheduling, register allocation.

```bash
coral start -c examples/kernel_builder/task.yaml
```

## Kernel Engineering

**Goal**: Optimize GPU kernel implementations for maximum throughput.

**Score**: `1000 / runtime_us` — lower kernel runtime = higher score.

```bash
coral start -c examples/kernel_engineering/trimul/task.yaml
```

## MNIST

**Goal**: Build an ML classifier for handwritten digits.

**What agents work on**: Neural network architecture, training procedures, data augmentation.

```bash
coral start -c examples/mnist/task.yaml
```

## Spaceship Titanic

**Goal**: Kaggle-style classification competition.

**Score**: Classification accuracy (0.50 = naive, 0.80+ = strong).

```bash
coral start -c examples/spaceship_titanic/task.yaml
```

## Stanford COVID Vaccine

**Goal**: Predict mRNA degradation rates.

**What agents work on**: Feature engineering, model selection, sequence analysis.

```bash
coral start -c examples/stanford_covid_vaccine/task.yaml
```

## Rubric-judged tasks

Three examples use LLM rubric judges instead of programmatic graders. They share the same architecture — a grader package spawns a Claude Code judge agent that scores the worker's output against a weighted list of PASS/FAIL criteria. See [Rubric Judges](/guides/rubric-judge) for the full pattern.

### Japan Elderly Market Analysis 2050 (RACE)

**Goal**: Write a market-size analysis report for Japan's elderly demographic, covering population projections, consumption patterns, and consumer willingness through 2050.

**Grader**: `race_japan_grader` — static 25-criterion rubric, Claude Code judge, fact-checks against a reference article bundled inside the grader package.

Four yamls exercise different experimental conditions:

| Config | Rubric visible to agent? | Feedback level |
|--------|--------------------------|----------------|
| `task.yaml` | Yes (baked into `task.description`) | `full` — per-criterion verdict + rationale |
| `task_baseline.yaml` | No — hidden under `grader.args.rubrics` | `score_only` |
| `task_aggregate_only.yaml` | Yes | `aggregate_only` — score + N/25 passed |
| `task_agent_judge.yaml` | No — dynamic rubric via `apex_judge` | `full` |

```bash
coral start -c examples/race-japan-elderly/task.yaml
```

### Eggshell Skull Legal Memorandum (APEX)

**Goal**: Draft a legal memo analyzing whether the eggshell skull rule applies to a wrongful-death complaint. Source materials ship as .docx / .pdf and are read via Archipelago MCP servers.

**Grader**: `apex_judge` — **dynamic rubric**. The judge auto-generates its own PASS/FAIL criteria on the first eval and evolves them when scores plateau.

```bash
export ARCHIPELAGO_PATH=/path/to/archipelago
python examples/apex-eggshell-skull/download_apex_data.py
coral start -c examples/apex-eggshell-skull/task.yaml
```

### Frontier BU Forecast (APEX)

**Goal**: Quantitative forecasting — estimate the size of Frontier's business units in 2035, assuming constant growth rates and market shares.

**Grader**: reuses the same `apex_judge` package from eggshell-skull via `grader.setup: ["uv pip install -e ../apex-eggshell-skull/grader"]`, so two tasks share one judge implementation.

```bash
coral start -c examples/apex-frontier-bu/task.yaml
```

## Creating your own

To create a new task from scratch:

```bash
coral init my-task
```

This scaffolds the directory structure. See [Quick Start](/getting-started/quickstart) and [Writing a Custom Grader](/guides/custom-grader) for the full walkthrough.
