creating-a-coral-task

creating-a-coral-task is a skill for Claude Code from Human-Agent-Society/CORAL. It costs 168 tokens per session (2,161 once invoked), scanned A, original, Apache-2.0.

A guide for creating a CORAL task: starter code for agents, a task.yaml settings file, and a packaged grader that scores the result. CORAL is a system for evaluating agents on coding tasks.

In plain words
What is it for?
Use it to scaffold a task, write its isolated Python grader, choose a scoring pattern, run validation, and smoke-test the evaluation.
Why use it?
It explains how to keep the task definition, starting files, and scoring code aligned, and how to check the task with CORAL before using it.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the coral plugin — 4 skills, 2 agents, 1 hook shipped together

Good fit Use it to scaffold a task, write its isolated Python grader, choose a scoring pattern, run validation, and smoke-test the evaluation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/human-agent-society/coral/creating-a-coral-task
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Human-Agent-Society/CORAL --skill creating-a-coral-task
Clone the repo
git clone --depth 1 https://github.com/Human-Agent-Society/CORAL

Made for: Claude Code.

Or install coral, the plugin that ships this one along with the rest of its 4 skills, 2 agents, 1 hook.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for creating-a-coral-task

README.md
[![agentmods](https://agentmods.dev/badge/skills/human-agent-society/coral/creating-a-coral-task/github.svg)](https://agentmods.dev/skills/human-agent-society/coral/creating-a-coral-task)
Your own site
<a href="https://agentmods.dev/skills/human-agent-society/coral/creating-a-coral-task"><img src="https://agentmods.dev/badge/skills/human-agent-society/coral/creating-a-coral-task/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for creating-a-coral-task

Your own site · 80×15
<a href="https://agentmods.dev/skills/human-agent-society/coral/creating-a-coral-task"><img src="https://agentmods.dev/badge/skills/human-agent-society/coral/creating-a-coral-task.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 168 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,161 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00168 $0.02161
Opus 5 $0.00084 $0.01081
Sonnet 5 $0.00034 $0.00432
Haiku 4.5 $0.00017 $0.00216

Measured 11d ago against content hash 57a5bcce645e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

creating-a-coral-task scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugin/skills/creating-a-coral-task/SKILL.md · 104 lines

How it starts

The opening of the file, as written. The whole thing — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Creating a CORAL task

A CORAL task is three things that must line up. Scaffold them with coral init, then iterate edit → coral validate until the grader scores the seed.

my-task/
├── task.yaml      # config: name, description, grader entrypoint, agent count
├── seed/          # starter code agents see at t=0 (this is workspace.repo_path)
│   └── solution.py
└── grader/        # standalone Python package — gets its own isolated venv
    ├── pyproject.toml
    └── src/my_task_grader/
        ├── __init__.py
        └── grader.py     # class Grader(TaskGrader): ...

The packaged grader is the only supported form — it gives the grader an isolated venv and bundles everything the eval needs (grader code, helpers, hidden answer keys). There is no eval/grader.py auto-discovery anymore.

Optimizing code the user already has? Scaffold inside a .coral_workspace/ at the root of their project (gitignored), and copy the code to optimize into seed/ — keeps CORAL's task/results out of their source tree. The coral-quickstart skill has the end-to-end .coral_workspace/ flow; this skill covers the grader you'll write once the code is in seed/.

"Optimize this" is a build instruction, not a question — never answer it with a process menu. A 1/2/3 like "point me to a task / create one / optimize outside coral" is the failure mode; do not produce it. The absence of a task.yaml is not ambiguity — it just means you build one from the current repo. Concretely: (1) dig for what's already measurable — a research/framework repo almost always ships an eval/benchmark script, a test suite, or a metric in its README/paper; that's your target and metric. (2) If no single number is obvious, construct one by wrapping the repo's existing evaluation — don't conclude "no measurable objective" just because there's no CORAL scaffold. (3) Scaffold the most plausible target and start building (a .coral_workspace/ + draft grader is cheap and reversible); state your assumption in one line and proceed. (4) Only as a last resort, if you've actually read the repo and it exposes nothing scorable, propose 2-3 concrete optimization targets you found (each with its metric), pick the most likely, and scaffold that — still not a process menu.

Read the full file on GitHub · 104 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 104 lines · 168 tokens per session scan A 57a5bcce645e

Subscribe to this mod's changes

creating-a-coral-task is a skill published in the GitHub repository Human-Agent-Society/CORAL (972 stars, last pushed 2d ago), licensed Apache-2.0. It adds 168 tokens to every session and 2,161 once invoked, about $0.0008 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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