arn-code-execute-task

A workflow for implementing one task from an existing task list with an optional review by another coding agent.

In plain words
What is it for?
Use it to execute one numbered task and optionally check whether the result meets its requirements.
Why use it?
It provides a focused way to retry a failed task, test one part of a plan, or make a single planned change without running the whole plan.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/appsvortex/arness/arn-code-execute-task
Any agent
npx skills add AppsVortex/arness --skill arn-code-execute-task
Clone the repo
git clone --depth 1 https://github.com/AppsVortex/arness

Made for: Claude Code, Codex.

Per session 86 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,839 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00086 $0.02839
Opus 5 $0.00043 $0.01419
Sonnet 5 $0.00017 $0.00568
Haiku 4.5 $0.00009 $0.00284

Measured yesterday against content hash 15017fef89a3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

arn-code-execute-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 yesterday.

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.

plugins/arn-code/skills/arn-code-execute-task/SKILL.md · 201 lines

How it starts

The opening of the file, as written. The whole thing — 201 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Arness Execute Task

Execute a single task from the task list by spawning a arn-code-task-executor agent. Optionally run a arn-code-task-reviewer to validate the implementation before marking the task complete.

Pipeline position (this is an alternative entry point, not in the main pipeline):

arn-code-taskify -> arn-code-execute-task (single task) -> [optional] arn-code-review-implementation

Use cases:

  • Re-running a failed task after manual intervention
  • Testing a single phase independently
  • Implementing one task without the full pipeline
  • Retrying a task that was escalated during arn-code-execute-plan

Prerequisites

If no ## Arness section exists in the project's CLAUDE.md, inform the user: "Arness is not configured for this project yet. Run /arn-implementing to get started — it will set everything up automatically." Do not proceed without it. Task list must exist (run /arn-code-taskify first).

Workflow

Step 1: Load Configuration

  1. Read the project's CLAUDE.md and extract the ## Arness section to find:

    • Plans directory -- base path where project plans are saved
    • Code patterns -- path to the directory containing stored pattern documentation
    • Template path -- path to the report template set (JSON templates)
    • Template version -- plugin version the templates were copied from (if present)
    • Template updates -- user preference: ask, auto, or manual (if present)
    • Specs directory -- path to the directory containing specification files (if present)

    Template version check: If Template version and Template updates fields are present, run the template version check procedure documented in arn-code-save-plan Step 1 (Template Version Check) before proceeding. If ## Arness does not contain these fields, treat as legacy and skip.


Step 2: Identify the Task

  • If user provided a task ID or number: verify it exists in TaskList
  • If user provided a description: search TaskList for a matching task
  • If no task specified: show all available tasks (pending, unblocked) and ask user to choose
  • Show the selected task: ID, description, status, dependencies
  • If task is blocked: warn user that dependencies haven't completed, ask if they want to proceed anyway

Read the full file on GitHub · 201 lines

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. yesterday First seen · 201 lines · 86 tokens per session scan A 15017fef89a3

Subscribe to this mod's changes

arn-code-execute-task is a skill published in the GitHub repository AppsVortex/arness (33 stars, last pushed 1mo ago), licensed MIT. It adds 86 tokens to every session and 2,839 once invoked, about $0.0004 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.