build-setup

build-setup is a skill for Claude Code, Codex from OpenHands/extensions. It costs 31 tokens per session (612 once invoked), scanned A, original, MIT.

A setup guide for moving programs from COBOL, an older business programming language, to Java. It prepares both build environments and creates test data for comparing the two versions.

In plain words
What is it for?
Use it to install GnuCOBOL, set up Maven or Gradle with JUnit, and create normal, edge-case, and error test inputs with expected outputs for major COBOL programs.
Why use it?
It provides a repeatable way to compile the COBOL code, build the Java project, and check that the migration keeps the same behavior.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to install GnuCOBOL, set up Maven or Gradle with JUnit, and create normal, edge-case, and error test inputs with expected outputs for major COBOL programs.

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Install with agentmods
npx agentmods add skills/openhands/extensions/build-setup
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 OpenHands/extensions --skill build-setup
Clone the repo
git clone --depth 1 https://github.com/OpenHands/extensions

Made for: Claude Code, Codex.

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 build-setup

README.md
[![agentmods](https://agentmods.dev/badge/skills/openhands/extensions/build-setup/github.svg)](https://agentmods.dev/skills/openhands/extensions/build-setup)
Your own site
<a href="https://agentmods.dev/skills/openhands/extensions/build-setup"><img src="https://agentmods.dev/badge/skills/openhands/extensions/build-setup/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 build-setup

Your own site · 80×15
<a href="https://agentmods.dev/skills/openhands/extensions/build-setup"><img src="https://agentmods.dev/badge/skills/openhands/extensions/build-setup.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 612 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 $0.00031 $0.00612
Opus 5.5 $0.00012 $0.00245
Sonnet 5.5 $0.00006 $0.00122
Haiku 4.5 $0.00003 $0.00061

Measured 1mo ago against content hash 922b0812ba60, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

build-setup 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 1mo ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/install-gnucobol.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/cobol-modernization/skills/build-setup/SKILL.md · 80 lines

How it starts

The opening of the file, as written. The whole thing — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Set up a build environment and create test fixtures for validating COBOL-to-Java migrations.

To install GnuCOBOL, run: ./scripts/install-gnucobol.sh On Windows, run that shell script from Git Bash/WSL (bash scripts/install-gnucobol.sh) or install GnuCOBOL with a Windows package manager and document the chosen command in build_notes.md.

Phase 1: Build Setup

COBOL Build

  • Find a way to compile and run the COBOL code (e.g., GnuCOBOL)
  • Verify at least one program compiles and executes
  • Note any dependencies or setup required

Java Build

  • Initialize a Java project alongside the COBOL code (Maven or Gradle)
  • Set up standard directory structure: src/main/java, src/test/java
  • Include JUnit 5 as a test dependency
  • Verify the project builds (even if empty)

Phase 2: Test Fixture Generation

For each major COBOL program:

Create Synthetic Test Inputs

  • Save to: test-fixtures/inputs/{PROGRAM_NAME}/
  • Create 3-5 test cases per program covering:
    • Normal/happy path (valid, typical data)
    • Edge cases (empty input, maximum values, boundary conditions)
    • Error cases (invalid formats, missing required fields)

Generate Golden Outputs

  • Run each COBOL program with each test input
  • Save COBOL output to: test-fixtures/expected_outputs/{PROGRAM_NAME}/
  • These become the "golden" outputs that Java must match

Create Test Manifest

Save to test_manifest.json:

{
  "PROGRAM1": {
    "description": "Brief description of what this program does",
    "test_cases": [
      {
        "name": "normal_invoice",
        "input": "inputs/PROGRAM1/test_001.dat",
        "expected": "expected_outputs/PROGRAM1/test_001.out",
        "description": "Happy path"
      }
    ]
  }
}

Deliverables

  1. build_notes.md — Build instructions for COBOL and Java
  2. test-fixtures/ — Directory with inputs/ and expected_outputs/
  3. test_manifest.json — JSON manifest of all test cases

Priority

Focus on programs with core business logic (transactions, calculations, data processing). UI-heavy programs (menu screens, reports) are lower priority.

Read the full file on GitHub · 80 lines

Files

What ships with it

1 file 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. 1mo ago First seen · 80 lines · 31 tokens per session scan A 922b0812ba60

Subscribe to this mod's changes

build-setup is a skill published in the GitHub repository OpenHands/extensions (167 stars, last pushed today), licensed MIT. It adds 31 tokens to every session and 612 once invoked, about $0.0001 per session on Opus 5.5. 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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