What is gnucobol CLAUDE.md?

Repository instructions for maintaining Docker containers for several versions of GnuCOBOL, a compiler for the COBOL programming language. They describe the directory layout, build scripts, container images, and test program.

Use them when building, testing, updating, or packaging the GnuCOBOL 3.0 through 4.0 container setups.

They show how this repository builds and organizes version-specific compiler environments, reducing the risk of using the wrong script or image.

How brazilofmux/gnucobol configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to brazilofmux/gnucobol. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/brazilofmux/gnucobol/master/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/brazilofmux/gnucobol

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/brazilofmux/gnucobol/claude-md/github.svg)](https://agentmods.dev/instructions/brazilofmux/gnucobol/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/brazilofmux/gnucobol/claude-md"><img src="https://agentmods.dev/badge/instructions/brazilofmux/gnucobol/claude-md/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/brazilofmux/gnucobol/claude-md"><img src="https://agentmods.dev/badge/instructions/brazilofmux/gnucobol/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,497 This file is loaded in full into every session.

When invoked 1,497 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.01497	$0.01497
Opus 5.5	$0.00599	$0.00599
Sonnet 5.5	$0.00299	$0.00299
Haiku 4.5	$0.00150	$0.00150

Measured 29d ago against content hash a7d39c3238db, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

gnucobol CLAUDE.md 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 29d 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.

CLAUDE.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

Container build recipes for GnuCOBOL, and for gcobol (GCC's COBOL front end), on Alpine. The GnuCOBOL images serve as oracles for ~/slow-32's COBOL compiler, and are published to Docker Hub as hurriedreformist/gnucobol. The fleet in ~/builder builds them (jobs/gnucobol.sh, jobs/gcobol.sh); this repository holds what they build from.

Repository Structure

gnucobol/
├── 3.1/   GNU release 3.1.2             -> gnucobol:3.1.2-*      and gnucobol:3.1-*
├── 3.2/   GNU release 3.2               -> gnucobol:3.2.0-*      and gnucobol:3.2-*
├── 3.3/   branches/gnucobol-3.x r5729   -> gnucobol:3.3-r5729-*  and gnucobol:3.3-*
├── 4.0/   trunk r5725                   -> gnucobol:4.0-r5725-*  and gnucobol:4.0-*
│   ├── builder/   Dockerfile + the vendored source tarball
│   ├── runtime/   libcob, cobcrun, and the runtime libraries
│   └── hello/     test.cob, compiled in builder and run on runtime
├── gcobol/15, gcobol/17   gcobol oracles (17 is amd64-only; see its Dockerfile)
├── daily.sh   local build of any line, as the fleet job does it
└── update.sh  moves a development line's pin (3.3, 4.0) -- see below

The directory name is the line's moving tag. Each line's pinned tag is written in its runtime/Dockerfile (COPY --from=gnucobol:<pinned>-builder) and hello/Dockerfile; daily.sh and the fleet job both read it from there. A pinned tag names exactly one build -- a GNU release padded to three components, or a development line's SVN revision -- and the fleet job never rebuilds a pin that is already in ECR. To move a line forward, change its pin.

Provenance

Every builder records what it was built from in /usr/local/share/gnucobol/SOURCE and in OCI labels.

3.1, 3.2: the GNU release tarballs, byte-identical to ftp.gnu.org's and signed by Simon Sobisch (key B9459D0CA8A740B323235CDF13E96B53C005604E, in the GNU keyring; verified 2026-10-08). Each Dockerfile checks the tarball's sha256.
3.3, 4.0: a git archive of the OCamlPro GitHub mirror's commit for the pinned SVN revision (r5729 = 91d1bd5ac4, r5725 = 72ab9a7518, matched against svn log). Pristine source, built with bootstrap, because make dist requires a TeX installation for the PDF manual.

Read the full file on GitHub · 65 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.

29d ago Changed · -19 lines · +707 tokens per session a7d39c3238db
2mo ago First seen · 84 lines · 790 tokens per session scan A 15a28f4cf348

Subscribe to this mod's changes

gnucobol CLAUDE.md is an instructions file published in the GitHub repository brazilofmux/gnucobol (5 stars, last pushed 29d ago), licensed MIT. It adds 1,497 tokens to every session, about $0.0060 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 2026-08-31.

gnucobol CLAUDE.md next to 6 instructions from other repositories
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gnucobol: Instructions file for Claude Code