Java CLI (picocli)

A Java command-line tool on picocli, built with Maven and make into one runnable jar. Layered TOML config (file, env, flags), one error table mapped to exit codes, text or JSON output, Logback logs to stderr, Error Prone and NullAway, and tests that run the packaged jar.

What done means

Your agent follows the brief, then runs stacks verify without weakening or skipping checks. What happens next

Declared steps: install, fmt-check, lint, compile, test, test-integration, build, smoke, readme-filled. View commands

Use this stack

Paste the prompt into the coding agent working on your project.

Full projectQuick local experiment

Uses the stack’s default fragments. Review the brief with your agent.Uses stated defaults and omits deploy, release, and app fragments unless explicitly requested.

View prompt

Use the java-cli stack for this project. 1. Run npx @steamfield/stacks show java-cli --json and check that it fits the project. If it does not, explain why before changing files. 2. Run npx @steamfield/stacks new java-cli and follow the brief it prints. 3. From the generated project directory, run npx @steamfield/stacks verify. Fix failures without weakening or skipping verification steps. 4. Summarize what changed and the verification result. Quote published stats only when they are available, including their interval and sample size. The stacks docs, written for agents, are at https://stacks.steamfield.io/llms.txt.

Use the java-cli stack for a quick local experiment. 1. Run npx @steamfield/stacks show java-cli --json and check that it fits the project. If it does not, explain why before changing files. 2. Run npx @steamfield/stacks new java-cli --sandbox and follow the brief it prints. 3. From the generated project directory, run npx @steamfield/stacks verify. Fix failures without weakening or skipping verification steps. 4. Summarize what changed and the verification result. Quote published stats only when they are available, including their interval and sample size. The stacks docs, written for agents, are at https://stacks.steamfield.io/llms.txt.

Or use the terminal

npx @steamfield/stacks new java-cli

npx @steamfield/stacks new java-cli --sandbox

Verify steps
Step	Phase	Layer	Command
install	setup	install	`make install`
fmt-check	check	lint	`make fmt-check`
lint	check	lint	`make lint`
compile	check	typecheck	`make compile`
test	check	test	`make coverage`
test-integration	check	test	`make test-integration`
build	check	build	`make build`
smoke	check	test	`make smoke`
readme-filled	check	check	`test -s README.md && ! grep -n 'stacks:fill' README.md`

Usage and outcomes

Usage over time

Showing 180 days of history.

History

The 28-day green rate at each weekly observation. Gaps mean the sample was too small to publish.

Shaded band: 95% Wilson interval. Dashed rules: content changes. Missing observations remain gaps.

Stacks projects · 28 days through 4 Nov 2026. Counts rounded to 5.

Data table

Through	Green rate	Projects	Content change
5 Jul 2026	hidden: too few projects	–	–
12 Jul 2026	hidden: too few projects	5	–
19 Jul 2026	hidden: too few projects	10	–
26 Jul 2026	hidden: too few projects	15	–
2 Aug 2026	hidden: too few projects	20	–
9 Aug 2026	hidden: too few projects	20	–
16 Aug 2026	hidden: too few projects	20	–
23 Aug 2026	hidden: too few projects	20	–
30 Aug 2026	hidden: too few projects	25	–
6 Sept 2026	hidden: too few projects	30	–
13 Sept 2026	hidden: too few projects	30	–
20 Sept 2026	hidden: too few projects	30	–
27 Sept 2026	hidden: too few projects	35	–
4 Oct 2026	hidden: too few projects	30	–
11 Oct 2026	hidden: too few projects	30	–
18 Oct 2026	hidden: too few projects	30	–
25 Oct 2026	79% (60–91%, n=25)	30	–
1 Nov 2026	76% (58–88%, n=30)	35	–

Weekly projects by preset

Non-overlapping seven-day project counts, grouped by the preset used to start the project.

default
sandbox

Stacks projects per UTC week through 4 Nov 2026. Published preset counts only; hidden cells are not zero.

Data table

Week ending	Preset	Projects
5 Jul 2026	default	–
12 Jul 2026	default	–
19 Jul 2026	default	–
26 Jul 2026	default	–
2 Aug 2026	default	–
9 Aug 2026	default	5
16 Aug 2026	default	–
23 Aug 2026	default	–
30 Aug 2026	default	–
6 Sept 2026	default	5
13 Sept 2026	default	–
20 Sept 2026	default	5
27 Sept 2026	default	10
4 Oct 2026	default	–
11 Oct 2026	default	5
18 Oct 2026	default	5
25 Oct 2026	default	5
1 Nov 2026	default	10
5 Jul 2026	sandbox	–
12 Jul 2026	sandbox	–
19 Jul 2026	sandbox	–
26 Jul 2026	sandbox	–
2 Aug 2026	sandbox	–
9 Aug 2026	sandbox	–
16 Aug 2026	sandbox	–
23 Aug 2026	sandbox	–
30 Aug 2026	sandbox	–
6 Sept 2026	sandbox	–
13 Sept 2026	sandbox	–
20 Sept 2026	sandbox	–
27 Sept 2026	sandbox	–
4 Oct 2026	sandbox	–
11 Oct 2026	sandbox	–
18 Oct 2026	sandbox	5
25 Oct 2026	sandbox	–
1 Nov 2026	sandbox	5

By preset

Green verify outcomes by the preset chosen at scaffold time.

default

71%50–86%, n=20

sandboxhidden: too few projects

Stacks projects · 28 days through 4 Nov 2026. Counts rounded to 5.

Data table

Name	Green rate	Projects
default	71% (50–86%, n=20)	25
sandbox	hidden: too few projects	15

By agent

Within this stack, listed alphabetically. These are project outcomes, not an agent ranking.

Not enough runs in this breakdown yet.

Stacks projects · 28 days through 4 Nov 2026. Counts rounded to 5.

Time to green

Published time summaries on a shared minutes scale. First passing test is a median; 75% reached green by the 75th percentile.

Verify runs to green: 1

Stacks projects · 28 days through 4 Nov 2026. Counts rounded to 5.

Data table

Measure	Time / runs
Median to green	25 minutes
75th percentile	31 minutes
First passing test	15 minutes
Verify runs to green	1

Where it breaks

A run can fail more than one step. Environment failures are shown separately.

test33%

fmt-check33%

test-integration14%

build10%

compile5%

smoke5%

Environment blocked0%

Share of failed runs before first green. Environment blocked describes the machine, not the stack.

Data table

Step	Share
test	33%
compile	5%
fmt-check	33%
build	10%
smoke	5%
test-integration	14%
Environment blocked	0%

What people change

Defaults people keep, and optional fragments they choose to attach.

Default, kept rate

agent-opshidden: too few projects

git-hookshidden: too few projects

ci-githubhidden: too few projects

Optional, attach rate

rrhidden: too few projects

ce-plugin22%

Share of the window's 35 projects. Kept rate is 1 minus the without rate.

Data table

Fragment	Measure	Share
agent-ops	Kept	–
git-hooks	Kept	–
ci-github	Kept	–
rr	Attached	–
ce-plugin	Attached	22%

By composition 6 fingerprints

Each row is a distinct fragment composition, with its own sample and content history.

Composition	Green rate	Seen	Change in life
defaults − git-hooks · 18d5523c	hidden: too few projects	26 Jul 2026 – 1 Nov 2026	None
defaults + ce-plugin + rr · 41049dcb	hidden: too few projects	6 Sept 2026 – 25 Oct 2026	None
defaults · 7bd8c81c	73% (52–87%, n=20)	12 Jul 2026 – 1 Nov 2026	None
defaults + ce-plugin · 97259cef	hidden: too few projects	12 Jul 2026 – 1 Nov 2026	None
defaults − agent-ops · b06c39d0	hidden: too few projects	30 Aug 2026 – 1 Nov 2026	None
defaults − ci-github · e0e6434c	hidden: too few projects	13 Sept 2026 – 1 Nov 2026	None

Computed 5 Nov 2026, through 4 Nov 2026. Numbers describe stacks projects, not the ecosystem.