Agent skill

Working With Config

Quarkus configuration conventions: @ConfigMapping interfaces, config phases, and migration from legacy @ConfigRoot classes.

Apache-2.0Auto-check passed

Install Working With Config

skills CLI

$ npx skills add quarkusio/quarkus --skill working-with-config -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install quarkusio/quarkus working-with-config --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/quarkusio/quarkus.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/working-with-config .claude/skills/working-with-config && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "working-with-config" agent skill from https://github.com/quarkusio/quarkus/tree/main/.agents/skills/working-with-config into .claude/skills/working-with-config/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "working-with-config", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/quarkusio/quarkus/tree/main/.agents/skills/working-with-config

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add quarkusio/quarkus --skill working-with-config -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install quarkusio/quarkus working-with-config --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/quarkusio/quarkus.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/working-with-config .agents/skills/working-with-config && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "working-with-config" agent skill from https://github.com/quarkusio/quarkus/tree/main/.agents/skills/working-with-config into .agents/skills/working-with-config/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "working-with-config", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add quarkusio/quarkus --skill working-with-config -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install quarkusio/quarkus working-with-config --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/quarkusio/quarkus.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/working-with-config .cursor/skills/working-with-config && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "working-with-config" agent skill from https://github.com/quarkusio/quarkus/tree/main/.agents/skills/working-with-config into .cursor/skills/working-with-config/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "working-with-config", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/quarkusio/quarkus.git --path .agents/skills/working-with-config

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add quarkusio/quarkus --skill working-with-config -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install quarkusio/quarkus working-with-config --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/quarkusio/quarkus.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/working-with-config .gemini/skills/working-with-config && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "working-with-config" agent skill from https://github.com/quarkusio/quarkus/tree/main/.agents/skills/working-with-config into .gemini/skills/working-with-config/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "working-with-config", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install quarkusio/quarkus working-with-config

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add quarkusio/quarkus --skill working-with-config -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/quarkusio/quarkus.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/working-with-config .github/skills/working-with-config && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "working-with-config" agent skill from https://github.com/quarkusio/quarkus/tree/main/.agents/skills/working-with-config into .github/skills/working-with-config/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "working-with-config", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add quarkusio/quarkus --skill working-with-config -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install quarkusio/quarkus working-with-config --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/quarkusio/quarkus.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/working-with-config .opencode/skills/working-with-config && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "working-with-config" agent skill from https://github.com/quarkusio/quarkus/tree/main/.agents/skills/working-with-config into .opencode/skills/working-with-config/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "working-with-config", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: working-with-config
GitHub stars: 16k
Token cost: ~1.3k tokens
SKILL.md length: 411 words
Files: 1
Skills in repo: 12
Repo updated: Oct 9, 2026
First seen: Oct 7, 2026
Licence: Apache-2.0

At a glance

Quarkus configuration conventions: @ConfigMapping interfaces, config phases, and migration from legacy @ConfigRoot classes.

SKILL.md covers Use @ConfigMapping Interfaces…, Config Phases, Naming and Annotation Processor…, plus 1 more section
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Working With Config is an agent skill from quarkusio/quarkus. Quarkus configuration conventions: @ConfigMapping interfaces, config phases, and migration from legacy @ConfigRoot classes.

Its SKILL.md is about 1.3k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It works with Java. The repository describes itself as: Quarkus: Supersonic Subatomic Java. The licence is Apache-2.0.

Example prompts

“/working-with-config”

What it can do on your machine

Read from SKILL.md and the folder at commit d58d0eb. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are java and xml).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Working With Config loads about 1.3k tokens when it runs. Until then it costs about 36 tokens; SKILL.md has 411 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~36
When it runs · the whole SKILL.md, loaded when a task matches: ~1.3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from quarkusio/quarkus at commit d58d0eb, republished under its Apache-2.0 licence (© quarkusio). 411 words, ~1,258 tokens.

Download SKILL.mdSave it as .claude/skills/working-with-config/SKILL.md (or your agent's skills folder).

name: working-with-config
description: Quarkus configuration conventions: @ConfigMapping interfaces, config phases, and migration from legacy @ConfigRoot classes.

Working with Configuration

Use @ConfigMapping Interfaces (Not Legacy Classes)

Quarkus configuration must use @ConfigMapping interfaces. The legacy @ConfigRoot-annotated classes with @ConfigItem have been fully removed (see adr/0008-phasing-out-config-classes.adoc).

Correct (current approach)

java

@ConfigMapping(prefix = "quarkus.my-extension")
@ConfigRoot(phase = ConfigPhase.RUN_TIME)
public interface MyExtensionRuntimeConfig {

    /** Description of the property. */
    @WithDefault("default-value")
    String myProperty();

    /** Optional property (absent means not set by the user). */
    Optional<String> optionalProperty();
}

Do NOT Use Optional to Define Default Values

Never use Optional and provide a default via .orElse(...) in application code. The default must be declared in the config mapping itself via @WithDefault:

java

// BAD — do not do this
String name = config.optName().orElse("theDefaultName");

// GOOD — declare the default in the config mapping
@WithDefault("theDefaultName")
String name();

Non-root @ConfigMapping (without @ConfigRoot)

@ConfigMapping can also be used without @ConfigRoot for non-root mappings. These are not auto-discovered — you must register them explicitly (e.g., via @Inject in a CDI bean or programmatically with SmallRye Config). Use this when mapping a sub-tree of configuration that does not represent an extension's top-level config root.

java

@ConfigMapping(prefix = "some.custom.prefix")
public interface MyCustomConfig {

    /** A non-root config property. */
    String someValue();
}

Wrong (legacy approach, do not use)

java

// DO NOT use this pattern
@ConfigRoot(name = "my-extension", phase = ConfigPhase.RUN_TIME)
public class MyExtensionConfig {
    @ConfigItem(defaultValue = "default-value")
    String myProperty;
}

Config Phases

@ConfigRoot defaults to BUILD_TIME when no phase is specified. Always set the phase explicitly — omitting it for a config injected at runtime will cause UnsatisfiedResolutionException because BUILD_TIME configs are not registered as CDI beans.

BUILD_TIME — Baked into the binary at build time, immutable at runtime. Use for settings that affect code generation. Only available in @BuildStep methods — not injectable via @Inject in runtime CDI beans.
BUILD_AND_RUN_TIME_FIXED — Read at build time, also available at runtime. Cannot change without rebuilding. Available in both @BuildStep methods and runtime CDI beans.
RUN_TIME — Read at application startup. Can change between runs. Available in runtime CDI beans via @Inject. Not available in @BuildStep methods.

Naming

Config interfaces: <Feature>Config.java, or split as <Feature>BuildTimeConfig.java / <Feature>RuntimeConfig.java
Config prefix: quarkus.<extension-name>

Show full SKILL.md (169 more words)Show less

Annotation Processor (`quarkus-extension-processor`)

The quarkus-extension-processor annotation processor is required for all extension modules, not just those with @ConfigRoot. It generates metadata files (including META-INF/quarkus-config-roots.list for config discovery) that Quarkus needs to wire extensions correctly. Without it, most extension functionality will silently fail.

Both runtime/ and deployment/ POMs must include:

xml

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <executions>
        <execution>
            <id>default-compile</id>
            <configuration>
                <annotationProcessorPaths>
                    <path>
                        <groupId>io.quarkus</groupId>
                        <artifactId>quarkus-extension-processor</artifactId>
                        <version>${project.version}</version>
                    </path>
                </annotationProcessorPaths>
            </configuration>
        </execution>
    </executions>
</plugin>

Most modules already have this. If you create a new module or notice missing metadata, verify the annotation processor is present in its pom.xml.

Key Rules

Always specify phase explicitly on @ConfigRoot — the default is BUILD_TIME, which is not injectable via CDI at runtime
Configuration is immutable — never mutate config objects
Use RUN_TIME phase unless the config genuinely affects build-time behavior
Do NOT access RUN_TIME config during build steps — it is not available yet
BUILD_TIME config changes require a rebuild
When adding new quarkus.* properties, always register them in a @ConfigMapping interface. Reading them programmatically via ConfigProvider.getConfig().getOptionalValue(...) is fine, but the corresponding key must still be defined in a @ConfigMapping — otherwise SmallRye Config will emit "unknown property" warnings at startup.

Files

Just SKILL.md in .agents/skills/working-with-config of quarkusio/quarkus.

Open the folder on GitHubat commit d58d0eb

Compare with similar skills

Working With Config next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

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Video Cover Imageitwanger/toBeBetterJavaer	18k	—	~3.3k	Automated safety check: Pass	None	today
Lancedb Update Lance Dependencylancedb/lancedb	12k	—	~1.1k	Automated safety check: Pass	Apache-2.0	today
Java SDK E2E Test with Replay Snapshotgithub/copilot-sdk	11k	—	~1.8k	Automated safety check: Pass	MIT	today

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Questions about Working With Config

What does Working With Config do?

Quarkus configuration conventions: @ConfigMapping interfaces, config phases, and migration from legacy @ConfigRoot classes. Working With Config is an agent skill from quarkusio/quarkus. Quarkus configuration conventions: @ConfigMapping interfaces, config phases, and migration from legacy @ConfigRoot classes.

How do I install Working With Config in Claude Code?

Run `npx skills add quarkusio/quarkus --skill working-with-config -a claude-code`. Or copy the skill folder (.agents/skills/working-with-config in quarkusio/quarkus) into .claude/skills/working-with-config in your project. Claude Code loads it when a task matches its description.

How do I install Working With Config in Codex?

Run `npx skills add quarkusio/quarkus --skill working-with-config -a codex`. Or copy the skill folder (.agents/skills/working-with-config in quarkusio/quarkus) into .agents/skills/working-with-config in your project. Codex loads it when a task matches its description.

Can I use Working With Config in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add quarkusio/quarkus --skill working-with-config -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/working-with-config, .gemini/skills/working-with-config, .github/skills/working-with-config and .opencode/skills/working-with-config in your project.

What does Working With Config need to run?

SKILL.md names no scripts, command-line tools or credentials: Working With Config is instructions for the agent only.

Does Working With Config access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Working With Config safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Working With Config use?

Working With Config is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Working With Config use?

About 1.3k tokens (SKILL.md is roughly 5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Working With Config?

Skills that share tags, products or a category with Working With Config: Brainstorming (xpinjection/test-driven-spring-boot, 112 stars), Android API Diff (gkd-kit/gkd, 43k stars), Video Cover Image (itwanger/toBeBetterJavaer, 18k stars) and Lancedb Update Lance Dependency (lancedb/lancedb, 12k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Working With Config?

quarkusio (a GitHub organization) maintains it in quarkusio/quarkus, which has 15,939 GitHub stars. The repository holds 12 skills in this directory. The repository was last updated on October 9, 2026.

Source: quarkusio/quarkus on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Working With Config

Facts

At a glance

What it does

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Working with Configuration

Use @ConfigMapping Interfaces (Not Legacy Classes)

Correct (current approach)

Do NOT Use Optional to Define Default Values

Non-root @ConfigMapping (without @ConfigRoot)

Wrong (legacy approach, do not use)

Config Phases

Naming

Annotation Processor (quarkus-extension-processor)

Key Rules

Files

Compare with similar skills

Similar skills

More from quarkusio/quarkus

Related

Questions about Working With Config

Annotation Processor (`quarkus-extension-processor`)