Agent skill

Devcontainer

Diagnose devcontainer configuration problems and guide development environment setup.

Install Devcontainer

skills CLI

$ npx skills add jwynia/agent-skills --skill devcontainer -a claude-code

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

GitHub CLI

$ gh skill install jwynia/agent-skills devcontainer --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/jwynia/agent-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/tech/development/tooling/devcontainer .claude/skills/devcontainer && 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 "devcontainer" agent skill from https://github.com/jwynia/agent-skills/tree/main/skills/tech/development/tooling/devcontainer into .claude/skills/devcontainer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "devcontainer", 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/jwynia/agent-skills/tree/main/skills/tech/development/tooling/devcontainer

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 jwynia/agent-skills --skill devcontainer -a codex

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

GitHub CLI

$ gh skill install jwynia/agent-skills devcontainer --agent codex

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

Manual copy

$ git clone --depth 1 https://github.com/jwynia/agent-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/tech/development/tooling/devcontainer .agents/skills/devcontainer && 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 "devcontainer" agent skill from https://github.com/jwynia/agent-skills/tree/main/skills/tech/development/tooling/devcontainer into .agents/skills/devcontainer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "devcontainer", 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 jwynia/agent-skills --skill devcontainer -a cursor

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

GitHub CLI

$ gh skill install jwynia/agent-skills devcontainer --agent cursor

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

Manual copy

$ git clone --depth 1 https://github.com/jwynia/agent-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/tech/development/tooling/devcontainer .cursor/skills/devcontainer && 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 "devcontainer" agent skill from https://github.com/jwynia/agent-skills/tree/main/skills/tech/development/tooling/devcontainer into .cursor/skills/devcontainer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "devcontainer", 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/jwynia/agent-skills.git --path skills/tech/development/tooling/devcontainer

--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 jwynia/agent-skills --skill devcontainer -a gemini-cli

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

GitHub CLI

$ gh skill install jwynia/agent-skills devcontainer --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/jwynia/agent-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/tech/development/tooling/devcontainer .gemini/skills/devcontainer && 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 "devcontainer" agent skill from https://github.com/jwynia/agent-skills/tree/main/skills/tech/development/tooling/devcontainer into .gemini/skills/devcontainer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "devcontainer", 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 jwynia/agent-skills devcontainer

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 jwynia/agent-skills --skill devcontainer -a github-copilot

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

Manual copy

$ git clone --depth 1 https://github.com/jwynia/agent-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/tech/development/tooling/devcontainer .github/skills/devcontainer && 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 "devcontainer" agent skill from https://github.com/jwynia/agent-skills/tree/main/skills/tech/development/tooling/devcontainer into .github/skills/devcontainer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "devcontainer", 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 jwynia/agent-skills --skill devcontainer -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 jwynia/agent-skills devcontainer --agent opencode

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

Manual copy

$ git clone --depth 1 https://github.com/jwynia/agent-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/tech/development/tooling/devcontainer .opencode/skills/devcontainer && 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 "devcontainer" agent skill from https://github.com/jwynia/agent-skills/tree/main/skills/tech/development/tooling/devcontainer into .opencode/skills/devcontainer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "devcontainer", 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: devcontainer
GitHub stars: 165
Token cost: ~1.2k tokens
SKILL.md length: 415 words
Files: 8 (incl. scripts, references, assets)
Skills in repo: 113
Repo updated: Feb 24, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Diagnose devcontainer configuration problems and guide development environment setup.

Asks to set up devcontainer
SKILL.md covers When to Use This Skill, Core Principle, Diagnostic States and Available Scripts, plus 3 more sections
Runs TypeScript scripts from its folder; calls deno
Fix container startup

What it does

Devcontainer is an agent skill from jwynia/agent-skills. Diagnose devcontainer configuration problems and guide development environment setup. This skill should be used when the user asks to 'set up devcontainer', 'fix container startup', 'configure VS Code dev container', 'Codespaces setup', or has Docker development environment issues. Keywords: devcontainer, docker, VS Code, Codespaces, container, development environment, Dockerfile.

Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. The skill folder holds 10 other files, including scripts, reference files and assets (for example `assets/devcontainer-compose.md`, `assets/devcontainer-dockerfile.md` and `assets/devcontainer-simple.md`). Compatibility notes: Requires Docker Desktop or compatible container runtime. Works with VS Code and GitHub Codespaces.

It sits in DevOps & Cloud, covering Containers. It works with Docker and Visual Studio Code. The licence is MIT.

When your agent uses it

Asks to set up devcontainer
Fix container startup
Configure VS Code dev container
Codespaces setup

Example prompts

“set up devcontainer”
“fix container startup”
“configure VS Code dev container”
“/devcontainer”

Requirements

Python 3
Node.js
Docker
Compatibility (from SKILL.md): Requires Docker Desktop or compatible container runtime. Works with VS Code and GitHub Codespaces.

What it can do on your machine

Read from SKILL.md and the folder at commit e02ec7e. 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
Ships 3 files in scripts/ (TypeScript), which the agent can run.
Shell commands in SKILL.md call:
- deno
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.
Compatibility
Requires Docker Desktop or compatible container runtime. Works with VS Code and GitHub Codespaces.
From compatibility in the SKILL.md frontmatter.

Context cost

Devcontainer loads about 1.2k tokens when it runs, and up to ~3.2k if it reads all its reference files. Until then it costs about 99 tokens; SKILL.md has 415 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~99
When it runs · the whole SKILL.md, loaded when a task matches: ~1.2k
With references · SKILL.md plus every file in references/, read only if the agent opens them: ~3.2k

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: notes

The automated check noted patterns worth knowing about, such as sudo or a known installer.

NoteMentions a .env fileSKILL.md:79

| Secrets | .env files work | Use Codespaces secrets |

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); the scripts in this folder are not scanned.

SKILL.md

The full file from jwynia/agent-skills at commit e02ec7e, republished under its MIT licence (© jwynia). 415 words, ~1,228 tokens.

Download SKILL.mdSave it as .claude/skills/devcontainer/SKILL.md (or your agent's skills folder). This skill also uses 7 other files; get the full folder from GitHub.

name: devcontainer
description: Diagnose devcontainer configuration problems and guide development environment setup. This skill should be used when the user asks to 'set up devcontainer', 'fix container startup', 'configure VS Code dev container', 'Codespaces setup', or has Docker development environment issues. Keywords: devcontainer, docker, VS Code, Codespaces, container, development environment, Dockerfile.
compatibility: Requires Docker Desktop or compatible container runtime. Works with VS Code and GitHub Codespaces.
license: MIT
metadata.author: jwynia
metadata.version: 1.0
metadata.type: diagnostic
metadata.mode: diagnostic+generative
metadata.domain: development

Devcontainer Diagnostic

Diagnose devcontainer and Docker development environment problems. Help create reproducible, fast-starting development environments that work consistently across VS Code, GitHub Codespaces, and team members.

When to Use This Skill

Use this skill when:

Setting up a new devcontainer
Container startup is too slow
Configuration errors or conflicts
Different behavior in VS Code vs Codespaces
Multi-service development environment needed

Do NOT use this skill when:

Writing application code
Deploying to production
Configuring CI/CD pipelines

Core Principle

Development containers should provide instant productivity. Every configuration choice affects startup time, reproducibility, and team onboarding. Make these trade-offs explicit.

Diagnostic States

DV0: No Devcontainer Strategy

Symptoms: Manual setup, "check the README", works on one machine fails on others

Interventions:

Start with pre-built devcontainer base image
Use assets/devcontainer-simple.md template

DV1: Slow Container Startup

Symptoms: 5+ minute startup, heavy postCreateCommand, avoiding rebuilds

Key Questions:

How long does startup actually take?
What's in postCreateCommand?
Are you using prebuilds?

Interventions:

Move npm install/pip install to Dockerfile (cached)
Use mcr.microsoft.com/devcontainers/* base images
Configure prebuilds for team repos
Run scripts/analyze-devcontainer.ts

DV2: Configuration Problems

Symptoms: JSON errors, VS Code won't connect, features conflicting

Checklist:

devcontainer.json passes JSON validation
Using only ONE of: image, build.dockerfile, dockerComposeFile
Features are compatible and ordered correctly
Extensions use correct publisher.extension-name format

DV3: Environment Parity Issues

Symptoms: Works in VS Code, fails in Codespaces (or vice versa)

Common Issues:

Issue	Local VS Code	Codespaces
Docker socket	Usually available	Docker-in-Docker needed
Secrets	.env files work	Use Codespaces secrets
File watching	Native	May need polling

Show full SKILL.md (167 more words)Show less

DV4: Multi-Service Complexity

Symptoms: Need database/cache/queue, services can't communicate

Interventions:

Use Docker Compose integration
Named volumes for persistence
Health checks for service readiness
Use assets/devcontainer-compose.md template

DV5: Dockerfile Issues

Symptoms: Build failures, huge images, no caching

Best Practices:

dockerfile

FROM mcr.microsoft.com/devcontainers/base:ubuntu

# Dependencies first (cached)
RUN apt-get update && apt-get install -y \
    build-essential && rm -rf /var/lib/apt/lists/*

# Copy deps then install (cached if deps unchanged)
COPY package*.json ./
RUN npm install

# Code last (changes frequently)
COPY . .

DV6: Devcontainer Validated

Indicators:

Startup under 2 minutes
Works in VS Code and Codespaces
New developers productive in 30 minutes

Available Scripts

Script	Purpose	Usage
`analyze-devcontainer.ts`	Find issues and optimizations	`deno run --allow-read scripts/analyze-devcontainer.ts`
`validate-dockerfile.ts`	Check Dockerfile best practices	`deno run --allow-read scripts/validate-dockerfile.ts`
`scan-image.ts`	Vulnerability scanning (wraps Trivy)	`deno run --allow-run scripts/scan-image.ts [image]`

Anti-Patterns

The Kitchen Sink

Installing every tool "just in case" - 10+ minute startups. Fix: Start minimal. Add only when needed.

The postCreateCommand Overload

Everything in postCreateCommand - runs every time. Fix: Move stable operations to Dockerfile.

The Snowflake Container

Manual changes inside running containers. Fix: ALL changes go in config files.

Templates

assets/devcontainer-simple.md - Basic single-container setup
assets/devcontainer-dockerfile.md - Custom Dockerfile approach
assets/devcontainer-compose.md - Multi-service setup

system-design - Multi-service architecture informs Compose config
pwa-development - Consistent environment for PWA toolchain

Files

SKILL.md and 7 other files (scripts, references, assets) in skills/tech/development/tooling/devcontainer of jwynia/agent-skills.

SKILL.md
assets/devcontainer-compose.md
assets/devcontainer-dockerfile.md
assets/devcontainer-simple.md
references/feature-catalog.md
scripts/analyze-devcontainer.ts
scripts/scan-image.ts
scripts/validate-dockerfile.ts

Open the folder on GitHubat commit e02ec7e

Compare with similar skills

Devcontainer 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.

Devcontainer compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Devcontainer this skilljwynia/agent-skills	165	—	~1.2k	Automated safety check: Notes	MIT	7 mo ago
Devsydevsy-org/devsy	109	—	~1.7k	Automated safety check: Pass	MPL-2.0	today
Cloud TestFreakStudioCN/mpy-hardware-extension	118	—	~1.7k	Automated safety check: Pass	Custom licence	9 days ago
Atmos Devcontainercloudposse/atmos	1.4k	—	~1.7k	Automated safety check: Pass	Apache-2.0	today
Azure Containerregistry Pymicrosoft/skills	3.1k	—	~2.2k	Automated safety check: Pass	MIT	yesterday
Review PRmicrosoft/vscode-containers	141	—	~900	Automated safety check: Pass	Custom licence	today

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Questions about Devcontainer

What does Devcontainer do?

Diagnose devcontainer configuration problems and guide development environment setup. Devcontainer is an agent skill from jwynia/agent-skills. Diagnose devcontainer configuration problems and guide development environment setup.

When should I use Devcontainer?

Devcontainer fits situations like: asks to set up devcontainer; fix container startup; configure VS Code dev container; codespaces setup.

How do I install Devcontainer in Claude Code?

Run `npx skills add jwynia/agent-skills --skill devcontainer -a claude-code`. Or copy the skill folder (skills/tech/development/tooling/devcontainer in jwynia/agent-skills) into .claude/skills/devcontainer in your project. Claude Code loads it when a task matches its description.

How do I install Devcontainer in Codex?

Run `npx skills add jwynia/agent-skills --skill devcontainer -a codex`. Or copy the skill folder (skills/tech/development/tooling/devcontainer in jwynia/agent-skills) into .agents/skills/devcontainer in your project. Codex loads it when a task matches its description.

Can I use Devcontainer 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 jwynia/agent-skills --skill devcontainer -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/devcontainer, .gemini/skills/devcontainer, .github/skills/devcontainer and .opencode/skills/devcontainer in your project.

What does Devcontainer need to run?

Going by SKILL.md and its folder, Devcontainer needs TypeScript for the scripts in its folder and the command-line tools its instructions call (deno). Our summary lists: Python 3; Node.js; Docker. Compatibility (from SKILL.md): Requires Docker Desktop or compatible container runtime. Works with VS Code and GitHub Codespaces..

Does Devcontainer 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 Devcontainer safe to install?

Our automated static check of SKILL.md found notes only (mentions a .env file), nothing it rates as a warning. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.

What licence does Devcontainer use?

Devcontainer is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Devcontainer use?

About 1.2k tokens (SKILL.md is roughly 4.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 2k tokens, read only when the agent opens those files.

What are the alternatives to Devcontainer?

Skills that share tags, products or a category with Devcontainer: Devsy (devsy-org/devsy, 109 stars), Cloud Test (FreakStudioCN/mpy-hardware-extension, 118 stars), Atmos Devcontainer (cloudposse/atmos, 1.4k stars) and Azure Containerregistry Py (microsoft/skills, 3.1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Devcontainer?

jwynia (a GitHub user) maintains it in jwynia/agent-skills, which has 165 GitHub stars. The repository holds 113 skills in this directory. The repository was last updated on February 24, 2026.

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

Install Devcontainer

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Compatibility

Context cost

Safety

SKILL.md

Devcontainer Diagnostic

When to Use This Skill

Core Principle

Diagnostic States

DV0: No Devcontainer Strategy

DV1: Slow Container Startup

DV2: Configuration Problems

DV3: Environment Parity Issues

DV4: Multi-Service Complexity

DV5: Dockerfile Issues

DV6: Devcontainer Validated

Available Scripts

Anti-Patterns

The Kitchen Sink

The postCreateCommand Overload

The Snowflake Container

Templates

Related Skills

Files

Compare with similar skills

Similar skills

More from jwynia/agent-skills

Related

Questions about Devcontainer