Devcontainer Setup

What it does

When your agent uses it

• Adding devcontainer support to a project
• Setting up isolated development environments
• Configuring sandboxed Claude Code workspaces

Example prompts

• “Use the devcontainer-setup skill to create devcontainers with Claude Code, language-specific tooling (Python/Node/Rust/Go), and persistent volumes”
• “/devcontainer-setup”

Requirements

• Python 3
• Node.js
• A Bash shell
• Docker
• A credential in CLAUDE_CODE_OAUTH_TOKEN

Workflow steps

2 steps, taken from the step headings in SKILL.md.

1. 1Project Reconnaissance
2. 2Generate Configuration

What it can do on your machine

Read from SKILL.md and the folder at commit 82fe822. 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 script files (Shell and Python), which the agent can run.

  Shell commands in SKILL.md call:

  • uv
  • npm
  • cargo
  • go
  • pnpm
  • yarn

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md. Its commands use uv, npm, pnpm and yarn, which can reach the network depending on how they are called.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names these keys or tokens, usually read from environment variables:

  • CLAUDE_CODE_OAUTH_TOKEN
  • ANTHROPIC_API_KEY

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Devcontainer Setup loads about 2k tokens when it runs, and up to ~3k if it reads all its reference files. Until then it costs about 69 tokens; SKILL.md has 632 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~69

When it runs · the whole SKILL.md, loaded when a task matches

~2k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~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

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 trailofbits/skills at commit 82fe822, republished under its CC-BY-SA-4.0 licence (© trailofbits). 632 words, ~2,010 tokens.

name

devcontainer-setup

description

Creates devcontainers with Claude Code, language-specific tooling (Python/Node/Rust/Go), and persistent volumes. Use when adding devcontainer support to a project, setting up isolated development environments, or configuring sandboxed Claude Code workspaces.

flowchart TB
    start([User requests devcontainer])
    recon[1. Project Reconnaissance]
    detect[2. Detect Languages]
    generate[3. Generate Configuration]
    write[4. Write files to .devcontainer/]
    done([Done])

    start --> recon
    recon --> detect
    detect --> generate
    generate --> write
    write --> done

uv run /opt/post_install.py && uv sync && npm ci

# Install Python via uv (fast binary download, not source compilation)
RUN uv python install <version> --default

"ms-python.python",
"ms-python.vscode-pylance",
"charliermarsh.ruff"

"python.defaultInterpreterPath": ".venv/bin/python",
"[python]": {
  "editor.defaultFormatter": "charliermarsh.ruff",
  "editor.codeActionsOnSave": {
    "source.organizeImports": "explicit"
  }
}

rm -rf .venv && uv sync && uv run /opt/post_install.py

"dbaeumer.vscode-eslint",
"esbenp.prettier-vscode"

"editor.defaultFormatter": "esbenp.prettier-vscode",
"editor.codeActionsOnSave": {
  "source.fixAll.eslint": "explicit"
}

"ghcr.io/devcontainers/features/rust:1": {}

"rust-lang.rust-analyzer",
"tamasfe.even-better-toml"

"[rust]": {
  "editor.defaultFormatter": "rust-lang.rust-analyzer"
}

uv run /opt/post_install.py && cargo build --locked

uv run /opt/post_install.py && cargo build

"ghcr.io/devcontainers/features/go:1": {
  "version": "latest"
}

"golang.go"

"[go]": {
  "editor.defaultFormatter": "golang.go"
},
"go.useLanguageServer": true

uv run /opt/post_install.py && go mod download

"mounts": [
  "source={{PROJECT_SLUG}}-<purpose>-${devcontainerId},target=<container-path>,type=volume"
]

© trailofbits, CC-BY-SA-4.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 9 other files (references, assets) in plugins/devcontainer-setup/skills/devcontainer-setup of trailofbits/skills.

• SKILL.md
• agents/openai.yaml
• assets/trail-of-bits-mark.svg
• references/dockerfile-best-practices.md
• references/features-vs-dockerfile.md
• resources/.zshrc
• resources/Dockerfile
• resources/devcontainer.json
• resources/install.sh
• resources/post_install.py

Open the folder on GitHubat commit 82fe822

Used in 3 other repositories

We found 12 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 3 other GitHub owners. This page covers the copy in trailofbits/skills, which our catalogue first saw on October 7, 2026.

• sickn33/agentic-awesome-skillsskills/devcontainer-setupplugins/agentic-awesome-skills/skills/devcontainer-setup+1 more
• lingxling/awesome-skills-cnantigravity-awesome-skills/skills/devcontainer-setupantigravity-awesome-skills/plugins/agentic-awesome-skills/skills/devcontainer-setup+1 more
• henryalouf/ruflow.agents/skills/devcontainer-setup.agents/skills/antigravity-awesome-skills/skills/devcontainer-setup+4 more