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Keep devcontainer.json in sync when software is installed, removed, or configured inside the dev container
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Write Bash commands that don't trigger unnecessary permission prompts. Use Read/Edit/Grep instead of head/tail/sed/awk/cat/echo; split chained commands (&&, ;, ||) into separate Bash calls; drop diagnostic suffixes like `; echo "EXIT=$?"`. The allowlist matches whole command strings — every mismatch costs the user attention.
Commit user-named files atomically via scripts/commit-pathspec.sh (which wraps `git commit -m "..." -- <files>` and writes the provenance token the pre-commit hook validates). Applies the CLAUDE.md "Pre-commit hook failures on unrelated changes" protocol when the hook fails. Never adds --no-verify silently — explicit user approval is required.
Scaffold a new epic file in docs/developers/tasks/open/ and run housekeep
Scaffold a new idea file in docs/developers/ideas/open/ and regenerate the ideas OVERVIEW.md
Set a task to active — updates status, moves to active/, runs housekeep. Also resumes paused tasks (paused/ → active/ or active/ with closed prerequisites).
Mark a task as closed — writes effort_actual, moves the file to closed/, runs housekeep, and commits
| name | devcontainer-sync |
| description | Keep devcontainer.json in sync when software is installed, removed, or configured inside the dev container |
Policy: Whenever you install, remove, or configure software while running inside a dev container,
you MUST also update .devcontainer/devcontainer.json so the change is persisted for the next
container rebuild. A change that exists only in the running container is lost on rebuild.
We are inside a dev container when any of the following is true:
REMOTE_CONTAINERS is set (VS Code Dev Containers).CODESPACES is set (GitHub Codespaces)./.dockerenv exists (generic Docker runtime)./workspaces/ (convention used by both VS Code and Codespaces).Check with:
[ -n "$REMOTE_CONTAINERS" ] || [ -n "$CODESPACES" ] || [ -f /.dockerenv ] && echo "inside devcontainer"
If none of these match, we are on a native host. Skip this skill — no devcontainer update is needed.
The file is at .devcontainer/devcontainer.json. Choose the right section:
| Change type | Where in devcontainer.json |
|---|---|
apt-get install <pkg> | Add <pkg> to the apt-get install invocation inside postCreateCommand |
apt-get remove <pkg> | Remove <pkg> from the apt-get install list in postCreateCommand |
npm install -g <pkg> | Add/remove from the npm install -g call in postCreateCommand |
pip install <pkg> | Add/remove from the pip install call in postCreateCommand |
uv tool install <pkg> | Add/remove from the uv tool install calls in postCreateCommand |
| New feature (e.g. Docker-in-Docker) | Add an entry under "features": {} |
| VS Code extension | Add/remove from customizations.vscode.extensions |
| Environment variable | Add/remove from "remoteEnv": {} |
| Mounted volume | Add/remove from "mounts": [] |
postCreateCommand as a single shell string joined with &&. Do not split it into an
array — the existing format uses a string.features over postCreateCommand for runtimes with an official Dev Container
Feature (Node.js, Python, Go, Docker, etc.). Only fall back to postCreateCommand for packages
that have no feature."
devcontainer.jsonupdated — rebuild the container (Dev Containers: Rebuild Container) to apply the change to fresh environments."
jqBefore (excerpt):
"postCreateCommand": "sudo apt-get update -q && sudo apt-get install -y -q lcov doxygen && npm install -g markdownlint-cli2 ..."
After:
"postCreateCommand": "sudo apt-get update -q && sudo apt-get install -y -q lcov doxygen jq && npm install -g markdownlint-cli2 ..."
Add a comment near the postCreateCommand key (or inline if the JSON allows) explaining jq is needed for the relevant script/skill.