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Use when adding or modifying a devcontainer feature in devcontainer.json - fetch its devcontainer-feature.json schema first and verify every option key exists, because features silently drop unknown options.
Codex 또는 Claude로 설치 이 Prompt를 복사해 Codex, Claude 또는 다른 어시스턴트에 붙여 넣으면 Skill 페이지를 검토하고 설치를 진행할 수 있습니다.
SOC 직업 분류 기준
Prepare for a /clear: bring all documentation up to date with this session's changes, persist recovery context (memory + handoff), and emit a copy-paste resume prompt so the next session begins the next task with zero context loss. Invoke explicitly as /clear-prep [next-task].
Use when creating branches, commits, pushes, or PRs with plain git. Branch BEFORE committing — never commit directly onto the default branch. Avoids virtual-branch composition bugs where commits silently depend on other applied branches.
Write a CROSS-SURFACE session handoff to a tracked path and push it, so a session on another surface (web, desktop, or CLI) can continue with zero context loss. Use when ending a session whose work must be picked up on a DIFFERENT machine/surface. For same-machine /clear continuity use /clear-prep instead. Invoke as /handoff [next-task].
Use when running parallel-scientist research - ALWAYS follow with an opus verification stage that re-probes load-bearing claims and surfaces gaps. Skipping the verifier almost shipped a wrong recommendation in session 2026-04-07e.
Use when sharing a single `~/.ssh/config` across macOS + Linux - apply OpenSSH `IgnoreUnknown` to tolerate macOS-only directives (`UseKeychain`, `AddKeysToAgent`) on Linux where they would otherwise be fatal.
Use when auditing whether the repo's pinned tools are current AND whether any hand-rolled custom code is now superseded by a native tool feature. Produces a retire/bump report from mise outdated + pkl/pin-vs-latest diff + a cache-first release-note scan.
| name | devcontainer-feature-schema-probe |
| description | Use when adding or modifying a devcontainer feature in devcontainer.json - fetch its devcontainer-feature.json schema first and verify every option key exists, because features silently drop unknown options. |
| type | learned-skill |
| extracted-from | session 2026-04-07e (dotfiles SSH model debugging) |
| applicability | devcontainer feature configuration in any project |
Before adding any feature option in devcontainer.json features:
block, especially for first-party features under
ghcr.io/devcontainers/features/*. Also useful when debugging "the
feature seems configured but doesn't behave like the option suggests."
Identify the feature source repo path. First-party features
live at https://github.com/devcontainers/features/tree/main/src/<name>.
The schema file is devcontainer-feature.json at that path.
Fetch the schema:
curl -sS https://raw.githubusercontent.com/devcontainers/features/main/src/<name>/devcontainer-feature.json \
| jq '.options'
Compare against your devcontainer.json config. Every key in
your feature options block MUST exist in the schema output. Any
key not in the schema is silently dropped at build time — no
warning, no error.
Also fetch the README to confirm the feature's intended use case:
curl -sS https://raw.githubusercontent.com/devcontainers/features/main/src/<name>/README.md
The schema tells you what the feature accepts; the README tells you what it does.
Cross-check by reading install.sh if you need to know the
actual install behavior, default values, hardcoded paths, or
started services:
curl -sS https://raw.githubusercontent.com/devcontainers/features/main/src/<name>/install.sh
// devcontainer.json — BROKEN, options silently dropped
"features": {
"ghcr.io/devcontainers/features/sshd:1": {
"username": "${localEnv:USER}", // does not exist in schema
"port": "4444", // does not exist in schema
"startNow": true // does not exist in schema
}
}
The sshd feature has only version and gatewayPorts. The above
configuration looked plausible and was committed in PR-2 commit B,
shipped to main, and went undetected for ~3 weeks because no test
exercised the SSH path.
$ curl -sS https://raw.githubusercontent.com/devcontainers/features/main/src/sshd/devcontainer-feature.json | jq '.options'
{
"version": {
"type": "string",
"proposals": ["latest"],
"default": "latest",
"description": "Currently unused."
},
"gatewayPorts": {
"type": "string",
"enum": ["no", "yes", "clientspecified"],
"default": "no",
"description": "Enable other hosts in the same network to connect to the forwarded ports"
}
}
Any option not listed there is dropped on the floor.
This applies to all devcontainer features, not just first-party.
Third-party features (devcontainers-contrib, custom) follow the same
schema convention — fetch their devcontainer-feature.json from the
source repo and verify.
feedback_sshd_feature_options_silently_dropped.md (project memory)feedback_use_tool_builtins.md — sibling principle: research the
tool's official docs before inventing custom logic.agent/wiki/feature-options-silently-dropped.md