Docker Encyclopedia

Docker documentation-first workflow for Docker-specific questions, troubleshooting, command planning, image/build work, container/runtime operations, Compose behavior, networking, volumes, registries, and diagnostics. Use when the request is clearly about Docker itself: the `docker` CLI, Docker Engine, Dockerfiles, BuildKit/buildx, Docker Compose, images, containers, registries, volumes, networks, contexts, rootless Docker, or Docker Desktop/Engine behavior where Docker-specific semantics matter. Do not use for generic Linux administration, generic OCI/container theory, generic shell work, or Kubernetes/orchestration questions unless the Docker layer is specifically what is being discussed or debugged.

Overview

Use a docs-first workflow for Docker work. Prefer the official Docker documentation at https://docs.docker.com/, consult cached local copies under .Docker-Encyclopedia/ before re-fetching, and record useful official-doc excerpts plus environment-specific operational learnings so future work gets faster and safer.

This skill is for the Docker product/runtime layer. It should trigger for real Docker behavior, configuration, build/runtime, and operational questions — not for generic Linux admin work, generic container theory, or generic orchestration talk where Docker-specific semantics are not the real issue.

Workflow

1. Classify the task

   • Decide whether the task is a Docker question, troubleshooting task, command-planning task, image/build task, Compose review, runtime review, or live operational task.
   • Use this skill when the request is specifically about Docker product behavior, Docker CLI semantics, Docker build/runtime behavior, Docker Compose behavior, image/container lifecycle, or Docker-specific networking/storage/registry details.
   • Do not use this skill for generic shell work, generic Linux admin, generic OCI/container theory, or Kubernetes questions unless the Docker layer is specifically in play.

2. Check local cache first

   • Use .Docker-Encyclopedia/ as the local knowledge/cache root.
   • Check these locations first when relevant:
     • .Docker-Encyclopedia/docs/docs.docker.com/...
     • .Docker-Encyclopedia/notes/components/...
     • .Docker-Encyclopedia/notes/patterns/...
     • .Docker-Encyclopedia/inventory/...
   • If a cached page or note already answers the question well enough, use it.

3. Consult official Docker docs before answering or touching the system

   • Before answering direct or indirect Docker questions that depend on command syntax, feature boundaries, configuration semantics, builder/runtime behavior, storage/network semantics, or version-sensitive details, consult the official docs unless the answer is already well-supported by the local cache.
   • Before performing direct Docker CLI or configuration work, consult the relevant docs first when:
     • the exact command path matters
     • build/runtime semantics are easy to misremember
     • the action could affect running containers, images, volumes, networks, registries, credentials, or host reachability
   • Do not improvise high-impact Docker commands or config changes from memory when the docs are easy to check.

4. Cache consulted docs locally

   • When you consult a Docker docs page, save a normalized markdown/text cache copy under .Docker-Encyclopedia/docs/docs.docker.com/....
   • Mirror the official docs path structure as much as practical.
   • Cache only pages actually consulted; do not try to mirror the whole docs site eagerly.
   • Use scripts/cache_doc.py when appropriate.

5. Separate official documentation from local observations

   • Store official-doc-derived material under .Docker-Encyclopedia/docs/....
   • Store environment-specific operational knowledge under:
     • .Docker-Encyclopedia/notes/components/
     • .Docker-Encyclopedia/notes/patterns/
     • .Docker-Encyclopedia/inventory/
   • Distinguish clearly between:
     • official documented behavior
     • observed local configuration/state
     • inferred best-practice guidance

6. Record useful local learnings

   • After useful live work, save durable notes such as:
     • host-specific Docker layout and runtime conventions
     • recurring build/runtime/debugging patterns
     • image/registry/credential-helper gotchas
     • Compose/deployment conventions
     • safe/unsafe operational boundaries for the environment
   • Prefer concise durable notes over re-learning the same Docker details later.

Live Work Rules

• Treat official Docker docs lookup as the default preflight for non-trivial Docker work.
• Prefer read/inspect first when entering a Docker area you have not recently reviewed.
• Treat image pruning, volume/network changes, Compose deployments, builder/registry config, daemon config, and credential-handling paths as high-sensitivity areas.
• When uncertainty remains after checking cache + docs, say so and avoid bluffing.
• When answering a question, mention when useful whether the answer comes from cached official docs, a fresh official docs lookup, or live observed environment state.

Data Root

Use this workspace-local root for cache and notes:

• .Docker-Encyclopedia/

Expected structure:

• .Docker-Encyclopedia/docs/docs.docker.com/...
• .Docker-Encyclopedia/notes/components/...
• .Docker-Encyclopedia/notes/patterns/...
• .Docker-Encyclopedia/inventory/...

Use scripts/init_workspace.py to create or repair the expected directory structure.

Note Destinations

• Component-specific observations → .Docker-Encyclopedia/notes/components/<component-name>.md
• Reusable Docker patterns/gotchas → .Docker-Encyclopedia/notes/patterns/<topic>.md
• Environment-wide deployment/access info → .Docker-Encyclopedia/inventory/*.md
• Cached official docs → .Docker-Encyclopedia/docs/docs.docker.com/...

Secrets / Sensitive Data

• Do not store plaintext credentials, API keys, session tokens, private URLs, recovery codes, or other secrets in the encyclopedia notes/inventory tree.
• If a note needs to mention access details, keep it high-level and redact or omit secret material.
• Treat these workspace notes as operational memory, not as a secrets vault.

Resources

• scripts/init_workspace.py — create or repair the .Docker-Encyclopedia/ directory tree.
• scripts/cache_doc.py — fetch and cache a consulted official Docker docs page under .Docker-Encyclopedia/docs/....
• references/workflow.md — detailed operating workflow and evidence-handling rules.
• references/cache-layout.md — canonical .Docker-Encyclopedia/ directory structure.
• references/topic-map.md — useful Docker topic groupings for faster doc lookup.

Good Outcomes

• Answer a Docker question using cached or freshly checked official docs instead of guesswork.
• Inspect a live Docker environment after checking the relevant docs and record any new local operational knowledge.
• Build a growing local Docker knowledge cache that makes later work faster, safer, and more grounded.
• Turn one-off Docker discoveries into durable notes so future work does not rediscover them from scratch.

Avoid

• Answering Docker-specific questions purely from memory when docs are easy to consult.
• Treating local observed behavior as if it were guaranteed official documented behavior.
• Dumping large amounts of low-value docs into the workspace without a reason.
• Writing component-specific observations into the official-doc cache tree.
• Making high-impact live changes before checking the relevant docs when exact behavior matters.