create persistent claude config storage using named volume

[IlmLV]

Summary

• Mounts a named volume at /claude-config (scoped to devcontainerId) so Claude data survives container rebuilds without manual configuration
• Sets CLAUDE_CONFIG_DIR=/claude-config in the container user's shell profiles, consolidating all Claude data — including the normally homeless ~/.claude.json — into the
  mounted volume
• postCreateCommand fixes volume directory ownership after mounting (Docker creates volumes as root)
  • Config is isolated from the host — the container gets its own Claude credentials and settings, independent of the host machine

Problem

Claude Code stores most data in ~/.claude/ but writes its main config file to ~/.claude.json (outside the directory). A volume mount at ~/.claude alone does not persist ~/.claude.json, requiring re-login on every rebuild.

Symlinking ~/.claude to a mounted volume does not work — the Claude CLI cannot read credentials through a symlinked directory.

Solution

Using CLAUDE_CONFIG_DIR redirects all Claude storage, including ~/.claude.json, into a single directory that is directly volume-mounted. No symlinks involved. The named volume is scoped to the devcontainer instance, keeping credentials isolated from the host and other containers.

Try it out

  "features": {
    "ghcr.io/ilmlv/anthropics-devcontainer-features-persistent-config/claude-code:1": {}
  },

Test plan

• First devcontainer run, execute Claude CLI — login required
• Rebuild devcontainer without cache, execute Claude CLI — config and auth still present
• echo $CLAUDE_CONFIG_DIR in terminal shows /claude-config
• ls /claude-config shows .claude.json and credentials after first login

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PR very similar to #34, difference is usage of ENV defined config directory.
Closes: #24
Related to: #34