${user_config.*} interpolation not supported in HTTP-type MCP server
headers — only works for subprocess-based servers. Revert to shell
env var reference. The userConfig + resolve_api_key() fallback chain
still fixes hook scripts for issue #4876.
Root cause: .mcp.json required ${MEM0_API_KEY} shell env var which
OAuth flow never populates — MCP server never started, only auth
stubs were exposed.
Fix: switch .mcp.json to ${user_config.MEM0_API_KEY} so Claude Code
reads the key from plugin userConfig (system keychain). Add
resolve_api_key() fallback chain (MEM0_API_KEY -> CLAUDE_PLUGIN_OPTION_MEM0_API_KEY)
to all hook scripts. Update onboard skill and setup_coding_categories.py
to handle keychain-only users. Add 3 tests for key resolution.
kartik-mem0