Initial agent skills setup

Common skills shared across Claude Code, Codex, and Antigravity,
plus per-agent extras. sync.sh deploys to each tool's config path.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

claude_extra.md

@@ -0,0 +1,30 @@
+# Claude Code — Agent-Specific Skills
+
+## CLAUDE.md & Project Context
+
+- Always check for `CLAUDE.md` at project root before starting tasks.
+- Instructions in `CLAUDE.md` override default behavior — follow them exactly.
+- Use `@path/to/file` syntax to import additional context files inline.
+
+## Tool Use
+
+- Prefer dedicated tools (Read, Edit, Write) over Bash when one fits.
+- Run independent tool calls in parallel to maximize efficiency.
+- Reserve Bash for shell-only operations.
+
+## Memory
+
+- Save non-obvious user preferences and feedback to `/root/.claude/projects/` memory files.
+- Do not save things derivable from code, git history, or documentation.
+- Verify memory against current file state before acting on it — memories can go stale.
+
+## MCP & Hooks
+
+- MCP servers extend tool capabilities — check available MCP tools before falling back to generic approaches.
+- Hooks in `settings.json` execute automatically on events; use them for automated behaviors.
+- Never skip hooks (`--no-verify`) unless the user explicitly requests it.
+
+## Permissions
+
+- For destructive or hard-to-reverse actions (force push, rm -rf, drop table), confirm with user first.
+- One-time approval does not mean blanket approval — re-confirm in new contexts.