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Agent Sync (Standalone Utility)
Type: Standalone Utility Category: 0XX Shared
Synchronizes skills and MCP server configurations from Claude Code (source of truth) to Gemini CLI and Codex CLI. Creates symlinks for skills, copies/converts MCP settings.
When to Use This Skill
- After adding/removing MCP servers in Claude Code settings
- After installing new plugins in Claude Code
- First-time setup of Gemini CLI or Codex CLI alongside Claude Code
- Periodic sync to keep all agents aligned
Input Parameters
| Parameter | Required | Default | Description |
|---|---|---|---|
| targets | No | both | gemini, codex, or both |
| mode | No | full | skills (symlinks only), mcp (MCP only), or full (both) |
| dry_run | No | false | Show planned actions without executing |
Workflow
Detect OS → Discover Configs → Sync Skills → Sync MCP → ReportPhase 0: OS Detection
| Check | Result | Impact |
|---|---|---|
uname or platform | win32 / darwin / linux | Junction vs symlink |
| Home directory | $HOME or $USERPROFILE | Config paths |
Paths by OS:
| Agent | Windows | macOS / Linux |
|---|---|---|
| Claude | %USERPROFILE%\.claude.json (primary) | ~/.claude.json (primary) |
| Claude | %USERPROFILE%\.claude\settings.json (fallback) | ~/.claude/settings.json (fallback) |
| Gemini | %USERPROFILE%\.gemini\settings.json | ~/.gemini/settings.json |
| Codex | %USERPROFILE%\.codex\config.toml | ~/.codex/config.toml |
Phase 1: Discover Current State
- Read Claude settings (check both sources, merge):
- Parse ~/.claude.json → extract mcpServers block (primary source, app state file) - Parse ~/.claude/settings.json → extract mcpServers block (fallback, user settings file) - Merge: primary overrides fallback by server name - If no mcpServers in either → WARN "No MCP servers configured in Claude", skip MCP sync
- Read target configs (if exist):
- Gemini: Parse ~/.gemini/settings.json → extract existing mcpServers - Codex: Parse ~/.codex/config.toml → extract existing [mcp_servers.*]
- Detect installed plugins:
- Glob ~/.claude/plugins/*/plugin.json → list plugin directories - Also check if skills repo itself is a plugin source
- Check existing symlinks:
- ~/.gemini/skills → exists? points where? - ~/.codex/skills → exists? points where?
- Show current state:
Current State: | Agent | Skills | MCP Servers | Config Exists | |-------|--------|-------------|---------------| | Claude (source) | 5 plugins | 4 servers | yes | | Gemini | no link | 2 servers | yes | | Codex | → ~/.claude/plugins | 4 servers | yes |
Phase 2: Sync Skills (symlinks/junctions)
FOR EACH target IN (gemini, codex) WHERE target in targets:
- Determine link path:
- Gemini: ~/.gemini/skills - Codex: ~/.codex/skills
- Check if already linked correctly:
- IF link exists AND points to correct source → SKIP (already synced) - IF link exists AND points to wrong source → WARN, ask user before replacing - IF regular directory (not link) exists → WARN "Target is a real directory, not a link. Skip to avoid data loss."
- Determine source:
- IF single plugin: link directly to plugin dir - IF multiple plugins: ask user which plugin to share
- Create link: OS Command Windows
cmd /c mklink /J "{target_path}" "{source_path}"macOS / Linuxln -s "{source_path}" "{target_path}" - Verify: Check link exists and resolves correctly
Phase 3: Sync MCP Settings
Source: ~/.claude.json (primary) + ~/.claude/settings.json (fallback) → merged mcpServers
3a: Claude → Gemini (JSON → JSON)
- Read Claude
mcpServersas JSON object - Read Gemini
settings.json(or create{}if missing) - Merge strategy: Claude servers override Gemini servers by key name. Gemini-only servers preserved.
- Write updated
settings.json
Conversion: Transport type mapping required:
| Claude field | Gemini field | Notes |
|---|---|---|
type: "http" + url | httpUrl | Streamable HTTP |
type: "sse" + url | url | SSE transport |
command + args | command + args + cwd | stdio (same format) |
env | env | Same format ($VAR_NAME syntax in Gemini) |
headers | headers | Same format (JSON object, for url/httpUrl) |
Gemini-only fields (not mapped from Claude):
timeout— request timeout in ms (default: 10min)trust— bypass tool confirmationsincludeTools/excludeTools— tool whitelist/blacklist
3b: Claude → Codex (JSON → TOML)
- Read Claude
mcpServersas JSON object - Read Codex
config.toml(or create empty if missing) - Convert each server: Claude JSON field Codex TOML field Notes
commandcommandSameargsargsJSON array → TOML arrayenv[mcp_servers.{name}.env]Nested tabletype: "http"+urlurlStreamable HTTP (Codex auto-detects byurlpresence)type: "sse"+urlurlSSE → Streamable HTTP (sameurlfield)headershttp_headersDifferent key name! Static header values Example conversion:"context7": {"command": "npx", "args": ["-y", "@upstash/context7-mcp"]}[mcp_servers.context7] command = "npx" args = ["-y", "@upstash/context7-mcp"] - Merge strategy: Claude servers override. Codex-only servers preserved.
- Write updated
config.toml
Codex-only fields (preserve as-is, no Claude equivalent):
bearer_token_env_var— Codex bearer token authenabled_tools/disabled_tools— Codex tool filteringstartup_timeout_sec/tool_timeout_sec— Codex timeoutsenabled/required— Codex server lifecycleenv_vars/env_http_headers— Codex env-based headers
Phase 4: Report
Sync Complete:
| Action | Target | Status |
|--------|--------|--------|
| Skills symlink | Gemini | Created → ~/.claude/plugins/... |
| Skills symlink | Codex | Already linked |
| MCP sync | Gemini | 4 servers synced (2 new, 2 updated) |
| MCP sync | Codex | 4 servers synced (1 new, 3 updated) |Critical Rules
- Claude = source of truth. Never write TO Claude settings. Read-only source.
- Non-destructive merge. Target-only servers/settings preserved. Only Claude servers added/updated.
- No data loss. If target is a real directory (not symlink) — warn and skip, never delete.
- Backup before write. Before modifying any config file, create
.bakcopy. - Dry run first. If
dry_run=true, show all planned actions without executing. - Ask on conflict. If symlink points to different source — ask user, don't auto-replace.
Anti-Patterns
- Writing TO Claude settings from Gemini/Codex (reverse sync)
- Deleting target-only MCP servers during sync
- Creating symlinks inside symlinks (circular)
- Modifying config files without backup
Definition of Done
- Claude settings read successfully
- Skills symlinks created/verified for each target
- MCP settings synced with format conversion (JSON→TOML for Codex)
- Backup files created before any config modification
- Report shown with all actions and warnings
Version: 1.1.0 Last Updated: 2026-03-09