refactor: consolidate Claude/Codex MCP runtime in common module

Author: benvinegar

README.md

@@ -40,6 +40,21 @@ Each plugin directory should include:
 3. `package.json` (if the target agent supports package-based install)
 4. Release automation (GitHub Actions workflow + documented version/tag convention)
 
+## Shared MCP runtime
+
+Claude and Codex now share one MCP runtime source at `common/mcp/glance-mcp.js`.
+
+To keep standalone npm packages working, package-local copies are synced to:
+
+- `claude/common/mcp/glance-mcp.js`
+- `codex/common/mcp/glance-mcp.js`
+
+If you change the shared runtime, run:
+
+```bash
+npm run sync:mcp-common
+```
+
 ## Adding a new plugin
 
 Create a directory for your agent (e.g. `cursor/`, `cline/`) with the files above and open a PR.