docs: explicitly forbid grepping rust source for mcp schemas and instruct usage of local json cache

instructions.md

@@ -110,3 +110,6 @@ To maintain absolute traceability, we link memory items directly to the exact gi
 The project contains two MCP binaries (win-nvim and linux-nvim) that bridge JSON-RPC over stdio directly to the active Neovim instance (using `active_nvim.txt` for Last Focused Wins telemetry). If no interactive instance is open, they will automatically spawn and connect to a persistent headless Neovim background instance.
 - These binaries expose basic tools (`nvim_get_cursor`, `nvim_get_active_buffer`, `nvim_list_buffers`, etc.).
 - **God Mode**: They also expose `nvim_execute_lua`. This is the ultimate fallback tool. If you need to access *any* Neovim API that does not have a dedicated Rust tool (e.g., getting LSP diagnostics, evaluating a visual selection block based on modes, setting registers), you MUST write a short Lua script and pass it to `nvim_execute_lua`. Do not attempt to recompile the Rust server to add new basic tools; use the Lua escape hatch dynamically.
+
+## 16. Tool Schema Discovery (Lazy Loading)
+Antigravity automatically caches all MCP tool schemas to your disk to save tokens. Do **NOT** grep or search the Rust source code to find tool schemas or arguments. To understand a tool`s arguments, directly read `~/.gemini/antigravity-cli/mcp/<server_name>/<tool_name>.json`. For simple tools, confidently guess the arguments instead of reading the schema to save time.