diff --git a/AGENTS.md b/AGENTS.md
index d0c9551..8e6c0d9 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -50,6 +50,18 @@ scl_lsp/
 └── grammar.js               # Tree-sitter grammar
 ```
 
+## Filetype Detection
+
+The LSP requires the `scl` filetype to be set. Add to your Neovim config (e.g., `ftdetect/scl.vim`):
+
+```vim
+au BufRead,BufNewFile *.scl set filetype=scl
+au BufRead,BufNewFile *.udt set filetype=scl
+au BufRead,BufNewFile *.db set filetype=scl
+```
+
+This enables LSP features (completion, goto definition, hover, etc.) for all SCL-related file types.
+
 ## Code Style Guidelines
 
 ### Module Pattern
@@ -235,6 +247,17 @@ Rules are checked in order; first match wins.
 | `:SCLExpandAllAttrBlocks` | Expand all `{...}` blocks in buffer |
 | `:SCLCollapseAllAttrBlocks` | Collapse all matching attribute blocks |
 
+## LSP Features
+
+### Goto Declaration (`gD`)
+The LSP supports goto declaration functionality for:
+- **Functions** - Jump to function definition in `.scl` files
+- **Function Blocks (FB)** - Jump to FB definition in `.scl` files
+- **Data Blocks (DB)** - Jump to DB definition in `.scl` and `.db` files
+- **User-Defined Types (UDT)** - Jump to type definition in `.scl` and `.udt` files
+
+Usage: Place cursor on a variable or type name and press `gD` (or use LSP client command).
+
 ## Keybindings (SCL/UDT files)
 
 ### Attribute Block Toggle
diff --git a/README.md b/README.md
index 18e59e0..46ee012 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ A comprehensive Neovim/LazyVim plugin providing **Language Server Protocol (LSP)
 |---------|-------------|
 | **Hover** | Press `K` to see variable type and struct fields |
 | **Completion** | `#` for variables, `.` for struct fields, `(` for functions |
-| **Go to Definition** | `gd` jump to variable declaration |
+| **Go to Definition** | `gD` jump to function, FB, DB, or UDT definition |
 | **Document Symbols** | Shows functions, variables, types |
 | **Workspace Symbols** | Search across all `.scl` files with fuzzy matching |
 | **Semantic Tokens** | Keywords, variables highlighted |