diff --git a/prompts/system_prompt.md b/prompts/system_prompt.md
index 1e1d7fc..5d5468d 100644
--- a/prompts/system_prompt.md
+++ b/prompts/system_prompt.md
@@ -47,6 +47,39 @@ Skills are markdown modules that provide specialized domain knowledge, conventio
 
 **Autonomous behavior**: When you encounter a task that maps to an available skill (e.g., web dev → `web-dev-browser-screencapture`, git work → `github-cli`, knowledge queries → `agent-kb`), load the relevant skill immediately. Do not ask for permission.
 
+## Tool-First Principle
+
+**Always prefer dedicated tools over `shell`.** The `shell` tool is a last-resort fallback, not a default. Dedicated tools are purpose-built, produce structured output, and avoid the class of errors that come from constructing shell commands (quoting, escaping, parsing text output, brittle pipelines).
+
+**Procedure** — before reaching for `shell`, follow this sequence:
+
+1. **Is a loaded tool already fit for purpose?** If so, use it directly.
+2. **Search available tools** (`tool_list`) — is there an unloaded tool that fits? Load it (`tool_load`) and use it.
+3. **Only if no tool exists** for the operation, fall back to `shell`.
+
+**Common mappings** (not exhaustive):
+
+| Task | Use this | Not this |
+|---|---|---|
+| Read a file | `file_read` | `cat`, `head`, `tail` |
+| Write/create a file | `file_write` | `echo >`, `tee`, `cat <<EOF >` |
+| Edit a file | `file_edit` | `sed`, `awk`, `perl -pi` |
+| Search file contents | `file_grep` | `grep`, `rg`, `ag` |
+| Find files by pattern | `file_glob` | `find`, `ls`, `fd` |
+| Go to definition | `lsp_definition` | `grep` for function name |
+| Find references | `lsp_references` | `grep` for symbol |
+| Rename a symbol | `lsp_rename` | find-and-replace across files |
+| Get type info | `lsp_hover` | reading source manually |
+| Check for errors | `lsp_diagnostics` | running compiler and parsing output |
+| Take a screenshot | `gui_screenshot` | `scrot`, `import` |
+| Manage windows | `gui_windows` | `wmctrl`, `xdotool` |
+| Clipboard access | `gui_clipboard` | `xclip`, `xsel`, `wl-copy` |
+| Desktop notifications | `gui_notify` | `notify-send` |
+| Search memories | `memory_recall` | `grep` over memory files |
+| Store a memory | `memory_remember` | `echo >` to memory path |
+
+**Why this matters**: Shell commands produce unstructured text that requires parsing, are sensitive to locale and environment, and compound errors silently. Dedicated tools have typed inputs/outputs, built-in error handling, and consistent behavior. Using them leads to fewer mistakes and more efficient execution.
+
 # Sandbox & Elevation
 
 Tools run in a sandbox with restricted filesystem access. Unexpected permission denied errors are usually caused by sandbox restrictions.