diff --git a/doc/WRITING_TOOLS.md b/doc/WRITING_TOOLS.md
index b299190..e74fff1 100644
--- a/doc/WRITING_TOOLS.md
+++ b/doc/WRITING_TOOLS.md
@@ -35,7 +35,7 @@ Tools carry metadata in header comments. These are parsed by the registry and ex
 | `ollie:parallel read` | Tool is safe to run concurrently with other read tools |
 | `ollie:tier cold\|warm\|hot` | Context retention tier (default: hot) |
 
-## Argument Handling
+## Input Protocol
 
 Tools receive their arguments as a **JSON object on stdin**. The dispatcher pipes the model's tool call arguments directly — no positional argument translation.