diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 63ff6981e7..588c1ca5ff 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -37,6 +37,7 @@ Use these instructions for test generation as well.
 -   If you have trouble generating safe, efficient, maintainable, and lint-free code, insert a `TODO` comment describing what should happen.
 -   All imported types, constants, functions, modules, and macros should be imported explicitly. Never import `*`.
 -   Do not modify generated code, found in `generated` subdirectories. These files are generated by external tools and should not be edited manually.
+-   When searching for function call chains in Rust code, be aware that rustfmt often formats method chains across multiple lines like `obj\n    .foo()\n    .bar()`. Use multi-line search patterns (e.g., `rg` with `-U` flag) or search for individual method names rather than complete call chains.
 
 ## Test Generation
 
diff --git a/.vscode/cspell.json b/.vscode/cspell.json
index 5a5594b32a..fcacec234c 100644
--- a/.vscode/cspell.json
+++ b/.vscode/cspell.json
@@ -71,6 +71,7 @@
     "pwsh",
     "reqwest",
     "runtimes",
+    "rustfmt",
     "rustup",
     "schannel",
     "seekable",