diff --git a/README.md b/README.md
index 3be6ea0..a8141fe 100644
--- a/README.md
+++ b/README.md
@@ -98,6 +98,8 @@ test: go::test go::docs-check bats::test
 
 - `JUST_MAIN_PACKAGE` - main package path (default: `main.go`)
 - `JUST_COVERAGE_DIR` - coverage output directory (default: `.coverage`)
+- `JUST_GO_FMT_EXCLUDES` - extra `find` exclusions for `fmt` / `fmt-check`
+  (e.g., `! -path '*/vendor/*'`)
 - `JUST_DOCS_DIR` - generated docs output directory (default: `docs/gen`)
 
 ### bats.just
diff --git a/go.just b/go.just
index f734af1..b57f51d 100644
--- a/go.just
+++ b/go.just
@@ -27,6 +27,7 @@
 git_root := `git rev-parse --show-toplevel`
 main_package := env("JUST_MAIN_PACKAGE", "main.go")
 coverage_dir := env("JUST_COVERAGE_DIR", ".coverage")
+go_fmt_excludes := env("JUST_GO_FMT_EXCLUDES", "")
 os_tags := if os() == "linux" { `if grep -iq 'ubuntu' /etc/os-release 2>/dev/null; then echo '-tags=ubuntu'; fi` } else { "" }
 
 # --- Private dependency recipes ---
@@ -120,14 +121,14 @@ test: mod fmt-check vet unit-cov
 # Reformat Go files with gofumpt + golines
 [group('fmt')]
 fmt: _fmt-deps
-    find . -type f -name '*.go' ! -name '*.gen.go' ! -name '*.pb.go' ! -path './.worktrees/*' ! -path './.claude/*' | xargs go tool mvdan.cc/gofumpt -l -w
-    find . -type f -name '*.go' ! -name '*.gen.go' ! -name '*.pb.go' ! -path './.worktrees/*' ! -path './.claude/*' | xargs go tool github.com/segmentio/golines --base-formatter="go tool mvdan.cc/gofumpt" -w
+    find . -type f -name '*.go' ! -name '*.gen.go' ! -name '*.pb.go' ! -path './.worktrees/*' ! -path './.claude/*' ! -path '*/node_modules/*' {{ go_fmt_excludes }} | xargs go tool mvdan.cc/gofumpt -l -w
+    find . -type f -name '*.go' ! -name '*.gen.go' ! -name '*.pb.go' ! -path './.worktrees/*' ! -path './.claude/*' ! -path '*/node_modules/*' {{ go_fmt_excludes }} | xargs go tool github.com/segmentio/golines --base-formatter="go tool mvdan.cc/gofumpt" -w
 
 # Check Go file formatting
 [group('fmt')]
 fmt-check: _fmt-deps
-    test -z "$(find . -type f -name '*.go' ! -name '*.gen.go' ! -name '*.pb.go' ! -path './.worktrees/*' ! -path './.claude/*' | xargs go tool mvdan.cc/gofumpt -d -e | tee /dev/stderr)"
-    test -z "$(find . -type f -name '*.go' ! -name '*.gen.go' ! -name '*.pb.go' ! -path './.worktrees/*' ! -path './.claude/*' | xargs go tool github.com/segmentio/golines --dry-run --base-formatter="go tool mvdan.cc/gofumpt" -l | tee /dev/stderr)"
+    test -z "$(find . -type f -name '*.go' ! -name '*.gen.go' ! -name '*.pb.go' ! -path './.worktrees/*' ! -path './.claude/*' ! -path '*/node_modules/*' {{ go_fmt_excludes }} | xargs go tool mvdan.cc/gofumpt -d -e | tee /dev/stderr)"
+    test -z "$(find . -type f -name '*.go' ! -name '*.gen.go' ! -name '*.pb.go' ! -path './.worktrees/*' ! -path './.claude/*' ! -path '*/node_modules/*' {{ go_fmt_excludes }} | xargs go tool github.com/segmentio/golines --dry-run --base-formatter="go tool mvdan.cc/gofumpt" -l | tee /dev/stderr)"
 
 # --- Codegen ---