diff --git a/mise.toml b/mise.toml
index 0b55d40..1819228 100644
--- a/mise.toml
+++ b/mise.toml
@@ -22,6 +22,10 @@ description = 'Run test suite'
 depends = ['littlecheck']
 file = 'scripts/test.fish'
 
+[tasks.test-clean]
+description = 'Remove the cached local test HOME used by `mise run test`'
+file = 'scripts/test_clean.fish'
+
 [tasks.clean]
 description = 'Remove generated test helper'
 run = 'rm -f littlecheck.py'
diff --git a/scripts/test.fish b/scripts/test.fish
index 99df253..fc1f950 100755
--- a/scripts/test.fish
+++ b/scripts/test.fish
@@ -20,8 +20,14 @@ exit \$test_status
 if test "$GITHUB_ACTIONS" = true #we can just have it work normally in CI, since it runs in a clean environment
     fish -c $inner_cmd
 else
-    set -l test_home (mktemp -d)
+    # Reuse a persistent HOME across local runs (shared across worktrees) so
+    # fisher/clownfish aren't reinstalled over the network every time. `fisher
+    # install .` still runs unconditionally, so local edits are always synced.
+    # Run `mise run test-clean` to wipe it if it ever gets into a bad state.
+    set -l cache_home $XDG_CACHE_HOME
+    test -n "$cache_home" || set cache_home $HOME/.cache
+    set -l test_home $cache_home/tide-test-home
+    mkdir -p $test_home
     env HOME=$test_home XDG_CONFIG_HOME=$test_home/.config fish -c $inner_cmd
-    command rm -rf $test_home
 end
 exit $status
diff --git a/scripts/test_clean.fish b/scripts/test_clean.fish
new file mode 100755
index 0000000..ea8fee7
--- /dev/null
+++ b/scripts/test_clean.fish
@@ -0,0 +1,12 @@
+#!/usr/bin/env fish
+
+set -l cache_home $XDG_CACHE_HOME
+test -n "$cache_home" || set cache_home $HOME/.cache
+set -l test_home $cache_home/tide-test-home
+
+if test -d $test_home
+    command rm -r $test_home
+    echo "Removed $test_home"
+else
+    echo "Nothing to clean: $test_home does not exist"
+end