diff --git a/bin/fm-brief.sh b/bin/fm-brief.sh
index e0f2ec78..bd88c043 100755
--- a/bin/fm-brief.sh
+++ b/bin/fm-brief.sh
@@ -154,6 +154,9 @@ The report is the only thing that survives, so anything worth keeping must be in
 5. If you hit the same obstacle twice, append \`blocked: {why}\` and stop; firstmate will help.
 6. If a decision belongs to a human (product choices, destructive actions),
    append \`needs-decision: {summary of options}\` and stop. Firstmate will reply with the decision.
+7. Never stop, restart, or update the shared \`no-mistakes\` daemon - it is one instance serving
+   every lane/home, so restarting it kills other lanes' in-flight pipeline runs. On ANY no-mistakes
+   daemon error, append \`blocked: {the daemon error}\` and stop; only firstmate manages the daemon.
 
 # Definition of done
 Write your findings to \`$DATA/$ID/report.md\`.
@@ -251,6 +254,9 @@ $RULE1
 5. If you hit the same obstacle twice, append \`blocked: {why}\` and stop; firstmate will help.
 6. If a decision belongs to a human (product choices, destructive actions, ask-user findings),
    append \`needs-decision: {summary of options}\` and stop. Firstmate will reply with the decision.
+7. Never stop, restart, or update the shared \`no-mistakes\` daemon - it is one instance serving
+   every lane/home, so restarting it kills other lanes' in-flight pipeline runs. On ANY no-mistakes
+   daemon error, append \`blocked: {the daemon error}\` and stop; only firstmate manages the daemon.
 
 # Project memory
 If \`AGENTS.md\` or \`CLAUDE.md\` already exists, or if this task produced durable project-intrinsic knowledge, run \`$FM_ROOT/bin/fm-ensure-agents-md.sh .\` in the worktree.
diff --git a/tests/fm-gotmp.test.sh b/tests/fm-gotmp.test.sh
index 8ea2a70c..3ebf0b7d 100755
--- a/tests/fm-gotmp.test.sh
+++ b/tests/fm-gotmp.test.sh
@@ -128,8 +128,10 @@ test_teardown_removes_tasktmp_dir() {
   fake=$(make_fake_root "$id" "$task_tmp")
   # Sanity: dir + contents exist before teardown.
   [ -d "$task_tmp/gotmp" ] || fail "precondition: gotmp missing before teardown"
-  # Run the REAL teardown against the fake root.
-  bash "$fake/bin/fm-teardown.sh" "$id" >/dev/null 2>&1 \
+  # Run the REAL teardown against the fake root. FM_HOME is pinned to the fake
+  # root so an ambient FM_HOME in the caller's environment cannot redirect
+  # teardown at a real home instead of this fixture.
+  FM_HOME="$fake" bash "$fake/bin/fm-teardown.sh" "$id" >/dev/null 2>&1 \
     || fail "teardown exited non-zero with a valid tasktmp"
   [ ! -e "$task_tmp" ] \
     || fail "teardown did not remove the tasktmp dir ($task_tmp still exists)"
@@ -169,7 +171,7 @@ kind=ship
 mode=no-mistakes
 yolo=off
 META
-  bash "$fake/bin/fm-teardown.sh" "$id" >/dev/null 2>&1 \
+  FM_HOME="$fake" bash "$fake/bin/fm-teardown.sh" "$id" >/dev/null 2>&1 \
     || fail "teardown exited non-zero when tasktmp= was absent"
   pass "fm-teardown skips gracefully when tasktmp= is absent (backward compat)"
 }
@@ -182,7 +184,7 @@ test_teardown_skips_gracefully_when_dir_missing() {
   [ ! -e "$task_tmp" ] || fail "precondition: task_tmp should not exist yet"
   local fake
   fake=$(make_fake_root "$id" "$task_tmp")
-  bash "$fake/bin/fm-teardown.sh" "$id" >/dev/null 2>&1 \
+  FM_HOME="$fake" bash "$fake/bin/fm-teardown.sh" "$id" >/dev/null 2>&1 \
     || fail "teardown exited non-zero when tasktmp dir was missing"
   [ ! -e "$task_tmp" ] || fail "teardown created/left the tasktmp dir unexpectedly"
   pass "fm-teardown skips gracefully when tasktmp= points to a nonexistent dir"
diff --git a/tests/fm-turnend-guard.test.sh b/tests/fm-turnend-guard.test.sh
index 5edbc3ac..7161be48 100755
--- a/tests/fm-turnend-guard.test.sh
+++ b/tests/fm-turnend-guard.test.sh
@@ -94,6 +94,11 @@ install_guard_scripts() {
 
 # A primary-shaped checkout: plain (non-worktree) git repo, AGENTS.md, bin/,
 # state/ - everything the hook's scoping check requires to treat it as primary.
+# Returns the CANONICALIZED path (cd && pwd): TMPDIR on macOS ends in a trailing
+# slash, so a path built by string concatenation off it carries a double slash
+# that string-compares unequal to the same path normalized elsewhere (e.g.
+# record_watcher_lock's `cd "$dir" && pwd`), which would falsely fail the
+# fm-home identity match the watcher-lock tests depend on.
 make_primary_dir() {
   local dir=$1
   mkdir -p "$dir/state"
@@ -101,14 +106,14 @@ make_primary_dir() {
   git -C "$dir" commit -q --allow-empty -m init
   : > "$dir/AGENTS.md"
   install_guard_scripts "$dir"
-  printf '%s\n' "$dir"
+  (cd "$dir" && pwd)
 }
 
 # Same shape as primary, plus the .fm-secondmate-home marker bin/fm-home-seed.sh
 # writes at seed time (regardless of treehouse-lease or git-clone acquisition).
 make_secondmate_dir() {
   local dir=$1
-  make_primary_dir "$dir" >/dev/null
+  dir=$(make_primary_dir "$dir")
   printf 'sm-test-1\n' > "$dir/.fm-secondmate-home"
   printf '%s\n' "$dir"
 }
@@ -127,7 +132,10 @@ make_crewmate_worktree_dir() {
 
 run_hook() {
   local dir=$1 stop_active=$2
-  printf '{"stop_hook_active":%s}' "$stop_active" | bash "$dir/bin/fm-turnend-guard.sh" 2>&1
+  # Pin FM_HOME to the scenario dir so an ambient FM_HOME in the caller's
+  # environment cannot redirect the hook at a real home's state instead of
+  # this fixture.
+  printf '{"stop_hook_active":%s}' "$stop_active" | FM_HOME="$dir" bash "$dir/bin/fm-turnend-guard.sh" 2>&1
 }
 
 nonexistent_pid() {