diff --git a/.mise/tasks/lint/bats-python-one-liner b/.mise/tasks/lint/bats-python-one-liner
new file mode 100644
index 0000000..7dd5165
--- /dev/null
+++ b/.mise/tasks/lint/bats-python-one-liner
@@ -0,0 +1,153 @@
+#!/usr/bin/env bash
+#MISE description="Flag unreadable Python assertion one-liners in BATS tests"
+#USAGE arg "<targets>..." help="Paths to codebases to check (one or more)"
+#USAGE example "codebase lint:bats-python-one-liner ." header="Flag inline Python assertions in BATS tests"
+
+set -euo pipefail
+
+# shellcheck source=../../../lib/shell-files.sh
+source "$MISE_CONFIG_ROOT/lib/shell-files.sh"
+
+# Rationale: BATS tests that embed Python assertions as inline
+# `python3 -c "...assert..."` one-liners are hard to review, hard to
+# diff, and easy to normalize across repos. The preferred alternative
+# is a heredoc Python script:
+#
+#   json_file="$BATS_TEST_TMPDIR/parse.json"
+#   printf '%s\n' "$output" > "$json_file"
+#   python3 - "$json_file" <<'PY'
+#   import json, sys
+#   data = json.load(open(sys.argv[1]))
+#   assert data["frontmatter"] == {}
+#   PY
+#
+# See fold/notes/bats-tool-testing.md for the broader BATS principle.
+#
+# Detection: flag any line containing `python3 -c` or `python -c` where
+# the inline code contains the word `assert`. This catches the primary
+# readability concern while avoiding false positives from short harmless
+# calls like `python3 -c 'print("hello")'`.
+
+IFS=' ' read -ra TARGETS <<< "${usage_targets}"
+
+if [[ ${#TARGETS[@]} -eq 0 ]]; then
+  echo "ERROR: at least one target is required" >&2
+  exit 1
+fi
+
+# Resolve relative paths against CALLER_PWD (see lib/shell-files.sh).
+for i in "${!TARGETS[@]}"; do
+  TARGETS[$i]=$(resolve_target "${TARGETS[$i]}")
+done
+
+# discover_bats_files <target>
+#
+# Emit paths of .bats files under <target>/test, excluding '*/fixtures/*'.
+discover_bats_files() {
+  local target="$1"
+  if [[ -d "$target/test" ]]; then
+    fd -t f -e bats --exclude fixtures . "$target/test"
+  fi
+}
+
+# is_heredoc_context <file> <lineno>
+#
+# Check if the given line is inside a heredoc block by scanning backward
+# for a heredoc delimiter. Returns 0 if inside a heredoc, 1 otherwise.
+is_heredoc_context() {
+  local file="$1" lineno="$2"
+  # Scan lines before the current one for heredoc start markers
+  sed -n "1,$((lineno - 1))p" "$file" | tac | grep -qE '<<[-]?["'"'"']?(PY|EOF|END|PYTHON|JSON)'
+}
+
+scan_file() {
+  local file="$1"
+  local lineno=0
+  local line
+
+  while IFS= read -r line || [[ -n "$line" ]]; do
+    lineno=$((lineno + 1))
+
+    # Skip @test description lines (they contain literal strings, not code).
+    if [[ "$line" =~ ^[[:space:]]*@test[[:space:]]+ ]]; then
+      continue
+    fi
+
+    # Skip full-line comments.
+    if [[ "$line" =~ ^[[:space:]]*# ]]; then
+      continue
+    fi
+
+    # Inline opt-out.
+    if [[ "$line" == *"codebase:ignore"* ]]; then
+      continue
+    fi
+
+    # Skip lines inside heredoc context.
+    if is_heredoc_context "$file" "$lineno"; then
+      continue
+    fi
+
+    # Flag python3 -c / python -c lines containing 'assert'.
+    if [[ "$line" =~ python3?[[:space:]]+-c[[:space:]]+ ]] && [[ "$line" == *"assert"* ]]; then
+      local trimmed="${line#"${line%%[![:space:]]*}"}"
+      echo "$lineno: $trimmed"
+      echo "    hint: Use a heredoc Python script instead of inline -c with assert"
+    fi
+  done < "$file"
+}
+
+failures=0
+
+for target in "${TARGETS[@]}"; do
+  if [[ ! -e "$target" ]]; then
+    echo "ERROR: target does not exist: $target" >&2
+    exit 1
+  fi
+
+  name=$(basename "$target")
+
+  # File-level ignore via mise.toml
+  toml="$target/mise.toml"
+  if [[ -f "$toml" ]] && rg -q 'codebase:ignore bats-python-one-liner' "$toml"; then
+    echo "SKIP  $name (codebase:ignore)"
+    continue
+  fi
+
+  files=()
+  while IFS= read -r f; do
+    [[ -n "$f" ]] && files+=("$f")
+  done < <(discover_bats_files "$target")
+
+  if [[ ${#files[@]} -eq 0 ]]; then
+    echo "OK    $name (no test/ .bats files found)"
+    continue
+  fi
+
+  hit_count=0
+  target_output=""
+  for file in "${files[@]}"; do
+    rel="${file#"$target"/}"
+    while IFS= read -r hit; do
+      [[ -z "$hit" ]] && continue
+      target_output+="  $rel:$hit"$'\n'
+      # Only count lines starting with a line number as findings.
+      # Hint lines (indented) are informational, not separate findings.
+      if [[ "$hit" =~ ^[0-9]+: ]]; then
+        hit_count=$((hit_count + 1))
+      fi
+    done < <(scan_file "$file")
+  done
+
+  if [[ "$hit_count" -gt 0 ]]; then
+    echo "FAIL  $name: $hit_count unreadable Python one-liner(s)"
+    printf '%s' "$target_output"
+    echo "  hint: Use a heredoc Python script instead of inline -c with assert —"
+    echo "        see fold/notes/bats-tool-testing.md"
+    failures=$((failures + 1))
+  else
+    echo "OK    $name (${#files[@]} file(s) clean)"
+  fi
+done
+
+exit "$failures"
diff --git a/test/lib/shell-files.bats b/test/lib/shell-files.bats
index a462482..5d6ed6e 100644
--- a/test/lib/shell-files.bats
+++ b/test/lib/shell-files.bats
@@ -7,9 +7,7 @@ setup() {
   source "$REPO_DIR/lib/shell-files.sh"
 }
 
-# ============================================================================
 # resolve_target
-# ============================================================================
 
 @test "resolve_target: absolute path passes through unchanged" {
   result=$(resolve_target "/some/absolute/path")
diff --git a/test/lint/bats-python-one-liner/bats-python-one-liner.bats b/test/lint/bats-python-one-liner/bats-python-one-liner.bats
new file mode 100644
index 0000000..1018800
--- /dev/null
+++ b/test/lint/bats-python-one-liner/bats-python-one-liner.bats
@@ -0,0 +1,113 @@
+#!/usr/bin/env bats
+# Tests for lint:bats-python-one-liner rule
+
+load ../../test_helper
+
+setup() {
+  FIXTURES="$BATS_TEST_DIRNAME/fixtures"
+}
+
+# Pass paths
+
+@test "bats-python-one-liner: passes on clean codebase with heredoc Python" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/clean"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"OK"*"clean"* ]]
+}
+
+@test "bats-python-one-liner: passes when target has no test/ dir" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/empty"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"OK"*"empty"* ]]
+  [[ "$output" == *"no test/ .bats files found"* ]]
+}
+
+@test "bats-python-one-liner: does not flag short harmless python3 -c print" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/clean"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"OK"* ]]
+}
+
+# Detection
+
+@test "bats-python-one-liner: flags python3 -c with assert" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/dirty-assert"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"FAIL"*"dirty-assert"* ]]
+  [[ "$output" == *"python3 -c"* ]]
+  [[ "$output" == *"assert"* ]]
+}
+
+@test "bats-python-one-liner: flags python -c with assert" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/dirty-python"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"FAIL"*"dirty-python"* ]]
+  [[ "$output" == *"python -c"* ]]
+  [[ "$output" == *"assert"* ]]
+}
+
+@test "bats-python-one-liner: flags long python3 -c with assert" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/dirty-long"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"FAIL"*"dirty-long"* ]]
+  [[ "$output" == *"assert"* ]]
+}
+
+# False positives — these should NOT be flagged
+
+@test "bats-python-one-liner: does NOT flag heredoc Python" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/heredoc"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"OK"* ]]
+}
+
+# Ignore directives
+
+@test "bats-python-one-liner: inline '# codebase:ignore' suppresses a single line" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/ignored-inline"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"OK"* ]]
+}
+
+@test "bats-python-one-liner: 'codebase:ignore bats-python-one-liner' in mise.toml skips target" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/ignored-file"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"SKIP"*"ignored-file"* ]]
+}
+
+# Output details
+
+@test "bats-python-one-liner: fail output includes file:line citations" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/dirty-assert"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"test/bad.bats:"*":"* ]]
+}
+
+@test "bats-python-one-liner: fail output includes remediation hint" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/dirty-assert"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"bats-tool-testing.md"* ]]
+  [[ "$output" == *"heredoc"* ]]
+}
+
+# Error handling
+
+@test "bats-python-one-liner: fails when no targets given" {
+  run codebase lint:bats-python-one-liner
+  [ "$status" -ne 0 ]
+}
+
+@test "bats-python-one-liner: fails when target does not exist" {
+  run codebase lint:bats-python-one-liner "/nonexistent/path/xyz"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"does not exist"* ]]
+}
+
+# Multi-target
+
+@test "bats-python-one-liner: accepts multiple targets and reports each" {
+  run codebase lint:bats-python-one-liner "$FIXTURES/clean" "$FIXTURES/dirty-assert"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"OK"*"clean"* ]]
+  [[ "$output" == *"FAIL"*"dirty-assert"* ]]
+}
diff --git a/test/lint/bats-python-one-liner/fixtures/clean/mise.toml b/test/lint/bats-python-one-liner/fixtures/clean/mise.toml
new file mode 100644
index 0000000..26bb173
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/clean/mise.toml
@@ -0,0 +1,2 @@
+[tools]
+bats = "1.13.0"
diff --git a/test/lint/bats-python-one-liner/fixtures/clean/test/example.bats b/test/lint/bats-python-one-liner/fixtures/clean/test/example.bats
new file mode 100644
index 0000000..d01226c
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/clean/test/example.bats
@@ -0,0 +1,14 @@
+#!/usr/bin/env bats
+load test_helper
+
+@test "parses frontmatter with heredoc" {
+  run mytool parse
+  json_file="$BATS_TEST_TMPDIR/parse.json"
+  printf '%s\n' "$output" > "$json_file"
+  python3 - "$json_file" <<'PY'
+import json, sys
+data = json.load(open(sys.argv[1]))
+assert data["frontmatter"] == {}
+PY
+  [ "$status" -eq 0 ]
+}
diff --git a/test/lint/bats-python-one-liner/fixtures/clean/test/short-print.bats b/test/lint/bats-python-one-liner/fixtures/clean/test/short-print.bats
new file mode 100644
index 0000000..4f54107
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/clean/test/short-print.bats
@@ -0,0 +1,8 @@
+#!/usr/bin/env bats
+load test_helper
+
+@test "short harmless print" {
+  run mytool version
+  result="$(python3 -c 'print("hello")')"
+  [ "$result" = "hello" ]
+}
diff --git a/test/lint/bats-python-one-liner/fixtures/dirty-assert/test/bad.bats b/test/lint/bats-python-one-liner/fixtures/dirty-assert/test/bad.bats
new file mode 100644
index 0000000..995356f
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/dirty-assert/test/bad.bats
@@ -0,0 +1,7 @@
+#!/usr/bin/env bats
+
+@test "parses frontmatter" {
+  run mytool parse
+  echo "$output" | python3 -c "import sys, json; data = json.load(sys.stdin); assert data['frontmatter'] == {}"
+  [ "$status" -eq 0 ]
+}
diff --git a/test/lint/bats-python-one-liner/fixtures/dirty-long/test/bad.bats b/test/lint/bats-python-one-liner/fixtures/dirty-long/test/bad.bats
new file mode 100644
index 0000000..12bfa88
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/dirty-long/test/bad.bats
@@ -0,0 +1,7 @@
+#!/usr/bin/env bats
+
+@test "complex transformation" {
+  run mytool transform
+  result="$(python3 -c "import sys; data = [l.strip().split(',') for l in sys.stdin]; assert all(len(d) > 2 for d in data)")"
+  [ -n "$result" ]
+}
diff --git a/test/lint/bats-python-one-liner/fixtures/dirty-python/test/bad.bats b/test/lint/bats-python-one-liner/fixtures/dirty-python/test/bad.bats
new file mode 100644
index 0000000..5077012
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/dirty-python/test/bad.bats
@@ -0,0 +1,7 @@
+#!/usr/bin/env bats
+
+@test "parses frontmatter with python" {
+  run mytool parse
+  echo "$output" | python -c "import sys, json; data = json.load(sys.stdin); assert data['frontmatter'] == {}"
+  [ "$status" -eq 0 ]
+}
diff --git a/test/lint/bats-python-one-liner/fixtures/heredoc/test/good.bats b/test/lint/bats-python-one-liner/fixtures/heredoc/test/good.bats
new file mode 100644
index 0000000..3151fcc
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/heredoc/test/good.bats
@@ -0,0 +1,17 @@
+#!/usr/bin/env bats
+
+@test "parses frontmatter with heredoc" {
+  run mytool parse
+  json_file="$BATS_TEST_TMPDIR/parse.json"
+  printf '%s\n' "$output" > "$json_file"
+  python3 - "$json_file" <<'PY'
+import json
+import sys
+
+data = json.load(open(sys.argv[1]))
+assert data["frontmatter"] == {}
+assert data["frontmatter_present"] is False
+assert data["diagnostics"] == []
+PY
+  [ "$status" -eq 0 ]
+}
diff --git a/test/lint/bats-python-one-liner/fixtures/ignored-file/mise.toml b/test/lint/bats-python-one-liner/fixtures/ignored-file/mise.toml
new file mode 100644
index 0000000..054b4a9
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/ignored-file/mise.toml
@@ -0,0 +1,3 @@
+[_.codebase]
+lint = ["bats-python-one-liner"]
+codebase:ignore bats-python-one-liner
diff --git a/test/lint/bats-python-one-liner/fixtures/ignored-file/test/bad.bats b/test/lint/bats-python-one-liner/fixtures/ignored-file/test/bad.bats
new file mode 100644
index 0000000..995356f
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/ignored-file/test/bad.bats
@@ -0,0 +1,7 @@
+#!/usr/bin/env bats
+
+@test "parses frontmatter" {
+  run mytool parse
+  echo "$output" | python3 -c "import sys, json; data = json.load(sys.stdin); assert data['frontmatter'] == {}"
+  [ "$status" -eq 0 ]
+}
diff --git a/test/lint/bats-python-one-liner/fixtures/ignored-inline/test/bad.bats b/test/lint/bats-python-one-liner/fixtures/ignored-inline/test/bad.bats
new file mode 100644
index 0000000..4b7b917
--- /dev/null
+++ b/test/lint/bats-python-one-liner/fixtures/ignored-inline/test/bad.bats
@@ -0,0 +1,7 @@
+#!/usr/bin/env bats
+
+@test "parses frontmatter with inline ignore" {
+  run mytool parse
+  echo "$output" | python3 -c "import sys, json; data = json.load(sys.stdin); assert data['frontmatter'] == {}"  # codebase:ignore bats-python-one-liner — intentional inline assertion for a trivial check
+  [ "$status" -eq 0 ]
+}
diff --git a/test/lint/bats-test-helper/bats-test-helper.bats b/test/lint/bats-test-helper/bats-test-helper.bats
index 27ebba4..f4b0e76 100644
--- a/test/lint/bats-test-helper/bats-test-helper.bats
+++ b/test/lint/bats-test-helper/bats-test-helper.bats
@@ -7,9 +7,7 @@ setup() {
   FIXTURES="$BATS_TEST_DIRNAME/fixtures"
 }
 
-# ============================================================================
 # Pass paths
-# ============================================================================
 
 @test "bats-test-helper: passes on clean wrapper-based tests" {
   run codebase lint:bats-test-helper "$FIXTURES/clean"
@@ -24,9 +22,7 @@ setup() {
   [[ "$output" == *"no test/ files found"* ]]
 }
 
-# ============================================================================
 # Invocation signatures — each form fails
-# ============================================================================
 
 @test "bats-test-helper: flags 'bash \$TASK' (var whose name contains TASK)" {
   run codebase lint:bats-test-helper "$FIXTURES/dirty-task-var"
@@ -84,9 +80,7 @@ setup() {
   [[ "$output" == *"bash \$REPO_DIR/.mise/tasks/lint/check"* ]]
 }
 
-# ============================================================================
 # False positives — none of these are actual invocations
-# ============================================================================
 
 @test "bats-test-helper: does NOT flag reading a task file as data (grep/cat)" {
   # Regression guard: 'grep "$MCR/.mise/tasks/foo"' reads the script, doesn't
@@ -97,9 +91,7 @@ setup() {
   [[ "$output" == *"OK"* ]]
 }
 
-# ============================================================================
 # Ignore directives
-# ============================================================================
 
 @test "bats-test-helper: inline '# codebase:ignore' suppresses a single line" {
   run codebase lint:bats-test-helper "$FIXTURES/ignored-inline"
@@ -113,9 +105,7 @@ setup() {
   [[ "$output" == *"SKIP"*"ignored-file"* ]]
 }
 
-# ============================================================================
 # Output details
-# ============================================================================
 
 @test "bats-test-helper: fail output includes file:line citations" {
   run codebase lint:bats-test-helper "$FIXTURES/dirty-task-var"
@@ -130,9 +120,7 @@ setup() {
   [[ "$output" == *"Call the Tool"* ]]
 }
 
-# ============================================================================
 # Error handling
-# ============================================================================
 
 @test "bats-test-helper: fails when no targets given" {
   run codebase lint:bats-test-helper
@@ -146,9 +134,7 @@ setup() {
   [[ "$output" == *"does not exist"* ]]
 }
 
-# ============================================================================
 # Multi-target
-# ============================================================================
 
 @test "bats-test-helper: accepts multiple targets and reports each" {
   run codebase lint:bats-test-helper "$FIXTURES/clean" "$FIXTURES/dirty-task-var"
diff --git a/test/lint/bats-test-task/bats-test-task.bats b/test/lint/bats-test-task/bats-test-task.bats
index 295d92f..f761f2b 100644
--- a/test/lint/bats-test-task/bats-test-task.bats
+++ b/test/lint/bats-test-task/bats-test-task.bats
@@ -7,9 +7,7 @@ setup() {
   FIXTURES="$BATS_TEST_DIRNAME/fixtures"
 }
 
-# ============================================================================
 # Pass paths
-# ============================================================================
 
 @test "bats-test-task: passes on the canonical pattern" {
   run codebase lint:bats-test-task "$FIXTURES/clean"
@@ -33,9 +31,7 @@ setup() {
   [[ "$output" == *"OK"*"shimmer-variant"* ]]
 }
 
-# ============================================================================
 # Failure modes
-# ============================================================================
 
 @test "bats-test-task: flags missing USAGE arg spec" {
   run codebase lint:bats-test-task "$FIXTURES/missing-usage-arg"
@@ -80,9 +76,7 @@ setup() {
   [[ "$output" != *"invocations found"* ]]
 }
 
-# ============================================================================
 # Ignore directive
-# ============================================================================
 
 @test "bats-test-task: 'codebase:ignore bats-test-task' in mise.toml skips the target" {
   run codebase lint:bats-test-task "$FIXTURES/ignored-file"
@@ -90,9 +84,7 @@ setup() {
   [[ "$output" == *"SKIP"*"ignored-file"* ]]
 }
 
-# ============================================================================
 # Output details
-# ============================================================================
 
 @test "bats-test-task: fail output includes the remediation hint" {
   run codebase lint:bats-test-task "$FIXTURES/missing-usage-arg"
@@ -109,9 +101,7 @@ setup() {
   [[ "$output" == *"invocations"* ]]
 }
 
-# ============================================================================
 # Error handling
-# ============================================================================
 
 @test "bats-test-task: fails when no targets given" {
   run codebase lint:bats-test-task
@@ -125,9 +115,7 @@ setup() {
   [[ "$output" == *"does not exist"* ]]
 }
 
-# ============================================================================
 # Multi-target
-# ============================================================================
 
 @test "bats-test-task: accepts multiple targets and reports each" {
   run codebase lint:bats-test-task "$FIXTURES/clean" "$FIXTURES/missing-examples"
diff --git a/test/lint/gum-table/gum-table.bats b/test/lint/gum-table/gum-table.bats
index 2dfddaa..809b670 100644
--- a/test/lint/gum-table/gum-table.bats
+++ b/test/lint/gum-table/gum-table.bats
@@ -7,9 +7,7 @@ setup() {
   FIXTURES="$BATS_TEST_DIRNAME/fixtures"
 }
 
-# ============================================================================
 # High confidence: column -t (always a true positive)
-# ============================================================================
 
 @test "column-t: detects piping to column -t" {
   run codebase lint:gum-table "$FIXTURES/manual-padding/task-c"
@@ -18,9 +16,7 @@ setup() {
   [[ "$output" == *"WARN"* ]]
 }
 
-# ============================================================================
 # High confidence: printf padding inside a loop
-# ============================================================================
 
 @test "loop-table: detects printf %-Ns inside while-read" {
   run codebase lint:gum-table "$FIXTURES/manual-padding/task-b"
@@ -45,9 +41,7 @@ setup() {
   echo "$output" | grep "padding" | grep -q "INFO"
 }
 
-# ============================================================================
 # Low confidence: printf padding outside loops (INFO only, not a failure)
-# ============================================================================
 
 @test "padding: printf %-Ns outside loop is INFO, not a failure" {
   run codebase lint:gum-table "$FIXTURES/manual-padding/task-a"
@@ -69,9 +63,7 @@ setup() {
   [[ "$output" == *"INFO"* ]]
 }
 
-# ============================================================================
 # True negatives — no output at all
-# ============================================================================
 
 @test "clean: already using gum table" {
   run codebase lint:gum-table "$FIXTURES/clean/task-gum"
@@ -103,9 +95,7 @@ setup() {
   [[ "$output" == *"OK"* ]]
 }
 
-# ============================================================================
 # Multi-file scanning
-# ============================================================================
 
 @test "directory scan finds high-confidence hits" {
   run codebase lint:gum-table "$FIXTURES/manual-padding"
@@ -121,9 +111,7 @@ setup() {
   [ "$status" -eq 0 ]
 }
 
-# ============================================================================
 # Output format
-# ============================================================================
 
 @test "WARN output includes file path, category, and line number" {
   run codebase lint:gum-table "$FIXTURES/manual-padding/task-b"
@@ -136,9 +124,7 @@ setup() {
   [[ "$output" =~ INFO.*task-a:\[padding\].*[0-9]+: ]]
 }
 
-# ============================================================================
 # Error handling
-# ============================================================================
 
 @test "fails when target does not exist" {
   run codebase lint:gum-table /nonexistent
@@ -146,9 +132,7 @@ setup() {
   [[ "$output" == *"ERROR"* ]]
 }
 
-# ============================================================================
 # Relative path resolution (regression: codebase#24)
-# ============================================================================
 
 @test "relative path resolves against CODEBASE_CALLER_PWD (dirty fixture)" {
   # Regression: relative targets resolved against codebase's install
diff --git a/test/lint/mcr-scope/mcr-scope.bats b/test/lint/mcr-scope/mcr-scope.bats
index 3ae6215..49869b4 100644
--- a/test/lint/mcr-scope/mcr-scope.bats
+++ b/test/lint/mcr-scope/mcr-scope.bats
@@ -7,9 +7,7 @@ setup() {
   FIXTURES="$BATS_TEST_DIRNAME/fixtures"
 }
 
-# ============================================================================
 # Detection
-# ============================================================================
 
 @test "mcr-scope: passes on a clean codebase" {
   run codebase lint:mcr-scope "$FIXTURES/clean"
@@ -102,9 +100,7 @@ setup() {
   [[ "$output" == *"no test/ or lib/ files found"* ]]
 }
 
-# ============================================================================
 # Ignore directives
-# ============================================================================
 
 @test "mcr-scope: inline '# codebase:ignore' suppresses a single line" {
   run codebase lint:mcr-scope "$FIXTURES/ignored-inline"
@@ -118,9 +114,7 @@ setup() {
   [[ "$output" == *"SKIP"*"ignored-file"* ]]
 }
 
-# ============================================================================
 # Output details
-# ============================================================================
 
 @test "mcr-scope: fail output includes file:line citations" {
   run codebase lint:mcr-scope "$FIXTURES/dirty-lib"
@@ -136,9 +130,7 @@ setup() {
   [[ "$output" == *"BASH_SOURCE"* ]]
 }
 
-# ============================================================================
 # Error handling
-# ============================================================================
 
 @test "mcr-scope: fails when no targets given" {
   run codebase lint:mcr-scope
@@ -153,9 +145,7 @@ setup() {
   [[ "$output" == *"does not exist"* ]]
 }
 
-# ============================================================================
 # Multi-target
-# ============================================================================
 
 @test "mcr-scope: accepts multiple targets and reports each" {
   run codebase lint:mcr-scope "$FIXTURES/clean" "$FIXTURES/dirty-test"
diff --git a/test/lint/mise-settings/mise-settings.bats b/test/lint/mise-settings/mise-settings.bats
index 565be0a..d925495 100644
--- a/test/lint/mise-settings/mise-settings.bats
+++ b/test/lint/mise-settings/mise-settings.bats
@@ -7,9 +7,7 @@ setup() {
   FIXTURES="$BATS_TEST_DIRNAME/fixtures"
 }
 
-# ============================================================================
 # Detection
-# ============================================================================
 
 @test "lint: passes when all settings present" {
   run codebase lint:mise-settings "$FIXTURES/complete"
@@ -54,9 +52,7 @@ setup() {
   [[ "$output" == *"FAIL"*"missing-both"* ]]
 }
 
-# ============================================================================
 # Fix mode
-# ============================================================================
 
 @test "fix: adds missing settings" {
   WORK_DIR="$BATS_TEST_TMPDIR/fix-test"
@@ -96,9 +92,7 @@ setup() {
   [[ "$output" == *"OK"* ]]
 }
 
-# ============================================================================
 # Error handling
-# ============================================================================
 
 @test "lint: fails when target does not exist" {
   run codebase lint:mise-settings /nonexistent
diff --git a/test/lint/or-true/or-true.bats b/test/lint/or-true/or-true.bats
index 31d7776..68cfaca 100644
--- a/test/lint/or-true/or-true.bats
+++ b/test/lint/or-true/or-true.bats
@@ -7,9 +7,7 @@ setup() {
   FIXTURES="$BATS_TEST_DIRNAME/fixtures"
 }
 
-# ============================================================================
 # Detection
-# ============================================================================
 
 @test "or-true: passes on a clean codebase" {
   run codebase lint:or-true "$FIXTURES/clean"
@@ -76,9 +74,7 @@ setup() {
   [[ "$output" == *"if !"* ]]
 }
 
-# ============================================================================
 # Corpus-calibrated diagnostics
-# ============================================================================
 
 @test "or-true: arithmetic increments get a safer arithmetic suggestion" {
   local tmp
@@ -173,9 +169,7 @@ EOF
   [[ "$output" == *"Intentional cases need a rule-specific reason"* ]]
 }
 
-# ============================================================================
 # Ignore directives
-# ============================================================================
 
 @test "or-true: inline '# codebase:ignore or-true — reason' skips the line" {
   run codebase lint:or-true "$FIXTURES/ignored-inline"
@@ -189,9 +183,7 @@ EOF
   [[ "$output" == *"SKIP"*"ignored-file"* ]]
 }
 
-# ============================================================================
 # Scope / discovery
-# ============================================================================
 
 @test "or-true: walks the whole target — finds hits outside .mise/tasks and lib/" {
   run codebase lint:or-true "$FIXTURES/broad-walk"
@@ -213,9 +205,7 @@ EOF
   [[ "$output" == *"no shell files"* ]]
 }
 
-# ============================================================================
 # Discovery correctness
-# ============================================================================
 
 @test "or-true: discovery skips non-bash/sh shebangs (fish, zsh, …)" {
   # Regression: the shebang regex '^#!.*(bash|sh)\b' matched 'sh' as
@@ -255,9 +245,7 @@ EOF
   rm -rf "$tmp"
 }
 
-# ============================================================================
 # Comment handling
-# ============================================================================
 
 @test "or-true: does not flag '|| true' inside a single-quoted string" {
   # Accidental protection: the closing quote ''' is not in the
@@ -293,9 +281,7 @@ EOF
   rm -rf "$tmp"
 }
 
-# ============================================================================
 # Multi-target
-# ============================================================================
 
 @test "or-true: checks multiple targets and reports each" {
   run codebase lint:or-true "$FIXTURES/clean" "$FIXTURES/dirty"
@@ -309,9 +295,7 @@ EOF
   [ "$status" -eq 2 ]
 }
 
-# ============================================================================
 # Error paths
-# ============================================================================
 
 @test "or-true: fails when target does not exist" {
   run codebase lint:or-true "$FIXTURES/does-not-exist"
@@ -328,9 +312,7 @@ EOF
   [[ "$output" == *"<targets>"* ]]
 }
 
-# ============================================================================
 # Relative path resolution (regression: codebase#24)
-# ============================================================================
 
 @test "or-true: relative path resolves against CODEBASE_CALLER_PWD, not codebase install dir" {
   # Regression: when invoked via the shiv shim, relative paths resolved
diff --git a/test/lint/shellcheck/shellcheck.bats b/test/lint/shellcheck/shellcheck.bats
index 370c7d6..f0ac032 100644
--- a/test/lint/shellcheck/shellcheck.bats
+++ b/test/lint/shellcheck/shellcheck.bats
@@ -7,9 +7,7 @@ setup() {
   FIXTURES="$BATS_TEST_DIRNAME/fixtures"
 }
 
-# ============================================================================
 # Detection
-# ============================================================================
 
 @test "lint: passes on a clean codebase" {
   run codebase lint:shellcheck "$FIXTURES/clean"
@@ -37,9 +35,7 @@ setup() {
   [[ "$output" == *"SC"* ]]
 }
 
-# ============================================================================
 # Ignore directive
-# ============================================================================
 
 @test "lint: skips when codebase:ignore shellcheck is set in mise.toml" {
   run codebase lint:shellcheck "$FIXTURES/ignored"
@@ -76,9 +72,7 @@ setup() {
   [[ "$output" == *"SC2154"* ]]
 }
 
-# ============================================================================
 # Scope
-# ============================================================================
 
 @test "lint: works on a codebase with no mise.toml" {
   run codebase lint:shellcheck "$FIXTURES/no-toml"
@@ -100,9 +94,7 @@ setup() {
   [[ "$output" == *"bad.sh"* ]]
 }
 
-# ============================================================================
 # Multi-target
-# ============================================================================
 
 @test "lint: checks multiple targets and reports each" {
   run codebase lint:shellcheck "$FIXTURES/clean" "$FIXTURES/dirty"
@@ -116,9 +108,7 @@ setup() {
   [ "$status" -eq 2 ]
 }
 
-# ============================================================================
 # Error paths
-# ============================================================================
 
 @test "lint: fails when target does not exist" {
   run codebase lint:shellcheck "$FIXTURES/does-not-exist"
diff --git a/test/migrations/task-pattern/task-pattern.bats b/test/migrations/task-pattern/task-pattern.bats
index d86c33e..5f8a90d 100644
--- a/test/migrations/task-pattern/task-pattern.bats
+++ b/test/migrations/task-pattern/task-pattern.bats
@@ -23,9 +23,7 @@ assert_matches_before() {
   diff -u "$FIXTURES/before/$file" "$WORK_DIR/$file"
 }
 
-# ============================================================================
 # Individual variant tests
-# ============================================================================
 
 @test "migrate: simple mise run → _task" {
   codebase migrate:task-pattern "$WORK_DIR"
@@ -57,9 +55,7 @@ assert_matches_before() {
   assert_matches_after ".mise/tasks/error-strings"
 }
 
-# ============================================================================
 # Full migration test
-# ============================================================================
 
 @test "migrate: all files match expected after state" {
   codebase migrate:task-pattern "$WORK_DIR"
@@ -68,9 +64,7 @@ assert_matches_before() {
   [ "$status" -eq 0 ]
 }
 
-# ============================================================================
 # Reverse migration tests
-# ============================================================================
 
 @test "reverse: _task → mise run" {
   # Start from the after state
@@ -101,9 +95,7 @@ assert_matches_before() {
   ! grep -q '_task' "$WORK_DIR/.mise/tasks/in-subshell"
 }
 
-# ============================================================================
 # Round-trip tests
-# ============================================================================
 
 @test "round-trip: forward then reverse restores lossless fixtures" {
   # Only test fixtures where forward is lossless (no -q flag)
@@ -114,9 +106,7 @@ assert_matches_before() {
   assert_matches_before ".mise/tasks/error-strings"
 }
 
-# ============================================================================
 # Error handling
-# ============================================================================
 
 @test "migrate: fails when target does not exist" {
   run codebase migrate:task-pattern /nonexistent
diff --git a/test/pre-commit/pre-commit.bats b/test/pre-commit/pre-commit.bats
index 96bd4f2..c0fbddc 100644
--- a/test/pre-commit/pre-commit.bats
+++ b/test/pre-commit/pre-commit.bats
@@ -24,9 +24,7 @@ EOF
   export CODEBASE_CALLER_PWD="$REPO"
 }
 
-# ============================================================================
 # Install — fresh repo
-# ============================================================================
 
 @test "install: creates dispatcher" {
   codebase pre-commit
@@ -97,9 +95,7 @@ EOF
   [ -x "$REPO/.git/hooks/pre-commit" ]
 }
 
-# ============================================================================
 # Install — existing dispatcher
-# ============================================================================
 
 @test "install: preserves existing dispatcher and other hooks" {
   mkdir -p "$REPO/.git/hooks/pre-commit.d"
@@ -121,9 +117,7 @@ EOF
   [ -f "$REPO/.git/hooks/pre-commit.d/codebase" ]
 }
 
-# ============================================================================
 # Install — existing plain hook (not a dispatcher)
-# ============================================================================
 
 @test "install: errors when existing plain hook is not a dispatcher" {
   cat > "$REPO/.git/hooks/pre-commit" <<'EOF'
@@ -137,9 +131,7 @@ EOF
   [[ "$output" == *"not a dispatcher"* ]]
 }
 
-# ============================================================================
 # Idempotent
-# ============================================================================
 
 @test "install: running twice is safe" {
   codebase pre-commit
@@ -149,9 +141,7 @@ EOF
   [ -f "$REPO/.git/hooks/pre-commit.d/codebase" ]
 }
 
-# ============================================================================
 # --check
-# ============================================================================
 
 @test "check: exits 0 when hook is current" {
   codebase pre-commit
@@ -189,9 +179,7 @@ EOF
   [ "$status" -ne 0 ]
 }
 
-# ============================================================================
 # --revert
-# ============================================================================
 
 @test "revert: removes codebase hook" {
   codebase pre-commit
@@ -225,9 +213,7 @@ EOF
   [[ "$output" == *"No codebase hook"* ]]
 }
 
-# ============================================================================
 # Scope
-# ============================================================================
 
 @test "scope: default scopes are delegated to aggregate lint" {
   cat > "$REPO/mise.toml" <<'EOF'
@@ -258,9 +244,7 @@ EOF
   ! grep -q 'src/scripts' "$REPO/.git/hooks/pre-commit.d/codebase"
 }
 
-# ============================================================================
 # Error handling
-# ============================================================================
 
 @test "error: fails outside git repo" {
   export CODEBASE_CALLER_PWD="$BATS_TEST_TMPDIR"
diff --git a/test/scan/scan.bats b/test/scan/scan.bats
index 9552433..e52a500 100644
--- a/test/scan/scan.bats
+++ b/test/scan/scan.bats
@@ -8,9 +8,7 @@ setup() {
   FIXTURES_B="$BATS_TEST_DIRNAME/fixtures-b"
 }
 
-# ============================================================================
 # Single target (basic matching)
-# ============================================================================
 
 @test "scan: finds mise run calls in extension-less task files" {
   run codebase scan -p 'mise run $$$ARGS' "$FIXTURES_A"
@@ -39,9 +37,7 @@ setup() {
   [[ -z "$output" ]]
 }
 
-# ============================================================================
 # Different patterns
-# ============================================================================
 
 @test "scan: finds _task calls with custom pattern" {
   run codebase scan -p '_task $$$ARGS' "$FIXTURES_A"
@@ -56,9 +52,7 @@ setup() {
   [ "$count" -eq 4 ]
 }
 
-# ============================================================================
 # Multiple targets
-# ============================================================================
 
 @test "multi: finds matches across multiple codebases" {
   run codebase scan -p 'mise run $$$ARGS' "$FIXTURES_A" "$FIXTURES_B"
@@ -84,9 +78,7 @@ setup() {
   [[ "$output" != *"fixtures-b:"* ]]
 }
 
-# ============================================================================
 # Exclude filter
-# ============================================================================
 
 @test "exclude: filters out files matching glob" {
   run codebase scan -p 'mise run $$$ARGS' -e '.mise/tasks/ci/*' "$FIXTURES_A"
@@ -110,9 +102,7 @@ setup() {
   [[ "$output" != *"ci/deploy"* ]]
 }
 
-# ============================================================================
 # Error handling
-# ============================================================================
 
 @test "error: fails when no pattern provided" {
   run codebase scan "$FIXTURES_A"