fix(elisp-hook): show a compact test summary in the terminal on failure

validate-el.sh dumped the full ERT batch output to the terminal on a red test, every backtrace frame, flooding the pane. It now prints a short summary there: the run tally plus the failing test names and their file:line. Claude still gets the full backtrace through additionalContext. fail_json takes an optional fourth argument for the terminal echo. Paren and byte-compile failures stay short, so they still print in full.

1 files changed, 13 insertions, 3 deletions

diff --git a/languages/elisp/claude/hooks/validate-el.sh b/languages/elisp/claude/hooks/validate-el.sh
index 782f04c..d6999ac 100755
--- a/languages/elisp/claude/hooks/validate-el.sh
+++ b/languages/elisp/claude/hooks/validate-el.sh
@@ -15,7 +15,11 @@ set -u
 # Emit a JSON failure payload and exit 2. Arguments:
 #   $1 — short failure type (e.g. "PAREN CHECK FAILED")
 #   $2 — file path
-#   $3 — emacs output (error body)
+#   $3 — emacs output (error body), always sent to Claude in additionalContext
+#   $4 — optional compact terminal echo; when set, the terminal shows this
+#        instead of the full $3 (Claude still gets the full $3). Used by the
+#        test runner so a failing suite prints a short summary to the pane
+#        rather than dumping every ERT backtrace.
 fail_json() {
     local ctx
     ctx="$(printf '%s: %s\n\n%s\n\nFix before proceeding.' "$1" "$2" "$3" \
@@ -23,7 +27,7 @@ fail_json() {
     cat <<EOF
 {"hookSpecificOutput": {"hookEventName": "PostToolUse", "additionalContext": $ctx}}
 EOF
-    printf '%s: %s\n%s\n' "$1" "$2" "$3" >&2
+    printf '%s: %s\n%s\n' "$1" "$2" "${4:-$3}" >&2
     exit 2
 }
 
@@ -97,7 +101,13 @@ if [ "$count" -ge 1 ] && [ "$count" -le "$MAX_AUTO_TEST_FILES" ]; then
                    --eval '(package-initialize)' \
                    -l ert "${load_args[@]}" \
                    --eval "(ert-run-tests-batch-and-exit '(not (tag :slow)))" 2>&1)"; then
-    fail_json "TESTS FAILED ($count test file(s))" "$f" "$output"
+    # Terminal gets a compact summary (the run tally + the failing test names);
+    # Claude still gets the full backtrace via additionalContext.  Keeps the
+    # pane from drowning in ERT stack frames on every red test.
+    summary="$(printf '%s\n' "$output" \
+        | grep -E '^Ran [0-9]+ tests|unexpected results:|^[[:space:]]+FAILED' || true)"
+    [ -n "$summary" ] && summary="${summary}"$'\n'"(full backtrace in Claude's context)"
+    fail_json "TESTS FAILED ($count test file(s))" "$f" "$output" "$summary"
   fi
 fi