Show the cause of an exception in bref logs

src/Cli/LogRenderer.php

@@ -6,7 +6,7 @@
  * Renders the log records returned by Bref Cloud, which already parsed and truncated them.
  *
  * One line per record: `2026-09-23 10:12:51.863 web 45f01a ERROR message {"context"}`,
- * then the exception on an indented line, if any.
+ * then the exception and its causes on indented lines, if any.
  *
  * @phpstan-type LogException array{class: string, message: string, file: string, frames: int, trace?: list<string>, previous?: array<string, mixed>}
  * @phpstan-type LogRecord array{timestamp: string, function: string, instance: string, level: string|null, message: string, context?: array<mixed>, extra?: array<mixed>, exception?: LogException}
@@ -71,19 +71,23 @@ private function renderException(array $exception, bool $isPrevious = false): st
         // Bref's runtime errors have no file
         $location = $exception['file'] !== '' ? " at {$exception['file']}" : '';
 
-        if (! $this->full) {
+        if ($this->full) {
+            $lines = [$prefix . $this->red($exception['class']) . ': ' . $this->indent($exception['message'], 2)];
+            if ($location !== '') {
+                $lines[] = self::INDENT . '  ' . $this->gray(ltrim($location));
+            }
+            foreach ($exception['trace'] ?? [] as $i => $frame) {
+                $lines[] = self::INDENT . '  ' . $this->gray("#$i $frame");
+            }
+        } elseif ($isPrevious) {
+            // Its message is usually the actual cause, e.g. the HTTP error behind a RuntimeException
+            $lines = [$prefix . $this->red($exception['class']) . ': ' . $this->indent($exception['message'], 2)];
+        } else {
+            // Its message is usually the log message already
             $frames = $exception['frames'] > 0 ? " ({$exception['frames']} frames)" : '';
-
-            return $prefix . $this->red($exception['class']) . $this->gray($location . $frames);
+            $lines = [$prefix . $this->red($exception['class']) . $this->gray($location . $frames)];
         }
 
-        $lines = [$prefix . $this->red($exception['class']) . ': ' . $this->indent($exception['message'], 2)];
-        if ($location !== '') {
-            $lines[] = self::INDENT . '  ' . $this->gray(ltrim($location));
-        }
-        foreach ($exception['trace'] ?? [] as $i => $frame) {
-            $lines[] = self::INDENT . '  ' . $this->gray("#$i $frame");
-        }
         if (isset($exception['previous'])) {
             /** @var LogException $previous */
             $previous = $exception['previous'];

src/Commands/Logs.php

@@ -35,7 +35,7 @@ protected function configure(): void
             ->setHelp(<<<'HELP'
                 Shows the logs of all the functions of an environment, oldest first. Times are in UTC.
 
-                Laravel logs show their level and context, and exceptions show their class and location
+                Laravel logs show their level and context, and exceptions show their class, location and cause
                 (their stack trace with --full). Other logs are shown as they are, one line per entry.
                 The lines that Lambda and PHP-FPM write on every invocation are hidden, --all shows them.
 

tests/Cli/LogRendererTest.php

@@ -63,6 +63,25 @@ public function test_no_level_column_when_no_line_has_a_level(): void
         $this->assertSame(['2026-09-23 10:14:00.000 web 0f9e8d START processing batch 12 of 40'], $lines);
     }
 
+    public function test_the_causes_of_an_exception_are_shown_with_their_message(): void
+    {
+        $record = self::ERROR;
+        $record['exception']['previous'] = [
+            'class' => 'GuzzleHttp\Exception\ServerException',
+            'message' => '502 Bad Gateway',
+            'file' => 'vendor/guzzlehttp/guzzle/src/Middleware.php:69',
+            'frames' => 0,
+        ];
+
+        $lines = (new LogRenderer(colors: false, full: false))->render([$record]);
+
+        $this->assertSame([implode("\n", [
+            '2026-09-23 10:12:51.863 web 45f01a ERROR Payment gateway returned 502',
+            '    ↳ RuntimeException at app/Billing.php:37 (2 frames)',
+            '    ↳ Caused by GuzzleHttp\Exception\ServerException: 502 Bad Gateway',
+        ])], $lines);
+    }
+
     public function test_full_records_show_the_stack_trace_and_the_previous_exceptions(): void
     {
         $record = self::ERROR;