diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 107aa2530..a57c5a804 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -11,6 +11,7 @@ on:
 env:
   COMPOSER_FLAGS: "--ansi --no-interaction --no-progress --prefer-dist"
   COMPOSER_UPDATE_FLAGS: ""
+  COMPOSER_TESTS_ARE_RUNNING: "1"
   SYMFONY_PHPUNIT_VERSION: "8.3"
   SYMFONY_PHPUNIT_REMOVE_RETURN_TYPEHINT: "1"
 
diff --git a/src/Composer/Console/Application.php b/src/Composer/Console/Application.php
index 622938476..acd0e4c0a 100644
--- a/src/Composer/Console/Application.php
+++ b/src/Composer/Console/Application.php
@@ -22,6 +22,7 @@ use Symfony\Component\Console\Helper\QuestionHelper;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\OutputInterface;
+use Seld\JsonLint\ParsingException;
 use Composer\Command;
 use Composer\Composer;
 use Composer\Factory;
@@ -191,6 +192,20 @@ class Application extends BaseApplication
                 }
             } catch (NoSslException $e) {
                 // suppress these as they are not relevant at this point
+            } catch (ParsingException $e) {
+                $details = $e->getDetails();
+
+                $file = realpath(Factory::getComposerFile());
+
+                $line = null;
+                if ($details && isset($details['line'])) {
+                    $line = $details['line'];
+                }
+
+                $ghe = new GithubActionError($this->io);
+                $ghe->emit($e->getMessage(), $file, $line);
+
+                throw $e;
             }
 
             $this->hasPluginCommands = true;
@@ -237,7 +252,7 @@ class Application extends BaseApplication
                 if (function_exists('posix_getuid') && posix_getuid() === 0) {
                     if ($commandName !== 'self-update' && $commandName !== 'selfupdate') {
                         $io->writeError('<warning>Do not run Composer as root/super user! See https://getcomposer.org/root for details</warning>');
-                        
+
                         if ($io->isInteractive()) {
                             if (!$io->askConfirmation('<info>Continue as root/super user</info> [<comment>yes</comment>]? ', true)) {
                                 return 1;
@@ -307,8 +322,13 @@ class Application extends BaseApplication
         } catch (ScriptExecutionException $e) {
             return (int) $e->getCode();
         } catch (\Exception $e) {
+            $ghe = new GithubActionError($this->io);
+            $ghe->emit($e->getMessage());
+
             $this->hintCommonErrors($e);
+
             restore_error_handler();
+
             throw $e;
         }
     }
diff --git a/src/Composer/Console/GithubActionError.php b/src/Composer/Console/GithubActionError.php
new file mode 100644
index 000000000..bbf5eaca1
--- /dev/null
+++ b/src/Composer/Console/GithubActionError.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace Composer\Console;
+
+use Composer\IO\IOInterface;
+
+final class GithubActionError
+{
+    /**
+     * @var IOInterface
+     */
+    protected $io;
+
+    public function __construct(IOInterface  $io)
+    {
+        $this->io = $io;
+    }
+
+    /**
+     * @param string $message
+     * @param null|string $file
+     * @param null|int $line
+     */
+    public function emit($message, $file = null, $line = null)
+    {
+        if (getenv('GITHUB_ACTIONS') && !getenv('COMPOSER_TESTS_ARE_RUNNING')) {
+            // newlines need to be encoded
+            // see https://github.com/actions/starter-workflows/issues/68#issuecomment-581479448
+            $message = str_replace("\n", '%0A', $message);
+
+            if ($file && $line) {
+                $this->io->write("::error file=". $file .",line=". $line ."::". $message);
+            } elseif ($file) {
+                $this->io->write("::error file=". $file ."::". $message);
+            } else {
+                $this->io->write("::error ::". $message);
+            }
+        }
+    }
+}
diff --git a/src/Composer/Installer.php b/src/Composer/Installer.php
index b98a88c12..f8c788e10 100644
--- a/src/Composer/Installer.php
+++ b/src/Composer/Installer.php
@@ -13,6 +13,7 @@
 namespace Composer;
 
 use Composer\Autoload\AutoloadGenerator;
+use Composer\Console\GithubActionError;
 use Composer\DependencyResolver\DefaultPolicy;
 use Composer\DependencyResolver\LocalRepoTransaction;
 use Composer\DependencyResolver\LockTransaction;
@@ -412,12 +413,18 @@ class Installer
             $ruleSetSize = $solver->getRuleSetSize();
             $solver = null;
         } catch (SolverProblemsException $e) {
-            $this->io->writeError('<error>Your requirements could not be resolved to an installable set of packages.</error>', true, IOInterface::QUIET);
-            $this->io->writeError($e->getPrettyString($repositorySet, $request, $pool, $this->io->isVerbose()));
+            $err = 'Your requirements could not be resolved to an installable set of packages.';
+            $prettyProblem = $e->getPrettyString($repositorySet, $request, $pool, $this->io->isVerbose());
+
+            $this->io->writeError('<error>'. $err .'</error>', true, IOInterface::QUIET);
+            $this->io->writeError($prettyProblem);
             if (!$this->devMode) {
                 $this->io->writeError('<warning>Running update with --no-dev does not mean require-dev is ignored, it just means the packages will not be installed. If dev requirements are blocking the update you have to resolve those problems.</warning>', true, IOInterface::QUIET);
             }
 
+            $ghe = new GithubActionError($this->io);
+            $ghe->emit($err."\n".$prettyProblem);
+
             return max(1, $e->getCode());
         }
 
@@ -571,10 +578,16 @@ class Installer
             $nonDevLockTransaction = $solver->solve($request, $this->ignorePlatformReqs);
             $solver = null;
         } catch (SolverProblemsException $e) {
-            $this->io->writeError('<error>Unable to find a compatible set of packages based on your non-dev requirements alone.</error>', true, IOInterface::QUIET);
+            $err = 'Unable to find a compatible set of packages based on your non-dev requirements alone.';
+            $prettyProblem = $e->getPrettyString($repositorySet, $request, $pool, $this->io->isVerbose(), true);
+
+            $this->io->writeError('<error>'. $err .'</error>', true, IOInterface::QUIET);
             $this->io->writeError('Your requirements can be resolved successfully when require-dev packages are present.');
             $this->io->writeError('You may need to move packages from require-dev or some of their dependencies to require.');
-            $this->io->writeError($e->getPrettyString($repositorySet, $request, $pool, $this->io->isVerbose(), true));
+            $this->io->writeError($prettyProblem);
+
+            $ghe = new GithubActionError($this->io);
+            $ghe->emit($err."\n".$prettyProblem);
 
             return max(1, $e->getCode());
         }
@@ -637,8 +650,14 @@ class Installer
                     return 1;
                 }
             } catch (SolverProblemsException $e) {
-                $this->io->writeError('<error>Your lock file does not contain a compatible set of packages. Please run composer update.</error>', true, IOInterface::QUIET);
-                $this->io->writeError($e->getPrettyString($repositorySet, $request, $pool, $this->io->isVerbose()));
+                $err = 'Your lock file does not contain a compatible set of packages. Please run composer update.';
+                $prettyProblem = $e->getPrettyString($repositorySet, $request, $pool, $this->io->isVerbose());
+
+                $this->io->writeError('<error>'. $err .'</error>', true, IOInterface::QUIET);
+                $this->io->writeError($prettyProblem);
+
+                $ghe = new GithubActionError($this->io);
+                $ghe->emit($err."\n".$prettyProblem);
 
                 return max(1, $e->getCode());
             }