diff --git a/azure-pipelines-PR.yml b/azure-pipelines-PR.yml
index 9f06d74493..fd0775609a 100644
--- a/azure-pipelines-PR.yml
+++ b/azure-pipelines-PR.yml
@@ -890,3 +890,130 @@ stages:
           - pwsh: .\tests\ILVerify\ilverify.ps1
             displayName: Run ILVerify
             workingDirectory: $(Build.SourcesDirectory)
+
+# ============================================================================
+# FAILURE REPORTING STAGE
+# ============================================================================
+- stage: report_failures
+  displayName: Report Build and Test Failures
+  dependsOn: build
+  condition: and(
+    always(),
+    eq(variables['Build.Reason'], 'PullRequest'),
+    eq(variables['System.TeamProject'], 'public'),
+    or(
+      eq(dependencies.build.result, 'Failed'),
+      eq(dependencies.build.result, 'SucceededWithIssues')
+    ))
+  jobs:
+  - job: CollectAndReportFailures
+    displayName: 'Report Build and Test Failures to GitHub PR'
+    pool:
+      vmImage: 'ubuntu-latest'
+    steps:
+    - checkout: self
+
+    # Check if PR author and assignee are allowed to receive failure reports
+    - task: PowerShell@2
+      displayName: 'Check PR Author and Assignee'
+      name: 'CheckAssignee'
+      inputs:
+        targetType: 'inline'
+        script: |
+          $allowedUsers = @('abonie', 'copilot', 'T-Gro')
+          $shouldRunReport = $false
+
+          try {
+            $prNumber = "$(System.PullRequest.PullRequestNumber)"
+            $repoName = "$(Build.Repository.Name)"
+
+            if ([string]::IsNullOrEmpty($prNumber) -or [string]::IsNullOrEmpty($repoName)) {
+              Write-Host "Missing PR number or repository name, skipping author/assignee check"
+              Write-Host "##vso[task.setvariable variable=shouldRunReport;isOutput=true]false"
+              exit 0
+            }
+
+            # Get PR details from GitHub API
+            $headers = @{
+              'Authorization' = "token $env:GITHUB_TOKEN"
+              'Accept' = 'application/vnd.github.v3+json'
+              'User-Agent' = 'Azure-DevOps-Build-Reporter'
+            }
+
+            $prUrl = "https://api.github.com/repos/$repoName/pulls/$prNumber"
+            Write-Host "Checking PR author and assignees for: $prUrl"
+
+            $prData = Invoke-RestMethod -Uri $prUrl -Headers $headers -Method Get
+
+            # Check PR author
+            $authorLogin = $prData.user.login
+            Write-Host "PR author: $authorLogin"
+            
+            $isAuthorAllowed = $authorLogin -in $allowedUsers
+            Write-Host "Is author allowed: $isAuthorAllowed"
+
+            # Check PR assignees
+            $assigneeLogins = @()
+            if ($prData.assignees -and $prData.assignees.Count -gt 0) {
+              $assigneeLogins = $prData.assignees | ForEach-Object { $_.login }
+              Write-Host "PR assignee(s): $($assigneeLogins -join ', ')"
+            } else {
+              Write-Host "PR has no assignees"
+            }
+
+            # Check if any assignee is in the allowed list
+            $allowedAssignee = $assigneeLogins | Where-Object { $_ -in $allowedUsers } | Select-Object -First 1
+            $hasAllowedAssignee = $null -ne $allowedAssignee
+
+            Write-Host "Has allowed assignee: $hasAllowedAssignee"
+            if ($hasAllowedAssignee) {
+              Write-Host "Found allowed assignee: '$allowedAssignee'"
+            }
+
+            # Both conditions must be met: author must be allowed AND at least one assignee must be allowed
+            if ($isAuthorAllowed -and $hasAllowedAssignee) {
+              Write-Host "Failure report will be generated (author '$authorLogin' is allowed and found allowed assignee: '$allowedAssignee')"
+              $shouldRunReport = $true
+            } else {
+              if (-not $isAuthorAllowed) {
+                Write-Host "Author '$authorLogin' is not in the allowed users list: $($allowedUsers -join ', ')"
+              }
+              if (-not $hasAllowedAssignee) {
+                if ($assigneeLogins.Count -gt 0) {
+                  Write-Host "No allowed assignees found. Assignees: $($assigneeLogins -join ', ')"
+                } else {
+                  Write-Host "PR has no assignees"
+                }
+              }
+              Write-Host "Skipping failure report - both author and assignee must be from allowed users list"
+            }
+          }
+          catch {
+            Write-Warning "Failed to check PR author/assignee: $($_.Exception.Message)"
+            Write-Host "Setting shouldRunReport to false due to error"
+          }
+
+          Write-Host "##vso[task.setvariable variable=shouldRunReport;isOutput=true]$shouldRunReport"
+          Write-Host "Final decision: shouldRunReport = $shouldRunReport"
+        pwsh: true
+      env:
+        GITHUB_TOKEN: $(github-pat)
+      continueOnError: true
+
+    # Run the failure reporting script
+    - task: PowerShell@2
+      displayName: 'Generate and Post Failure Report'
+      inputs:
+        filePath: '$(Build.SourcesDirectory)/eng/scripts/Report-BuildFailures.ps1'
+        arguments: >-
+          -BuildId $(Build.BuildId)
+          -Organization "$(System.CollectionUri)"
+          -Project "$(System.TeamProject)"
+          -Repository "$(Build.Repository.Name)"
+          -PullRequestId $(System.PullRequest.PullRequestNumber)
+        pwsh: true
+      env:
+        SYSTEM_ACCESSTOKEN: $(System.AccessToken)
+        GITHUB_TOKEN: $(github-pat)
+      condition: and(always(), eq(variables['CheckAssignee.shouldRunReport'], 'true'))
+      continueOnError: true
\ No newline at end of file
diff --git a/eng/scripts/Report-BuildFailures.ps1 b/eng/scripts/Report-BuildFailures.ps1
new file mode 100644
index 0000000000..c9df94901c
--- /dev/null
+++ b/eng/scripts/Report-BuildFailures.ps1
@@ -0,0 +1,445 @@
+param(
+    [Parameter(Mandatory)]
+    [string]$BuildId,
+
+    [Parameter(Mandatory)]
+    [string]$Organization,
+
+    [Parameter(Mandatory)]
+    [string]$Project,
+
+    [Parameter(Mandatory)]
+    [string]$Repository,
+
+    [Parameter(Mandatory)]
+    [string]$PullRequestId,
+
+    # Testing parameter - when set, script only defines functions but doesn't execute
+    [switch]$WhatIf
+)
+
+# Set up authentication headers
+$azureHeaders = @{
+    'Authorization' = "Bearer $env:SYSTEM_ACCESSTOKEN"
+    'Content-Type' = 'application/json'
+}
+
+$githubHeaders = @{
+    'Authorization' = "token $env:GITHUB_TOKEN"
+    'Accept' = 'application/vnd.github.v3+json'
+    'User-Agent' = 'Azure-DevOps-Build-Reporter'
+}
+
+# Job name mappings for user-friendly display
+$script:jobMappings = @{
+    "WindowsCompressedMetadata" = "Windows Tests (Compressed Metadata)"
+    "WindowsCompressedMetadata_Desktop" = "Windows Desktop Tests"
+    "WindowsNoRealsig_testCoreclr" = "Windows CoreCLR Tests"
+    "WindowsNoRealsig_testDesktop" = "Windows Desktop Tests"
+    "WindowsLangVersionPreview" = "Windows Language Version Preview"
+    "WindowsStrictIndentation" = "Windows Strict Indentation Tests"
+    "WindowsNoStrictIndentation" = "Windows No Strict Indentation Tests"
+    "Linux" = "Linux Tests"
+    "MacOS" = "macOS Tests"
+    "Determinism_Debug" = "Determinism Tests"
+    "CheckCodeFormatting" = "Code Formatting Check"
+    "EndToEndBuildTests" = "End-to-End Build Tests"
+    "Plain_Build_Windows" = "Plain Build (Windows)"
+    "Plain_Build_Linux" = "Plain Build (Linux)"
+    "Plain_Build_MacOS" = "Plain Build (macOS)"
+    "Build_And_Test_AOT_Windows" = "AOT/Trimming Tests"
+    "ILVerify" = "IL Verification"
+    "Benchmarks" = "Performance Benchmarks"
+    "MockOfficial" = "Mock Official Build"
+    "Check_Published_Package_Versions" = "Package Version Check"
+}
+
+# ============================================================================
+# HELPER FUNCTIONS
+# ============================================================================
+
+function ConvertTo-FailedJobs {
+    param($TimelineRecords)
+
+    $failedJobs = @()
+
+    if ($TimelineRecords) {
+        foreach ($record in $TimelineRecords) {
+            # Check for failed jobs/tasks
+            if ($record.result -eq "failed" -or $record.result -eq "canceled") {
+
+                $jobInfo = @{
+                    Id = $record.id
+                    Name = $record.name
+                    Type = $record.type
+                    Result = $record.result
+                    StartTime = $record.startTime
+                    FinishTime = $record.finishTime
+                    Issues = $record.issues
+                    LogId = $record.log.id
+                    ParentId = $record.parentId
+                    DisplayName = Get-JobDisplayName -JobName $record.name
+                }
+
+                # Categorize the failure type
+                switch ($record.type) {
+                    "Job" {
+                        $jobInfo.Category = "Job Failure"
+                    }
+                    "Task" {
+                        $jobInfo.Category = "Task Failure"
+                    }
+                    default {
+                        $jobInfo.Category = "Build Failure"
+                    }
+                }
+
+                $failedJobs += $jobInfo
+            }
+        }
+    }
+
+    return $failedJobs
+}
+
+function Get-BuildTimeline {
+    param($BuildId, $Headers, $Organization, $Project)
+
+    $uri = "$Organization$Project/_apis/build/builds/$BuildId/timeline?api-version=7.0"
+    Write-Host "📡 Calling: $uri"
+
+    try {
+        $response = Invoke-RestMethod -Uri $uri -Headers $Headers -Method Get
+        $failedJobs = ConvertTo-FailedJobs -TimelineRecords $response.records
+
+        Write-Host "🔍 Found $($failedJobs.Count) failed jobs/tasks"
+        return $failedJobs
+
+    } catch {
+        Write-Warning "Failed to get build timeline: $_"
+        return @()
+    }
+}
+
+function Get-JobDisplayName {
+    param($JobName)
+
+    # Return mapped name or original name if not found
+    return $script:jobMappings[$JobName] ?? $JobName
+}
+
+function Get-TestFailures {
+    param($BuildId, $Headers, $Organization, $Project)
+
+    # Extract organization name from URL if a full URL was passed
+    $orgName = $Organization
+    if ($Organization -match 'https?://[^/]+/([^/]+)/?') {
+        $orgName = $matches[1]
+        Write-Host "🔧 Extracted organization name '$orgName' from URL '$Organization'"
+    }
+
+    # Get test results directly by build ID using the resultsbybuild endpoint
+    $testResultsUri = "https://vstmr.dev.azure.com/$orgName/$Project/_apis/testresults/resultsbybuild?buildId=$BuildId&outcomes=Failed&outcomes=Aborted&outcomes=Timeout&api-version=7.1-preview.1"
+
+    Write-Host "📊 Calling: $testResultsUri"
+
+    try {
+        $testResults = Invoke-RestMethod -Uri $testResultsUri -Headers $Headers -Method Get
+        $allTestFailures = @()
+
+        if ($testResults -and $testResults.value) {
+            foreach ($result in $testResults.value) {
+                $testFailure = @{
+                    TestName = $result.testCaseTitle
+                    TestMethod = $result.automatedTestName
+                    Outcome = $result.outcome
+                    ErrorMessage = $result.errorMessage
+                    StackTrace = $result.stackTrace
+                    Duration = $result.durationInMs
+                    TestRun = $result.testRun.name
+                    JobName = Extract-JobNameFromTestRun -TestRunName $result.testRun.name
+                }
+                $allTestFailures += $testFailure
+            }
+        }
+
+        Write-Host "🧪 Found $($allTestFailures.Count) test failures"
+        return $allTestFailures
+
+    } catch {
+        Write-Warning "Failed to get test results: $_"
+        return @()
+    }
+}
+
+function Extract-JobNameFromTestRun {
+    param($TestRunName)
+
+    # Extract job name from test run names like "WindowsCompressedMetadata testCoreclr"
+    if ($TestRunName -match "^([^\s]+)") {
+        return $matches[1]
+    }
+    return $TestRunName
+}
+
+function Format-FailureReport {
+    param($BuildErrors, $TestFailures, $BuildId, $Organization, $Project)
+
+    $report = @{
+        HasFailures = ($BuildErrors.Count -gt 0 -or $TestFailures.Count -gt 0)
+        BuildErrors = $BuildErrors
+        TestFailures = $TestFailures
+        BuildUrl = "$Organization$Project/_build/results?buildId=$BuildId"
+    }
+
+    if (-not $report.HasFailures) {
+        return $report
+    }
+
+    # Generate markdown report
+    $markdown = @"
+@copilot
+
+## 🔴 Build/Test Failures Report
+
+"@
+
+    # Build Failures Section
+    if ($BuildErrors.Count -gt 0) {
+        $markdown += @"
+
+### 🏗️ Build Failures
+
+"@
+
+        $groupedErrors = $BuildErrors | Group-Object DisplayName
+        foreach ($group in $groupedErrors) {
+            $markdown += "**$($group.Name)**`n"
+
+            foreach ($buildError in $group.Group | Select-Object -First 3) {
+                $markdown += "- $($buildError.Category): $($buildError.Result)"
+                if ($buildError.Issues -and $buildError.Issues.Count -gt 0) {
+                    $firstIssue = $buildError.Issues[0]
+                    if ($firstIssue.message) {
+                        $shortMessage = $firstIssue.message.Substring(0, [Math]::Min(100, $firstIssue.message.Length))
+                        if ($firstIssue.message.Length -gt 100) { $shortMessage += "..." }
+                        $markdown += " - $shortMessage"
+                    }
+                }
+                $markdown += "`n"
+            }
+
+            if ($group.Count -gt 3) {
+                $markdown += "- ... and $($group.Count - 3) more errors`n"
+            }
+            $markdown += "`n"
+        }
+    }
+
+    # Test Failures Section
+    if ($TestFailures.Count -gt 0) {
+        $markdown += @"
+
+### 🧪 Test Failures
+
+"@
+
+        $groupedTests = $TestFailures | Group-Object JobName
+        foreach ($group in $groupedTests) {
+            $jobDisplayName = Get-JobDisplayName -JobName $group.Name
+
+            # Add job display name to markdown only if it's not empty
+            if ([string]::IsNullOrWhiteSpace($jobDisplayName)) {
+                $markdown += "**$($group.Count) failed tests**`n"
+            } else {
+                $markdown += "**$jobDisplayName** - $($group.Count) failed tests`n"
+            }
+
+            foreach ($test in $group.Group | Select-Object -First 5) {
+                $markdown += "- ``$($test.TestName)``"
+                if ($test.ErrorMessage) {
+                    $shortError = $test.ErrorMessage.Substring(0, [Math]::Min(100, $test.ErrorMessage.Length))
+                    if ($test.ErrorMessage.Length -gt 100) { $shortError += "..." }
+                    $markdown += ": $shortError"
+                }
+                $markdown += "`n"
+            }
+
+            if ($group.Count -gt 5) {
+                $markdown += "- ... and $($group.Count - 5) more test failures`n"
+            }
+            $markdown += "`n"
+        }
+    }
+
+    # Summary Section
+    $totalJobs = ($BuildErrors | Group-Object DisplayName).Count + ($TestFailures | Group-Object JobName).Count
+    $markdown += @"
+[📋 View full build details]($($report.BuildUrl))
+
+---
+*This comment was automatically generated by the F# CI pipeline*
+"@
+
+    $report.MarkdownContent = $markdown
+    return $report
+}
+
+function Publish-GitHubComment {
+    [CmdletBinding()]
+    param(
+        [Parameter(Mandatory)]
+        [ValidateNotNull()]
+        $Report,
+
+        [Parameter(Mandatory)]
+        [ValidatePattern('^[a-zA-Z0-9_.-]+/[a-zA-Z0-9_.-]+$')]
+        [string]$Repository,
+
+        [Parameter(Mandatory)]
+        [ValidateRange(1, [int]::MaxValue)]
+        [int]$PullRequestId,
+
+        [Parameter(Mandatory)]
+        [ValidateNotNull()]
+        [hashtable]$Headers
+    )
+
+    if (-not $Report.HasFailures) {
+        Write-Host "✅ No failures to report, skipping GitHub comment"
+        return
+    }
+
+    # With this hashtable-friendly validation:
+    if (-not $Report.ContainsKey('MarkdownContent') -or [string]::IsNullOrWhiteSpace($Report.MarkdownContent)) {
+        Write-Warning "❌ Report is missing MarkdownContent property"
+        return
+    }
+
+    try {
+        # Construct URLs with validated inputs
+        $commentsUrl = "https://api.github.com/repos/$Repository/issues/$PullRequestId/comments"
+        $commentMarker = "<!-- F# CI Build Failure Report -->"
+
+        Write-Host "� Creating new failure report comment on PR #$PullRequestId"
+
+        # Prepare the comment body with proper escaping
+        $sanitizedMarkdown = $Report.MarkdownContent -replace '[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]', ''
+        $commentBody = @"
+$commentMarker
+$sanitizedMarkdown
+"@
+
+        # Validate comment body length (GitHub has limits)
+        if ($commentBody.Length -gt 65536) {
+            Write-Warning "⚠️ Comment body is too long ($($commentBody.Length) chars), truncating..."
+            $footnote = "`n`n---`n*This comment was automatically generated by the F# CI pipeline*"
+            $truncationNote = "`n`n*[Content truncated due to length]*"
+            $maxContentLength = 65536 - $commentMarker.Length - $footnote.Length - $truncationNote.Length - 10 # extra buffer
+            $commentBody = $commentBody.Substring(0, $maxContentLength) + $truncationNote + $footnote
+        }
+
+        $requestBody = @{
+            body = $commentBody
+        } | ConvertTo-Json -Depth 10 -Compress
+
+        # Always create new comment
+        $response = Invoke-RestMethod -Uri $commentsUrl -Headers $Headers -Method Post -Body $requestBody -ContentType 'application/json'
+        Write-Host "✅ Successfully posted GitHub comment: $($response.html_url)"
+
+    } catch {
+        $errorMessage = $_.Exception.Message
+        Write-Warning "❌ Failed to post GitHub comment: $errorMessage"
+
+        # Safely extract status code and response details
+        try {
+            if ($_.Exception.Response) {
+                $statusCode = [int]$_.Exception.Response.StatusCode
+                Write-Warning "HTTP Status Code: $statusCode"
+
+                # Safely read error response with proper disposal
+                $responseStream = $null
+                $reader = $null
+                try {
+                    $responseStream = $_.Exception.Response.GetResponseStream()
+                    if ($responseStream) {
+                        $reader = New-Object System.IO.StreamReader($responseStream)
+                        $responseBody = $reader.ReadToEnd()
+                        if (-not [string]::IsNullOrWhiteSpace($responseBody)) {
+                            # Sanitize response body before logging (remove potential secrets)
+                            $sanitizedResponse = $responseBody -replace '"token":\s*"[^"]*"', '"token": "[REDACTED]"'
+                            Write-Warning "Response details: $sanitizedResponse"
+                        }
+                    }
+                }
+                catch {
+                    Write-Verbose "Could not read error response details: $($_.Exception.Message)"
+                }
+                finally {
+                    # Properly dispose of resources
+                    if ($reader) { $reader.Dispose() }
+                    if ($responseStream) { $responseStream.Dispose() }
+                }
+            }
+        }
+        catch {
+            Write-Verbose "Could not extract exception details: $($_.Exception.Message)"
+        }
+    }
+}
+
+# ============================================================================
+# MAIN EXECUTION (only run if not in WhatIf mode)
+# ============================================================================
+
+if (-not $WhatIf) {
+    # Validate required environment variables
+    if ([string]::IsNullOrEmpty($env:SYSTEM_ACCESSTOKEN)) {
+        throw "SYSTEM_ACCESSTOKEN environment variable is required but not set"
+    }
+
+    if ([string]::IsNullOrEmpty($env:GITHUB_TOKEN)) {
+        throw "GitHubToken parameter is required but not provided"
+    }
+
+    # Set up authentication headers
+    $azureHeaders = @{
+        'Authorization' = "Bearer $env:SYSTEM_ACCESSTOKEN"
+        'Content-Type' = 'application/json'
+    }
+
+    $githubHeaders = @{
+        'Authorization' = "token $env:GITHUB_TOKEN"
+        'Accept' = 'application/vnd.github.v3+json'
+        'User-Agent' = 'Azure-DevOps-Build-Reporter'
+    }
+
+    try {
+        Write-Host "🔍 Starting failure collection for Build ID: $BuildId"
+
+        # Step 1: Get failed jobs from build timeline
+        Write-Host "📡 Fetching build timeline..."
+        $failedJobs = Get-BuildTimeline -BuildId $BuildId -Headers $azureHeaders -Organization $Organization -Project $Project
+
+        # Step 2: Get test failures
+        Write-Host "🧪 Fetching test failures..."
+        $testFailures = Get-TestFailures -BuildId $BuildId -Headers $azureHeaders -Organization $Organization -Project $Project
+
+        # Step 3: Generate failure report
+        $failureReport = Format-FailureReport -BuildErrors $failedJobs -TestFailures $testFailures -BuildId $BuildId -Organization $Organization -Project $Project
+
+        # Step 4: Post to GitHub PR
+        if ($failureReport.HasFailures) {
+            Write-Host "📝 Failure report generated:"
+            Write-Host $failureReport.MarkdownContent
+            Write-Host ""
+            Publish-GitHubComment -Report $failureReport -Repository $Repository -PullRequestId $PullRequestId -Headers $githubHeaders
+        } else {
+            Write-Host "✅ No failures found to report"
+        }
+
+    } catch {
+        Write-Error "❌ Failed to process build failures: $($_.Exception.Message)"
+        exit 1
+    }
+}