You know the moment. CI goes red, or a build that took 8 seconds yesterday nowtakes 40, and you're staring at a wall of MSBuild output trying to find the oneline that matters. The answer is almost always sitting in the binary log(.binlog) - it records every project, target, task, property, and diagnosticin the build. The problem is that reading one has meant firing up a separateviewer and already knowing where to look.What if you could just ask?That's the idea behind the MSBuild Binlog Analyzer for VS Code, now inPreview on theVisual Studio Marketplace.It brings binlog analysis right into your editor and hands the tedious detectivework to GitHub Copilot Chat - so you can stay in the flow and keep shipping.Just want an agent to investigate builds for you - say, unattended in CI?Check out the Microsoft Binlog MCP Server -the same analysis engine, driven headlessly. This post is about the interactive, in-editor experience.The problems it solvesBuild logs are the best evidence you have and the most annoying to read. TheBinlog Analyzer turns that evidence into answers:"Why did my build fail?" Get a plain-language root cause instead ofscrolling NuGet restore noise - and fix it with a single click, right inVS Code."Why is this slow?" See the slowest targets and tasks ranked, with thecritical path that actually gates your build time highlighted for you."What changed?" Compare two builds side by side and get an itemizeddiff of timing, diagnostics, properties, and package versions - so "it feelsslower" becomes "CoreCompile regressed by 14.7s.""Is my incremental build working?" Find out which targets rebuilt andwhy, instead of guessing.No context-switching, no separate tool, no decoding MSBuild by hand.What it isUnder the hood, the extension pairs with a .NET global-tool MCP server,Microsoft.AITools.BinlogMcp,which exposes dozens of build-analysis tools over the Model Context Protocol.Copilot calls those tools to ground its answers in your actual log - notguesswork. Best of all, the server is auto-installed on first use, sothere's nothing to wire up by hand.InstallInstall the extension from the Marketplace. You'll need VS Code 1.99+,GitHub Copilot, and the .NET SDK.Open a .binlog in one of three ways: Binlog: Load File from the CommandPalette (Ctrl+Shift+P), Build & Collect Binlog to build and capture inone step, or Open in VS Code from theStructured Log Viewer.Ask @binlog in Copilot Chat:@binlog why did the build fail?@binlog what are the slowest targets?@binlog /perfA tour of the best partsThe Binlog Explorer is your mapThe sidebar tree lays the whole build out at a glance: Loaded Binlogs,Projects, Errors, Warnings, and a Performance section with theslowest targets, slowest tasks, rebuild reasons, and analyzer timing.Diagnostics also light up VS Code's native Problems panel with per-projectCodeLens and an Ask @binlog action - so an error in the tree is one clickfrom an explanation.@binlog chat - and fixing the build in one clickThis is where analysis becomes a conversation. Ask open-ended questions, orreach for slash commands like /errors, /perf, /timeline, /compare,/summary, /incremental, and /buildcheck. Because the participant calls theMCP tools directly, every answer cites real data from the log.Then comes the part people love: Fix all issues. Copilot reads the failingproject, applies the fix, rebuilds, and loads the before/after binlogs so youcan confirm it worked - all without leaving the editor. Prefer to go one at atime? Right-click any diagnostic and choose Auto-fix with Copilot.Catch regressions before they shipSet any loaded .binlog as a baseline, and every new build is comparedagainst it automatically. A Build: +X% vs baseline badge appears in thestatus bar, and a Regressions node spells out exactly what changed: slowertargets, added or removed diagnostics, MSBuild property diffs, and NuGet packageversion changes. Hand any single regression straight to @binlog to dig in.Compare two builds, visuallyThe Build Comparison view lines up two logs target-by-target with deltas,and the project graph highlights the critical path computed by the MCPserver. In the example below, Copilot traces a +473% spike straight to acold-start CoreCompile and explains it's a first-compile cost - not a problemwith your code. That's the difference between a number and an answer.And there's moreThe extension is packed with extras worth exploring:Build Timeline - visual bar charts of target and task durations, withclick-to-analyze in Copilot.Optimize build - pick optimizations, let Copilot apply them, and verifythe win with an automatic A/B comparison.CI/CD integration - download binlogs from Azure DevOps Pipelines andGitHub Actions, filtered by branch or PR, and analyze a failed CI buildwithout leaving VS Code.Search - query across every build event: targets, tasks, messages, andproperties.Language Model tools (binlog_lm_overview, binlog_lm_errors,binlog_lm_search, binlog_lm_perf, binlog_lm_compare) - available toagent mode and custom chat modes, plus a ready-made Build Analysis chatmode that works with any agent.Try itThe MSBuild Binlog Analyzer is in Preview and under active development.Install it from theVisual Studio Marketplace,point it at a .binlog, and ask @binlog your next build question. The nextred build might just fix itself. We'd love your feedback.FeedbackThe MSBuild Binlog Analyzer is built in the open, and your feedback shapeswhere it goes next. Found a bug, hit a rough edge, or have an idea for afeature? Please open an issue in thedotnet/skills repository - bugreports, feature requests, and general feedback are all welcome. Let us knowwhat's working, what isn't, and what you'd like to see next.