BinlogMcp

An MCP (Model Context Protocol) server for reading and analyzing MSBuild binary log files (.binlog).

Overview

This server exposes 52 tools that allow AI assistants to analyze MSBuild binary logs, including:

Build Info - Summaries, errors, warnings, properties, items
Performance - Slowest targets/tasks, compiler timing, parallelism analysis, I/O bottlenecks
Dependencies - Project graph, assembly references, NuGet packages
Comparison - Diff two builds, incremental build analysis
Diagnostics - Failure diagnosis with root cause detection and fix suggestions
Debugging - Target execution reasons, skipped targets, property origins, import chains
Evaluation - Flattened project view showing final properties, items, and imports

Standalone Tools

BinlogMCP Client - Interactive Build Investigator

An interactive REPL for analyzing MSBuild binlogs, powered by AIDavid - a virtual MSBuild debugging expert inspired by David Federman's debugging methodology. Uses the GitHub Copilot SDK for AI-powered analysis.

# Start interactive session with a binlog
dotnet run --project src/BinlogMcp.Client -- ./build.binlog

# Or launch and provide the path when prompted
dotnet run --project src/BinlogMcp.Client

Requirements: Authenticate with GitHub CLI first: gh auth login

Once loaded, you'll see an interactive prompt:


  ▐█▌ BinlogMCP ───────────────────────────────────
  🔨 Build Log Investigator
     inspired by dfederm.com/debugging-msbuild

     msbuild.binlog loaded
     50 analysis tools ready

  ───────────────────────────────────────────────────

  Quick start:

    [1] diagnose            Automated build analysis
    [2] visualize timeline  Gantt chart of execution
    [3] visualize slowest   Slowest targets chart
    [4] help                All commands

  Or ask: "Why did this build fail?"

  ───────────────────────────────────────────────────

binlog>

Interactive Commands:

diagnose - Run automated AIDavid diagnosis
visualize timeline - Open Gantt chart of build execution in browser
visualize slowest - Open bar chart of slowest targets
set baseline <path> - Set a baseline binlog for comparisons
compare - Compare current build with baseline
visualize comparison - Visual comparison chart (requires baseline)
help - Show available commands
exit - Exit the program

Or just ask questions naturally:

"Why did this build fail?"
"What targets took the longest?"
"Show me the errors"
"What version of Newtonsoft.Json is being used?"

The client maintains conversation history, so you can ask follow-up questions that reference previous answers.

Model Configuration:

The default model is claude-opus-4.7, configured in the session setup.

Logging: All LLM and tool interactions are logged to binlog-client.log in the current directory.

Requires GitHub CLI authentication (gh auth login) for Copilot SDK model access.

Casing Analyzer

Fixes path casing in MSBuild source files. On Windows, incorrect casing in paths (e.g., ..\librarya\ instead of ..\LibraryA\) can cause cache issues with NuGet and other tools.

# Fix casing in all .props, .targets, *proj files in a repo
dotnet run --project src/BinlogMcp.CasingAnalyzer -- /path/to/repo

The tool walks the filesystem to get canonical casing (disk is the source of truth), then fixes any path segments in source files that don't match.

Requirements

.NET 10 SDK (pinned via global.json with rollForward: latestFeature)

Building

dotnet build

The repo uses Central Package Management (Directory.Packages.props), Nerdbank.GitVersioning, ReferenceTrimmer, and TreatWarningsAsErrors. All builds must be warning-free.

Running

dotnet run --project src/BinlogMcp

Testing

# Run unit tests (~293 tests)
dotnet test tests/BinlogMcp.Tests

# Run LLM integration tests (requires OpenAI API key, costs money - run sparingly)
dotnet test tests/BinlogMcp.IntegrationTests

Integration tests require an OpenAI API key. Configure via user secrets:

dotnet user-secrets set "OpenAI:ApiKey" "sk-..." --project tests/BinlogMcp.IntegrationTests

Or via environment variable: OPENAI_API_KEY. Tests skip automatically if no key is configured.

The interactive client (BinlogMcp.Client) uses the GitHub Copilot SDK instead and requires gh auth login.

MCP Configuration

Add to your MCP client configuration (e.g., Claude Desktop):

{
  "mcpServers": {
    "binlog": {
      "command": "dotnet",
      "args": ["run", "--project", "/path/to/binlog-mcp/src/BinlogMcp"]
    }
  }
}

Available Tools

Tool	Description
`GetCacheStats`	Gets binlog cache statistics and optionally clears the cache
`ListBinlogs`	Lists all binlog files in a directory (with optional recursive search)
`GetBuildSummary`	Gets build summary: result, duration, error/warning counts, projects
`GetErrors`	Extracts all errors with file, line, column, code, and message
`GetWarnings`	Extracts all warnings with the same detail as errors
`GetTargets`	Gets target execution details sorted by duration (slowest first)
`GetTasks`	Gets task execution details with aggregation by task type
`GetCriticalPath`	Identifies targets on the critical path that determined build duration
`GetProjectDependencies`	Gets project dependency graph, build order, and parallel execution info
`SearchBinlog`	Searches binlog content for messages, errors, warnings, targets, tasks, or properties
`GetProperties`	Gets MSBuild properties with optional filtering and highlights important ones
`GetItems`	Gets MSBuild item groups (Compile, Reference, PackageReference, etc.)
`CompareBinlogs`	Compares two binlogs showing timing changes, new/fixed errors, and target differences
`DiffProperties`	Compares property values between builds - added, removed, changed properties
`DiffItems`	Compares items between builds - added/removed files, package version changes
`DiffTargetExecution`	Compares target execution between builds - what ran differently
`DiffImports`	Compares import chains between builds - .props/.targets file changes
`GetIncrementalBuildAnalysis`	Analyzes incremental build behavior - executed vs skipped targets
`GetNuGetRestoreAnalysis`	Analyzes NuGet restore - packages, timing, and any restore issues
`GetAssemblyReferences`	Gets assembly and project references with metadata
`GetPerformanceReport`	Comprehensive performance analysis - bottlenecks, slow targets/tasks, optimization hints
`GetCompilerPerformance`	Detailed C#/VB/F# compilation timing analysis
`GetParallelismAnalysis`	Build parallelism efficiency - concurrent operations, sequential bottlenecks
`GetSlowOperations`	Analyzes slow file I/O operations (Copy, Move, Delete, Exec)
`GetProjectPerformance`	Per-project timing rollup - identify which projects are slowest
`ComparePerformance`	Focused performance comparison between builds - timing regressions/improvements
`GetParallelismBlockers`	Identifies what's blocking parallelism - serialization points, dependency bottlenecks
`AnalyzeTarget`	Deep dive into a single target - tasks, parameters, I/O, timing breakdown
`GetFailureDiagnosis`	Analyzes build failures - categorizes errors, identifies root causes, suggests fixes
`GetDuplicateFileWrites`	Detects files written multiple times during build (wasteful I/O)
`GetPropertyReassignments`	Finds MSBuild properties set multiple times (conflicts/overrides)
`GetRedundantOperations`	Detects tasks running with identical inputs (wasted work)
`GetUnusedProjectOutputs`	Finds projects built but whose outputs aren't referenced (dead code)
`GetTargetDependencyGraph`	Analyzes target dependencies, finds circular and redundant deps
`GetWarningTrendsAnalysis`	Categorizes warnings, suggests bulk fixes and suppressions
`GetFileAccessPatterns`	Identifies frequently read files and caching opportunities
`GetSdkFrameworkMismatch`	Detects SDK/framework version conflicts across projects
`GetTargetExecutionReasons`	Shows why targets executed (DependsOnTargets, BeforeTargets, AfterTargets)
`GetSkippedTargets`	Lists targets that were skipped and explains why
`GetPropertyOrigin`	Traces property values back to their source file and location
`GetImportChain`	Shows the import hierarchy (.props/.targets files) for projects
`TraceProperty`	Full property evaluation trace: initial → each assignment → final
`TraceItem`	Track items through build (consumed, transformed, output)
`GetItemTransforms`	Show item transformations within targets
`GetMSBuildTaskCalls`	Show MSBuild task invocations between projects
`GetEnvironmentVariables`	Extract environment variables used during the build
`GetItemMetadata`	Deep dive into item metadata (versions, HintPaths, CopyLocal settings)
`GetTargetInputsOutputs`	Show target incremental build inputs/outputs for debugging re-runs
`GetTimeline`	Export timeline data for external visualization tools
`GetEvaluatedProject`	Shows flattened project view - final properties, items, imports after evaluation
`ListEmbeddedSourceFiles`	Lists all embedded source files in the binlog's source archive (.csproj, .props, .targets, etc.)
`GetEmbeddedSourceFile`	Reads the content of a specific embedded source file from the binlog

Output Formats

21 high-value tools support multiple output formats via a format parameter:

Format	Description
`json`	Default. Structured JSON for programmatic use
`markdown`	Human-readable reports with tables and bullet lists
`csv`	Tabular data for spreadsheet import
`timeline`	JSON format for timing visualization

Tools supporting formats: GetBuildSummary, GetErrors, GetWarnings, GetTargets, GetTasks, GetCriticalPath, GetPerformanceReport, GetParallelismAnalysis, GetFailureDiagnosis, CompareBinlogs, DiffProperties, DiffTargetExecution, GetProjectDependencies, GetAssemblyReferences, GetProperties, GetItems, GetEvaluatedProject, GetProjectPerformance, ComparePerformance, GetParallelismBlockers, AnalyzeTarget.

Performance

Parsed binlogs are cached in memory for ~18x faster repeated access. This means calling multiple tools on the same binlog only parses it once.

Configuration (optional):

BINLOG_CACHE_SIZE=10 - Maximum binlogs to cache (default: 10)
BINLOG_CACHE_ENABLED=false - Disable caching

Use GetCacheStats to view cache status or clear it.

Example Usage

Once configured, you can ask your AI assistant questions like:

"List the binlog files in C:\builds"
"What errors are in the latest build?"
"Which targets took the longest to execute?"
"What's on the critical path of this build?"

Generating Binlog Files

To create a binlog from any MSBuild/dotnet build:

dotnet build -bl                    # Creates msbuild.binlog
dotnet build -bl:mybuild.binlog     # Custom filename
msbuild MySolution.sln -bl          # Works with msbuild too

Dependencies

ModelContextProtocol - MCP SDK for .NET
MSBuild.StructuredLogger - Library for reading binlog files

License

MIT

Name		Name	Last commit message	Last commit date
Latest commit History 3 Commits
.github		.github
src		src
test-data		test-data
tests		tests
.editorconfig		.editorconfig
.gitignore		.gitignore
BinlogMcp.slnx		BinlogMcp.slnx
Directory.Build.props		Directory.Build.props
Directory.Packages.props		Directory.Packages.props
LICENSE		LICENSE
README.md		README.md
global.json		global.json
test.binlog		test.binlog
version.json		version.json

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Repository files navigation

BinlogMcp

Overview

Standalone Tools

BinlogMCP Client - Interactive Build Investigator

Casing Analyzer

Requirements

Building

Running

Testing

MCP Configuration

Available Tools

Output Formats

Performance

Example Usage

Generating Binlog Files

Dependencies

License

About

Uh oh!

Releases

Packages

Uh oh!

Contributors

Uh oh!

Languages

Folders and files

Latest commit

History

Repository files navigation

BinlogMcp

Overview

Standalone Tools

BinlogMCP Client - Interactive Build Investigator

Casing Analyzer

Requirements

Building

Running

Testing

MCP Configuration

Available Tools

Output Formats

Performance

Example Usage

Generating Binlog Files

Dependencies

License

About

Resources

License

Uh oh!

Stars

Watchers

Forks

Releases

Packages 0

Uh oh!

Contributors

Uh oh!

Languages

Packages