| name | build-performance-analysis |
| description | Analyze MSBuild build performance and find bottlenecks using binlog-insights MCP tools. Use when a build is slow, you need to optimize build times, or identify expensive projects, targets, tasks, or Roslyn analyzers. Also triggers for build duration, build speed, and compilation time. |
| metadata | {"traits":"MSBuild|DotNet|CSharp|Build|Binlog|Performance"} |
Build Performance Analysis
Overview
Find what's making an MSBuild build slow by analyzing .binlog files. Identifies expensive projects, targets, tasks, and Roslyn analyzers using binlog-insights MCP tools.
Quick Start
dotnet build /bl:build.binlog
Then ask: "Why is my build slow? Analyze build.binlog performance."
Workflow
- Run
binlog_overview to get total build duration and project count
- Run
binlog_expensive_projects to find the slowest projects
- For each slow project, run
binlog_project_target_times to see which targets take the most time
- Run
binlog_expensive_targets for a build-wide view of the slowest targets
- Run
binlog_expensive_tasks to find the most expensive individual tasks
- Run
binlog_expensive_analyzers to check if Roslyn analyzers are a bottleneck
- For suspicious targets, use
binlog_tasks_in_target and binlog_task_details to inspect what they do
Task Progress:
- [ ] Step 1: binlog_overview — total duration
- [ ] Step 2: binlog_expensive_projects — slowest projects
- [ ] Step 3: binlog_project_target_times — target breakdown per project
- [ ] Step 4: binlog_expensive_targets — global target hotspots
- [ ] Step 5: binlog_expensive_tasks — global task hotspots
- [ ] Step 6: binlog_expensive_analyzers — analyzer impact
- [ ] Step 7: Deep dive into suspicious targets
Tool Reference
| Tool | Purpose |
|---|
binlog_overview | Build status, duration, project count |
binlog_expensive_projects | Slowest projects by duration |
binlog_project_target_times | Target timing for a specific project |
binlog_expensive_targets | Slowest targets across all projects |
binlog_expensive_tasks | Slowest tasks across all projects |
binlog_expensive_analyzers | Roslyn analyzer performance |
binlog_tasks_in_target | Tasks within a specific target |
binlog_task_details | Details of a specific task execution |
binlog_projects | Project list with status and duration |
Common Patterns
Slow build — find the bottleneck:
Action: binlog_expensive_projects → find 60s project → binlog_project_target_times → discover ResolveAssemblyReference takes 45s
Analyzer overhead:
Action: binlog_expensive_analyzers → find analyzer taking 15s per project → disable or move to CI-only
Unexpected target running:
Action: binlog_expensive_targets → spot GenerateNuspec running for 30 projects that don't ship packages → check IsPackable property
Troubleshooting
- No binlog file: Rebuild with
dotnet build /bl:build.binlog
- Tool not found: Ensure
binlog-insights-mcp is installed: dotnet tool install -g BinlogInsights.Mcp
- Filter to one project: Use
--project <substring> on any tool to narrow results
