check-bin-obj-clash

What it does

Detects MSBuild projects with conflicting OutputPath or IntermediateOutputPath across evaluations, to surface clashes that cause file-in-use or missing/overwritten outputs in multi-project or multi-targeting builds. It guides users to identify when multiple evaluations share the same output directories and how global properties or shared BaseOutputPath/BaseIntermediateOutputPath contribute to clashes. It provides a step-by-step workflow using binary logs and MCP tooling to surface, compare, and report clashes, and offers fixes like ensuring unique intermediate paths or including TargetFramework in OutputPath.

How it works

• Invoke the skill when you see common MSBuild path-related issues (e.g., Cannot create a file when that file already exists, file-in-use errors, or intermittent failures).
• Step 1: Generate a Binary Log with binlog-generation.
• Step 2: Use MCP overview and projects tools to list all participating projects.
• Step 3: Use MCP evaluations and evaluation_global_properties to find per-project evaluations and differing global properties (TargetFramework, Configuration, RuntimeIdentifier, SolutionFileName, PublishReadyToRun, etc.).
• Step 4: Use MCP properties to query OutputPath, IntermediateOutputPath, BaseOutputPath, and BaseIntermediateOutputPath for each evaluation.
• Step 5: If available, use MCP double_writes to detect files written by multiple project instances.
• Step 6: Compare OutputPath and IntermediateOutputPath across evaluations:
  1. Normalize paths to absolute form
  2. Group by path
  3. Exclude BuildProjectReferences=false evaluations
  4. Report any group with more than one evaluation as a clash
• Fallback: If MCP is unavailable, replay the binlog to a diagnostic text log and grep signals for evaluations, OutputPath/IntermediateOutputPath, and global properties; identify clashes similarly and exclude non-build evaluations.

When to use it

Use immediately when you encounter build failures or intermittent failures tied to file access or missing outputs, especially in multi-project or multi-targeting scenarios where bin/obj or project.assets.json may collide.

What it can touch

• The workflow references tools for querying binlogs via MCP (tools/list, evaluations, evaluation_global_properties, properties, double_writes). It does not modify source files or perform builds; it analyzes build metadata produced by prior steps.

Caveats

• Requires binary logs and MCP tooling to be available; the fallback relies on text-log replay if MCP is unavailable. Do not rely on MCP when it cannot be started. The skill describes how to distinguish same-project vs cross-project publish scenarios and how to interpret global properties in relation to paths.