Binlog Failure Analysis

What it does

When your agent uses it

• : build errors that are unclear from console output
• Diagnosing cascading failures across multi-project builds
• Tracing MSBuild target execution order
• Investigating common errors like CS0246 (type not found)

Example prompts

• “/binlog-failure-analysis”

Workflow steps

5 steps, taken from the step headings in SKILL.md.

1. 1Replay the binlog to text logs
2. 2Read the errors
3. 3Search for context around specific errors
4. 4Detect cascading failures
5. 5Examine project files for root causes

What it can do on your machine

Read from SKILL.md and the folder at commit e7e6474. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • dotnet

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Binlog Failure Analysis loads about 1.1k tokens when it runs. Until then it costs about 195 tokens; SKILL.md has 244 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~195

When it runs · the whole SKILL.md, loaded when a task matches

~1.1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from runceel/ReactiveProperty at commit e7e6474, republished under its MIT licence (© runceel). 244 words, ~1,141 tokens.

name

binlog-failure-analysis

description

Analyze MSBuild binary logs to diagnose build failures by replaying binlogs to searchable text logs. Only activate in MSBuild/.NET build context. USE FOR: build errors that are unclear from console output, diagnosing cascading failures across multi-project builds, tracing MSBuild target execution order, investigating common errors like CS0246 (type not found), MSB4019 (imported project not found), NU1605 (package downgrade), MSB3277 (version conflicts), and ResolveProjectReferences failures. Requires an existing .binlog file. DO NOT USE FOR: generating binlogs (use binlog-generation), build performance analysis (use build-perf-diagnostics), non-MSBuild build systems. INVOKES: dotnet msbuild binlog replay, grep, cat, head, tail for log analysis.

metadata.github-path

plugins/dotnet-msbuild/skills/binlog-failure-analysis

metadata.github-pinned

v1.0.0

metadata.github-ref

refs/tags/v1.0.0

metadata.github-repo

https://github.com/dotnet/skills

metadata.github-tree-sha

dea43446699a1f7263359a184f0c8d7d2655b0d4

dotnet msbuild build.binlog -noconlog \
  -fl  -flp:v=diag;logfile=full.log;performancesummary \
  -fl1 -flp1:errorsonly;logfile=errors.log \
  -fl2 -flp2:warningsonly;logfile=warnings.log

cat errors.log

# Find all occurrences of a specific error code with surrounding context
grep -n -B2 -A2 "CS0246" full.log

# Find which projects failed to compile
grep -i "CoreCompile.*FAILED\|Build FAILED\|error MSB" full.log

# Find project build order and results
grep "done building project\|Building with" full.log | head -50

# List all projects that ran CoreCompile
grep 'Target "CoreCompile"' full.log | grep -oP 'project "[^"]*"'

# Compare against projects that had errors to identify cascading failures
grep "project.*FAILED" full.log

# Read the .csproj of the failing project
cat path/to/Services/Services.csproj

# Check PackageReference and ProjectReference entries
grep -n "PackageReference\|ProjectReference" path/to/Services/Services.csproj

# The PerformanceSummary is at the end of full.log
tail -100 full.log   # shows target/task timing summary
grep "Target Performance Summary\|Task Performance Summary" -A 50 full.log

# Check evaluation properties
grep -i "OutputPath\|IntermediateOutputPath\|TargetFramework" full.log | head -30
# Check item groups
grep "PackageReference\|ProjectReference" full.log | head -30

dotnet build /bl:build.binlog

© runceel, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in .agents/skills/binlog-failure-analysis of runceel/ReactiveProperty.

Open the folder on GitHubat commit e7e6474