optimizing-msbuild-performance

Guides performance optimization for MSBuild engine code. Consult when working on hot paths in evaluation or execution, reducing allocations, choosing collection types, handling strings efficiently, modifying Expander.cs or Evaluator.cs, using Span<T>/stackalloc, caching values, or profiling build performance. Also applies when reviewing PRs for performance regression.

Quality

87%

Does it follow best practices?

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Securityby

Passed

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Quality

Content

83%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The body is an exemplary lean, actionable performance reference with concrete APIs and anti-pattern fixes. Its main limitation is workflow_clarity, since as a guidelines reference it lacks an explicit validation feedback loop, and its external references are not backed by bundle files.

Suggestions

Add a short ordered 'Optimization workflow' (profile -> identify hot path -> apply rule -> re-measure) with an explicit verify/re-measure checkpoint to raise workflow_clarity.

Either provide the referenced files under a references/ bundle (evaluation-profiling.md, General_perf_onepager.md) or relabel the links as external repo documentation so progressive_disclosure reflects real bundle structure.

Consider a one-line 'Use when' trigger summary at the top of the body to mirror the description's trigger guidance.

Dimension	Reasoning	Score
Conciseness	Lean and efficient throughout — assumes Claude knows C#, LINQ, and MSBuild; every table, rule, and code snippet earns its place with no padded concept explanations.	5 / 5
Actionability	Fully executable guidance: named APIs (MSBuildNameIgnoreCaseComparer, TryGetValue, ImmutableArray<T>), copy-pasteable GOOD/BAD code, and a concrete anti-pattern table each with a specific fix.	5 / 5
Workflow Clarity	This is a reference/guideline skill rather than a multi-step process, and while the guiding principle prescribes 'profile before optimizing' with measurement tools as a checkpoint, there is no explicit validate->fix->retry sequence to push it above the mid anchor.	3 / 5
Progressive Disclosure	Well-organized into clear sections with one-level-deep external references, but the two referenced documentation files point outside the bundle and no references/scripts/assets bundle files exist, leaving minor organization gaps versus a fully self-contained overview.	4 / 5
	Total	17 / 20 Passed

Description

91%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

The description is specific, complete, and distinctive, clearly stating both the capability set and the situations that should trigger it. Trigger term quality is strong but slightly favors technical phrasing over the most colloquial synonyms.

Dimension	Reasoning	Score
Specificity	Lists multiple concrete actions — 'reducing allocations, choosing collection types, handling strings efficiently, modifying Expander.cs or Evaluator.cs, using Span<T>/stackalloc, caching values, or profiling build performance' — giving comprehensive coverage of the skill's capabilities.	5 / 5
Completeness	Explicitly answers both what ('Guides performance optimization for MSBuild engine code') and when ('Consult when working on hot paths... Also applies when reviewing PRs for performance regression') with concrete trigger phrases.	5 / 5
Trigger Term Quality	Good natural-term coverage with 'hot paths', 'performance regression', 'reviewing PRs', and 'profiling build performance'; not a 5 because it leans slightly technical and omits common synonyms a user might say like 'slow build' or 'speed up MSBuild'.	4 / 5
Distinctiveness Conflict Risk	A clear niche — MSBuild engine performance, named source files (Expander.cs, Evaluator.cs) and APIs — makes it highly distinguishable with minimal conflict risk against other skills.	5 / 5
	Total	19 / 20 Passed

Validation

87%

Warnings & errors only

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 14 / 16 Passed

Validation for skill structure

Criteria	Description	Result
frontmatter_unknown_keys	Unknown frontmatter key(s) found; consider removing or moving to metadata	Warning
relative_links	Relative link issues: 2 suspicious	Warning

	Total	14 / 16 Passed

Repository: dotnet/msbuild
Path: .github/skills/optimizing-msbuild-performance/SKILL.md
Commit: b75ae9e

Reviewed: 1 day ago

Table of Contents

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