cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-*.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating user timing marks.

Quality

78%

Does it follow best practices?

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Securityby

Low

Low-risk findings worth noting

Fix and improve this skill with Tessl

tessl review fix ./.github/skills/cpu-profile-analysis/SKILL.md

Quality

Content

65%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.

Highly actionable content with excellent executable code and reference tables, but it is long and monolithic with some redundancy and a destructive in-place reformat step lacking validation. Splitting reference material into bundle files and adding a backup/validation checkpoint would materially improve it.

Suggestions

Move the phase-type and category reference tables plus the buffer-parsing functions into files under references/ or scripts/ and link to them from SKILL.md to reduce inline length and enable progressive disclosure.

Deduplicate the file-size check/parse procedure (currently repeated in Part 1, Part 2, and 'Handling Huge Files') into a single shared snippet or reference.

Add a validation/backup checkpoint before the 'Reformat the File' step that overwrites the original profile/trace file in place (e.g. write to a .pretty.json sibling or confirm with the user first).

Dimension	Reasoning	Score
Conciseness	Mostly efficient dense technical content, but the file-size check and parse logic is repeated across Part 1 step 1, Part 2 step 1, and the 'Handling Huge Files' section, and the 514-line body could be tightened by deduplicating those procedures.	3 / 5
Actionability	Fully executable, copy-paste-ready JavaScript (e.g. parseProfileFromBuffer, parseTraceFromBuffer) with concrete filter thresholds (> 50000 for 50ms) covering the common analysis cases.	5 / 5
Workflow Clarity	Clear numbered sequences for both file types, but the 'Reformat the File' step overwrites the user's original file (fs.writeFileSync(profilePath, ...)) with no backup/validation checkpoint, and there are no explicit validate-fix-retry feedback loops for error recovery.	3 / 5
Progressive Disclosure	Well-sectioned with clear headers, but all content is inlined in a single 514-line SKILL.md; the large phase/category reference tables and buffer-parsing code that belong in separate reference files are inline, and the referenced 'parseSnapshot.ts' has no corresponding bundle file.	3 / 5
	Total	14 / 20 Passed

Description

92%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.

A strong, specific description that clearly states capabilities and explicit 'Use when' triggers with file extensions. Minor room for improvement in adding a few more natural-language synonyms.

Dimension	Reasoning	Score
Specificity	Lists multiple concrete actions ('Analyze V8/Chrome CPU profiles', 'investigating slow functions', 'comparing code paths', 'finding bottlenecks', 'analyzing layout/paint/rendering', 'investigating user timing marks') with comprehensive coverage across both file types.	5 / 5
Completeness	Explicitly answers both what ('Analyze V8/Chrome CPU profiles and DevTools trace files') and when ('Use when: profiling performance, investigating slow functions...') with concrete trigger phrases.	5 / 5
Trigger Term Quality	Good keyword coverage including file extensions ('.cpuprofile', 'Trace-*.json') and natural phrases ('profiling performance', 'slow functions', 'bottlenecks', 'call trees'); a few terms like 'timeToRequest' lean technical and some common synonyms (e.g. 'flame chart', 'performance trace') are missing.	4 / 5
Distinctiveness Conflict Risk	Clear niche tied to specific file extensions (.cpuprofile, Trace-*.json) and profiler-specific triggers; minimal overlap risk with other skills.	5 / 5
	Total	19 / 20 Passed

Validation

93%

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 — 15 / 16 Passed

Validation for skill structure

Criteria	Description	Result
skill_md_line_count	SKILL.md is long (518 lines); consider splitting into references/ and linking	Warning

	Total	15 / 16 Passed

Repository: posit-dev/positron
Path: .github/skills/cpu-profile-analysis/SKILL.md
Commit: 10323ef

Reviewed: 2 days ago

Table of Contents

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