Install the "experimental-code-coverage-config-validator" agent skill from https://github.com/nwjs/chromium.src/tree/main/agents/skills/experimental-code-coverage-config-validator into .claude/skills/experimental-code-coverage-config-validator/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experimental-code-coverage-config-validator", then confirm the skill loads.
Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
skills CLI
$ npx skills add nwjs/chromium.src --skill experimental-code-coverage-config-validator -a codex
Project install goes to .agents/skills/; add -g for ~/.codex/skills/.
Install the "experimental-code-coverage-config-validator" agent skill from https://github.com/nwjs/chromium.src/tree/main/agents/skills/experimental-code-coverage-config-validator into .agents/skills/experimental-code-coverage-config-validator/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experimental-code-coverage-config-validator", then confirm the skill loads.
Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
skills CLI
$ npx skills add nwjs/chromium.src --skill experimental-code-coverage-config-validator -a cursor
Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.
Install the "experimental-code-coverage-config-validator" agent skill from https://github.com/nwjs/chromium.src/tree/main/agents/skills/experimental-code-coverage-config-validator into .cursor/skills/experimental-code-coverage-config-validator/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experimental-code-coverage-config-validator", then confirm the skill loads.
Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
skills CLI
$ npx skills add nwjs/chromium.src --skill experimental-code-coverage-config-validator -a gemini-cli
Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.
Install the "experimental-code-coverage-config-validator" agent skill from https://github.com/nwjs/chromium.src/tree/main/agents/skills/experimental-code-coverage-config-validator into .gemini/skills/experimental-code-coverage-config-validator/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experimental-code-coverage-config-validator", then confirm the skill loads.
Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
skills CLI
$ npx skills add nwjs/chromium.src --skill experimental-code-coverage-config-validator -a github-copilot
Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.
Install the "experimental-code-coverage-config-validator" agent skill from https://github.com/nwjs/chromium.src/tree/main/agents/skills/experimental-code-coverage-config-validator into .github/skills/experimental-code-coverage-config-validator/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experimental-code-coverage-config-validator", then confirm the skill loads.
GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
skills CLI
$ npx skills add nwjs/chromium.src --skill experimental-code-coverage-config-validator -a opencode
OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
Install the "experimental-code-coverage-config-validator" agent skill from https://github.com/nwjs/chromium.src/tree/main/agents/skills/experimental-code-coverage-config-validator into .opencode/skills/experimental-code-coverage-config-validator/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experimental-code-coverage-config-validator", then confirm the skill loads.
OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
Skill name
experimental-code-coverage-config-validator
GitHub stars
160
Token cost
~1.1k tokens
SKILL.md length
399 words
Files
1
Skills in repo
64
Repo updated
First seen
Licence
BSD-3-Clause
At a glance
Validates Chromium generated builder configurations (gn-args.json) for code coverage correctness based on language context.
Works in 5 steps: Locate GN Args File: Search for… → Inspect Configuration: Examine the… → Perform Checks: Check each required… → …
Tasks that involve Test coverage
SKILL.md covers Inputs, When to Use This Skill, Validation Checks and Step-by-Step Execution, plus 1 more section
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Experimental Code Coverage Config Validator is an agent skill from nwjs/chromium.src. Validates Chromium generated builder configurations (gn-args.json) for code coverage correctness based on language context.
Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Testing & QA, covering Test coverage. It works with C++. The repository describes itself as: Chromium codebase with NW.js modifications. Based on https://chromium.googlesource.com/chromium/src.git. The licence is BSD-3-Clause.
When your agent uses it
Tasks that involve Test coverage
Example prompts
“Use the experimental-code-coverage-config-validator skill to validate Chromium generated builder configurations (gn-args.json) for code coverage…”
“/experimental-code-coverage-config-validator”
Requirements
Python 3
Workflow steps
5 steps, taken from the first numbered list in SKILL.md.
1Locate GN Args File: Search for builder_name inside
2Inspect Configuration: Examine the "gn_args" dictionary in the JSON.
3Perform Checks: Check each required key-value pair as defined in the
4Generate Report
5Environment Reminder: If language_context is "cpp", "objc", or
What it can do on your machine
Read from SKILL.md and the folder at commit a9e8946. 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
No scripts in the folder and no shell commands in SKILL.md.
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
Experimental Code Coverage Config Validator loads about 1.1k tokens when it runs. Until then it costs about 42 tokens; SKILL.md has 399 words of instructions outside code blocks.
Always· name and description, kept in context so the agent knows when to use it
~42
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
Auto-check passed
The automated check found no risky patterns in SKILL.md.
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.
Download SKILL.mdSave it as .claude/skills/experimental-code-coverage-config-validator/SKILL.md (or your agent's skills folder).
name
experimental-code-coverage-config-validator
description
Validates Chromium generated builder configurations (gn-args.json) for code coverage correctness based on language context.
Code Coverage Config Validator
Use this skill to verify if a Chromium builder is correctly configured in its
generated GN arguments (gn-args.json) to produce code coverage data.
Inputs
When invoking this skill, the caller MUST pass the following inputs in the
prompt:
builders_of_concern: Target builder names to validate (e.g.,
["linux-rel"]). To locate the Starlark .star definition file for each
builder, reference:
builder_star_map.json.
language_context: The programming language context ("cpp", "objc",
"rust", "java", "js", or "ts"). Consult
language_coverage_map.json for authoritative mappings.
When to Use This Skill
Verifying if a builder has the correct GN arguments for code coverage.
Debugging why code coverage artifacts are missing or not updated.
Triaging a code coverage bug where builder configuration needs validation.
Validation Checks
Consult language_coverage_map.json for the required settings mapped
to language_context. Verify that the builder's configuration (gclient_config
and generated gn-args.json) satisfies both:
gclient Configuration: Inspect builder_spec.gclient_config to confirm
any required_gclient_vars (e.g., checkout_clang_coverage_tools set via
apply_configs = ["use_clang_coverage"]).
GN Arguments (gn_args): Inspect generated gn-args.json to confirm all
required_gn_args are present.
Step-by-Step Execution
Locate GN Args File: Search for builder_name inside
infra/config/generated/builders/gn_args_locations.json to resolve its
relative path (e.g., "try/linux-rel/gn-args.json"). Read the JSON file at
infra/config/generated/builders/<relative_path>.
Inspect Configuration: Examine the "gn_args" dictionary in the JSON.
Perform Checks: Check each required key-value pair as defined in the
Validation Checks section for the given language_context.
Generate Report:
Validation Success: If all checks pass, report builder is valid.
Validation Failure: Detail missing or incorrect configurations.
Recommend updating the builder's Starlark file and regenerating configs via
lucicfg generate infra/config/main.star.
Environment Reminder: If language_context is "cpp", "objc", or
"rust", append a reminder that local Clang code coverage generation
requires "checkout_clang_coverage_tools": True in the developer's
~/.gclient file under custom_vars.
Show full SKILL.md (119 more words)Show less
Example Outputs
Example 1: Successful Validation (C++)
Builder linux-rel validation successful for language context cpp. All
required GN arguments (use_clang_coverage = true, is_clang = true, and
is_debug = false) are present in gn-args.json.
Example 2: Failed Validation (C++)
Builder linux-rel for language context cpp requires updates:
LACKING: "is_debug": false is missing in gn-args.json.
SUGGESTED CHANGE: Update the Starlark builder definition to set
is_debug = False and run lucicfg generate infra/config/main.star.
REMINDER: For local C++ coverage generation, ensure your ~/.gclient
file contains:
Experimental Code Coverage Config Validator next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
Experimental Code Coverage Config Validator compared with similar skills
Skill
Stars
Used in
Tokens
Auto-check
Licence
Repo updated
Experimental Code Coverage Config Validator this skillnwjs/chromium.src
Sets the test-writing workflow for the repository: risk-first scenario lists, behavior-focused Vitest tests, a full run before each commit and a coverage target.
Diagnose Chromium GN dependency and include-visibility failures, including BUILD.gn deps/publicdeps, DEPS include rules, private headers, and circular dependencies.
Questions about Experimental Code Coverage Config Validator
What does Experimental Code Coverage Config Validator do?
Validates Chromium generated builder configurations (gn-args.json) for code coverage correctness based on language context. src.json) for code coverage correctness based on language context.
When should I use Experimental Code Coverage Config Validator?
Experimental Code Coverage Config Validator fits situations like: tasks that involve Test coverage.
How do I install Experimental Code Coverage Config Validator in Claude Code?
Run `npx skills add nwjs/chromium.src --skill experimental-code-coverage-config-validator -a claude-code`. Or copy the skill folder (agents/skills/experimental-code-coverage-config-validator in nwjs/chromium.src) into .claude/skills/experimental-code-coverage-config-validator in your project. Claude Code loads it when a task matches its description.
How do I install Experimental Code Coverage Config Validator in Codex?
Run `npx skills add nwjs/chromium.src --skill experimental-code-coverage-config-validator -a codex`. Or copy the skill folder (agents/skills/experimental-code-coverage-config-validator in nwjs/chromium.src) into .agents/skills/experimental-code-coverage-config-validator in your project. Codex loads it when a task matches its description.
Can I use Experimental Code Coverage Config Validator in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add nwjs/chromium.src --skill experimental-code-coverage-config-validator -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/experimental-code-coverage-config-validator, .gemini/skills/experimental-code-coverage-config-validator, .github/skills/experimental-code-coverage-config-validator and .opencode/skills/experimental-code-coverage-config-validator in your project.
What does Experimental Code Coverage Config Validator need to run?
SKILL.md names no scripts, command-line tools or credentials: Experimental Code Coverage Config Validator is instructions for the agent only. Our summary lists: Python 3.
Does Experimental Code Coverage Config Validator access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Experimental Code Coverage Config Validator safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Experimental Code Coverage Config Validator use?
Experimental Code Coverage Config Validator is published under the BSD-3-Clause licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Experimental Code Coverage Config Validator use?
About 1.1k tokens (SKILL.md is roughly 4.4k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Experimental Code Coverage Config Validator?
Skills that share tags, products or a category with Experimental Code Coverage Config Validator: OpenROAD Module Test Adder (The-OpenROAD-Project/OpenROAD, 3.2k stars), Testing (hw-native-sys/pypto, 126 stars), Review Op Test Coverage (CVCUDA/CV-CUDA, 2.7k stars) and Coverage (thun-res/vlink, 115 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Experimental Code Coverage Config Validator?
nwjs (a GitHub organization) maintains it in nwjs/chromium.src, which has 160 GitHub stars. The repository holds 64 skills in this directory. The repository was last updated on October 3, 2026.
Source: nwjs/chromium.src on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.
