Gauntlet
anomalyco/browser-control
Run a real-world navigation and capability gauntlet on Browser Control across live websites, fix general DOM/ARIA/CDP root causes, benchmark speed and token efficiency, and finish with a mandatory…
Render the running viewer in a real headless browser and assert on what it drew — element geometry, computed colours, wrap points, truncated labels, console errors.
Install Viewer Render
$ npx skills add iopsystems/rezolus --skill viewer-render -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install iopsystems/rezolus viewer-render --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/iopsystems/rezolus.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/viewer-render .claude/skills/viewer-render && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "viewer-render" agent skill from https://github.com/iopsystems/rezolus/tree/main/.claude/skills/viewer-render into .claude/skills/viewer-render/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "viewer-render", 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.
$skill-installer install https://github.com/iopsystems/rezolus/tree/main/.claude/skills/viewer-renderType 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.
$ npx skills add iopsystems/rezolus --skill viewer-render -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install iopsystems/rezolus viewer-render --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/iopsystems/rezolus.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/viewer-render .agents/skills/viewer-render && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "viewer-render" agent skill from https://github.com/iopsystems/rezolus/tree/main/.claude/skills/viewer-render into .agents/skills/viewer-render/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "viewer-render", 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.
$ npx skills add iopsystems/rezolus --skill viewer-render -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install iopsystems/rezolus viewer-render --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/iopsystems/rezolus.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/viewer-render .cursor/skills/viewer-render && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "viewer-render" agent skill from https://github.com/iopsystems/rezolus/tree/main/.claude/skills/viewer-render into .cursor/skills/viewer-render/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "viewer-render", 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.
$ gemini skills install https://github.com/iopsystems/rezolus.git --path .claude/skills/viewer-render--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add iopsystems/rezolus --skill viewer-render -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install iopsystems/rezolus viewer-render --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/iopsystems/rezolus.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/viewer-render .gemini/skills/viewer-render && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "viewer-render" agent skill from https://github.com/iopsystems/rezolus/tree/main/.claude/skills/viewer-render into .gemini/skills/viewer-render/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "viewer-render", 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.
$ gh skill install iopsystems/rezolus viewer-renderInstalls 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).
$ npx skills add iopsystems/rezolus --skill viewer-render -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/iopsystems/rezolus.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/viewer-render .github/skills/viewer-render && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "viewer-render" agent skill from https://github.com/iopsystems/rezolus/tree/main/.claude/skills/viewer-render into .github/skills/viewer-render/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "viewer-render", 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.
$ npx skills add iopsystems/rezolus --skill viewer-render -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install iopsystems/rezolus viewer-render --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/iopsystems/rezolus.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/viewer-render .opencode/skills/viewer-render && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "viewer-render" agent skill from https://github.com/iopsystems/rezolus/tree/main/.claude/skills/viewer-render into .opencode/skills/viewer-render/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "viewer-render", 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
viewer-render- GitHub stars
- 275
- Token cost
- ~1.7k tokens
- SKILL.md length
- 792 words
- Files
- 1
- Skills in repo
- 11
- Repo updated
- First seen
- Licence
- Custom licence
At a glance
Render the running viewer in a real headless browser and assert on what it drew — element geometry, computed colours, wrap points, truncated labels, console errors.
- A change moves pixels (navbar/badge/chart layout
- SKILL.md covers Why this exists, Two traps, both of which bite…, Setup and Use it, plus 6 more sections
- Calls cargo, node and npm
- Responsive behavior
What it does
Viewer Render is an agent skill from iopsystems/rezolus. Render the running viewer in a real headless browser and assert on what it drew — element geometry, computed colours, wrap points, truncated labels, console errors. Use when a change moves pixels (navbar/badge/chart layout, CSS, responsive behavior, theme), when a PR says it "needs a visual check", or when reviewing frontend work under src/viewer/assets/. Covers the gap viewer-smoke names: it asserts payload shape, this asserts rendering.
Its SKILL.md is about 1.7k 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 Productivity & Automation, covering Browser automation. The repository describes itself as: High-resolution, low-overhead systems and service telemetry.
When your agent uses it
- A change moves pixels (navbar/badge/chart layout
- Responsive behavior
- A PR says it needs a visual check
- Reviewing frontend work under src/viewer/assets/
Example prompts
- “needs a visual check”
- “/viewer-render”
Requirements
- Node.js
What it can do on your machine
Read from SKILL.md and the folder at commit 91b85ca. 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:
cargonodenpm
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use npm, which can reach the network depending on how they are called.
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
Viewer Render loads about 1.7k tokens when it runs. Until then it costs about 114 tokens; SKILL.md has 792 words of instructions outside code blocks.
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.
SKILL.md
Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 792 words (~1,694 tokens).
“Three layers of viewer testing already exist and none of them can see the page:”
- name
- viewer-render
Files
Just SKILL.md in .claude/skills/viewer-render of iopsystems/rezolus.
Open the folder on GitHubat commit 91b85ca
Compare with similar skills
Viewer Render 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.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Viewer Render this skilliopsystems/rezolus | 275 | — | ~1.7k | Automated safety check: Pass | Custom licence | |
| Gauntletanomalyco/browser-control | 440 | — | ~1.1k | Automated safety check: Pass | MIT | |
| Browsemr-daedalium/ostack-saas | 114 | 1 repos | ~5.3k | Automated safety check: Notes | MIT | |
| Tabz BrowserGGPrompts/TabzChrome | 147 | — | ~730 | Automated safety check: Pass | MIT | |
| Preview Rostradpc/rostra | 110 | — | ~2.3k | Automated safety check: Pass | None | |
| Pstackno-session/pstack | 134 | — | ~5.6k | Automated safety check: Notes | MIT |
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Preview Rostra
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Use agent-browser to interact with Rostra's live development UI through accessibility snapshots, semantic controls, text entry, and screenshots.
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Write or update the CLI --help text and README section for a new or changed rezolus feature (a subcommand, flag, mode, or behavior change), then prove the help is usable by dispatching a fresh…
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A skill your agent uses when reviewing a Rezolus sampler change before merge — a new sampler, a change to an existing sampler's probes/refresh/metrics, or core changes that affect samplers; or…
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Tag and push a prerelease from the current Cargo.toml version.
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PR
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Create a feature branch, commit changes, push, and open a PR against iopsystems/rezolus
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Related
Questions about Viewer Render
What does Viewer Render do?
Render the running viewer in a real headless browser and assert on what it drew — element geometry, computed colours, wrap points, truncated labels, console errors. Viewer Render is an agent skill from iopsystems/rezolus. Render the running viewer in a real headless browser and assert on what it drew — element geometry, computed colours, wrap points, truncated labels, console errors.
When should I use Viewer Render?
Viewer Render fits situations like: A change moves pixels (navbar/badge/chart layout; responsive behavior; A PR says it needs a visual check; reviewing frontend work under src/viewer/assets/.
How do I install Viewer Render in Claude Code?
Run `npx skills add iopsystems/rezolus --skill viewer-render -a claude-code`. Or copy the skill folder (.claude/skills/viewer-render in iopsystems/rezolus) into .claude/skills/viewer-render in your project. Claude Code loads it when a task matches its description.
How do I install Viewer Render in Codex?
Run `npx skills add iopsystems/rezolus --skill viewer-render -a codex`. Or copy the skill folder (.claude/skills/viewer-render in iopsystems/rezolus) into .agents/skills/viewer-render in your project. Codex loads it when a task matches its description.
Can I use Viewer Render 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 iopsystems/rezolus --skill viewer-render -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/viewer-render, .gemini/skills/viewer-render, .github/skills/viewer-render and .opencode/skills/viewer-render in your project.
What does Viewer Render need to run?
Going by SKILL.md and its folder, Viewer Render needs the command-line tools its instructions call (cargo, node and npm). Our summary lists: Node.js.
Does Viewer Render access the network?
SKILL.md contains no URLs. Its commands use npm, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is Viewer Render 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 Viewer Render use?
Viewer Render has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.
How many tokens does Viewer Render use?
About 1.7k tokens (SKILL.md is roughly 6.8k 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 Viewer Render?
Skills that share tags, products or a category with Viewer Render: Gauntlet (anomalyco/browser-control, 440 stars), Browse (mr-daedalium/ostack-saas, 114 stars), Tabz Browser (GGPrompts/TabzChrome, 147 stars) and Preview Rostra (dpc/rostra, 110 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Viewer Render?
iopsystems (a GitHub organization) maintains it in iopsystems/rezolus, which has 275 GitHub stars. The repository holds 11 skills in this directory. The repository was last updated on October 7, 2026.
Source: iopsystems/rezolus on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.