Mole Bug Patterns
tw93/Mole
A catalog of recurring bug shapes in the Mole Mac cleaner, used to review safety-sensitive diffs for deletion safety, unbounded commands, shell traps and weak tests.
A skill your agent uses when reviewing scripts, client components, bundles, or runtime behavior related to Parse JSON safely with error handling.
Install JSON Safety
$ npx skills add thedaviddias/Front-End-Checklist --skill json-safety -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install thedaviddias/Front-End-Checklist json-safety --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/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/json-safety .claude/skills/json-safety && 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 "json-safety" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/json-safety into .claude/skills/json-safety/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "json-safety", 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/thedaviddias/Front-End-Checklist/tree/main/skills/json-safetyType 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 thedaviddias/Front-End-Checklist --skill json-safety -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install thedaviddias/Front-End-Checklist json-safety --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/json-safety .agents/skills/json-safety && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "json-safety" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/json-safety into .agents/skills/json-safety/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "json-safety", 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 thedaviddias/Front-End-Checklist --skill json-safety -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install thedaviddias/Front-End-Checklist json-safety --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/json-safety .cursor/skills/json-safety && 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 "json-safety" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/json-safety into .cursor/skills/json-safety/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "json-safety", 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/thedaviddias/Front-End-Checklist.git --path skills/json-safety--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 thedaviddias/Front-End-Checklist --skill json-safety -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install thedaviddias/Front-End-Checklist json-safety --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/json-safety .gemini/skills/json-safety && 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 "json-safety" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/json-safety into .gemini/skills/json-safety/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "json-safety", 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 thedaviddias/Front-End-Checklist json-safetyInstalls 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 thedaviddias/Front-End-Checklist --skill json-safety -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/json-safety .github/skills/json-safety && 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 "json-safety" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/json-safety into .github/skills/json-safety/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "json-safety", 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 thedaviddias/Front-End-Checklist --skill json-safety -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install thedaviddias/Front-End-Checklist json-safety --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/json-safety .opencode/skills/json-safety && 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 "json-safety" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/json-safety into .opencode/skills/json-safety/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "json-safety", 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
json-safety- GitHub stars
- 74k
- Token cost
- ~512 tokens
- SKILL.md length
- 221 words
- Files
- 2 (incl. references)
- Skills in repo
- 390
- Repo updated
- First seen
- Licence
- MIT
At a glance
A skill your agent uses when reviewing scripts, client components, bundles, or runtime behavior related to Parse JSON safely with error handling.
- Reviewing scripts
- SKILL.md covers Quick Reference, Check, Fix and Explain, plus 1 more section
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Client components
What it does
JSON Safety is an agent skill from thedaviddias/Front-End-Checklist. Use when reviewing scripts, client components, bundles, or runtime behavior related to Parse JSON safely with error handling. Inspect both source code and the browser execution path so fixes target the real bottleneck or bug.
Its SKILL.md is about 510 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/rule.md`).
It sits in Development, covering Error handling. The repository describes itself as: 🗂 The essential checklist for modern web development, for humans and AI agents. The licence is MIT.
When your agent uses it
- Reviewing scripts
- Client components
- Runtime behavior related to Parse JSON safely with error handling
Example prompts
- “/json-safety”
What it can do on your machine
Read from SKILL.md and the folder at commit e8d14d0. 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
Links to these hosts (documentation or services it may open):
frontendchecklist.io
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
JSON Safety loads about 512 tokens when it runs, and up to ~1.5k if it reads all its reference files. Until then it costs about 59 tokens; SKILL.md has 221 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
The full file from thedaviddias/Front-End-Checklist at commit e8d14d0, republished under its MIT licence (© thedaviddias). 221 words, ~512 tokens.
Download SKILL.mdSave it as
.claude/skills/json-safety/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.- name
- json-safety
- description
- Use when reviewing scripts, client components, bundles, or runtime behavior related to Parse JSON safely with error handling. Inspect both source code and the browser execution path so fixes target the real bottleneck or bug.
- metadata.category
- javascript
- metadata.priority
- medium
- metadata.difficulty
- beginner
- metadata.estimatedTime
- 10
- metadata.source
- frontendchecklist.io
- metadata.url
- https://frontendchecklist.io/rules/javascript/json-safety
Parse JSON safely with error handling
JSON.parse() on invalid input throws a SyntaxError that will crash your application if uncaught. API responses, localStorage values, and user-provided data can all be malformed. Safe parsing with validation catches these errors at the point of parsing, not deep in your application logic when a missing property causes an unexpected error.
Quick Reference
- JSON.parse() throws a SyntaxError on invalid input — always use try/catch
- Validate the shape of parsed data before accessing its properties
- JSON.stringify() can return undefined for values that can't be serialized
- Use a type-safe parser (Zod, Valibot) for data from external sources
Check
Find all JSON.parse() calls in this file and check whether each one is wrapped in try/catch and whether the result is validated before use.
Fix
Add try/catch error handling to all JSON.parse() calls and add shape validation to protect against unexpected data structures.
Explain
Explain why JSON.parse can throw, what safe JSON parsing looks like, and when to use schema validation libraries.
Code Review
Review scripts, client components, and browser execution paths related to Parse JSON safely with error handling. Flag exact imports, event handlers, runtime side effects, or blocking operations that violate the rule, and state how the change should be verified in the browser.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/rules/javascript/json-safety
© thedaviddias, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 1 other file (references) in skills/json-safety of thedaviddias/Front-End-Checklist.
- SKILL.md
- references/rule.md
Open the folder on GitHubat commit e8d14d0
Compare with similar skills
JSON Safety 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 |
|---|---|---|---|---|---|---|
| JSON Safety this skillthedaviddias/Front-End-Checklist | 74k | — | ~512 | Automated safety check: Pass | MIT | |
| Mole Bug Patternstw93/Mole | 70k | — | ~2k | Automated safety check: Pass | GPL-3.0 | |
| Native Data FetchingCherryHQ/cherry-studio-app | 4k | 6 repos | ~2.9k | Automated safety check: Notes | MIT | |
| Rust Best Practicesfarm-fe/farm | 5.6k | 3 repos | ~1.1k | Automated safety check: Pass | MIT | |
| R Function Input Validationtidyverse/dplyr | 5.1k | 1 repos | ~2.3k | Automated safety check: Pass | Custom licence | |
| Next Best Practicesvercel-labs/openreview | 1.7k | 18 repos | ~1k | Automated safety check: Pass | None |
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Error Handling
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统一错误处理系统。在添加 API 端点、修改错误处理、添加前端 API 调用、编写错误相关测试时使用. An agent skill from microsoft/data-formulator.
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Related
Categories
Questions about JSON Safety
What does JSON Safety do?
A skill your agent uses when reviewing scripts, client components, bundles, or runtime behavior related to Parse JSON safely with error handling. JSON Safety is an agent skill from thedaviddias/Front-End-Checklist. Use when reviewing scripts, client components, bundles, or runtime behavior related to Parse JSON safely with error handling.
When should I use JSON Safety?
JSON Safety fits situations like: reviewing scripts; client components; runtime behavior related to Parse JSON safely with error handling.
How do I install JSON Safety in Claude Code?
Run `npx skills add thedaviddias/Front-End-Checklist --skill json-safety -a claude-code`. Or copy the skill folder (skills/json-safety in thedaviddias/Front-End-Checklist) into .claude/skills/json-safety in your project. Claude Code loads it when a task matches its description.
How do I install JSON Safety in Codex?
Run `npx skills add thedaviddias/Front-End-Checklist --skill json-safety -a codex`. Or copy the skill folder (skills/json-safety in thedaviddias/Front-End-Checklist) into .agents/skills/json-safety in your project. Codex loads it when a task matches its description.
Can I use JSON Safety 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 thedaviddias/Front-End-Checklist --skill json-safety -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/json-safety, .gemini/skills/json-safety, .github/skills/json-safety and .opencode/skills/json-safety in your project.
What does JSON Safety need to run?
SKILL.md names no scripts, command-line tools or credentials: JSON Safety is instructions for the agent only.
Does JSON Safety access the network?
SKILL.md names 1 domain. As links in the text: frontendchecklist.io. This is read from the text; nothing was executed.
Is JSON Safety 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 JSON Safety use?
JSON Safety is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does JSON Safety use?
About 512 tokens (SKILL.md is roughly 2k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 1k tokens, read only when the agent opens those files.
What are the alternatives to JSON Safety?
Skills that share tags, products or a category with JSON Safety: Mole Bug Patterns (tw93/Mole, 70k stars), Native Data Fetching (CherryHQ/cherry-studio-app, 4k stars), Rust Best Practices (farm-fe/farm, 5.6k stars) and R Function Input Validation (tidyverse/dplyr, 5.1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains JSON Safety?
thedaviddias (a GitHub user) maintains it in thedaviddias/Front-End-Checklist, which has 74,421 GitHub stars. The repository holds 390 skills in this directory. The repository was last updated on October 6, 2026.
Source: thedaviddias/Front-End-Checklist on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.