Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/bskimball/tanstack-hono/react-expertnpx skills add bskimball/tanstack-hono --skill react-expertgit clone --depth 1 https://github.com/bskimball/tanstack-honoWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00034 | $0.02624 |
| Opus 5 | $0.00017 | $0.01312 |
| Sonnet 5 | $0.00007 | $0.00525 |
| Haiku 4.5 | $0.00003 | $0.00262 |
Grade A, and why
react-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 336 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Expert Research Skill
Overview
This skill produces exhaustive documentation research on any React API or concept by searching authoritative sources (tests, source code, PRs, issues) rather than relying on LLM training knowledge.
Red Flags - STOP if you catch yourself thinking:
- "I know this API does X" → Find source evidence first
- "Common pattern is Y" → Verify in test files
- Generating example code → Must have source file reference
Invocation
/react-expert useTransition
/react-expert suspense boundaries
/react-expert startTransition
Sources (Priority Order)
- React Repo Tests - Most authoritative for actual behavior
- React Source Code - Warnings, errors, implementation details
- Git History - Commit messages with context
- GitHub PRs & Comments - Design rationale (via
ghCLI) - GitHub Issues - Confusion/questions (facebook/react + reactjs/react.dev)
- React Working Group - Design discussions for newer APIs
- Flow Types - Source of truth for type signatures
- TypeScript Types - Note discrepancies with Flow
- Current react.dev docs - Baseline (not trusted as complete)
No web search - No Stack Overflow, blog posts, or web searches. GitHub API via gh CLI is allowed.
Workflow
Step 1: Setup React Repo
First, ensure the React repo is available locally:
# Check if React repo exists, clone or update
if [ -d ".claude/react" ]; then
cd .claude/react && git pull origin main
else
git clone --depth=100 https://github.com/facebook/react.git .claude/react
fi
Get the current commit hash for the research document:
cd .claude/react && git rev-parse --short HEAD
Step 2: Dispatch 6 Parallel Research Agents
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 336 lines · 34 tokens per session scan A bdaa978ac67a
react-expert is a skill published in the GitHub repository bskimball/tanstack-hono (119 stars, last pushed 21d ago), licensed MIT. It adds 34 tokens to every session and 2,624 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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