A Claude Code skill that lets Claude query the MirrorMarket Prediction Market Intelligence API — a live comparison layer between Polymarket and Kalshi.

When installed, you can ask Claude things like:

• "Where are Polymarket and Kalshi disagreeing the most right now?"
• "Which platform has stronger longshot bias today?"
• "Top 5 Polymarket markets by 24h volume"
• "Find tradeable arbitrage with both sides liquid"

Claude will pick the right endpoint, filter, and return the answer.

The skill teaches Claude:

• The base URL and every endpoint (/arbitrage, /calibration, /markets/polymarket, /markets/kalshi, /refresh)
• The schema of every response object
• How to filter noisy matches (similarity threshold, both-sides-liquid)
• Sensible jq recipes for the most common questions
• The known limitations (snapshot-only, fuzzy matching, no resolution data)

git clone https://github.com/fozagtx/mirrormarkets.git

Claude Code reads user-level skills from ~/.claude/skills/. Each skill lives in its own subfolder.

mkdir -p ~/.claude/skills
mv mirrormarkets ~/.claude/skills/mirrormarket

The folder name (mirrormarket) becomes the slash command — /mirrormarket.

Project-scoped install instead? Drop the folder at <project-root>/.claude/skills/mirrormarket and it'll only load inside that project.

Skills are picked up at startup. Quit and reopen Claude Code (or run /reload if your version supports it).

In any Claude Code session, type:

/mirrormarket

…or just ask a natural-language question:

Are there any arbitrage opportunities between Polymarket and Kalshi today?

Claude should invoke the skill automatically.

mirrormarkets/
├── README.md     ← this file
└── SKILL.md      ← the skill definition Claude reads

SKILL.md is the only file Claude needs. The YAML frontmatter (name, description) tells Claude when to invoke it; everything below is the playbook.

No API key required — the MirrorMarket API is currently public.

If the API URL changes, edit SKILL.md and update the Base URL line.

cd ~/.claude/skills/mirrormarket
git pull

Restart Claude Code to pick up changes.

rm -rf ~/.claude/skills/mirrormarket

The API and this skill output are not financial advice. Match-quality is fuzzy — always check the similarity score on arbitrage rows before acting on them.