SKILL.md
API Research
Find and validate real, live data sources. No hardcoded data allowed.
Step 1: Search for APIs
# Web search for APIs
web_search "<topic> free API"
web_search "<topic> public API documentation"
web_search "<topic> real-time data API"
web_search "<topic> JSON API no auth"
Step 2: Validate API Endpoints
Test each potential API:
# Test endpoint directly
curl -s "<api_endpoint>" | head -c 500
# Check response
# ✅ Returns JSON with real data
# ✅ No authentication required (or has free tier)
# ✅ Response time < 5 seconds
# ❌ Returns error or empty
# ❌ Requires paid API key
Common Free Data Sources
Finance & Crypto
| API |
Endpoint |
Notes |
| DeFiLlama |
https://api.llama.fi/v2/chains |
TVL, yields, derivatives |
| CoinGecko |
https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=usd |
Prices, trending |
| Yahoo Finance |
https://query1.finance.yahoo.com/v8/finance/chart/AAPL |
Stocks (unofficial) |
| Exchange Rates |
https://api.exchangerate.host/latest |
Currency rates |
Weather & Environment
| API |
Endpoint |
Notes |
| Open-Meteo |
https://api.open-meteo.com/v1/forecast?latitude=52&longitude=13¤t_weather=true |
No key needed |
| wttr.in |
https://wttr.in/London?format=j1 |
Simple weather |
| NOAA Space Weather |
https://services.swpc.noaa.gov/products/noaa-scales.json |
Space weather |
Geology & Space
| API |
Endpoint |
Notes |
| USGS Earthquakes |
https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/significant_week.geojson |
Real-time |
| NASA APOD |
https://api.nasa.gov/planetary/apod?apikey=DEMOKEY |
Demo key works |
| ISS Location |
http://api.open-notify.org/iss-now.json |
Real-time position |
General Purpose
| API |
Endpoint |
Notes |
| IP Geolocation |
http://ip-api.com/json/ |
IP info |
| Countries |
https://restcountries.com/v3.1/all |
Country data |
| Universities |
http://universities.hipolabs.com/search?country=united+states |
School data |
| Random User |
https://randomuser.me/api/ |
Test data |
| Quotes |
https://api.quotable.io/random |
Random quotes |
| Jokes |
https://v2.jokeapi.dev/joke/Any |
Random jokes |
| Books |
https://openlibrary.org/search.json?q=lord+of+the+rings |
Book data |
| Wikipedia |
https://en.wikipedia.org/api/restv1/page/summary/Claude(AI) |
Summaries |
| GitHub |
https://api.github.com/users/langoustine69 |
User/repo data |
Sports & Entertainment
| API |
Endpoint |
Notes |
| ESPN |
https://site.api.espn.com/apis/site/v2/sports/football/nfl/scoreboard |
Live scores |
| OMDB |
https://www.omdbapi.com/?t=inception&apikey=<free_key> |
Movies (free key) |
Step 3: Design Endpoints
Based on validated APIs, design 6 endpoints:
| Endpoint |
Type |
Price |
Data Source |
overview |
Free |
$0 |
Quick summary for discovery |
lookup |
Paid |
$0.001 |
Single item by ID/name |
search |
Paid |
$0.002 |
Filtered list query |
top |
Paid |
$0.002 |
Rankings/leaderboards |
compare |
Paid |
$0.003 |
Multi-item comparison |
report |
Paid |
$0.005 |
Comprehensive analysis |
Output
Provide:
- Validated API endpoints (tested, working)
- 6 endpoint designs with descriptions
- Data mapping (which API feeds which endpoint)
Red Flags
- ❌ API requires paid key with no free tier
- ❌ Rate limits too strict (< 100 req/day)
- ❌ Data is stale (not updated regularly)
- ❌ Endpoint returns HTML instead of JSON
- ❌ Requires OAuth/complex auth flow
Next Step
→ Use lucid-agents-sdk skill to create the agent code
