Curl Skill¶

HTTP client for API testing, validation, and debugging.

Overview¶

The curl skill teaches Amplifier how to:

Test REST APIs
Validate responses
Debug HTTP requests
Send webhooks
Handle authentication

Loading the Skill¶

> Load the curl skill

Once loaded, Amplifier knows HTTP best practices.

When to Use¶

Task	Use Curl
Test API endpoint	✅
Send webhook	✅
Debug HTTP issue	✅
Validate JSON response	✅
Navigate website	❌ Use playwright
Fill web form	❌ Use playwright

Core Patterns¶

Basic GET¶

curl https://api.example.com/users

POST with JSON¶

curl -X POST https://api.example.com/users \
  -H "Content-Type: application/json" \
  -d '{"name": "Alice", "email": "alice@example.com"}'

With Authentication¶

# Bearer token
curl https://api.example.com/me \
  -H "Authorization: Bearer $TOKEN"

# Basic auth
curl -u username:password https://api.example.com/private

Show Headers¶

curl -I https://api.example.com/health  # Headers only
curl -i https://api.example.com/users   # Headers + body

Verbose Mode¶

curl -v https://api.example.com/debug

Response Validation¶

Check Status Code¶

# Get just the status code
curl -o /dev/null -s -w "%{http_code}" https://api.example.com/health

Validate JSON¶

# Pretty print JSON
curl https://api.example.com/users | jq .

# Extract specific field
curl https://api.example.com/users/1 | jq '.name'

# Check array length
curl https://api.example.com/users | jq 'length'

Check Response Time¶

curl -o /dev/null -s -w "Time: %{time_total}s\n" https://api.example.com/

Common Methods¶

GET¶

curl https://api.example.com/resource
curl "https://api.example.com/search?q=term"

POST¶

curl -X POST https://api.example.com/resource \
  -H "Content-Type: application/json" \
  -d '{"key": "value"}'

PUT¶

curl -X PUT https://api.example.com/resource/1 \
  -H "Content-Type: application/json" \
  -d '{"name": "Updated"}'

DELETE¶

curl -X DELETE https://api.example.com/resource/1

PATCH¶

curl -X PATCH https://api.example.com/resource/1 \
  -H "Content-Type: application/json" \
  -d '{"status": "active"}'

Headers¶

Common Headers¶

# Content-Type
-H "Content-Type: application/json"
-H "Content-Type: application/x-www-form-urlencoded"

# Accept
-H "Accept: application/json"

# Authorization
-H "Authorization: Bearer TOKEN"
-H "Authorization: Basic BASE64"

# Custom
-H "X-API-Key: your-key"

Multiple Headers¶

curl https://api.example.com/ \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $TOKEN" \
  -H "Accept: application/json"

File Operations¶

Upload File¶

curl -X POST https://api.example.com/upload \
  -F "file=@document.pdf"

Download File¶

curl -o output.pdf https://example.com/document.pdf

Error Handling¶

Follow Redirects¶

curl -L https://example.com/redirecting-url

Retry on Failure¶

curl --retry 3 https://api.example.com/flaky

Timeout¶

curl --connect-timeout 5 --max-time 10 https://api.example.com/slow

Debugging¶

Verbose Output¶

curl -v https://api.example.com/debug

Shows: - DNS resolution - TCP connection - TLS handshake - Request headers - Response headers

Trace¶

curl --trace - https://api.example.com/debug

Full byte-level trace.

Try It Yourself¶

Exercise 1: Test an API¶

> Load curl skill
> Test the GitHub API: GET https://api.github.com/users/octocat

Exercise 2: POST Request¶

> Send a POST to httpbin.org/post with JSON body {"test": "data"}

Exercise 3: Validate Response¶

> Check if https://api.github.com is returning 200 OK

Common Errors¶

"Connection refused"¶

Server not running
Wrong port
Firewall blocking

"SSL certificate problem"¶

# Skip verification (only for testing!)
curl -k https://self-signed.example.com

"401 Unauthorized"¶

Check authentication header
Verify token is valid
Check token format

Source¶

robotdad/skills/curl/
├── SKILL.md           # Core patterns
├── patterns.md        # Advanced usage
└── troubleshooting.md # Common issues