quickstart-debug-api-endpoints

Systematic API testing and debugging workflow for the Tessl quickstart guide.

Overview

This tile provides a skill that guides your coding agent through a systematic workflow for testing and debugging Express.js API endpoints. The skill activates when you ask your agent to test or debug APIs.

Type: Skill Name: tessl-labs/quickstart-debug-api-endpoints Version: 1.0.0

What's Included

Skill: debug-api-endpoints

Located in skills/debug-api-endpoints/SKILL.md, this skill provides a 4-step systematic testing workflow:

1. Verify Infrastructure

   • Server starts successfully
   • Health check responds
   • Database connection works
   • Environment variables loaded

2. Verify Security

   • Authentication (no token → 401, invalid token → 401, valid token → success)
   • Authorization (wrong role → 403, correct role → success)

3. Verify Validation

   • Required fields
   • Data formats and types
   • Boundary conditions
   • Sanitization (XSS, SQL injection prevention)

4. Verify Functionality

   • Happy paths (valid requests succeed)
   • Edge cases (duplicates, not found, empty lists)
   • Error scenarios (database errors, timeouts, race conditions)

Installation

From Tessl Registry

tessl install tessl-labs/quickstart-debug-api-endpoints

From Local Path

tessl install file:./tiles/tessl-demo/quickstart-debug-api-endpoints

How It Works

Skills are lazy push - they load when relevant:

1. Install the tile
2. Skill becomes available to your agent
3. When you ask to test/debug an API, the skill activates
4. Your agent follows the systematic workflow

Example Usage

After installing this tile, ask your agent:

"Test the /api/posts endpoint"

Your agent will:

• Follow the 4-step workflow systematically
• Check infrastructure before testing endpoints
• Verify security before validation
• Test validation before functionality
• Provide organized, comprehensive test coverage

Instead of random test patterns, you get:

✓ Infrastructure: Server running, health check OK
✓ Security: Auth token required, 401 without token
✓ Validation: Required fields checked, formats validated
✓ Functionality: Happy path works, errors handled correctly

When to Use

Use this skill when you need to:

• Write tests for a new API endpoint
• Debug issues with an existing endpoint
• Verify changes didn't break anything
• Ensure coverage of security and validation

Troubleshooting Order

The skill teaches your agent to debug in this order:

1. Infrastructure problem? → Check logs, database, environment
2. Security problem? → Verify tokens, permissions
3. Validation problem? → Review payload, required fields
4. Functionality problem? → Debug business logic, queries

Used In

This tile is referenced in:

• Quick Start: Skills, Docs, and Rules

Related Tiles

• quickstart-express-api-standards - API coding standards (rules)