Config Validator

KrakenD Configuration Validator

Purpose

Validates KrakenD configurations with specific error fixes, edition compatibility checks, anti-pattern detection, and automatic Flexible Configuration support with actionable feedback.

When to activate

• User asks to validate a KrakenD configuration
• User mentions "check config", "validate krakend", "is this valid", "config errors"
• User has JSON syntax errors in krakend.json
• User wants to verify CE vs EE compatibility

What this skill does

Validates JSON syntax with specific line/column error reporting, checks edition compatibility (CE vs EE features), detects configuration issues using smart three-tier validation (native → Docker → schema), auto-detects Flexible Configuration (CE and EE variants), and provides specific fixes with exact locations and documentation links.

CRITICAL: Anti-Hallucination Rules

YOU MUST FOLLOW THESE RULES - NO EXCEPTIONS:

✅ DO:

• Only fix errors explicitly listed in validation output
• Read the guidance field in every validation result (contains binding instructions)
• Search KrakenD documentation when uncertain about syntax
• Trust validation output as authoritative

❌ DON'T:

• Suggest fixes based on assumptions, patterns, or intuition
• Add corrections that aren't in the error list
• Guess syntax based on patterns from other systems
• Add fields that "should be there" without validation saying so

Example:

• ❌ WRONG: Validation says "unknown field: 'backend'" → You suggest "backends" (hallucination)
• ✅ CORRECT: Validation says "missing field 'timeout'" → You suggest adding timeout

KrakenD-Specific Quirks

Flexible Configuration: CE uses .tmpl files with Go templates (requires FCENABLE=1, FCSETTINGS env vars). EE uses flexible_config.json (auto-detected, no env vars). Skill auto-detects FC variant and adjusts validation commands automatically. Schema: Always use versionless https://www.krakend.io/schema/krakend.json Docker/Edition: CE uses krakend image, EE uses krakend/krakend-ee image (requires LICENSE file) Validation Tiers: Native krakend check (most accurate) > Docker > JSON Schema

Dynamic Sources

• Documentation: Search KrakenD documentation to verify syntax when uncertain
• Edition Compatibility: Check edition requirements (CE vs EE) or browse https://www.krakend.io/features/
• Runtime Detection: ALWAYS call detect_runtime_environment tool BEFORE running any KrakenD command. Use its command_template and recommended_image fields - NEVER invent Docker images or commands.
• KrakenD MCP Tools: Use the available tools for validation, edition checking, and documentation search. Always read the guidance field in validation results.

Example Interaction

User: "Validate my krakend.json" Response pattern: Detect runtime environment, run validation, read guidance field from results, report errors with exact locations, suggest fixes ONLY for errors listed (never assume), offer to re-validate after fixes.

Edge Cases

• Flexible Configuration detected: Auto-detect CE (.tmpl) or EE (flexible_config.json) variant, adjust validation
• EE features in config: Report which features require Enterprise Edition, explain their benefits - only suggest CE workarounds if user asks
• Validation tool unavailable: Fall back through tiers (native → Docker → schema), inform user of method

Integration

• Create new config → Hand off to config-builder skill
• "How to add X" → Hand off to feature-explorer skill
• Validation passes but user wants security audit → Hand off to security-auditor skill
• Validation passes and user wants to run KrakenD → Hand off to runtime-detector skill

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: krakend
• Source: krakend/claude-code-plugin
• License: Apache-2.0
• Homepage: https://github.com/krakend/claude-code-plugin

Install and usage instructions live in the source repository linked above.