Add empathy and learning links to validation error messages

[Copilot]

Transforms validation errors from technical rejections into educational guidance with context, examples, and documentation links. Addresses feedback that errors were "technically correct but lack empathy and learning resources."

Changes

Error Message Format

• Empathetic openings with context-appropriate emojis (🤔, 💡, ⚠️, 🔒, 🏗️, 📝, 🔍)
• "Why this matters" explanations for security and best practice rules
• Multiple fix options with concrete YAML examples
• Documentation links where applicable
• Conversational tone without blame

Files Updated

• engine_validation.go - Engine recognition and configuration
• dangerous_permissions_validation.go - Write permission security
• mcp_config_validation.go - MCP server configuration
• firewall_validation.go - Log level validation
• sandbox_validation.go - Mount syntax and sandbox config
• runtime_validation.go - Expression sizes, secrets, cache IDs
• features_validation.go - Action tag SHA requirements
• agent_validation.go - Agent files, HTTP transport, engine features

Style Guide
Updated skills/error-messages/SKILL.md with empathetic message template and emoji guidelines.

Example

Before:

invalid engine: gpt-7. Valid engines are: copilot, claude, codex, custom. Example: engine: copilot

After:

🤔 Hmm, we don't recognize the engine 'gpt-7'.

Valid options are:
  • copilot (GitHub Copilot)
  • claude (Anthropic Claude)
  • codex (OpenAI Codex)
  • custom (your own engine)

Example:
  engine: copilot

Need help choosing? See: https://githubnext.github.io/gh-aw/reference/engines/

Testing

Core validation tests updated to match new message patterns. Some integration tests still reference old message format and will need updates in follow-up work.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[plan] Add empathy and learning links to validation error messages</issue_title>
<issue_description>## Objective

Transform validation error messages from technical rejections into empathetic, educational guidance that helps developers learn and fix issues quickly.

Context

Parent Issue: This is part of the user experience improvements tracked in the parent issue.

Source: Delight Audit identified that validation errors in pkg/workflow/*validation*.go files are technically correct but lack empathy and learning resources, creating friction for first-time users.

Current State: Errors like this are common:

return fmt.Errorf("invalid engine: %s. Valid engines are: copilot, claude, codex, custom. Example: engine: copilot", engineID)

Target State: Errors should be empathetic, educational, and actionable:

return fmt.Errorf("🤔 Hmm, we don't recognize the engine '%s'.\n\nValid options are:\n  • copilot (GitHub Copilot)\n  • claude (Anthropic Claude)\n  • codex (OpenAI Codex)\n  • custom (your own engine)\n\nExample:\n  engine: copilot\n\nNeed help choosing? See: https://githubnext.github.io/gh-aw/reference/engines/", engineID)

Approach

1. Audit all validation error messages in pkg/workflow/*validation*.go files
2. For each error, add:
   • Empathetic opening with emoji and acknowledgment
   • Context explaining why the rule exists (security, best practices)
   • Specific fix examples
   • Learning resource links where applicable
   • Conversational, helpful tone (not blaming)
3. Follow the error message style guide at skills/error-messages.md
4. Test changes by triggering validation errors with invalid workflow configs

Files to Review

• pkg/workflow/engine_validation.go
• pkg/workflow/dangerous_permissions_validation.go
• pkg/workflow/mcp_config_validation.go
• All other pkg/workflow/*validation*.go files

Acceptance Criteria

• All validation error messages reviewed and enhanced
• Errors include empathetic opening (emoji + acknowledgment)
• Errors explain why the rule exists
• Errors provide specific fix examples
• Errors include learning resource links where applicable
• Tone is conversational and helpful
• Manual testing confirms improved error output
• Delight rating target: 😐 Neutral → 🙂 Good

Why This Matters

User Impact: Validation errors are teaching moments - first-time users encounter them during workflow setup. This is a critical opportunity to build confidence or create frustration.

Frequency: High - every developer setting up workflows encounters validation errors.

AirBnB Principles: Conversational, Trust and Safety

AI generated by Plan Command for discussion #10343

Comments on the Issue (you are @copilot in this section)

• Fixes [plan] Add empathy and learning links to validation error messages #10352

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