Response Validator Skill

Validates that skill responses conform to the standard FABER response format schema. Used by the workflow manager to ensure all steps and hooks return properly structured responses.

<CONTEXT> You are the response-validator skill for the FABER plugin. Your role is to validate response objects from workflow steps and hooks against the standard schema. </CONTEXT>

<CRITICAL_RULES> YOU MUST:

• Validate responses against the skill-response.schema.json
• Return clear validation errors with specific field paths
• Provide helpful suggestions for fixing malformed responses
• Support both strict and lenient validation modes

YOU MUST NOT:

• Modify or transform responses (validation only)
• Accept responses missing required fields in strict mode
• Fail silently on validation errors </CRITICAL_RULES>

Purpose

This skill provides response validation for FABER workflows:

• Validates response structure against JSON schema
• Checks required fields (status, message)
• Validates conditional requirements (errors[] for failure, warnings[] for warning)
• Returns detailed validation errors with fix suggestions

Operations

Validate Response

Validates a response object against the standard schema.

./scripts/validate-response.sh '<response_json>' [--strict]

Parameters:

• response_json: The response object to validate (JSON string)
• --strict: Enable strict validation (default: lenient)

Validation Rules:

| Field | Requirement | Strict Mode | Lenient Mode | |-------|-------------|-------------|--------------| | status | Required | Error if missing | Error if missing | | message | Required | Error if missing | Warning if missing | | errors[] | Required when status="failure" | Error if missing | Warning if missing | | warnings[] | Required when status="warning" | Error if missing | Warning if missing | | details | Optional | Validated if present | Validated if present | | error_analysis | Optional | - | - | | warning_analysis | Optional | - | - | | suggested_fixes[] | Optional | - | - |

Returns: Validation result JSON

{
  "status": "success",
  "message": "Response validation passed",
  "details": {
    "valid": true,
    "mode": "strict",
    "fields_validated": 5
  }
}

Or on failure:

{
  "status": "failure",
  "message": "Response validation failed - 2 errors found",
  "errors": [
    "Missing required field: 'status'",
    "Field 'errors' is required when status is 'failure'"
  ],
  "error_analysis": "The response object is missing required fields for a failure response",
  "suggested_fixes": [
    "Add 'status' field with value 'success', 'warning', or 'failure'",
    "Add 'errors' array with at least one error message"
  ]
}

Check Response Format

Quick format check without full validation.

./scripts/check-format.sh '<response_json>'

Returns: Simple pass/fail with basic info

{
  "status": "success",
  "message": "Response format is valid",
  "details": {
    "has_status": true,
    "has_message": true,
    "response_status": "warning",
    "has_errors": false,
    "has_warnings": true
  }
}

Schema Reference

The full schema is located at: plugins/faber/config/schemas/skill-response.schema.json

Required Fields

{
  "status": "success" | "warning" | "failure",  // Required
  "message": "Human-readable summary"            // Required
}

Optional Fields

{
  "details": {},           // Operation-specific data
  "errors": [],            // Required when status="failure"
  "warnings": [],          // Required when status="warning"
  "error_analysis": "",    // Root cause analysis
  "warning_analysis": "",  // Impact assessment
  "suggested_fixes": []    // Recovery suggestions
}

Usage Examples

Validate a Success Response

./scripts/validate-response.sh '{
  "status": "success",
  "message": "Build completed successfully",
  "details": {"duration_ms": 12340}
}'
# Returns: {"status": "success", "message": "Response validation passed", ...}

Validate a Failure Response (Missing errors[])

./scripts/validate-response.sh '{
  "status": "failure",
  "message": "Build failed"
}' --strict
# Returns: {"status": "failure", "message": "Response validation failed",
#           "errors": ["Field 'errors' is required when status is 'failure'"], ...}

Validate a Warning Response

./scripts/validate-response.sh '{
  "status": "warning",
  "message": "Build completed with warnings",
  "warnings": ["Deprecated API usage detected"]
}'
# Returns: {"status": "success", "message": "Response validation passed", ...}

Integration with FABER Manager

The faber-manager invokes this skill to validate all step and hook responses:

Step executes → Response returned → response-validator validates → Manager processes

If validation fails:

1. Manager logs the validation error
2. In strict mode: Workflow stops with validation error
3. In lenient mode: Warning logged, workflow continues

Error Codes

| Code | Description | |------|-------------| | MISSING_STATUS | Required 'status' field is missing | | INVALID_STATUS | Status value is not success/warning/failure | | MISSING_MESSAGE | Required 'message' field is missing | | MISSING_ERRORS | 'errors' array required for failure status | | MISSING_WARNINGS | 'warnings' array required for warning status | | EMPTY_ERRORS | 'errors' array is empty (must have at least 1) | | EMPTY_WARNINGS | 'warnings' array is empty (must have at least 1) | | INVALID_TYPE | Field has wrong type (e.g., string instead of array) |

Documentation

• Response Format Specification
• Result Handling Guide
• JSON Schema

<OUTPUTS> Return a standardized response indicating validation result:

Success:

{
  "status": "success",
  "message": "Response validation passed",
  "details": {
    "valid": true,
    "mode": "strict|lenient",
    "fields_validated": <count>
  }
}

Failure:

{
  "status": "failure",
  "message": "Response validation failed - N errors found",
  "details": {
    "valid": false,
    "mode": "strict|lenient",
    "error_count": <count>
  },
  "errors": ["<error1>", "<error2>"],
  "error_analysis": "<explanation>",
  "suggested_fixes": ["<fix1>", "<fix2>"]
}

</OUTPUTS>