Class: Otto::MCP::Validator

Inherits:
Object
  • Object
show all
Defined in:
lib/otto/mcp/schema_validation.rb

Overview

JSON Schema validator for MCP protocol requests

Constant Summary collapse

JSON_SCHEMER_REQUIREMENT = 
'~> 2.0'

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Validator

Returns a new instance of Validator.



28
29
30
31
 
# File 'lib/otto/mcp/schema_validation.rb', line 28

def initialize
  self.class.ensure_available!
  @schemas = {}
end

Class Method Details

.ensure_available! ⇒ Object 



18
19
20
21
22
23
24
25
26
 
# File 'lib/otto/mcp/schema_validation.rb', line 18

def self.ensure_available!
  Otto::OptionalDependency.require!(
    'json_schemer',
    JSON_SCHEMER_REQUIREMENT,
    require_path: 'json_schemer',
    feature: 'MCP JSON Schema validation',
    alternative: 'Or pass `enable_validation: false` when enabling MCP.'
  )
end

Instance Method Details

#validate_request(data) ⇒ Object 



33
34
35
36
37
38
39
40
41
42
43
 
# File 'lib/otto/mcp/schema_validation.rb', line 33

def validate_request(data)
  schema            = mcp_request_schema
  validation_errors = schema.validate(data).to_a

  unless validation_errors.empty?
    error_messages = validation_errors.map { |error| error['details'] || error['error'] || error.to_s }.join(', ')
    raise ValidationError, "Invalid MCP request: #{error_messages}"
  end

  true
end

#validate_tool_arguments(tool_name, arguments, schema) ⇒ Object 



45
46
47
48
49
50
51
52
53
54
55
56
57
 
# File 'lib/otto/mcp/schema_validation.rb', line 45

def validate_tool_arguments(tool_name, arguments, schema)
  return true unless schema

  schemer           = JSONSchemer.schema(schema)
  validation_errors = schemer.validate(arguments).to_a

  unless validation_errors.empty?
    error_messages = validation_errors.map { |error| error['details'] || error['error'] || error.to_s }.join(', ')
    raise ValidationError, "Invalid arguments for tool #{tool_name}: #{error_messages}"
  end

  true
end