Class: Otto::MCP::Server

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

Overview

MCP server implementation providing Model Context Protocol endpoints

Constant Summary collapse

UNAUTHENTICATED_WARNING =

Warning emitted when the MCP HTTP endpoint is exposed with no token authentication. Unconditional (not gated on Otto.debug): an unauthenticated MCP endpoint lets any caller invoke every registered tool, so it must be visible in normal boot output.

<<~MSG.gsub(/\s+/, ' ').strip.freeze
  [MCP] HTTP endpoint %s is enabled without authentication:
  any caller can list and invoke MCP tools and resources.
  Pass auth_tokens: ['<token>'] to require a bearer token, or
  allow_unauthenticated: true to acknowledge this intentionally.
MSG

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(otto_instance) ⇒ Server

Returns a new instance of Server.



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# File 'lib/otto/mcp/server.rb', line 30

def initialize(otto_instance)
  @otto_instance = otto_instance
  @protocol      = Protocol.new(otto_instance)
  @enabled       = false
end

Instance Attribute Details

#otto_instance ⇒ Object (readonly)

Returns the value of attribute otto_instance.



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# File 'lib/otto/mcp/server.rb', line 18

def otto_instance
  @otto_instance
end

#protocol ⇒ Object (readonly)

Returns the value of attribute protocol.



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# File 'lib/otto/mcp/server.rb', line 18

def protocol
  @protocol
end

Class Method Details

.normalize_options(opts = {}, scope = :explicit) ⇒ Object

Normalize raw options into the canonical MCP option hash.

Parameters:

  • opts (Hash) (defaults to: {}) —

    raw options

  • scope (Symbol) (defaults to: :explicit) —

    :explicit (strict, for #enable_mcp!) or :constructor (ignores non-MCP keys, for Otto.new)

See Also:



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# File 'lib/otto/mcp/server.rb', line 26

def self.normalize_options(opts = {}, scope = :explicit)
  Otto::MCP::Options.normalize(opts, scope)
end

Instance Method Details

#enable!(options = {}) ⇒ Object

Enable the MCP server.

Enabling is one-shot. Each call appends a route, an endpoint-setting proc and the MCP middleware to the Otto instance without removing the previous set, so a second call with a different endpoint would leave the first endpoint routed but guarded by nothing (the auth middleware only matches the newest endpoint). Rather than try to unwind that, a second call raises.

Parameters:

  • options (Hash) (defaults to: {}) —

    canonical or aliased options; normalized via normalize_options, so both the canonical keys (:http_endpoint, :auth_tokens, ...) and their mcp_-prefixed spellings (:mcp_endpoint, :mcp_auth_tokens, ...) are accepted.

Raises:

  • (ArgumentError) —

    if the server is already enabled



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# File 'lib/otto/mcp/server.rb', line 61

def enable!(options = {})
  if @enabled
    raise ArgumentError,
          "MCP server is already enabled on #{@http_endpoint}; pass all MCP options " \
          'in a single Otto.new or enable_mcp! call'
  end

  options = self.class.normalize_options(options)

  Validator.ensure_available! if options[:enable_validation]
  Otto::Security::RateLimiting.ensure_available! if options[:enable_rate_limiting]

  @enabled               = true
  @http_endpoint         = options[:http_endpoint]
  @auth_tokens           = options[:auth_tokens]
  @enable_validation     = options[:enable_validation]
  @enable_rate_limiting  = options[:enable_rate_limiting]
  @allow_unauthenticated = options[:allow_unauthenticated]

  apply_rate_limits(options)

  # Configure middleware
  configure_middleware(options)

  # Add MCP endpoint route to Otto
  add_mcp_endpoint_route

  warn_if_unauthenticated!

  Otto.logger.info "[MCP] Server enabled with HTTP endpoint: #{@http_endpoint}" if Otto.debug
end

#enabled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/otto/mcp/server.rb', line 93

def enabled?
  @enabled
end

#register_mcp_route(route_info) ⇒ Object 



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# File 'lib/otto/mcp/server.rb', line 97

def register_mcp_route(route_info)
  case route_info[:type]
  when :mcp_resource
    register_resource(route_info)
  when :mcp_tool
    register_tool(route_info)
  end
end